Tough nylon

More recently interest has been shown in the appearmce of exceptionally tough nylon plastics. 

In contrast to the impact tests, these can be analysed toughness is reported as the critical energy release rate (7, or the stress concentration factor K Values may tange from 5000 J. nr for a tough nylon or polycarbonate down to 350. J/m lor buttle unmodified polystyrene. The values can be sensitive to rale and temprature... 

When thermoplastics are reinforced with short fibres, both stiffness and strength may be increased, but these improvements are accompanied by a reduction of the ultimate strain for high concentrations of fibres [1-5]. This brittle behaviour is incompatible with growing engineering applications in which tlie parts are subjected to cyclic loadings or impacts, as in automotive under-the-hood applications. Thus, very tough nylon thermoplastics with enhanced creep and impact resistances have been produced by the introduction of a rubbery phase to the... 

A typical example of reactive blending is a system containing polyamide (PA) and polyolefins (PC) with a small amount of maleic anhydride (MA). This type of blending has been used to produce Super-tough Nylon . The particle size during reactive blending of PA-6 and MA-functionalized polystyrene (PS) decreased by two orders of magnitude, in comparison to the non-reactive PA-6/PS = 80/20 system, in which particle size was about 3.2 pm [Park et al, 1992]. 

With nylon, toughening and technology advancements super tough nylons became available. Their notched Izod impact values are over 10 J/m (20 ft-lb/in), and they foil in a ductile manner. 

Because of its toughness, nylon fiber is suitable for nonwoven needle-punched floorcovering products. Nylon nonwoven fiber can be found in garment interlinings and wipes for its strength and resilience. It is also used Ni/H and Ni/Cd batteries as nonwoven separators in high performance wipes, synthetic suede, heat insulators, battery separators, and specialty papers and in automotive products, athletic wear, and conveyor belts. 

Figure 6.73 Stress vs. strain in compression at 23°C for DuPont Zytel ST-801—super tough Nylon 66 resin [6],...

Figure 6.93 Stress vs. strain at various temperatures for DuPont Zytel ST811 HS NC010—super tough Nylon 66 resin (conditioned at 50% RH) [6].

Super-tough nylon is a case of the inverse-Y-type graft copolymer, which is hardly pulled out at all and stays at the interface to act as the emulsifier. It seems to be a clever and reasonable choice. 

The commercially successful super-tough nylon (e.g., Zytel ST801, DuPont ) is based on a reactive blending technology using PA-66 and a maleated (m-) EPDM rubber (Epstein 1979). The resulting PA-66/m-EPDM blend exhibits... 

Maleic anhydride grafted EPDM. Maleic anhydride grafted EPDM reacts with the matrix resin, typically nylon, to become its own compatibilizer. This type of modifier provides for excellent balance in impact, hardness, modulus, and tensile strength and is the major additive component of super tough nylon. 

Super Tough Acetal PET Polyesters Super Tough Nylon PBT Polyesters Modified PPO Polycarbonate GR Nylon Acetal Nylon Resins... 

Roney, C., and Becka, L. For Straight Shooters A Super Tough Nylon Casing. Du Pont Engineering Magazine, pp. 6-7, spring 1987. 

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