Pyrolytical Sifting of Poly (styrene-co-methyl methacrylate) Blended with Stannic Chloride: An Investigation Engaging IR and Py-GC-MS Techniques

Abstract

Pyrolytic study of copolymer, i. e., P(S-co-MMA) blended with SnCl4 was performed using inert atmosphere. Five different proportions of polymer-additive blends (additive ratio from 2.5% to 12.5%) were formulated using a common solvent, i. e., acetone. Thermal degradations proceed with two-stage for neat copolymer and three-stage for blends and additive alike. Residue was observed only for additive. Thermoanalytical scrutiny of these blends reveals that copolymer is more stable than blends (when To = temperature at which first mass-loss is detected, is compared), however, blends appear more stable than copolymer on the basis of their Tmax (temperature at which maximum mass-loss is observed). Chlorobenzene, 1,2-dichlorobenzene, 1-chlorostyrene, α-methylstyrene, etc. were believed to be the  outcome of interaction between the copolymer and the additive. The arising of benzene, although one of the degradation products of the neat copolymer, was linked with the influence of additive on copolymer due to its increased amount. Chlorine (free radicals) initiated the early degradation of the copolymer (after being generated by the decomposition of the additive) and also appeared as a ‘pendent element’ to the compounds consisting of few carbon units (short chain entities). In the whole study, the degradation of styrene units does not end in oligomers. The effectiveness of additive regarding flame retardance furnished a linear trend as HBR (horizontal burning rate) which indicated that higher the concentration of additive in the blend, lower was the burning rate and this also confirmed the homogeneous spread of additive in the neat copolymer.