Rubber-toughened plastics

This chapter on applications of PAB s focuses on polymer systems giving synergistic and generally high performance properties. Low performance PAB s of commodity plastics, rubber toughened plastics, copolymers, and interpenetrating networks are excluded. Some of the more common PAB s are described elsewhere in this book. 

R. Siebert, "Rubber-Modified Thermoset Resins," in C. K. Riew and J. K. GiUham, eds., ACS Advances in Chemistry Series 208, American Chemical Society, Washington, D.C., 1983, p. 179 W. D. Bascom and D. L. Hunston, "Rubber Toughened Plastic," Adv. Chem. Ser. No. 222, American Chemical Society, Washington, D.C., 1989. 

J. C. Hedrick, N. M. Patel, and J. E. McGrath, Toughening of Epoxy Resin Networks with Functionalized Engineering Thermoplastics, in Rubber Toughened Plastics, K. Riew (Ed.), American Chemical Society, Washington, DC, 1993. 

Pramanik, P.K. and Baker, W.E., Toughening of ground rubber tire fibed thermoplastic compounds using different compatibilizer systems, Plastics Rubber Comp., Process. Appl, 24, 229, 1995. 

A.A. Collyer, Rubber Toughened Engineering Plastics, Chapman Hall, London (1994). 

In this report we will only consider type 3, i.e. mixtures of a rigid amorphous thermoplast with small amounts of an elastomer which is the underlying principle for all rubber toughened plastics to improve impact behavior. 

Fond et al. [84] developed a numerical procedure to simulate a random distribution of voids in a definite volume. These simulations are limited with respect to a minimum distance between the pores equal to their radius. The detailed mathematical procedure to realize this simulation and to calculate the stress distribution by superposition of mechanical fields is described in [173] for rubber toughened systems and in [84] for macroporous epoxies. A typical result for the simulation of a three-dimensional void distribution is shown in Fig. 40, where a cube is subjected to uniaxial tension. The presence of voids induces stress concentrations which interact and it becomes possible to calculate the appearance of plasticity based on a von Mises stress criterion. 

As in rubber toughening, the cavitated particles induce shear yielding of the matrix, producing a plastic zone smaller than the cavitated zone. These mechanisms induce a significant toughening effect. Should matrix yielding precede the cavitation of CSR particles, the croiding mechanism would be suppressed. 

The technical and commercial success of high impact polystyrene (HIPS) and acrylonitrile-butadiene-styrene (ABS) has led to a widespread research program on the use of rubbers as toughening agents for plastics. There is now an impressive 11st of rubber-toughened polymers including both amorphous and... 

Presented in this paper are the results of an investigation concerning the link between structure and properties of rubber-toughened plastics. An attempt has been made to assess the importance of the spatial distribution of rubber particles in terms of their effectiveness in controlling craze initiation and growth. Also studied in particular were the effects of rubber particle size on the mechanical properties of HIPS materials. A... 

Walker I, Collyer AA (1994) Rubber toughening mechanisms in polymeric materials. In Collyer AA (ed) Rubber Toughened Engineering Plastics. Chapman Hall, London, p29... 

Acrylonitrile-butadiene-styrene (ABS) and acrylonitrile-styrene-acry- late (ASA) are rubber-toughened plastics based upon the styrene-acrylonitrile (SAN) copolymer matrix. The combination of the stiffness and toughness exhibited by these materials has made them increasingly attractive in engineering applications, and the activity of the patent literature testifies to a continuing interest in improving properties through modifications of structure. The aim of this paper is to discuss a quantitative approach to structure-property relationships in ABS and ASA polymers. 

The loss of modulus caused by crazing becomes less pronounced as the draw ratio is increased, especially in tests carried out at lower stress levels. This observation supports earlier conclusions drawn from creep studies on other rubber-toughened plastics (6) if the specimen can reach a strain of 5% largely or entirely by shear mechanisms, the loss of modulus resulting from the creep and recovery program is quite small if, on the other hand, crazing is the dominant mechanism, the loss in modulus is large. 

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