Preparation and characterisation of aggregating comblike poly(propylene oxide)

Poly(propylene oxide)s with a combine architecture were prepared by using an ethylene-vinyl alcohol copolymer as a macroinitiator for anionic graft polymerisation of propylene oxide. The densely grafted polymers were subsequently modified by capping the terminal hydroxyl groups with hexadecanoyl chloride to produce aggregating polymers. Dilute solution viscometry showed that the hydroxyl and hexadecanoyl content of the uncapped and capped polymers, respectively, largely determined their state of aggregation in methanol and toluene. Thermal analysis of the uncapped polymers in the solid state showed a decrease in glass transition temperature with increasing average molecular weight of the grafts. Analysis of the capped polymers revealed crystallisation and melting of the hexadecanoyl chain ends in connection with the glass transition of the poly(propylene oxide) phase. It is conceivable that in the solid state the comblike poly(propylene oxide) chains were interconnected by 'micellar-like' microdomains formed by the hexadecanoyl chain ends. (C) 2000 Elsevier Science Ltd. All rights resented.