Study of polymer-plasticizer interaction by <SUP>13</SUP>C CP/MAS NMR spectroscopy: poly(vinyl chloride)-bis (2-ethylhexyl) phthalate system

Solid state 13C CP/MAS studies of poly(vinyl chloride) (PVC)-bis(2-ethylhexyl) phthalate (DOP) have been carried out to elucidate the dynamics of polymer-plasticizer interaction at the molecular level. 13C NMR spectra, spin-lattice relaxation time T1(C) and spin-spin relaxation time T2(C) were obtained for various PVC-DOP samples. Line widths of &gt;CH - Cl show a sharp increase due to the strong hydrogen-bonding interaction between the &gt;C = O (ester) group of DOP and &gt;CHCl of PVC with various concentrations of DOP. The spin-lattice relaxation time T1(C) also confirms the presence of a strong interaction due to hydrogen bonding. The less mobile intermediate phase is mostly affected by the presence of plasticizer. The spin-spin relaxation time T2(C) shows that DOP is a mixed type plasticizer showing the features of both molecular and structural type plasticization