Plastics rubber-modified

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. 

Elastomers, plastics, fabrics, wood and metals can be joined with themselves and with each other using nitrile rubber/epoxy resin blends cured with amines and/or acidic agents. Ethylene-propylene vulcanizates can also be joined using blends of carboxylated nitrile rubber, epoxy resin and a reactive metal filler (copper, nickel, cobalt). However, one of the largest areas of use of nitrile rubber modified epoxy systems is in the printed circuit board area [12]. 

Styrene maleic anhydride SMA is a copolymer made with or without rubber modifiers. They are sometimes alloyed with ABS and offer good heat resistance, high impact strength and gloss but with little appreciable improvement in weatherability or chemical resistance over other styrene based plastics. 

When these AN/S copolymers, are manufactured into Lopac containers, they remain essentially unmodified and in their pure state. Many of the desirable barrier and organoleptic properties of the containers can be attributed to the fact that no plasticizers, rubber, or other common modifiers are incorporated. 

Report 86 High Performance Engineering Plastics, D.J. Kemmish, Victrex Ltd. Report 113 Rubber-Modified Thermoplastics, H. Keskkula, University of Texas at Austin. 

Applications Although Soxtec combines the best qualities of reflux and Soxhlet extractions up to now fairly little evidence has been reported concerning the efficacy of this system for polymer and rubber analysis. Nevertheless, it appears that oligomers and other reaction residues, softeners, antioxidants (e.g. BHT) and several other additives used to modify polymers are easily extracted from PVC, PP, PE, PS, rubber and many other polymeric materials. Also, some leading international plastic, rubber and packaging companies have made Soxtec an integral part of their quality control routines. Some application examples where Soxtec has proved successful are [148] ... 

Transition from liquid behavior to solid behavior has been reported with fine particle suspensions with increased filler content in both Newtonian and non-Newtonian liquids. Industrially important classes are rubber-modified polymer melts (small rubber particles embedded in a polymer melt), e.g. ABS (acrylo-nitrile-butadiene-styrene) or HIPS (high-impact polystyrene) and fiber-reinforced polymers. Another interesting suspension is present in plasticized polyvinylchloride (PVC) at low temperatures, when suspended PVC particles are formed in the melt [96], The transition becomes evident in the following... 

Fig. 8.1. Toughening mechanisms in rubber-modified polymers (1) shear band formation near rubber particles (2) fracture of rubber particles after cavitation (3) stretching, (4) debonding and (5) tearing of rubber particles (6) transparticle fracture (7) debonding of hard particles (8) crack deflection by hard particles (9) voided/cavitated rubber particles (10) crazing (II) plastic zone at craze tip (12) diffuse shear yielding (13) shear band/craze interaction. After Garg and Mai (1988a).

Mechanical properties of rubber-modified epoxy resins depend on the extent of mbber-phase separation and on the morphological features of the mbber phase. Dissolved mbber causes plastic deformation and necking at low strains, but does not result in impact toughening. The presence of mbber particles is a necessary but not sufficient condition for achieving impact resistance. Optimum properties are obtained with materials comprising both dissolved and phase-separated mbber (305). 

STYRENE. Styrene, CgH5CH=CH2, is the simplest and by far the most important member of a series of aromatic monomers. Also known commercially as styrene monomer (SM). styrene is produced in large quantities for polymerization. It is a versatile monomer extensively used for the manufacture of plastics, including crystalline polystyrene, rubber-modified impact polystyrene, expandable polystyrene, acrylonitrile-butadiene-styrene copolymer (ABS), styrene-acrylonitrile resins (SAN), styrene-butadiene latex, styrene-butadiene rubber (SBR). and unsaturated polyester resins. See also Acrylonitrile Polymers. 

Comparative studies are presented that demonstrate that homopolyurethane and segmented copolyurethane elastomers and plastics and rubber-modified polyurethane glasses with properties similar to counterparts formed from oil-... 

In the notched Izod impact test, with the exception of some rubber modified plastics, the fracture surface of a specimen that has failed ductilely exhibits significant inward collapsing on the sides of the impact bar near the notch, indicating that a large amount of plastic flow has... 

Amount of Rubber. Generally the impact strength of rubber-modified plastics increases with an increase in rubber content. Although the impact improves, it is usually at the sacrifice of other properties such as strength, modulus, heat distortion, weather resistance, and creep. 

Aggression of a liquid upon a rubber-modified polymer under stress is well studied and depends upon capillary transport of the liquid to the crack tip. Crack propagation is resisted by the molecular weight of the continuous phase and aided by the plasticization effect of the aggressive liquid or plasticizer in the polymer matrix. High molecular weight, unplasticized products can be expected to have enhanced ESCR to aggressive liquids. 

This chapter discusses the dynamic mechanical properties of polystyrene, styrene copolymers, rubber-modified polystyrene and rubber-modified styrene copolymers. In polystyrene, the experimental relaxation spectrum and its probable molecular origins are reviewed further the effects on the relaxations caused by polymer structure (e.g. tacticity, molecular weight, substituents and crosslinking) and additives (e.g. plasticizers, antioxidants, UV stabilizers, flame retardants and colorants) are assessed. The main relaxation behaviour of styrene copolymers is presented and some of the effects of random copolymerization on secondary mechanical relaxation processes are illustrated on styrene-co-acrylonitrile and styrene-co-methacrylic acid. Finally, in rubber-modified polystyrene and styrene copolymers, it is shown how dynamic mechanical spectroscopy can help in the characterization of rubber phase morphology through the analysis of its main relaxation loss peak. 

In multiphase systems, like in rubber modified plastics, stabilizers can partition between different phases of the system [37]. The actual stabilizer concentration in either elastomer or thermopl tic phases may differ very significantly from the average stabilizer concentration declared for the whole multiphase system. In polymers like ABS, the partitioning of stabilizers may exert a controlling influence on the final stabilization effect. A proper chemical modification of the stabilizer molecule can enhance its affinity to a phase of the multiphase system which is more sensitive to degradation. 

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