Thermal analysis of polystyrenes crosslinked by p‐di(chloromethyl)benzene

Series of progressively crosslinked polystyrene have been prepared by the reaction off linear polystyrene with p‐di(chloromethyl)benzene in dichloroethylene solution with stannic chloride as catalyst. By using a DTA technique it has been shown that the glass transition temperature Tg increases with crosslinking very much faster than is accounted for purely by increase in molecular weight. This type of crosslink is only about half as effective in increasing Tg as are crosslinks introduced by copolymerization of styrene with divinylbenzene. Thermal analysis by use of the thermal volatilization analysis (TVA) technique shows that stability, as measured by the evolution of volatile products, decreases as crosslinking progresses, and thermal gravimetric analysis (TGA) confirms this.