Elastomers polymer morphology

Raman microimaging is used to estimate the effect of the silica filler on phase separation in binary polymer blends composed of BIMS and BR. The domain sizes, relative concentration of polymer components within domains, and distribution of particulate silica filler and zinc stearate curative are characterised for blends of different compositions and history of ageing treatments. The presence of increased concentrations of precipitated silica results in better polymer morphology since domain sizes are reduced. Increased temperature treatment also decreases domain sizes up to about 150 deg.C, but treatment at 200 deg.C appears to induce separation of the elastomer components. Silica is usually found near the centres of the BIMS domains. There is little difference in silica distribution before and after curing. 6 refs. 

Kim, C. M., Michler, C. H., Cahleitner, M., and MiUhaupt, R. 1998. Influence of morphology on the toughening mechanisms of polypropylene modified with coie-sheU particles derived from thermoplastic elastomers. Polymer Advance Technology 9 709-715. 

Muppalla, R. Jewrajka, S. K., Synthesis, Morphology and Properties of Poly(dimethylsiloxane)/Poly(n-butyl acrylate) mixed Soft Block-Based Copolymers A New Class of Thermoplastic Elastomer. Polymer 2012,53, 1453-1464. 

Initially compounding was mainly performed between amorphous polymers and elastomers, resulting in a polymer matrix with small domains of elastomers. This morphology can increase the mechanical properties considerably. In later developments special attention was paid to better and controlled phase separation, to control the domain size, and to increase the impact strength, as for instance in high-impact polystyrene (HIPS) and in ABS-latex mixtures. The search for better compatibility between the phases leads also to fully compatible combinations of polymers. Although over 300 pairs of miscible polymers are known (2), only a few systems have actually been commercialized, like PS/PPE... 

Applications showing the range of microscopy techniques and specimen preparation methods used on commercial impact polymers will be described. Changes in polymer morphology are expected upon addition of an elastomer for instance, such addition is expected to cause a decrease in the spherulite size as the elastomer domains can act as nucleating sites [274]. This has been observed for many polymers including... 

Celia, R.J., Morphology of segmented polyester thermoplastic elastomers. / Polym Sci, Part C, Polym Symp, (42) p. 727.1973. 

Prick E M and Hillmeyer M A (2002) Morphological, rheological and mechanical characterization of polylactide-6-polyisoprene-6-polylactide triblock copolymers New partially biodegradable thermoplastic elastomers, Polym Mat Sci Eng 87 110. 

Rubber-Modified Copolymers. Acrylonitrile—butadiene—styrene polymers have become important commercial products since the mid-1950s. The development and properties of ABS polymers have been discussed in detail (76) (see Acrylonitrile polymers). ABS polymers, like HIPS, are two-phase systems in which the elastomer component is dispersed in the rigid SAN copolymer matrix. The electron photomicrographs in Figure 6 show the difference in morphology of mass vs emulsion ABS polymers. The differences in stmcture of the dispersed phases are primarily a result of differences in production processes, types of mbber used, and variation in mbber concentrations. 

Hashimoto T., Order disorder transition in block copolymers. Thermoplastic Elastomers A Comprehensive Review (Legge N.R., Holden G., and Schroeder H.E., eds.), Hanser Publishers, Munich, 1987. Bianchi U. and Pedemonte E., Morphology of styrene butadiene styrene copolymer. Polymer, 11, 268, 1970. 

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