FIELD: polymer materials. SUBSTANCE: invention, in particular, relates to binding monovinylydene aromatic polymer resins for applying them in the form of polymers and foams in articles as sound absorbers and heat insulation. Process consists in mixing vinylaromatic polymer with binding amount of at least one poly(sulfonyl azide), passing mixture into melting apparatus, melting vinylaromatic polymer or mixture and keeping mixture at melting temperature without thermal decomposition of vinylaromatic polymer. EFFECT: enabled binding of vinylaromatic polymers to form higher-molecular weight polymers with improved properties of their melt and expansion properties of foam based on these polymers. 10 cl, 4 tbl, 22 ex _
