Analysis of the β-methylene carbon-13 NMR chemical shifts: from vinylidene chloride copolymers to a general analysis of polymers

Analysis of the carbon-13 NMR chemical shifts of β-methylene of vinylidene chloride copolymers has been done. The analysis, based on the empirical additivity rules, proposes chemical shift additive parameters for the monomer units in vinylidene chloride copolymers. Genetic algorithm has been applied for the optimization of additive parameters. To simplify and generalize the analysis, common functional groups present in the pendant groups; Cl, COOCH3, CH3, OCOCH3, CN, CONH2, C6H5 and COOH substituents were modeled and their additive effects were optimized. The additive parameters enabled to predict the carbon-13 NMR chemical shifts of β-methylene of homopolymers and copolymers at tetrad level of compositional sensitivity.