Cationic Polymerization of Styrene Dimer and Styrene Trimer as Thermal Degradation Products of Polystyrene

Cationic polymerizations of a styrene dimer (SD), 2,4-diphenyl-1-butene, and a styrene trimer (ST), 2,4,6-triphenyl-1-hexene, as thermal degradation products of polystyrene were carried out with the HCl/SnCl(4)- or CH(3)CH(C(6)H(5))Cl/SnCl(4)-initiatitig systems. The polymerizations reached 100% monomer conversion and the number-average molecular weights (M(n)) of the products were about 400-600. The structure of the products, was analyzed by GC-MS, FAB-MS, and (13)C NMR spectroscopy. These spectroscopic results showed that the main products from SD and ST were linear olefinic dimers and trimers of SD and linear olefinic dimers of ST, respectively. The formation of these oligomeric products comes from the frequent occurronce of chain-transfer reactions via beta-proton elimination. The glass transition temperatures (T(g)) of these oligomeric products were different depending on their structures (T(g): dimer of SD, -16 degrees C; trimer of SD, 30 degrees C; dimer of ST, -4 degrees C). Cationic copolymerization of SD with styrene produced low-molecular-weight-copolymers of SD and Styrene with M(n)-similar to 1000.