NMR Study on Tacticity of Polyvinyl Acetate Synthesized from Various Catalysts by Free Radical Polymerization

Polyvinyl acetate was synthesized by free radical polymerization using benzoyl peroxide (BPO) initiator in the presence of various catalysts (Zinc chloride, Tin chloride and Cobalt acetoacetonate)at 60ºC in bulk and solution. Stereosequences at pentad level of methine, hexad level of methylene, and triad level of carbonyl carbons in polyvinyl acetate were investigated by 13C NMR spectroscopy in deuterated chloroform (CDCl3) at room temperature. Bernoullian statistical analysis was applied on carbon atoms and compared with the result from the experimental statistical method. The Bernoullian results indicated the probability (Pm) and mean length (Nm) for meso addition for the catalyst: Co(acac)2 < ZnCl2 < SnCl2.The sensitivity of vicinal and geminal couplings of methine and methylene protons in the sequence distribution and composition was characterized using 2DTOCSY NMR method

Keywords:

Polyvinyl acetate , 1H-NMR , 13C-NMR , Bernoullian statistics , Co(acac)2 , ZnCl2