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ABSTRACT
Over the last 5 years the global fibre market has moved further into a global commodity market. This change is redefining and accelerating global trade patterns at all levels of the high value chain. The development of special fibers is the consequence of merging fundamentals scientific and technical knowledge, as there is a quest for high performance fibres. Thus, constant and continued endeavors of fibre scientists jointly ventured with material technologies had made dreams into reality. These special fibres totally provide the potential for providing new technology. Over all world textiles, challenging a continued growth of hi-tech fibres in various fields. These fibres have high tenacity, high strength to weight ratio which are the prerequisites characteristics of industrial textiles.
These find applications in every walk of life including Space, Ocean, composites, aircrafts, defense automobile and many more. Our present paper deals with these special fibres and explores the wealth of their properties and application.
INTRODUCTION: -
Up to this time, two types of fibers have been available to human society, natural fibers that have existed for 4000 years and synthetic fibers. Artificial silk invented was a human dream. Then nylon introduced was finer than spider’s thread, stronger than steel and more elegant than silk.
Today synthetic fibers are not a mere alternative to natural fibers but are new materials of high functionality and high performance, which play a key role in the field of high technology. These new materials can be designed and produced according to nature of their utilization. Synthetic fibers are made to replace natural fibers and to some extent it is succeeded. High performance fibers are developed now a days fibers of high modulus and high strength can now be produced from synthetic polymers of light wt and are widely employed in space. Due to limitations of natural fibers, synthetic fibers are developed and now-a-days developments are done in the fibers to achieve desired properties.
The need for ultra light fibers of high strength is increasing as high technology responds to changes in the social environment so, developments are going on in the synthetic fibers. In future decades, metals are expected to be replaced by newly developed synthetic fibers, which can be superior to metal with respect to their strength and modulus. In all the fields, there is wide application of fibers.
These find applications in every walk of life including Space, Ocean, composites, aircrafts, defense automobile and many more. Our present paper deals with these special fibres and explores the wealth of their properties and application.
INTRODUCTION: -
Up to this time, two types of fibers have been available to human society, natural fibers that have existed for 4000 years and synthetic fibers. Artificial silk invented was a human dream. Then nylon introduced was finer than spider’s thread, stronger than steel and more elegant than silk.
Today synthetic fibers are not a mere alternative to natural fibers but are new materials of high functionality and high performance, which play a key role in the field of high technology. These new materials can be designed and produced according to nature of their utilization. Synthetic fibers are made to replace natural fibers and to some extent it is succeeded. High performance fibers are developed now a days fibers of high modulus and high strength can now be produced from synthetic polymers of light wt and are widely employed in space. Due to limitations of natural fibers, synthetic fibers are developed and now-a-days developments are done in the fibers to achieve desired properties.
The need for ultra light fibers of high strength is increasing as high technology responds to changes in the social environment so, developments are going on in the synthetic fibers. In future decades, metals are expected to be replaced by newly developed synthetic fibers, which can be superior to metal with respect to their strength and modulus. In all the fields, there is wide application of fibers.
Kevlar
|
Application cables, rope making, fiber
reinforcement, Industrial paper, friction
products, thermo chromic fiber changes
color as per environmental conditions.
|
Solar – X
|
Stores solar energy
|
BEMBERG Micro-porous membrane
(BMM)
|
Diagnosis and treatment of AIDS
|
HIGH PERFORMANCE FIBRES:-
High performance fibres refer to high strength, high modulus, and wear resistant deformation resistant and high temperature resistant fibres. The high performance fibre industry is targeting those areas which are the domain of glass, polyester and nylon fibre reinforcements. Major applications for the high performance fibres are transportation, aerospace, protective clothing, marine ( ropes and sails), hostile thermal and chemical environments ( replacement for asbestos ) and leisure activities industries ( golf clubs and tennis rackets ). Some of the successful high performance fibres are mentioned below.
having Low (0.97) specific gravity, high Chemical & abrasion resistances and high strength comparable to Kevlar. It is used in anti ballistic protection, floatable ropes, and nets.
ALUMINA SILICA:-
Ceramic fibres reported with a very high temperature resistance, used for furnace insulation and hot air filtration.
MELAMINE:-
These fibres having 50% by weight of melamine cross-linked polymer (specific gravity about 1.44).It is having outstanding heat blocking properties with low thermal conductivity and good elongation at break (about 18%).
DOMESTIC FIBRES:-
Cotton, silk polyester, polyamide are used in medical applications. PP and Polyester is used in geo textiles and dry/liquid filtration due to its compatibility. Jute and coir (Ligno-Cellulosic) used in biodegradable products and in packaging industry. Nylon is been used in the anti- ballistic, Cord, protection and filtration applications.
ARMID FIBRES (PPTA) :-
Kevlar was the first Armid fibre produced by Du. Pont. Poly (p-phenylene Terephthalamide ) PPTA is the polymer from which Kevlar Armid fibres are produced. The term Armid was adoped to distinguish the group from the aliphatic polymide. Prior to 1985 Du Pont was the company producing commercial quantities of PPTA, HM – 50. PPTA is generally synthesized via an acid chloride condensation of terephthaloy1 chloride (TPC ), with p- Phenylene diamine (PDA)
PPTA fibres have been designed for high strength applications. On an equal weight basis, these Armid fibers are up to 10 times stronger than steel fibres of the same diameter. Along with exceptional strength, Armids are also exceptionally stable in many corrosive environments.
Acrylic fibers: -
Acrylic fiber's remarkable performance creates the year-around comfort consumers demand while producing a range of fabric advantages apparel manufacturers can utilize regardless of the season.
Moisture Transport Is The Key To Comfort.
Acrylic fiber, with its inherent polarity (the ability to attract and convey moisture), is the leading synthetic fiber for natural moisture transport (wicking), and is superior to fibers with topical finishes, which wash away. Acrylic fiber provides lifetime wicking capability to fabrics made from it. With acrylic garments in warm or cold climates, whether in active wear or spectator wear, you feel more comfortable because moisture management controls comfort.
Increased Comfort In The “Dermisphere”: -
The dermisphere is the air space between your skin and your clothing (as shown in fig). The type of fibers and construction of the fabric directly affect the climate in your dermisphere, and determine how comfortable, or uncomfortable, you are regardless of the air temperature or activity in which you are engaged.
A “dermisphere” covered by MICROSUPREME acrylic micro fiber. The skin is dry and comfortable because moisture is picked up by the fibers and transported to the garment’ souter surface where it evaporates. The uncomfortable alternative is a damp (either hot or cold) dermisphere caused by fibers, which are not effective at insulating or transporting moisture
Moisture dissipation: -
In the moisture dissipation test, fabrics are “spun dry” to evaluate drying time. All fabrics are started with their own percentage of moisture based on the fiber’s moisture regain. Cotton, retaining the greatest amount of moisture and having the highest dry time, is used as a comparison. Data are expressed in percentages as compared to cotton, i.e. MICROSUPREME acrylic micro fiber dries 75% faster than cotton.
High performance fibres refer to high strength, high modulus, and wear resistant deformation resistant and high temperature resistant fibres. The high performance fibre industry is targeting those areas which are the domain of glass, polyester and nylon fibre reinforcements. Major applications for the high performance fibres are transportation, aerospace, protective clothing, marine ( ropes and sails), hostile thermal and chemical environments ( replacement for asbestos ) and leisure activities industries ( golf clubs and tennis rackets ). Some of the successful high performance fibres are mentioned below.
ULTRA HIGH MOLECULAR WEIGHT POLYETHYLENE(UHMWPE):-
It is having high molecular weight (106), produced by Gel spinning technique. It is having Low (0.97) specific gravity, high Chemical & abrasion resistances and high strength comparable to Kevlar. It is used in anti ballistic protection, floatable ropes, and nets.
ALUMINA SILICA:-
Ceramic fibres reported with a very high temperature resistance, used for furnace insulation and hot air filtration.
MELAMINE:-
These fibres having 50% by weight of melamine cross-linked polymer (specific gravity about 1.44).It is having outstanding heat blocking properties with low thermal conductivity and good elongation at break (about 18%).
DOMESTIC FIBRES:-
Cotton, silk polyester, polyamide are used in medical applications. PP and Polyester is used in geo textiles and dry/liquid filtration due to its compatibility. Jute and coir (Ligno-Cellulosic) used in biodegradable products and in packaging industry. Nylon is been used in the anti- ballistic, Cord, protection and filtration applications.
ARMID FIBRES (PPTA) :-
Kevlar was the first Armid fibre produced by Du. Pont. Poly (p-phenylene Terephthalamide ) PPTA is the polymer from which Kevlar Armid fibres are produced. The term Armid was adoped to distinguish the group from the aliphatic polymide. Prior to 1985 Du Pont was the company producing commercial quantities of PPTA, HM – 50. PPTA is generally synthesized via an acid chloride condensation of terephthaloy1 chloride (TPC ), with p- Phenylene diamine (PDA)
PPTA fibres have been designed for high strength applications. On an equal weight basis, these Armid fibers are up to 10 times stronger than steel fibres of the same diameter. Along with exceptional strength, Armids are also exceptionally stable in many corrosive environments.
Acrylic fibers: -
Acrylic fiber's remarkable performance creates the year-around comfort consumers demand while producing a range of fabric advantages apparel manufacturers can utilize regardless of the season.
Moisture Transport Is The Key To Comfort.
Acrylic fiber, with its inherent polarity (the ability to attract and convey moisture), is the leading synthetic fiber for natural moisture transport (wicking), and is superior to fibers with topical finishes, which wash away. Acrylic fiber provides lifetime wicking capability to fabrics made from it. With acrylic garments in warm or cold climates, whether in active wear or spectator wear, you feel more comfortable because moisture management controls comfort.
Increased Comfort In The “Dermisphere”: -
The dermisphere is the air space between your skin and your clothing (as shown in fig). The type of fibers and construction of the fabric directly affect the climate in your dermisphere, and determine how comfortable, or uncomfortable, you are regardless of the air temperature or activity in which you are engaged.
 |
Moisture dissipation: -
In the moisture dissipation test, fabrics are “spun dry” to evaluate drying time. All fabrics are started with their own percentage of moisture based on the fiber’s moisture regain. Cotton, retaining the greatest amount of moisture and having the highest dry time, is used as a comparison. Data are expressed in percentages as compared to cotton, i.e. MICROSUPREME acrylic micro fiber dries 75% faster than cotton.
Fabric %
|
drying time faster than cotton
|
MICROSUPREME
Coolmax
Aquatec®
Nylon
Tactel®
|
75%
70%
70%
60%
35%
|
MICROSUPREME Acrylic Microfiber Takes Acrylic Into A New Dimension of Performance.
Garments made from fabrics of MICROSUPREME acrylic fiber take performance to a new dimension of creativity. Because of acrylic’s ability to transport moisture and increase the “comfort-ability” of a garment, fabric designers can create constructions for all four seasons, enabling both the spectator and active participant to benefit. You not only get performance, but also luxurious touch and drape previously thought impossible. Due to its lower specific gravity, acrylic fiber also produces fabrics having more bulk without extra weight. Independent tests show that MICROSUPREME acrylic micro fiber is superior in comfort performance compared to other leading fibers.
MICROSUPREME Acrylic Micro fiber - The Right Choice For All Reasons And Seasons.
Acrylic, especially micro denier, not only creates greater comfort for the wearer, it also brings significant fabric advantages to all kinds of apparel.
Uses: -
The new fiber is developing to be like cotton. There are `crevasses` in the fiber that diffuses light. This results in a more natural looking fiber, while regular acrylic is smooth and refracts light, giving the fiber an overall shine.
Low pill acrylic: -
Now a day’s low pill acrylic fiber also manufactured. That is especially good for school, career and military uniforms and a high performing fiber for socks. Along with all this `antimicrobial acrylic`, `acrylic blends`, and `acrylic-acetate blends also manufactured.
Magic fiber for AIDS diagnosis and treatment: -
Ashai Chemical Industry Co. have developed a porous hollow fiber membrane BEMBERG MICROPOROUS MEMBRANE [BMM] to filter out and isolate AIDS virus [acquired immune deficiency syndrome virus] and hepatitis type B in blood. BMM is made from cellulose fiber [BEMBERG] regenerated from cuprammonium solutions of cotton linters.
Synthetic polymers are known to cause blood clotting as a result of protein adsorption. However, regenerated cellulose is free from this problem, and for this reason, is used for the artificial kidney in the form of hollow fiber. In order to allow proteins to permeate, but isolate viruses using the same membrane, it is necessary to have homogeneous pores in the membrane, which are larger than proteins but smaller than viruses. To produce such cellulose membranes having homogeneously distributed pores of predetermined diameter. Spherical B-type hepatitis virus and AIDS virus have a diameter of 42 nm and 90-100 nm. Respectively. Thus the membrane needs to have pores of 30-40 nm or 40-75 in diameter, respectively, to isolate these viruses. A single layer of membrane is not sufficient to isolate such viruses completely. Consequently BMM has a multi-layer structure of 100-150 layers. This manufacturing multi layer hollow fiber membrane is produced by wet spinning from cuprammonium solution of cotton linter mixed with an organic solvent. The solution undergoes phase separation and is composed of two phases made up of concentrated and a dilute organic solvent. The concentrated phase forms a continuous organic solvent layer, and the dilute phase make up small organic solvent holes of a uniform size in the cotton linter solution. When spun, the resulting hollow fiber is made of 100-150 layers of cellulose membrane, with pores of a predetermined diameter [see Photo6.2] The pore size and the degree of crystallinity of BMM depends on many external factors such as temperature, solvent composition, component purity and time. Usually BMM is 300 to 400 um in outer diameter, 250 to 350 um in inner diameter, and is composed 40 um in thickness. The actual module is made of 300 BMM hollow fibers which together are 3 cm in diameter and 15 cm in length. Each layer of BMM has over a billion pores, which enables complete filtration and isolation of the viruses.
Uses: -
It is capable of removing virus from plasma and so suppresses its multiplication. AIDS virus immersed into lymphocytes, grows there, and then overflows into plasma. If the isolation rate of virus from plasma is fast, the clinical progress of AIDS can be suppressed. This suppression of the AIDS virus can allow the reactivation of the metabolic functions of the human body, so that treatment efficiency will improve when combined with other medical treatments.
Other applications of BMM are found, for example, in the complete isolation of virus during plasma medicines manufacture, the administration of fractionated plasma-producing medicines for hemophiliacs, and the prevention of virus infection during ordinal plasma transfusion.
BMM is also useful for the isolation of hepatitis non-A non-B virus and in the study of unknown viruses or other physiologically active substances
Super absorbent fiber: -
In last few years, super absorbents in fiber from have become a commercial reality. The recent commercial availability of super absorbent fibres has spurred an enormous amount of development activity in many market applications including telecommunications, packaging, horticulture, electronics and disposable hygiene products. Most recently the potential to benefit from their outstanding properties in a wide range of medical products have been recognized. The product is marketed as ‘OASIS’. The product is based upon similar polymer chemistry to that for powders that is a cross-linked copolymer of acrylic acid. The advantages that fiber offers compared to fibers is due to their physical form, or dimensions, rather than their chemical nature. Whilst they do absorb fluids to a similar level as powders, they do, however, do it faster. This is due to the small diameter of the fibers, which is about 30 microns, which gives a very high surface area for contact with the liquid. Also the fiber surface is not smooth .It has a crenulated structure with longitudinal grooves. These are believed to be beneficial in transporting moisture along the surface. The lubricant has also been selected to enhance this wetting effect and results in a very high rate of moisture absorption. Typically the fiber will absorb 95% of its ultimate capacity in 15sec.
PROPERTIES
Garments made from fabrics of MICROSUPREME acrylic fiber take performance to a new dimension of creativity. Because of acrylic’s ability to transport moisture and increase the “comfort-ability” of a garment, fabric designers can create constructions for all four seasons, enabling both the spectator and active participant to benefit. You not only get performance, but also luxurious touch and drape previously thought impossible. Due to its lower specific gravity, acrylic fiber also produces fabrics having more bulk without extra weight. Independent tests show that MICROSUPREME acrylic micro fiber is superior in comfort performance compared to other leading fibers.
MICROSUPREME Acrylic Micro fiber - The Right Choice For All Reasons And Seasons.
Acrylic, especially micro denier, not only creates greater comfort for the wearer, it also brings significant fabric advantages to all kinds of apparel.
- Comfortable.
- Soft, lasting hand
- Fabulous drapes.
- Easy washing, wrinkle resistance.
- Beautiful, full-color dyeing.
- Brightly colorfast.
- Odor and mildew resistance.
Uses: -
- Outerwear-Pile Fabrics
- Thermal Underwear
- Socks/Tights
- Sweaters
- Sleepwear
The new fiber is developing to be like cotton. There are `crevasses` in the fiber that diffuses light. This results in a more natural looking fiber, while regular acrylic is smooth and refracts light, giving the fiber an overall shine.
Low pill acrylic: -
Now a day’s low pill acrylic fiber also manufactured. That is especially good for school, career and military uniforms and a high performing fiber for socks. Along with all this `antimicrobial acrylic`, `acrylic blends`, and `acrylic-acetate blends also manufactured.
Magic fiber for AIDS diagnosis and treatment: -
Ashai Chemical Industry Co. have developed a porous hollow fiber membrane BEMBERG MICROPOROUS MEMBRANE [BMM] to filter out and isolate AIDS virus [acquired immune deficiency syndrome virus] and hepatitis type B in blood. BMM is made from cellulose fiber [BEMBERG] regenerated from cuprammonium solutions of cotton linters.
Synthetic polymers are known to cause blood clotting as a result of protein adsorption. However, regenerated cellulose is free from this problem, and for this reason, is used for the artificial kidney in the form of hollow fiber. In order to allow proteins to permeate, but isolate viruses using the same membrane, it is necessary to have homogeneous pores in the membrane, which are larger than proteins but smaller than viruses. To produce such cellulose membranes having homogeneously distributed pores of predetermined diameter. Spherical B-type hepatitis virus and AIDS virus have a diameter of 42 nm and 90-100 nm. Respectively. Thus the membrane needs to have pores of 30-40 nm or 40-75 in diameter, respectively, to isolate these viruses. A single layer of membrane is not sufficient to isolate such viruses completely. Consequently BMM has a multi-layer structure of 100-150 layers. This manufacturing multi layer hollow fiber membrane is produced by wet spinning from cuprammonium solution of cotton linter mixed with an organic solvent. The solution undergoes phase separation and is composed of two phases made up of concentrated and a dilute organic solvent. The concentrated phase forms a continuous organic solvent layer, and the dilute phase make up small organic solvent holes of a uniform size in the cotton linter solution. When spun, the resulting hollow fiber is made of 100-150 layers of cellulose membrane, with pores of a predetermined diameter [see Photo6.2] The pore size and the degree of crystallinity of BMM depends on many external factors such as temperature, solvent composition, component purity and time. Usually BMM is 300 to 400 um in outer diameter, 250 to 350 um in inner diameter, and is composed 40 um in thickness. The actual module is made of 300 BMM hollow fibers which together are 3 cm in diameter and 15 cm in length. Each layer of BMM has over a billion pores, which enables complete filtration and isolation of the viruses.
Uses: -
It is capable of removing virus from plasma and so suppresses its multiplication. AIDS virus immersed into lymphocytes, grows there, and then overflows into plasma. If the isolation rate of virus from plasma is fast, the clinical progress of AIDS can be suppressed. This suppression of the AIDS virus can allow the reactivation of the metabolic functions of the human body, so that treatment efficiency will improve when combined with other medical treatments.
Other applications of BMM are found, for example, in the complete isolation of virus during plasma medicines manufacture, the administration of fractionated plasma-producing medicines for hemophiliacs, and the prevention of virus infection during ordinal plasma transfusion.
BMM is also useful for the isolation of hepatitis non-A non-B virus and in the study of unknown viruses or other physiologically active substances
Super absorbent fiber: -
In last few years, super absorbents in fiber from have become a commercial reality. The recent commercial availability of super absorbent fibres has spurred an enormous amount of development activity in many market applications including telecommunications, packaging, horticulture, electronics and disposable hygiene products. Most recently the potential to benefit from their outstanding properties in a wide range of medical products have been recognized. The product is marketed as ‘OASIS’. The product is based upon similar polymer chemistry to that for powders that is a cross-linked copolymer of acrylic acid. The advantages that fiber offers compared to fibers is due to their physical form, or dimensions, rather than their chemical nature. Whilst they do absorb fluids to a similar level as powders, they do, however, do it faster. This is due to the small diameter of the fibers, which is about 30 microns, which gives a very high surface area for contact with the liquid. Also the fiber surface is not smooth .It has a crenulated structure with longitudinal grooves. These are believed to be beneficial in transporting moisture along the surface. The lubricant has also been selected to enhance this wetting effect and results in a very high rate of moisture absorption. Typically the fiber will absorb 95% of its ultimate capacity in 15sec.
PROPERTIES
Property
|
saline
|
water
|
Free swell absorbency.
Retention (0.5psi)
Absorbency under load(0.25g/g)
|
40g/g
30 g/g
23 g/g
|
80 g/g
60 g/g
45 g/g
|
When the fibers absorb fluid it does not its fibrous structure. The resulting hydrogel is an entangled mass of swollen fibers. The gel has coherence and strength. A feature of the process is that the gel characteristics can be altered according to the end use requirements.
When the fibers are allowed to dry out they return to their original form and are still absorbent. When the super absorbents absorb heterogeneous fluid such as blood, milk, or lattices the total absorbency is reduced due to deposition on the surface which access of water. In the case of blood proteins are absorbed on the surface attached by the carboxylic acid groups in the polymer. With milk, the removal of the water causes the emulsion to break depositing faton the surface in addition to protein absorption. The magnitude of this effect is naturally affected by the surface to volume ratio of the super absorbent. The ratio about 8 times higher for oasis super absorbent fiber compared to typical super absorbent powder.
The following features that may be required for use in medical product can be build up into nonwoven containing super absorbent fibers: -
This feature of fibers not to migrate is a very important advantage. It allows the Super absorbent to be blended at high levels into an open structure without it falling out or its distribution in the fabric changing during storage, transport and use. This natural advantage gives more flexibility as to where the absorbent can be located.
The rate at which a non-woven fabric will absorb a liquid is a very important feature, which will particularly influence the likelihood of leakage in a hygiene product. It is a particular feature of super absorbent fibers that they absorb aqueous fluids very rapidly. Their free swell absorbency after only 15 seconds is equal to, or greater than, their retention capacity. This compares to less than half this absorbency for super absorbent powder containing fabrics. For all aqueous fluids a very rapid rate of absorption is always observed compared to powders.
A unique advantage of a super absorbent in fiber form is that staple yarns can be spun in blends with other fibers. Yarns can be produced on warp woollen, DREF and semi worsted spinning systems but warp spinning is the preferred route as the lack of twist provides a yarn free to swell easily. It is possible to blend Oasis in these yarns with both natural and synthetics fibers.
Applications in medical products: -
Non-woven fabrics and yarns containing OASIS fiber superabsorbent can be used for numerous applications where the properties of absorbency and/or swelling can be of use.
Disposable Incontinence Products:
High levels of super absorbent fiber can be incorporated into absorbent cores allowing the constructing of thin products with high absorbency.
Wipes and absorbed pads: Addition of oasis to pads and wipes to improve their ability to rapidly immobilize large amounts of blood and other aqueous spillages in operating theatre, Analytical laboratory or general hospital use.
Disposal containers:
Superabsorbent non-woven fabrics can be used as a lining for containers designed for the disposal of items contaminated with hazardous fluids to prevent leakage.
Drapes:
In surgical gowns, oasis can be incorporated around the arm and neck cuffs to prevent blood ingress.
Wound care:
Oasis can be included within secondary wound care products to provide additional capacity to absorbs wound exudates. This helps to decreases the frequency of dressing changes.
Ostomy bags:
Oasis can be incorporated into ostomy and colostomy products and waste management devices to quickly solidify body fluids to improve ease of disposal.
Miscellaneous products:
A number of other applications in the medical field are currently being evaluated including:
The above figure shows use of multimode fibers in medical. So we can say that fiber plays an important role in our life.
Bard backs smart fibres for surgery :-
Shape-memory polymers have the potential to completely revolutionise medical surgery, as well as having a broad range of other applications, and the first product developed by mnemo Science was smart suture that ties itself into the perfect knot. This means that potentially, surgeons will be able to seal hard-to-reach wounds with the aid of a shape-shifiting thread that knows how to tie itself and never needs to be removed. The new ‘smart’ biodegradable plastic fibre can knot itself when heated to a few degrees above body temperature. Researchers belive the same material could be made to last much longer and one day be used for self repairing medical devices and also to shrink otherwise bulky implants such as screws that hold bones together.
Spider silk: -
What is spider silk made of? It is a fibrous protein secreted as a fluid, which hardens as it oozes out of the spinnerets, which are mobile finger-like projections. As the fluid oozes out, the protein molecules are aligned in such a way that they form a solid; the process is not yet well understood. The spider hauls out the silk with its legs, stretching, fluffing it up or changing it in other ways to suit the purpose at hand.
Weight for weight, spider silk is up to 5 times stronger than steel of the same diameter. It is believed that the harder the spider pulls on the silk as it is produced, the stronger the silk gets. Spider silk is so elastic that it doesn’t break even if stretched 2-4 times its length. Spider silk is also waterproof, and doesn’t break at temperatures as low as -40C.
There are 7 types of silk glands and “nozzles” but no spider has all 7 types
The material is elastic and only breaks at between 2 - 4 times its length. In the pictures a strand of a social spider, stegodyphus sarasinorum, is shown as normal size, stretched 5 times and 20 times its original length. Spider’s silk is made up of chains of amino acids. In other words, it is simply a protein .The two primary amino acids are glycine and alanine. Spider silk is extremely strong — it is about five times stronger than steel and twice as strong as Kevlar of the same weight. Spider silk also has the ability to stretch about 30- percent longer than its original length without breaking, which makes it very resilient
Aramids: -
High tenacity aramide fiber: -
Organic fibers. Closely related to the nylons, aramids are polyamides derived from aromatic acids and amines. Because of the stability of the aromatic rings and the added strength of the amide linkages, due to conjugation with the aromatic structures, aramids exhibit higher tensile strength and thermal resistance than the aliphatic polyamides (nylons). The para- aramids, based on terephthalic acid and p-phenylene diamine, or paminobenzoic acid, exhibit higher strength and thermal resistance than those with the linkages in meta positions on the benzene rings. The greater degree of conjugation and more linear geometry of the para linkages, combined with the greater chain orientation derived from this linearity, are primarily responsible for the increased strength. The high impact resistance of the para-aramids makes them popular for “bullet-proof” body armor. For many less demanding applications, aramids may be blended with other fibers.
High resistance aramide fibers: -
Teiji conex is a meta linked aromatic polyamide fiber known for its heat resistance .it is a synthetic organic fiber comprised of polymetaphenylene iosthalic amide, which is formed by reaction from meta-phenylenediamine and isophthaloyl chloride. It decomposes at 4000C and having LOI 30. It is a white, highly functional fiber, which can be used for clothing to industrial material.
Continuous meta-type amide bonds to benzene rings render the following properties: -
HDPE (high-density polyethylene): -
It can be extruded using special technology to produce very high molecular orientation. The resulting fiber combines high strength; chemical resistance and good wear properties with lightweight, making it highly desirable for applications ranging from cut-proof protective gear to marine ropes.
Since it is lighter than water, ropes made of HDPE float. Its primary drawback is its low softening and melting temperature.
Spectra fiber 1000: -
High-strength, lightweight polyethylene fiber: -
Spectra® fiber 1000, the second in a series of Spectra® fibers, was developed to meet customers’ needs for increased performance. It is available in a multitude of deniers for use in a wide range of applications. This extended chain polyethylene fiber has one of the highest strength to weight ratios of any manmade fiber. Spectra® fiber 1000 has a tenacity 15 – 20 percent higher than that of Spectra® fiber 900. Spectra® fiber is, pound-for-pound, 10 times stronger than steel, more durable than polyester and has a specific strength that is 40 percent greater than aramid fiber. Specific performance is dependent upon denier and filament count.
Characteristics:
Definition for Melamine Fiber:
A manufactured fiber in which the fiber-forming substance is a synthetic polymer composed of at least 50% by weight of a cross-linked melamine polymer.
Fiber is primarily known for its inherent thermal resistance and outstanding heat blocking capability in direct flame applications. This high stability is due to the cross linked nature of the polymer and the low thermal conductivity of melamine resin. In comparison to other melamine fiber offers an excellent value for products designed for direct flame contact and elevated temperature exposures.
Moreover, the dielectric properties and cross section shape and distribution make it ideal for high temperature filtration applications. It is sometimes blended with aramid or other performance fibers to increase final fabric strength.
Production: -
The production process is proprietary. It is based on a unique melamine chemistry that results in a cross-linked, non-thermoplastic polymer of melamine units joined by methylene and dimethylene ether linkages.In the polymerization reaction, methylol derivatives of melamine react with each other to form a three-dimensional structure. This structure is the basis for the fiber’s heat stability, solvent resistance, and flame resistance.
Characteristic: -
Lead Zirconate Titanate (PZT) active fibers, from 80 to 250 micrometers in diameter, are produced for the AFOSR / DARPA funded Active Fiber Composites
Consortium** (AFCC) Program and commercial customers. Cera Nova has developed a proprietary ceramics-based technology to produce PZT mono-filaments of the required purity, composition, straightness, and piezoelectric properties for use in active fiber composite structures. CeraNova’s process begins with the extrusion of continuous lengths of mono-filament precursor fiber from a plasticized mix of PZT-5A powder. The care that must be taken to avoid mix contamination is described using illustrations from problems experienced with extruder wear and metallic contamination.
Manufacturing:
CeraNova has developed a proprietary extrusion and firing method to ake round, straight and contamination free PZT fibers having composition and piezoelectric performance suitable for AFC use.
Raw materials and mixing:
PZT-5A powder is mixed under high-shear conditions with a proprietary binder formulation until a homogeneous blend is achieved.
The PZT particle size is submicron. Binders are added sequentially during the mixing process. As only 100 kilograms of mix are required to produce sufficient fiber for 20,000 AFC packs per year, mixing capacity will not constrain future AFCC production requirements.
Batch blending and remixing improves mix consistency and extrusion performance. Great care is taken to avoid contamination as this can result in extruder die blockage or unacceptable defects in fired fibers.
Properties: -
Recently designed a bicomponent spin pack that resulted in spinning a very unusual fiber (see below). This fiber is a type of island-in-the-sea bicomponent where a dissolvable polymer (blue) is used to surround islands of a standard polymer such as polypropylene, nylon or polyester. In this case the fiber was spun with a 50/50 ratio of polyethylene and polypropylene. It is not know at this time if this same cross-section can be obtained with other polymer combinations.
After dissolving away the blue polymer, the resulting fiber consists of a single high denier snowflake center surrounded by multiple round and oval shaped microfilaments. The large core should provide good fiber and fabric strength and large surface area for absorption, and the microfilaments will provide softness as well as absorption. This type of fiber should be ideal for filtration applications both in woven and nonwoven construction. The dual shape microfilaments will enhance the loft of the fabric while the grooves in the core filaments may enhance particle trapping and absorption.
Power fibers that store solar energy: -
Heat regenerating fibers are produced from ceramic composites by applying heat insulation processing technology, which utilizes the far infrared radiation effect of ceramic. When heated ceramics radiate far infra –red radiation, which penetrates into the material and heats it homogeneously by activating molecular motion. Zirconium, magnesium oxide or iron oxide can be blended into synthetic fibers, because these materials radiate Ca.60 mW far infrared of wavelengths 8-14 um at a body temperature of 36 0C. These heat reradiating fibers are used for sports wear, bead-sheets, bed-cover materials ,etc.
A futuristic fiber material solar-α has been developed, which absorbs and preserves the optical energy of the sun. solar-α has been employed for a downhill skiing suit. In addition to its smooth surface and aerodynamic form, this downhill suit aimed to increase the insulating efficiency by solar-α in order to warm the muscle and bring out its best power.
Oxygen consumption must be reduced t o minimum to bring out power efficiently from muscle in severe climatic conditions. Zirconium carbide compounds are used is used for their excellent characteristics in absorbing and storing heat in a new type of solar system, including domestic water heaters and large-scale generators turbine. Zirconium carbide traps heat energy. It absorbs visible
rays and reflects the light of long wavelength, which makes up 95% of sunlight, and converts it into stored heat energy. Descente researchers applied these characteristics of Zirconium carbide on polyamide or polyester fibers. They developed the technology to enclose Zirconium carbide powder within the core of synthetic fibers (as shown in fig.)
The cloths made of these fibers solar-α absorbs solar visible radiation efficiently and converted it into heat in the form of infra-red radiation which released in the clothing.
Body-responsive hollow fiber :-
Hollow fiber has been scientifically proven to significantly increase oxygenated blood flow, which cans increase circulation and build strength. For diabetics, this improvement in skin oxygenation can accelerate wound healing and help eliminate pain due to decreased 90 blood flow. For people not affected by diabetes, this skin oxygenation helps speed recovery after exercise, boost energy levels and improve overall circulation.
Diabetics face two major issues neuropathy, or the loss of sensation, and atherosclerosis, or hardening of the arteries, which reduces the circulation of blood in the body. Atherosclerosis can lead to a number of conditions, including aching feet, leg pain and problems with wound healing. Symptoms include cold feet, pain in the legs when walking and pain in the feet when reclining. When worn on or near the skin, Hollow fiber responds to available light and the energy produced naturally by the body, converting light and they body’s own energy in to the necessary wavelengths that make this usually unavailable energy accessible to the body-improving the body’s circulation and oxygen levels.
In addition to helping diabetics, this breakthrough textile has been shown to improve physical performance and recovery time among those without circulation problems. Holofiber is already being lauded by some of the world’s top athletes, including top ranked female triathlete and Olympic silver medalists Michellie jones, who has been testing Holofiber for nearly two years. “As a professional athlete, you want everything you can possibly find to help get the best performance possible, “she said. “That’s one of the things I like about Holofiber – the fact that it helps with recovery and circulation. What better way-there’s no extra effort, and it really helps and benefits you.” World’s leading experts in diabetic foot complications, proved the effectiveness of Holofiber products in increasing oxygen levels in diabetic subject. There was a”… statistically significant change in transcutaneous oxygen – or the oxygen delivery to the skin – in hands and feet, on subjects wearing Holofiber gloves and socks compared to those wearing comparable non-Holofiber gloves and socks.”
Among the manufacturers already offering Holofiber products or planning to introduce them are wickers in its t-shirts, shorts, sock and glove liners, Super feet in custom insoles, Achieve 02 in diabetic and medical socks and Callaway Golf in shoes. Holofiber is a proprietary product with a patent pending. It is a responsive material for textiles and other uses, and is not an additive or coating applied by spraying or dipping. Its properties do not wash or leach out of the fabric. All of the Holofiber material are incorporated into the fibre and are non-toxic and biologically benign
POLYESTER : -
FORMALDEHYDE FUMES ABSORB POLYESTER: -
A polyester fiber can be spun and woven into fabrics for upholstery, which will adsorb the fumes released by the formaldehyde adhesives used to make furniture. The fibers, and so the fabrics made from them, contain a nitrogen compound that is firmly bonded to the surface. It is this that absorbs the gas.
The tests are conducted in environments in which the level formaldehyde was as high as 14 parts per million [ppm]. The fabrics reduced this level to just 0.06 ppm in 24 hours, the upper safety limit is considered to be 0.08 ppm. This fiber so much useful in the industry, for worker apparel and other purposes also.
Lightweight and air-insulating polyester fiber:
Sinkong Synthetic Fibers Corp. has adopted a new spinning technology to create Thermo Tech, a lightweight and air-insulating polyester fiber with a hollow cross-sectional area. The functional fiber is suitable for sportswear, thermal underwear, socks and bed sheets
The hollowness of the fiber can be up to 30 percent, yielding a lower fiber density and enabling air to be trapped within the fiber to preserve body heat. The firm, resilient fiber lends a cotton like hand, rich feel, wrinkle-free and easy-to-clean properties to fabrics.
Thermo Tech is available in SDY and FOY versions in 60d/50f, 75d/50f, 75d/30f and 75d/36f specifications.
Cross sections of some of the new developed fibers: -
Kevlar: -
Five times stronger than steel, Kevlar is a synthetic fiber of the DuPont corporation that was first created in 1965 by scientists Stephanie Kwolek and Herbert Blades. Since that time, Kevlar has been utilized in a wide variety of applications and has helped save thousands of lives through its use in bulletproof vests. Sometimes referred to as a Space Age material, it is the chemical structure and processing of Kevlar that makes it so strong. More specifically, Kevlar contains both aromatic and amide molecular groups. When molten Kevlar is spun into fibers at the processing plant, the polymers produced exhibit a crystalline arrangement, with the polymer chains oriented parallel to the fiber’s axis. The amide groups are able to form hydrogen bonds between the polymer chains, holding the separate chains together like glue. Also, the aromatic components of Kevlar have a radial orientation, which provides an even higher degree of symmetry and strength to the internal structure of the fibers.
Strength is not, however, the only advantageous feature of Kevlar fiber. Kevlar is also lightweight, flexible, and resistant to chemicals and flames. Together these characteristics make Kevlar extremely useful to humans. Some of the common items that contain Kevlar include sports equipment, such as skis and tennis rackets, highly protective gloves, parachutes, and tires. Kevlar is also frequently used to construct lightweight ropes, which have been used for such crucial applications as mooring the large vessels of the United States Navy and securing the airbags in the landing apparatus of the Mars Pathfinder
Fiber optics
Optical fibers are thin strands of super-clean glass (fused silica), about the size of a human hair. Almost all fibers used today are single strands. Fiber bundles find use primarily in coherent and image transmitting optical systems. There are also plastic fibers for inexpensive, short distance transmission. The basic design of an optical fiber consists of two components - the core and the cladding. They build an optical waveguide, which conducts optical power (photons) in the form of light rays. Core and cladding differ primarily in the refractive index of the glass. The core’s refractive index is slightly higher than the cladding’s, thereby creating a boundary for a circular wave-guide. Fiber optic signaling in data transmission is increasingly being used in high-density applications. In the military, the Standard Electronic Modules (SEM) of the Standard Hardware Acquisition and Reliability Program (SHARP) are widely used for high density electrical interconnects in card-edge-to-backplane interfacing.
The advantages of fiber optics can be summarized as:
Natural fibers have good properties but have some limitations; to overcome those synthetic fibers are produced. Still they have some drawbacks, to remove them developments are going on. Now days, almost in all the fields’ fibers are used. Fibres can replace even metals, so enormous developments are done in fiber field. Now the aspect of eco-friendly, environment friendly (fiber) have came in future. Now in that respect development, research is going on.
REFERENCES
When the fibers are allowed to dry out they return to their original form and are still absorbent. When the super absorbents absorb heterogeneous fluid such as blood, milk, or lattices the total absorbency is reduced due to deposition on the surface which access of water. In the case of blood proteins are absorbed on the surface attached by the carboxylic acid groups in the polymer. With milk, the removal of the water causes the emulsion to break depositing faton the surface in addition to protein absorption. The magnitude of this effect is naturally affected by the surface to volume ratio of the super absorbent. The ratio about 8 times higher for oasis super absorbent fiber compared to typical super absorbent powder.
The following features that may be required for use in medical product can be build up into nonwoven containing super absorbent fibers: -
- High absorbency, even under pressure
- Softness and flexibility
- Low migration of the super absorbent when dry and wet
- High rate of liquid up-take.
- Fabric dispersion when wet
This feature of fibers not to migrate is a very important advantage. It allows the Super absorbent to be blended at high levels into an open structure without it falling out or its distribution in the fabric changing during storage, transport and use. This natural advantage gives more flexibility as to where the absorbent can be located.
The rate at which a non-woven fabric will absorb a liquid is a very important feature, which will particularly influence the likelihood of leakage in a hygiene product. It is a particular feature of super absorbent fibers that they absorb aqueous fluids very rapidly. Their free swell absorbency after only 15 seconds is equal to, or greater than, their retention capacity. This compares to less than half this absorbency for super absorbent powder containing fabrics. For all aqueous fluids a very rapid rate of absorption is always observed compared to powders.
A unique advantage of a super absorbent in fiber form is that staple yarns can be spun in blends with other fibers. Yarns can be produced on warp woollen, DREF and semi worsted spinning systems but warp spinning is the preferred route as the lack of twist provides a yarn free to swell easily. It is possible to blend Oasis in these yarns with both natural and synthetics fibers.
Applications in medical products: -
Non-woven fabrics and yarns containing OASIS fiber superabsorbent can be used for numerous applications where the properties of absorbency and/or swelling can be of use.
Disposable Incontinence Products:
High levels of super absorbent fiber can be incorporated into absorbent cores allowing the constructing of thin products with high absorbency.
Wipes and absorbed pads: Addition of oasis to pads and wipes to improve their ability to rapidly immobilize large amounts of blood and other aqueous spillages in operating theatre, Analytical laboratory or general hospital use.
Disposal containers:
Superabsorbent non-woven fabrics can be used as a lining for containers designed for the disposal of items contaminated with hazardous fluids to prevent leakage.
Drapes:
In surgical gowns, oasis can be incorporated around the arm and neck cuffs to prevent blood ingress.
Wound care:
Oasis can be included within secondary wound care products to provide additional capacity to absorbs wound exudates. This helps to decreases the frequency of dressing changes.
Ostomy bags:
Oasis can be incorporated into ostomy and colostomy products and waste management devices to quickly solidify body fluids to improve ease of disposal.
Miscellaneous products:
A number of other applications in the medical field are currently being evaluated including:
- Headbands for sweat control by surgeons,
- Diagnostic testing,
- Hand sticks,
- Dental pads.
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Bard backs smart fibres for surgery :-
Shape-memory polymers have the potential to completely revolutionise medical surgery, as well as having a broad range of other applications, and the first product developed by mnemo Science was smart suture that ties itself into the perfect knot. This means that potentially, surgeons will be able to seal hard-to-reach wounds with the aid of a shape-shifiting thread that knows how to tie itself and never needs to be removed. The new ‘smart’ biodegradable plastic fibre can knot itself when heated to a few degrees above body temperature. Researchers belive the same material could be made to last much longer and one day be used for self repairing medical devices and also to shrink otherwise bulky implants such as screws that hold bones together.
Spider silk: -
What is spider silk made of? It is a fibrous protein secreted as a fluid, which hardens as it oozes out of the spinnerets, which are mobile finger-like projections. As the fluid oozes out, the protein molecules are aligned in such a way that they form a solid; the process is not yet well understood. The spider hauls out the silk with its legs, stretching, fluffing it up or changing it in other ways to suit the purpose at hand.
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| Spider silk |
There are 7 types of silk glands and “nozzles” but no spider has all 7 types
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| Fig. Two types of silk releasing tubes. |
Aramids: -
High tenacity aramide fiber: -
Organic fibers. Closely related to the nylons, aramids are polyamides derived from aromatic acids and amines. Because of the stability of the aromatic rings and the added strength of the amide linkages, due to conjugation with the aromatic structures, aramids exhibit higher tensile strength and thermal resistance than the aliphatic polyamides (nylons). The para- aramids, based on terephthalic acid and p-phenylene diamine, or paminobenzoic acid, exhibit higher strength and thermal resistance than those with the linkages in meta positions on the benzene rings. The greater degree of conjugation and more linear geometry of the para linkages, combined with the greater chain orientation derived from this linearity, are primarily responsible for the increased strength. The high impact resistance of the para-aramids makes them popular for “bullet-proof” body armor. For many less demanding applications, aramids may be blended with other fibers.
High resistance aramide fibers: -
Teiji conex is a meta linked aromatic polyamide fiber known for its heat resistance .it is a synthetic organic fiber comprised of polymetaphenylene iosthalic amide, which is formed by reaction from meta-phenylenediamine and isophthaloyl chloride. It decomposes at 4000C and having LOI 30. It is a white, highly functional fiber, which can be used for clothing to industrial material.
Continuous meta-type amide bonds to benzene rings render the following properties: -
- High melting point and decomposition point.
- High glass transition point.
- Low oxidation decomposition rate.
- High modulus.
- High tenacity with low weight.
- Low electrical conductivity.
- High cut resistance.
- High chemical and temperature resistance.
- Low thermal shrinkage.
- Excellent dimensional stability.
- Do not corrode.
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It can be extruded using special technology to produce very high molecular orientation. The resulting fiber combines high strength; chemical resistance and good wear properties with lightweight, making it highly desirable for applications ranging from cut-proof protective gear to marine ropes.
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Spectra fiber 1000: -
High-strength, lightweight polyethylene fiber: -
Spectra® fiber 1000, the second in a series of Spectra® fibers, was developed to meet customers’ needs for increased performance. It is available in a multitude of deniers for use in a wide range of applications. This extended chain polyethylene fiber has one of the highest strength to weight ratios of any manmade fiber. Spectra® fiber 1000 has a tenacity 15 – 20 percent higher than that of Spectra® fiber 900. Spectra® fiber is, pound-for-pound, 10 times stronger than steel, more durable than polyester and has a specific strength that is 40 percent greater than aramid fiber. Specific performance is dependent upon denier and filament count.
Characteristics:
- Light enough to float (.097 Specific Gravity)
- High resistance to chemicals, water, and UV light
- Excellent vibration damping
- Highly resistant to flex fatigue
- Low coefficient of friction
- Good resistance to abrasion
- Low dielectric constant makes it virtually transparent to radar
- Police and military ballistic vests and helmets
- Composite armor for vehicles and aircraft
- Marine lines and commercial fishing nets
- Industrial cordage and slings
Definition for Melamine Fiber:
A manufactured fiber in which the fiber-forming substance is a synthetic polymer composed of at least 50% by weight of a cross-linked melamine polymer.
Fiber is primarily known for its inherent thermal resistance and outstanding heat blocking capability in direct flame applications. This high stability is due to the cross linked nature of the polymer and the low thermal conductivity of melamine resin. In comparison to other melamine fiber offers an excellent value for products designed for direct flame contact and elevated temperature exposures.
Moreover, the dielectric properties and cross section shape and distribution make it ideal for high temperature filtration applications. It is sometimes blended with aramid or other performance fibers to increase final fabric strength.
Production: -
The production process is proprietary. It is based on a unique melamine chemistry that results in a cross-linked, non-thermoplastic polymer of melamine units joined by methylene and dimethylene ether linkages.In the polymerization reaction, methylol derivatives of melamine react with each other to form a three-dimensional structure. This structure is the basis for the fiber’s heat stability, solvent resistance, and flame resistance.
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- White and Dyeable .
- Flame resistance and low thermal conductivity
- High heat dimensional stability.
- Processable on standard textile equipment
- Fire Blocking Fabrics: Aircraft seating, fire blockers for upholstered furniture in high-risk occupancies.
- Protective Clothing: Firefighters ‘turnout gear, insulating thermal liners, knit hoods, molten metal splash apparel, heat resistant gloves.
- Filter Media: High capacity, high efficiency, high temperature bag house air filters.
Lead Zirconate Titanate (PZT) active fibers, from 80 to 250 micrometers in diameter, are produced for the AFOSR / DARPA funded Active Fiber Composites
Consortium** (AFCC) Program and commercial customers. Cera Nova has developed a proprietary ceramics-based technology to produce PZT mono-filaments of the required purity, composition, straightness, and piezoelectric properties for use in active fiber composite structures. CeraNova’s process begins with the extrusion of continuous lengths of mono-filament precursor fiber from a plasticized mix of PZT-5A powder. The care that must be taken to avoid mix contamination is described using illustrations from problems experienced with extruder wear and metallic contamination.
Manufacturing:
CeraNova has developed a proprietary extrusion and firing method to ake round, straight and contamination free PZT fibers having composition and piezoelectric performance suitable for AFC use.
Raw materials and mixing:
PZT-5A powder is mixed under high-shear conditions with a proprietary binder formulation until a homogeneous blend is achieved.
The PZT particle size is submicron. Binders are added sequentially during the mixing process. As only 100 kilograms of mix are required to produce sufficient fiber for 20,000 AFC packs per year, mixing capacity will not constrain future AFCC production requirements.
Batch blending and remixing improves mix consistency and extrusion performance. Great care is taken to avoid contamination as this can result in extruder die blockage or unacceptable defects in fired fibers.
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| Figure: Cross section (a) and top view (b) of Continuum Control’s Active Fiber Composite using an experimental electrode system. Note conformability of electrode around fiber. Fiber diameter is 130 micrometers; electrode spacing is 1 mm with a width of 0.5 mm. |
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| Fig. shows the some of the single PZT fibers. |
- Diameters from 5 microns to 250 microns.
- Flexible and lightweight.
- Converts waste mechanical energy into electrical energy (vibration, motion)
- When the fibers are exposed to an electric field, they mechanically deform.
- Used in sonar, ultrasound, acoustic reproduction, energy harvesting, smart materials, smart sporting goods, and medical applications.
- Can be used to power independent Electronic Systems
Recently designed a bicomponent spin pack that resulted in spinning a very unusual fiber (see below). This fiber is a type of island-in-the-sea bicomponent where a dissolvable polymer (blue) is used to surround islands of a standard polymer such as polypropylene, nylon or polyester. In this case the fiber was spun with a 50/50 ratio of polyethylene and polypropylene. It is not know at this time if this same cross-section can be obtained with other polymer combinations.
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Power fibers that store solar energy: -
Heat regenerating fibers are produced from ceramic composites by applying heat insulation processing technology, which utilizes the far infrared radiation effect of ceramic. When heated ceramics radiate far infra –red radiation, which penetrates into the material and heats it homogeneously by activating molecular motion. Zirconium, magnesium oxide or iron oxide can be blended into synthetic fibers, because these materials radiate Ca.60 mW far infrared of wavelengths 8-14 um at a body temperature of 36 0C. These heat reradiating fibers are used for sports wear, bead-sheets, bed-cover materials ,etc.
A futuristic fiber material solar-α has been developed, which absorbs and preserves the optical energy of the sun. solar-α has been employed for a downhill skiing suit. In addition to its smooth surface and aerodynamic form, this downhill suit aimed to increase the insulating efficiency by solar-α in order to warm the muscle and bring out its best power.
Oxygen consumption must be reduced t o minimum to bring out power efficiently from muscle in severe climatic conditions. Zirconium carbide compounds are used is used for their excellent characteristics in absorbing and storing heat in a new type of solar system, including domestic water heaters and large-scale generators turbine. Zirconium carbide traps heat energy. It absorbs visible
rays and reflects the light of long wavelength, which makes up 95% of sunlight, and converts it into stored heat energy. Descente researchers applied these characteristics of Zirconium carbide on polyamide or polyester fibers. They developed the technology to enclose Zirconium carbide powder within the core of synthetic fibers (as shown in fig.)
 |
 |
Hollow fiber has been scientifically proven to significantly increase oxygenated blood flow, which cans increase circulation and build strength. For diabetics, this improvement in skin oxygenation can accelerate wound healing and help eliminate pain due to decreased 90 blood flow. For people not affected by diabetes, this skin oxygenation helps speed recovery after exercise, boost energy levels and improve overall circulation.
Diabetics face two major issues neuropathy, or the loss of sensation, and atherosclerosis, or hardening of the arteries, which reduces the circulation of blood in the body. Atherosclerosis can lead to a number of conditions, including aching feet, leg pain and problems with wound healing. Symptoms include cold feet, pain in the legs when walking and pain in the feet when reclining. When worn on or near the skin, Hollow fiber responds to available light and the energy produced naturally by the body, converting light and they body’s own energy in to the necessary wavelengths that make this usually unavailable energy accessible to the body-improving the body’s circulation and oxygen levels.
In addition to helping diabetics, this breakthrough textile has been shown to improve physical performance and recovery time among those without circulation problems. Holofiber is already being lauded by some of the world’s top athletes, including top ranked female triathlete and Olympic silver medalists Michellie jones, who has been testing Holofiber for nearly two years. “As a professional athlete, you want everything you can possibly find to help get the best performance possible, “she said. “That’s one of the things I like about Holofiber – the fact that it helps with recovery and circulation. What better way-there’s no extra effort, and it really helps and benefits you.” World’s leading experts in diabetic foot complications, proved the effectiveness of Holofiber products in increasing oxygen levels in diabetic subject. There was a”… statistically significant change in transcutaneous oxygen – or the oxygen delivery to the skin – in hands and feet, on subjects wearing Holofiber gloves and socks compared to those wearing comparable non-Holofiber gloves and socks.”
Among the manufacturers already offering Holofiber products or planning to introduce them are wickers in its t-shirts, shorts, sock and glove liners, Super feet in custom insoles, Achieve 02 in diabetic and medical socks and Callaway Golf in shoes. Holofiber is a proprietary product with a patent pending. It is a responsive material for textiles and other uses, and is not an additive or coating applied by spraying or dipping. Its properties do not wash or leach out of the fabric. All of the Holofiber material are incorporated into the fibre and are non-toxic and biologically benign
POLYESTER : -
FORMALDEHYDE FUMES ABSORB POLYESTER: -
A polyester fiber can be spun and woven into fabrics for upholstery, which will adsorb the fumes released by the formaldehyde adhesives used to make furniture. The fibers, and so the fabrics made from them, contain a nitrogen compound that is firmly bonded to the surface. It is this that absorbs the gas.
The tests are conducted in environments in which the level formaldehyde was as high as 14 parts per million [ppm]. The fabrics reduced this level to just 0.06 ppm in 24 hours, the upper safety limit is considered to be 0.08 ppm. This fiber so much useful in the industry, for worker apparel and other purposes also.
Lightweight and air-insulating polyester fiber:
Sinkong Synthetic Fibers Corp. has adopted a new spinning technology to create Thermo Tech, a lightweight and air-insulating polyester fiber with a hollow cross-sectional area. The functional fiber is suitable for sportswear, thermal underwear, socks and bed sheets
 |
Thermo Tech is available in SDY and FOY versions in 60d/50f, 75d/50f, 75d/30f and 75d/36f specifications.
Cross sections of some of the new developed fibers: -
 |
| Cross sections of some of the new developed fibers |
Five times stronger than steel, Kevlar is a synthetic fiber of the DuPont corporation that was first created in 1965 by scientists Stephanie Kwolek and Herbert Blades. Since that time, Kevlar has been utilized in a wide variety of applications and has helped save thousands of lives through its use in bulletproof vests. Sometimes referred to as a Space Age material, it is the chemical structure and processing of Kevlar that makes it so strong. More specifically, Kevlar contains both aromatic and amide molecular groups. When molten Kevlar is spun into fibers at the processing plant, the polymers produced exhibit a crystalline arrangement, with the polymer chains oriented parallel to the fiber’s axis. The amide groups are able to form hydrogen bonds between the polymer chains, holding the separate chains together like glue. Also, the aromatic components of Kevlar have a radial orientation, which provides an even higher degree of symmetry and strength to the internal structure of the fibers.
 |
Fiber optics
Optical fibers are thin strands of super-clean glass (fused silica), about the size of a human hair. Almost all fibers used today are single strands. Fiber bundles find use primarily in coherent and image transmitting optical systems. There are also plastic fibers for inexpensive, short distance transmission. The basic design of an optical fiber consists of two components - the core and the cladding. They build an optical waveguide, which conducts optical power (photons) in the form of light rays. Core and cladding differ primarily in the refractive index of the glass. The core’s refractive index is slightly higher than the cladding’s, thereby creating a boundary for a circular wave-guide. Fiber optic signaling in data transmission is increasingly being used in high-density applications. In the military, the Standard Electronic Modules (SEM) of the Standard Hardware Acquisition and Reliability Program (SHARP) are widely used for high density electrical interconnects in card-edge-to-backplane interfacing.
The advantages of fiber optics can be summarized as:
- Insensitive to EMI, RFI and EMP
- Does not radiate energy
- Low transmission losses
- Wide transmission bandwidth
- Unaffected by Lightning
- Lightweight & non-corrosive.
- Absolutely safe in explosive environments
Natural fibers have good properties but have some limitations; to overcome those synthetic fibers are produced. Still they have some drawbacks, to remove them developments are going on. Now days, almost in all the fields’ fibers are used. Fibres can replace even metals, so enormous developments are done in fiber field. Now the aspect of eco-friendly, environment friendly (fiber) have came in future. Now in that respect development, research is going on.
REFERENCES
- High performance fibers, J.W.S.Hearle, Woodhead publishing company, a. Cambridge,2001
- New Millennium fibers, Tatsuya Hongu et al, 1st edition, Woodhead publishing company,Cambridge,2005
- Advanced Fiber Spinning Technology, Prof.T.Nakajimn, Woodhead publishing company,Cambridge,1994
- Carbon fibers, Jean – Baptiste Donnet et al 3rd edition, Marcel Dekker inc., Newyork,1998
- High performance synthetic fibers for composites, National Research Council,National academy press, Washington, 1992
- Developments in fiber science –V.K. Kothari
- New fibers – Philips and Hongu
- Millennium of new fibers – Philips and Hongu
- High technology fibers for technical textiles- S.K. Mukhopadhyay
- Kevlar aramide fiber- H.H Yang
- New fibres, Tatsuya Hongu, Glyn.O.Philips.” (1997)
- Synthetic metals,( R.V.Gregory , W.C.Kimbrell, H.H.Kuhn,1989)
- Handbook of technical textiles, Horrocks, Ananad,”
- Indian journal of Fiber & Textile reasearch, Vol 31, March 2006
- International Journal of Chemical reactor Engineering, Vol 3 (2005)
- “Hand book of Technical textiles,” edited by A.R.Hrrocks and S.C.Annand, Textile Institute Publications-2000 edition.
- “Industrial Textiles”, by Sabit Adanur, Wellington seris-1995 edition.
- “Textile terms and Definition”, textiles institute publications –1994 edition.
- “Manufactured Fibre Technology”, V.B.Guptha and V.K.Kothari, Chapman hall, London- 1997edition.
- http://www.dupont.com/newproducts
- http://www.nomex.com
- http://www.toyobo.co.jp
- http://www.basf.com/newfibers
- http://www.performancefiber.com
- http://www.hillsinc.net/images/striped.jbg
- http:// www.precisionliftinc.com/polyrope.html
- http://www.technicaltextiles.com
1 Responses to "Recent Developments in High Performance Fibers"
Thanks for sharing!
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