THERMAL-DEGRADATION OF POLY(TERTBUTYL AZIRIDINE) POLY(METHYL METHACRYLATE) GRAFT COPOLYMER

The degradation behaviour of a high molecular weight PMMA sample in wh ich approximately 2% of the MMA units have been modified and grafted w ith PTBA chains of molecular weight 5000, to give a product containing about 50% by weight of PTBA, has been investigated. The techniques us ed were the same as in recently reported investigations of PTBA, PTBA- PMMA block copolymer and poly(N-methyl-N-tertbutyl-aminoethyl methacry late) (PMTBAEM), and included TG, DTA and thermal volatilisation analy sis (TVA). Products from the TVA experiments were separated and charac terised. The graft copolymer is less stable than PMMA and comparable i n stability to PTBA. It appears that the grafted side chains degrade p rimarily to PTBA-related oligomeric material, accompanied by a small p roportion of volatile products also derived from the PTBA chains, wher eas the main backbone gives predominantly MMA monomer. (C) 1997 Elsevi er Science Limited.