Thermal stability of poly(vinyl bromide) and copolymers of vinyl bromide with methyl vinyl ketone

Thermal stability and degradation behaviour have been studied for PVB and VB-MVK copolymers spanning the whole composition range, using thermogravimetric analysis. The reactivity ratios in the radial copolymerization were determined by using an NMR technique, leading to r_i(VB) = 3.6 ± 0.2 and r₂(MVK) = 0.2 ± 0.1. The introduction of MVK units into the VB chain leads to an interaction with release of methyl bromide. The stability of the copolymers increases with increasing MVK concentration.