Technical Textile Fibers Basic information about Technical Textile fibers by Dr. Muhammad Mushtaq Mangat www.mushtaqmangat.org Nov 26, 2012

Lecture 2 Technical Textile Fibers Following fibers will be discussed: 1.  Conventional and Regenerated fibers 2.  Synthetic fibers 3.  High strength and high modulus organic fires 4.  High chemical- and combustion-resistant organic fibers 5.  High performance inorganic fibers 6.  Ultra-fine and novelty fibers 7.  Civil and agricultural engineering 8.  Automotive and aeronautics 9.  Medical and hygiene applications 10.  Protection and defense

19/11/12 Dr. Muhammad Mushtaq Mangat

Use of natural fibers as technical fibers

  Egyptians and Chinese used papyrus mats in foundation for reinforcement of buildings

  In recent past, synthetic fibers were used in floods in 1953 in Netherlands, it could be seen as start of geotextile

  Cotton bales in foundation for earthquake protection

  Silk used for military clothing, due to light weight and for protection from arrows. Commonly used by Mongolian armies,

  Silk as wound dressing was very common by Chinese and Egyptian [1]

Jute for soil stabilization

Cotton

Cotton Characteristics   Moderate uniformity, tapper shape, 18-20 μm diameter, 2.2 cm

to 3.3 cm lenght , good luster,

  Tenacity dry 3.0–5.0 g/d and wet 3.3–6.0 g/d

  Density 1.54–1.56 g/cm³ (1540-1560 Kgm-3)

  Moisture absorption, raw cotton 8.5, saturation 15-25%, mercerized 8.5-10.3% , saturation 15-27+

  Poor resistance to acids, strong resistance to alkalis and solvents, prolonged exposure to sunlight weakens fibers, can be attacked by insects [2]

Wool   Wool, a protein fiber, consumption second to cotton

  High extensible, natural waviness, trap air, low thermal conductivity, high thermal resistance, gives comfort and warmth

  Due to morphology of wool, some technical fibers have been produced

  Wool is comparatively fire retardant

  Zirconium-and titanium-treated wool has much higher for example Zirpro (IWS) wool used for fire proof padding in aero planes [1]

Wool Parameters   Ultra fine <15.5, Superfine Merino 15.6–18.5, Fine

Merino, 18.6–20 – , Medium Merino 20.1–23 μm–

  Coarse crossbred: 36> microns, Carpet wools: 35–45 microns[3]

Flax, Jute, Hemp, Ramie   Not very common under use

  Jute is used in geotextile, where biodegradable fibers are required

Silk   Protein-based fiber produced naturally by

the silkworm,

  Structurally similar to wool

  High tenacity, high luster and good dimensional stability.

  Used as luxury item,

  Biocompatibility and gradual disintegration an advantage in in medical textiles [1]

Regenerated Fibers   Viscose rayon was regenerated

fibers in the early 1920s. Has inferior physical properties

  Improved shape has better tenacity in wet and dry conditions

  Textured and hollow viscose fibers are comparable to cotton

  Fire-retardant (FR) viscose introduced in the 1960s. For example produced by Lenzing in Austria by incorporating

organophosphorous compounds

  In 1990s Kemira (now Sateri Fibres) of Finland introduced alternative version of FR viscose known as Visil. The fiber chars upon heating leaving a silica residue.

  Latest addition is Lyocell also known as Tencel (Acordis) environmentally friendly production method [1].

Viscose

Synthetic Fibers   Made from coal or oil.

  Nylon 6.6 first fiber in 1939 by DuPont

  Many nylon fibers known as polyamides produced by using melt extrusion, many cross-sectional shapes are possible

  High extensibility, significant recovery, more dimensional stability, low moisture

  Used in carpets, clothing, curtain, packaging

Polyester (PET)   Introduced as Dacron by DuPont in

1951. Now second major fiber

  Made by condensation polymerization of ethylene glycol and terephthalic acid followed

  Durability and compatibility with cotton in blend, low moisture absorbency, resilience and good dimensional stability are additional qualities.

  Glass transition temperature is approximately 70 °C, resistance to heat and chemical degradation, good for Technical Textile

  Flame-retardant Trevira CS and Trevira high tenacity, developed by Trevira GmbH in Germany

Acrylic Polyacrylic fibers produced by the

polymerization of acrylonitrile

  Orlon14 was produced by DuPont.

  Acrilan15 produced by Monsanto and Courtelle, Wool-like characteristics.

  Chemically modified acrylics has low burning behavior and having high absorbency, applicable in hygiene and medical care

Polyethylene and Polypropylene

  PE moderate physical properties, low melting temperature, 110 °C for low density and 140 °C for high density

  PP high strength, low melting point, difficult to do iron press, singeing is not possible

  Density less than water, available at low cost, good resistance to acid and alkaline environments

  PP is most popular in industrial geotextile applications.

PE and PP

Spandex Yarn   Polyurethane structure, can stretch

more than 8 times

  Rubber-like properties,

  Used in combination with other fibers

  Produced by DuPont in 1959 (Lycra).

  Expensive fiber, used in fabric

formation, during knitting, yarn is also produced by twisting with spandex yarn

High Strength And High Modulus Organic Fibers

  Development of long chains of molecules, which form folded-chain crystals is start of high strength fibers

  In 1970s DSM developed gel spinning, high tensile strength fibers were produced e.g. 70GNm-2, 15 times stronger than steel and twice as strong as aromatic polyamides such as Kevlar, low density, chemically inert, high abrasion resistant melting at around 150 °C and thermally degrades at 350 °C [1]

Conti…   In 1970 Kevlar by DuPont and

Twaron by Akzo (now Acordis) were produced

  New developments like, Kevlar HT 20% tenacity than Kevlar, Kevlar HM has 40% higher modulus than the original Kevlar 29

  One common issue photo degradation

High Chemical- And Combustion-resistant Organic Fibers

  Meta-aramids are Solvent-spun e.g. Nomex and Conex made from poly(meta-phenylene isophthalamide)

  DuPont produced in in 1962 and by Teijin in 1972

  Meta -aramids creates a zig-zag molecular structure, it has poor tensile properties, high combustion resistance,

High Performance Inorganic Fibers

  Organic fibers can withstand only up to 500°C

  Glass, asbestos and carbon inorganic fibers, can bear high temperature, bitter in nature, under use from centuries, best use is in by mixing with other materials, plastic sheets one example made by using glass fiber and polymers

  High purity, pyrolysed acrylic-based fibers are classified as carbon fibers.

Ceramic Fibers   Aluminosilicate compounds,

which are made by mixing aluminium oxide (Al2 O) and silicon oxide (SiO2 ).

  They can bear 1400°C, main use is insulation, friction materials, gaskets and packing etc. [1]

  Silicon carbide (SiC) can withstand in oxidizing conditions

up to 1800 °C, has higher electrical conductivity.

Ultra-fine And Novelty Fibers   Ultra fine fibers have 1.0 dtex or less

  Linear density of extra-fine and micro-fine is less than 0.1 dtex

  Commonly PET and Nylon are used

  First made in Japan e.g. Mitrelle, Setila, Micrell, Tactel

  Once in woven fabric form their fine diameter and tight weave allows

  Up to 30000 filaments cm-2, highly dense, water proof but air and moisture vapor can pass [1]

Conti…

  Solar-Aloha, developed by Descente and Unitika in Japan can absorb light less than 2μm

  It converts sunlight into heat, winter sports clothing is made by using this material

  Heat sensitive dyes are also used to indicate heat variation

  Cripy 65 keeps fragrance and release slowly, used for Pillows and bed linen [1]

Stress and Strain [1] [1]

Civil And Agricultural Engineering   Flax, jute and ramie is used for slope stabilization to control soil erosion. They gradually degraded and

become part of soil

  Following are generally used:

  polypropylene

  • polyester

  • polyethylene

  • polyvinyl chloride

  • polyamide

  • aramids.

[1]

Tensile Strength of fibers   Tensile strength is force per unit area Pa [Nm-2], also

denoted psi (pounds per square inch), In case of fiber, area is so small,

  used cN/tex

Tenacity Values [4]

Conversion: Grams-force/Denier (G/D) -> x 8.830 centiNewton/tex (cN/tex) centiNewton/tex (cN/tex)-> x 0.1132 Grams-force/Denier (G/D) Tenacity of PP is 6-8 G/D or 50-65 cN/Tex

Stress-Strain Curve

Stress vs. strain curve typical of structural steel, 1. Ultimate strength, 2. Yield strength, 3. Fracture, 4. Strain hardening region, 5. Necking region

Future Fibers

  Nano fibers

  Commercial production has been started

  Use in the filed of membrane

Activity   Write 8-10 pages on Technical Textile fibers and their

usage in industry

References [1] Miraftab, M., Technical Fibres, in Handbook of Technical Textiles A.R. Horrocks, Anand, S. C., Editor 2000, Woodhead Publishing Ltd Cambridge. [2] http://en.wikipedia.org/wiki/Cotton [3] Preparation of Australian Wool Clips, Code of Practice 2010–2012, Australian Wool Exchange (AWEX), 2010 [4] http://www.rieter.com/cz/rikipedia/articles/rotor-spinning/applications-engineering/fiber-properties/fiber-tenacity-and-fiber-elongation/