Synthesis and Ring-Opening Metathesis Polymerization of Norbornene-Terminated Syndiotactic Polypropylene

Using nonliving bis(phenoxyimine)titanium catalysts activated by methylaluminoxane (MAO) in the presence of propylene, allyl-terminated syndiotactic polypropylene macromonomers with varying tacticity ([rrrr] = 0.80 and 0.94) and molecular weight (M-n = 3600 and 5600 g/mol) were produced. The end-functionalized polymers were converted to hydroxyl- and subsequently norbornene-terminated macromonomers. Two series of syndiotactic polypropylene comb-polymers were synthesized through metathesis polymerization of the norbornene-functionalized polypropylene. The molecular weight (M-n = 46 000-172 000 g/mol) and polydispersity (M-w/M-n = 1.21-1.89) of the comb polymers was determined by gel permeation chromatography (GPC). Using differential scanning calorimetry (DSC), melting temperature (T-m) and crystallization temperature (T-c) were determined and both were observed to decrease with increasing conversion to poly(macromonomer). To the best of our knowledge, this is the first synthesis of comb-polymers from end-functionalized syndiotactic polypropylene.