INVESTIGATION OF GAMMA-IRRADIATED SYNDIOTACTIC POLY(2-METHYLHEPTYL METHACRYLATE) USING NMR-SPECTROSCOPY

Syndiotactic poly(2-methylheptyl methacrylate) which was gamma-irradia ted at room temperature to a dose of 1600 kGy was investigated by NMR spectroscopy. The H-1 and C-13 resonances for the macromolecular chain were assigned by using the 2D and the DEFT (distortionless enhancemen t by polarization transfer) technique. The spin-echo modified 2D NMR p ulse sequence was used to investigate the small molecules and new stru ctures which were formed during gamma-irradiation. The radiation mecha nisms for cleavage of the side chain from the main chain and formation of double bonds from both the main chain and the side chain have been formulated based upon the NMR analysis.