Synthesis, structural characterization, thermal studies and chain dynamicsof poly (methacrylonitrile peroxide) by NMR spectroscopy

Poly(methacrylonitrile peroxide) (PMNP) has been synthesized from methacryl onitrile by free radical initiated oxidative polymerization and characteriz ed by different spectroscopic methods. NMR spectroscopy confirmed the alter nating copolymer structure with labile peroxy bonds in the main chain. The extreme instability of PMNP was noted from FTIR spectroscopy. Thermal degra dation studies by using differential scanning calorimetry and thermogravime try have revealed that PMNP degrades highly exothermically and the heat of degradation, 42.5 kcal mol(-1), is of the same order as that reported for o ther vinyl polyperoxides. Mass spectral fragmentation pattern under electro n impact (EI) condition has also been investigated. The mechanism of the pr imary exothermic degradation has been substantiated by thermochemical calcu lations. The chain dynamics of the polyperoxide chain has been studied by m eans of C-13 spin-lattice relaxation times (T-1) of the main chain as well as the side chain carbons. The temperature dependence of the spin-lattice r elaxation times shows that the PMNP is more flexible compared to the analog ous poly(styrene peroxide). (C) 2001 Elsevier Science Ltd. All rights reser ved.