Rubber-Modified Thermoplasts

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

Report 113 Rubber-Modified Thermoplastics, H. Keskkula, University of Texas at Austin. 

Edwards, S. A. and Choudhury, N. R., Variations in Surface Gloss on Rubber-Modified Thermoplastics Relation to Morphological and Rheological Behavior, Polym. Eng. Set, 44, 96 (2004)... 

M. C. O. Chang, On the Study of Surface Defects in the Injection Molding of Rubber-modified Thermoplastics, SPE ANTEC Tech. Papers, 40, 360-367 (1994). 

It is worth noting that this semi-ductile behavior has been found in other polymers Newmann and Williams [4] observed stable crack propagation before brittle fracture in ABS over the temperature range from —40 to 0°C Bernal and Frontini also observed this type of behavior in a rubber-modified thermoplastic at room temperature [12]. 

Acrylate Styrene Acrylonitrile Polymer Acrylic rubber-modified thermoplastic with high weatherability. Acrylate Styrene Acrylonitrile Polymer has good heat and chemical resistance, toughness, rigidity, and antistatic properties. Processed by extrusion, thermoforming, and molding. Used in construction, leisure, and automotive applications such as siding, exterior auto trim, and in outdoor furniture. 

Rubber-modified thermoplasts behave quite differently from the pure thermoplasts when under tensile stress (Figure 35-12). Poly(styrene) is a brittle material Crazing occurs at about 35 MPa after a linear deformation... 

Crazing is an important source of toughness in rubber-modified thermoplastics. A craze can be described as a layer of polymer a nanometer to a few micrometers thick, which has undergone plastic deformation approximately in the direction normal to the craze plane as a response to tension applied in this direction (Kambour 1986). Crazing occurs without lateral contraction. As a result, the polymer volume fraction in the craze is proportional to lA, where X is the draw ratio in the craze. The reduction in density occurs on such a small scale that the refractive index is markedly reduced, which accounts for the reflectivity of the craze (Kramer 1983). 

The comparatively low impact strength of many well-known polymers, such as PMMA, polystyrene and PVC, led to the production of rubber-modified thermoplastics with high impact strength. The best-known examples are high-impact polystyrene (HIPS) and ABS copolymer, where the rubbery phase is dispersed throughout the polymer in the form of small aggregates or balls. Other polymers that have been toughened in this way include PMMA, PVC, polypropylene, polycarbonate, nylons and thermosets such as epoxies, polyesters and polyimides. 

Bucknall, C.B. (1967) Relationship between structure and mechanical properties of rubber-modified thermoplastics. Br. Blast., 40, 84. 

The addition of a rubbery phase during the polymerization of a monomer of a second polymer to obtain a rubber-modified thermoplastic material has two main advantages towards the melt-mixing process of high... 

Melt mixing method 1 utilizes well established technologies and is therefore generally preferred to obtain rubber-modified thermoplastics of improved impact properties. As the two components are immiscible, the addition of a third component (compatibilizing agent) is frequently used to increase the adhesion between the elastomeric and the thermoplastic phases and to achieve finer dispersions of the rubbery particles in the thermoplastic matrix. 

Dompas D, Groeninckx G (1994) Toughening behavior of rubber-modified thermoplastic polymers involving very small rubber partides. 1. A criterion for internal rubber cavitation. Polymer 35 4743... 

One important consequence of bound antioxidants is that the antioxidant can be attached to those domains in the polymer that are most susceptable to oxidation. In the case of rubber-modified thermoplastics, for example, these are normally the rubber domains. Attachment through the double bonds of the rubber, therefore, leads to molecular dispersion of the protective agent in high concentration exactly where it is required most. ... 

Neuray D and Off K-H (1981) New rubber-modified thermoplastics, Angew Makromol Chem 98 213-224 (in German). 

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