Radical-addition-fragmentation and co-polymerization of methyl methacrylate macromonomers from catalytic chain transfer polymerization (CCTP)

Catalytic chain transfer polymerization (CCTP) of methacrylates is an efficient method to produce low molecular weight poly(methacrylates). The mechanism is such that the products each have a terminal vinyl group which is then available for subsequent further reaction. This study involves the use of matrix assisted laser/desorption ionization time-of-flight mass spectrometry (MALDI TOF MS) to investigate the effect of the addition of methyl methacrylate macromonomers as prepared by CCTP to the polymerization of perdeutero-methyl methacrylate and n-butyl methacrylate in the presence and absence of catalytic chain transfer agent. The experiments have demonstrated that methyl methacrylate dimer as prepared by CCTP may copolymerize with deutero-methyl methacrylate. Addition fragmentation is demonstrated to dominate over CCT, contrary to that predicted from a consideration of C-s values. No evidence for copolymerization with butyl methacrylate has been observed. Inevitably this will result in small amounts of branching during CCTP taken to high conversion. (C) 1997 Elsevier Science Ltd