Microstructural Study on Polyvinyl Chloride by One and Two Dimensional Nuclear Magnetic Resonance Spectroscopy Methods

In this research, the tacticity and microstructure of polyvinyl chloride (PVC)were studied through back bone methylene and methine carbons and protonssplitting by carbon (13C NMR), proton (1H NMR) and two-dimensional (2DNMR) nulear magnetic resonance spectroscopy in deuterated tetrahydrofuran.Polyvinyl chloride was synthesized by emulsion polymerization of vinyl chloride(VCM) under pressure to about %90 conversion with %45 solid content at 60C. Theassignments of all stereosequences were done at tetrad and pentad levels of methyleneand methine carbons of the polyvinyl chloride respectively, using by 13C liquidNMR. Bernoullian and first-order Markov statistics models were calculated and theresults are compared with the experimental NMR results. It was shown thatBernoullian and first-order Markov statistics fit almost equal for the assigned methyleneand methine carbons and that the probability of meso addition (Pm) value inpolyvinyl chloride chains was calculated to be 0.447. 1H NMR of PVC was assignedvia heteronuclear multiple quantum coherence technique (HMQC) for methylene andmethine groups at triad sequence levels. Finally, by increasing the NMR acquisitiontemperature from 20 to 50oC higher resolution in methylene and methine carbonswere achieved. In this case, the atactic sequence peaks splitted more than isotacticand syndiotactic sequence peaks