Two series of poly(a-methyl styrene), PaMS, based copolymers have been synthesized. In the PaMS (I) series the phenyl ring in the a-methyl styrene unit has been modified to varying degrees by the introduction of a methyl carbinol unit, whereas the trifluoro methyl carbinol unit has been used in the PaMS (II) series. These groups are potential hydrogen bond donor sites of differing acidic strength. It has been found that the introduction of these specific interaction sites allows the formation of one-phase blends with polymers containing an acceptor site, with which unmodified poly(a-methyl styrene) is immiscible. When these acceptor polymers are poly(alkyl acrylate)s and poly(alkyl methacrylate)s then one-phase blends are obtained with the methyl, ethyl and t-butyl derivatives. The range of one-phase blends can be extended to include the n-propyl derivatives if the modified PaMS are mixed with poly(di-alkyl itaconate)s. Glass transition temperatures, Tg and lower cloud point (LCP) temperatures have been recorded for all the one-phase blends. The Tg values are usually higher than predicted by the simple rule of mixtures and all blends then phase separate on raising the temperature well above Tg. These observations, and the differences in phase equilibrium behaviour exhibited amongst the various blends, are discussed in relation to steric restrictions to hydrogen bond formation, and the effect of both the number and strength of the hydrogen bonds formed on the phase stability of the blends. © 1993.
|Number of pages||9|
|Journal||European Polymer Journal|
|Publication status||Published - Feb 1993|