Fibre temperature resistance

Grade Selection Criteria Mechanical properties determined by reinforcement, e.g. glass and carbon fibres. Temperature resistance and lubricant addition. Processed by injection moulding. ... 

Technical advantage/function Basalt rock wool is used for noise insulation in automotive exhaust units for the purposes of noise absorption. Vital technical requirements are temperature resistance, noise absorption behaviour, corrosion resistance and mechanical stability. Now textile continuous glass fibres and biosoluble mineral wools are also used for this application in exhaust units. 

Reinforcements in the form of continuous fibres, short fibres, whiskers or particles are available commercially. Continuous ceramic fibres are very attractive as reinforcements in high-temperature structural materials. They provide high strength and elastic modulus with high temperature-resistant capability and are free from environmental attack. Ceramic reinforcement materials are divided into oxide and non-oxide categories, listed in Table 3.1. The chemical compositions of some commercially available oxide and non-oxide reinforcements are given in Table 3.2 and Table 3.3. 

The very wide range of the numerical values of the mechanical properties is evident. The modulus of organic polymer fibres varies between 1 and 350 GPa. The tenacities or tensile strengths may even vary from about 0.07 GPA (0.05 N/tex) for the weakest (cellulose acetate) to about 7 GPa (4 N/tex) for the strongest fibre (PIPD or M5 ) the compressive strengths reaches up to 1.7 GPa and the temperature resistance up to 400 °C. The ultimate elongation may vary from about 1% for the stiffest fibre (carbon) to about 600% for the most rubber-elastic. 

Phenolic Low cost. Good physical strength and high temperature resistance. Good toughness with fillers and fibres. 

Mild alkalis have less effect, but again temperature and concentration are important factors. Sodium carbonate is used in wool scouring and small quantities of ammonia are sometimes added to a dyebath. Slight damage caused by an alkali in scouring can render the fibre less resistant to subsequent processes. Ammonia, ammonium carbonate, borax, sodium hexa-metaphosphate, tetrasodium pyrophosphate, and sodium triphosphate can be used at temperatures up to 60 to 70°C (140° to 158°F) with safety. 

Rubber consumption is dominated by tyre production. In these, conveyor belts, and pressure hoses, thin layers of either steel wire or polymeric fibre reinforcement take the main mechanical loads. These layers, with rubber interlayers, allow flexibility in bending, whereas the reinforcement limits the in-plane stretching of the product. The applications are dominated by natural rubber and styrene butadiene copolymer rubber (SBR). Other rubbers have specialised properties butyl rubbers have low air permeability, nitrile rubbers have good oil resistance, while silicone rubbers have high and low temperature resistance. Rubbers play a relatively small role in this book, but the rubbery behaviour of the amorphous phase in semi-crystalline thermoplastics is important. 

Polyethylene fibres are made by several different processes and their thermal characteristics vary, but lack of high temperature resistance is very noticeable compared with other reinforcing fibres. Most polyethylene fibres begin to lose their mechanical properties at about 120°C and they melt soon afterwards. 

Poly(metaphenylene isophthalamide) (Nomex high temperature resistant fibre) 126-135 50 14-17 1-38... 

Types and production of textiles used for building and construction 21 Table 2.2 Temperature resistance of fibres... 

Figure 3.7 Length changes of 700 filament tows of 1.5 denier Courtelle PAN fiber in air at 220°C with different tensile loads. Source Reprinted from Watt W, Johnson W, Conference on High Temperature Resistant Fibres, Amer Chem Soc, Interscience, Atlantic City, 1968.

Watt W, Johnson W, Conf. High Temperature Resistant Fibres, American Chemical Society, Interscience, Atlantic City, 1968. 

Logsdail DH, Aspects of carbon fibre development at AERE, Harwell, Preston J ed.. High temperature Resistant Fibers from Organic Polymers, Interscience, New York, 245, 1969. 

Brydges WT, Badami DV, Joiner JC, Jones GA, The stmcture and elastic properties of earbon fibres, Preston J ed.. High Temperature Resistant Fibres from Organic Polymers, Interscienee, New York, 255, 1969. 

PR-5104 containing 66% bromine is a dust-free, 100% active FR masterbatch for engineering plastics. It is based on the company s experience of high-molecular weight polymeric brominated FRs as carriers. This material provides good processibility, high temperature resistance and outstanding compatibility between fibre reinforcement and the resin matrix. 

Vyncolit sells carbon-fibre filled phenolic resin, for superior wear resistance, high temperature resistance and high stifihess. Applications include pump components, thrust washers, bearings and EMI shielding. 

The family of polyesters comprises all polymers with ester functional groups in the polymer backbone. Polyesters were the first family of synthetic condensation polymers. Their connecting ester groups can be varied over an immensely broad range, making the polyesters a diverse group, with applications from labile biomedical matrices to liquid crystals, fibres and temperature-resistant performance materials [61, 62]. 

This is a fruitful area for specially developed formulations which combine lubricity with good creep and temperature resistance. The Audi 80 gear shift mechanism is composed of two snap-fitted components in a nylon-based composite containing PTFE and silicone as well as glass fibre in another case an actuator tube in reinforced PPS moves in contact with the PEI housing for an automatic gear shift. (Both these examples feature formulations from the LNP Company.)... 

Others explored techniques to improve the elasticity and flexibility of the fibre after washing (US 2,309,113 see Table 13.2). Acetylation, sometimes using acetic anhydride at temperatures of 80°C or above, could be used to improve colour, handle and dyeing performance." Atlantic Research Associates used this approach to stabilising fibres formed from either milk or soya bean protein. The acylating agent, which could be in gaseous form, was used to make the newly formed fibres more resistant to water, acids and alkalis (GB... 

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