Preparation and characterisation of aggregating comblike poly(propylene oxide)

Poly(propylene oxide)s with a combine architecture were prepared by using a n ethylene-vinyl alcohol copolymer as a macroinitiator for anionic graft po lymerisation of propylene oxide. The densely grafted polymers were subseque ntly modified by capping the terminal hydroxyl groups with hexadecanoyl chl oride to produce aggregating polymers. Dilute solution viscometry showed th at the hydroxyl and hexadecanoyl content of the uncapped and capped polymer s, respectively, largely determined their state of aggregation in methanol and toluene. Thermal analysis of the uncapped polymers in the solid state s howed a decrease in glass transition temperature with increasing average mo lecular weight of the grafts. Analysis of the capped polymers revealed crys tallisation and melting of the hexadecanoyl chain ends in connection with t he glass transition of the poly(propylene oxide) phase. It is conceivable t hat in the solid state the comblike poly(propylene oxide) chains were inter connected by 'micellar-like' microdomains formed by the hexadecanoyl chain ends. (C) 2000 Elsevier Science Ltd. All rights resented.