INFLUENCE OF SIDE-CHAIN BEARING UNITS ON THE PHASE-BEHAVIOR OF A SERIES OF COPOLY(ESTER ETHER)S

Appending a short flexible side-chain to a semiflexible poly(ester eth er) results in substantial changes to the phase behaviour; in particul ar, where comparisons are possible, there is a considerable reduction in the phase transition temperature for the side-chain-bearing system compared to the unsubstituted polymer. A further difference was seen i n the tendency for liquid crystal phase formation; side-chain containi ng systems exhibit liquid crystalline behaviour over a relatively broa d temperature range. This may be, at least in part, related to the dif fering tendencies of the two systems towards crystallization. A non-si de-chain substituted polymer is, albeit partly, crystalline at room te mperature; in contrast, the side-chain substituted polymer is mainly a morphous. On varying the side-chain concentration in the copolymer, a systematic change in phase behaviour is revealed. The effect of copoly merization on the phase transition temperature is discussed and a comp arison with similar copolymers without side-chains reveals the importa nce of geometric over statistical constraints on the formation of the solid phase.