High-resolution carbon nuclear magnetic resonance study of styrene/alpha-methylstyrene/acrylonitrile terpolymers

摘要

Terpolymers formed from styrene, a-methylstyrene (AMS), and acrylonitrile (AN) were prepared in different proportions. According to the reaction conditions, the terpolymers presented random sequence distributions. AMS, because of steric hindrance, presented a high degree of instability, which promoted depolymerization. AN promoted a long insertion of AMS monomers, which caused an acceleration of the propagation reaction. This also caused a depolymerization process. With C-13-NMR solution analysis, it was possible to detect the depolymerization process. With solid-state NMR results, it was demonstrated that AMS constituted the highest mobility domain. Finally, the values determined for the proton spin-lattice relaxation time in the rotating frame confirmed that the prepared terpolymers were random, but a homogeneous monomer distribution sequence was also observed from this parameter. (C) 2003 Wiley Periodicals, Inc. [References: 11]