THERMAL-CONVERSIONS OF COPOLYMERS OF ACRY LONITRILE WITH ACRYLIC-ACID- ROLE OF CARBOXY GROUPS

Thermal conversions occurring in polyacrylonitrile and copolymers cont aining acrylic acid were compared using LR spectroscopy, The presence of carboxy groups induces the hydrolysis of nitrile groups, which occu rs concurrently with cyclization, so that the rate of cyclization in t he copolymers is smaller than in homopolymer. Above the glass transiti on temperature, the carboxy groups assoiate in clusters, which become more compact as the temperature increases.