M-aramid fibres

Denier, 38-51 mm staple fibres of 1.5 m-aramid and m-aramid fibre. High crystallinity higher... 

Some high performance fibres (e.g., p-aramid and m-aramid fibres) have poor abrasion resistance in this case, they are usually blended with fibres having superior abrasion resistance properties, combined with polyurethane coating, or layered with nylon fabrics. Fabric containing nylon filaments has been widely used as a durable layer for military and civil PPE to protect military personnel, chainsaw operators and motorcyclists. For example, the rigorous requirements of abrasion, impact, cut and burst... 

Some three decades ago, scientists from the Du Pont company developed polycondensation methods which allowed the preparation of high molecular weight wholly aromatic polyamides. The first commercially produced wholly aromatic polyamide fibre was poly(m-phenyleneisophthalamide) (Nomex, Du Pont, 1967) [la, c]. Some years later, development of the preparation and processing of poly(p-phenyleneterephthalamide) (PPTA) led to the commercialization of the para product Kevlar (Du Pont) in the early seventies [lb, c]. While Nomex shows excellent thermal stability and flame-retardance, and indeed is referred to as a heat and flame resistant aramid fibre, Kevlar fibre also has similar properties, but in addition it has exceptional tensile strength and modulus, and is referred to as an ultra-high strength, high modulus aramid fibre. 

There are three types of major commercial aramid fibres in the market para-aramid (or p-aramid, poly-(p-phenylene terephthalamide), PPTA), meta-aramid (or m-aramid, poly-(meta-phenylene isophthalamides), MPIA) and co-polyamides fibres. 

Staple fibres of 1.5 100% meta-aramid A blend of 95% A blend of 93% 100% m-aramid filament yarn ... 

Heppenstall-Butler, M., Bannister, D.J. and Young, R.J. (1996) A study of transcrystalline polypropylene/single-aramid-fibre pull-out behaviour using Raman spectroscopy. Composites A, 27A, 833-838. 

Kawagoe M, Hashimoto S, Nomiya M, Morita M, Qiu J, Mizuno W, Kitano H (1999) Effect of water absorption and desorption on the interfacial degradation in a model composite of an aramid fibre and unsaturated polyester evaluated by Raman and FT infra-red microspectroscopy. J Raman Spectrosc 30(10) 913-918... 

J. Lynch, M. Mazar, P. Nosker, T. Nosker, Rutgers University, Materials Science and Engineering MICROMECHANICAL ANALYSIS OF INTERFACIAL SHEAR STRENGTH OF ARAMID FIBRE... 

Conventional aliphatic polyamides, like PA-66, melt at 250 °C. By inserting aromatic rings between the amide groups, near-infusible polymers are formed. Aromatic polyamides (aramides) are known mainly in the form of fibres. Two grades of DuPont are widely used. Nomex is made from m-phenylene diamine and isophthalic acid (anhydride). In Kevlar, phenylene groups are para-substituted by amide groups,... 

An interesting development for thermoplastics is a technique for pulping or fibrillation that greatly increases the surface area of short-length fibres of para-aramid, and renders them suitable for reinforcement of plastics and elastomers. While a typical staple fibre will have a surface area of about 0.1 m g K the new compounding process increases this to 7-9 g, so increasing the area... 

An advanced form of this is based on biaxial thermoplastics in the form of fibres (PA, PBT, PET, PP/PPS, PEI, APC-2, or PSUl), with carbon, aramid, and glass pre-impregnated tape. The pre-preg is unidirectional and interlaced in a biaxial form in continuous lengths. The manufacturers claim that an unprecedented width (up to 3.04 m) is possible. 

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