Thermal Stability of Polydivinylbenzene and of Copolymers of Styrene With Divinylbenzene and With Trivinylbenzene

Samples of polydivinylbenzene (PDVB) and of copolymers of styrene with divinylbenzene (DVB) and with trivinylbenzene (TVB) were pyrolyzed in a vacuum in the temperature range of 346 to 450 °C. The volatile products were collected in two fractions: A heavy fraction volatile at the temperature of pyrolysis and a light fraction volatile at room temperature. Mass spectrometer analysis of the light fraction showed that for the copolymer containing 2 percent DVB the yield of styrene monomer is somewhat greater than for the pure polystyrene. On pyrolysis, of copolymers containing 25 percent of DVB or of TVB yield reduced amounts of styrene monomer; those containing about 50 percent of DVB do not yield any styrene monomer. Rates of thermal degradation of PDVB and of the copolymers were studied in the temperature range of 330 to 390 °C; the activation energies calculated on the basis of these rates were 53, 54, 58, 58, 61, and 65 kcal/mole for the copolymers containing 2 percent DVB, 25 percent DVB, 48 percent DVB, 56 percent DVB, 25 percent TVB, and for PDVB, respectively.