Abstract
he polymerization of α-methylstyrene was studied in the absence of a separately added cationogen (i.e., initiator) and in the presence of a proton trap, using boron halides (BX 3 , X = Cl, Br, and I). The effect of the monomer and BX 3 concentration, solvent polarity, and temperature was examined. The polymerization rates increased with decreasing temperature and with increasing solvent polarity. The molecular weight (M n ) of the products also increased with decreasing temperature; however it was relatively independent of solvent polarity. Under identical conditions the M n 's were highest with BCl 3 , lower with BBr 3 , and lowest with BI 3 . Kinetic experiments support that initiation is by haloboration, but direct proof was only obtained for BI 3 . For polymers made with BI 3 the presence of one boron per chain was confirmed by elemental analysis, while the high M n 's obtained with BCl 3 and BBr 3 prevented quantitative analysis of head and end groups.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
