Thermal Interaction in Polymer Blends consisting of two Separate phases

• Published in: Kobunshi Kagaku Vol. 27; no. 308; pp. 878 - 884
• Main Author: Murakami, Ryoichi
• Format: Journal Article
• Language: Japanese
• Published: The Society of Polymer Science, Japan 1970
• Subjects: Glasstransition Temperature; Polybutadiene; Polystyrene; Thermal Expansion Coefflcient; Thermal Stress
• ISSN: 0023-2556; 1884-8079
• DOI: 10.1295/koron1944.27.878

The glass transition temperature (Tg) of polystyrene in polystyrene (PS) -polybutadiene (PBD) blends consisting of two separate phases was found to shift to the higher temperature than that of pure polystyrene. The similar phenomenon was observed also in PS-styrene·butadiene rubber (SBR), PSacrylonitrile·butadiene rubber (NBR), PS-polyvinylacetate (PVAc), PS-vinylacetate-vinylchloride (VAc/VC) and PS-polyvinylcholoride (PVC) blend systems. The larger the difference between thermal expansion coefficient of suspended particles and thermal expansion coefficient of suspending medium (polystyrene), the larger the degree of rise of Tg of polystyrene. The rise of Tg of suspending medium in the blend systems mentioned above was observed in polymethylmethacrylate (PMMA) -SBR, PVC-SBR and styrene·acrylonitrile copolymer (St/AN, AN; 25%) -PBD blend systems. The rise of Tg of suspending medium in the blend systems mentioned above was observed in polymethylmethacrylate (PMMA) -SBR, PVC-SBR and styrene·acrylonitrile copolymer (St/AN, AN; 25%) PBD blend systems. The degree of rise of Tg of PS, PMMA, PVC and St/AN copolymer (AN; 25%) differed mutually. This rising phenomenon of Tg was qualitatively explained by the concept of thermal stress, that is, the rise of Tg of suspending medium was caused by the thermal stress due to the difference of both polymers and the degree of rise of Tg differed in compliance with the potentiality of relaxation of the thermal stress of suspending medium. However, several fundamental questions can not be explained by this concept.