Reinforcing fibres polyamide

The reinforcing filler usually takes the form of fibres but particles (for example glass spheres) are also used. A wide range of amorphous and crystalline materials can be used as reinforcing fibres. These include glass, carbon, boron, and silica. In recent years, fibres have been produced from synthetic polymers-for example, Kevlar fibres (from aromatic polyamides) and PET fibres. The stress-strain behaviour of some typical fibres is shown in Fig. 3.2. 

EMS hybrid yarns or Schappe s preimpregnated yarns are a combination of reinforcing fibres (glass, aramid or carbon) and polyamide 12. 

Table 6.30 shows the properties of the same thermoplastic (short fibre reinforced polyamide) reinforced with the same level of the three main reinforcement fibres, illustrating the effect of the fibre nature. 

Aromatic polyamide Kevlar Du Pont 220 — v-0 Reinforcing fibre... 

S. Ohgishi, H. Onoand I. Tanahashi, Mechanical properties of cement mortar pastes reinforced with polyamide fibres , Trans. Japan Concr. inst. 6,1984, 309-315. 

Frames and seat slides of front and back seats can be made out of GMTs. Long glass fibre reinforced polyamides are used for very light seats intended for sports cars. 

Table 3.18 shows the effects of several lubricating fillers on the friction properties of polyamides 6 or 66 possibly reinforced with glass or carbon fibres. 

More than 60% of polyamides are reinforced with glass fibres (in more than 80% of reinforced grades) or mineral fillers (more than 10%). 

Creep is rather low or very low, the more so as semi-aromatic polyamides are very often reinforced with high glass fibre contents. It changes moderately when the temperature rises. 

For a carbon fibre reinforced polyamide-imide, compared to the value at ambient temperature, the percentage retention of flexural strength is roughly ... 

Figure 4.113 displays three examples of flexural strength retention versus temperature for neat, carbon fibre reinforced and glass fibre reinforced polyamide-imides. The three curves are not distinguishable note the steady decay up to 260°C. 

Mat and continuous glass fibre reinforcements theoretically all the thermoplastics are usable in these forms, but up to now developments have concentrated on polypropylenes (PP), polyamides (PA) and thermoplastic polyesters (PET) fibre-reinforced PEEK, polyetherimide (PEI) and polyphenylene sulfide (PPS) are used for high-performance applications. They are presented in a range of forms from stampable sheets to pellets, prepregs, ribbons, impregnated or coated continuous fibre rods. More rarely (as in the case of PA 12, for example), the thermoplastic is provided in liquid form. 

Figure 6.8 plots the reinforcement ratios for short glass fibre reinforced polyamide (PA-GF) versus neat polyamide for six important characteristics calculated versus density and material cost. These characteristics are tensile strength, tensile and flexural modulus, impact strength, HDT A and B. 

Short fibre reinforced polyamide E-glass Aramid Carbon... 

Other textile fibres - polyester, rayon, polyamide - have low moduli (see Table 6.12), which limits their plastic reinforcing power. They are used particularly for the reinforcement of soft thermoplastics such as plasticized PVC. 

Some basic property examples of short aramid, glass and carbon fibre reinforced polyamide are shown earlier in Table 6.30. 

Table 6.35 displays some basic property examples of long glass fibre reinforced polyamides and polypropylenes. 

The use of glass fibre reinforced polyamide or BMC for engine covers the two techniques are industrialized. One is predominant in the USA, the other in Europe and Japan. The main characteristics are roughly similar, as shown in Table 7.3. 

Table 7.3 displays property examples of glass fibre reinforced polyamide and BMC. 

Flexible plastics and rubbers can, as a matter of fact, only be treated with rubber-elastic lacquers, mainly on the basis of polyurethane, which, moreover, should be resistant to oxidation, oils, fuel and UV light. Besides, polyurethane lacquers are often used for several other plastics, such as PVC, polyamides, ABS and glass-fibre reinforced resins. 

Braun, U., Schartel, B., Fichera, M.A., and Jaeger, C. 2007. Flame retardancy mechanisms of aluminium phosphinate in combination with melamine polyphosphate and zinc borate in glass-fibre reinforced polyamide 6,6. Polym. Deg. Stab. 92 1528-1545. 

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