Direct pyrolysis mass spectrometry of acrylonitrile-cellulose graft copolymer prepared by radiation-induced graft polymerization in presence of styrene as homopolymer suppressor

Graft polymerization of acrylonitrile onto cellulosic filter paper competin g with the homopolymerization by mutual irradiation technique was studied i n the presence of homopolymer suppressors. Addition of FeCl3 decreased both homopolymerization and graft polymerization, whereas inclusion of a low ra tio of styrene monomer with acrylonitrile leads to successful grafting of a crylonitrile with little homopolymer formation. Chemical structure and ther mal behavior of the produced graft copolymers were investigated by gradual healing in the solid probe of a mass spectrometer equipped with a GCMS data system. The resulting total ion current (TIC) showed that the degradation of graft copolymers follows two-step pyrolysis. The presence of a low ratio of styrene comonomer increased thermal stability of the prepared acrylonit rile-cellulose graft copolymer, The pyrolysis products have mass spectra ch aracteristic of the copolymer composition; they contain the repeating unit of the oligomers. Total ion current and spectrum subtractions were used to separate and measure spectra of graft copolymers at distinctly different te mperatures. (C) 2001 Elsevier Science Ltd. All rights reserved.