STUDY OF POLYMER-PLASTICIZER INTERACTION BY C-13 CP MAS NMR-SPECTROSCOPY - POLY(VINYL CHLORIDE)-BIS(2-ETHYLHEXYL) PHTHALATE SYSTEM/

Solid state C-13 CP/MAS studies of poly(vinyl chloride) (PVC)-bis(2-et hylhexyl) phthalate (DOP) have been carried out to elucidate the dynam ics of polymer-plasticizer interaction at the molecular level. C-13 NM R spectra, spin-lattice relaxation time T-1(C) and spin-spin relaxatio n time T-2(C) were obtained for various PVC-DOP samples. Line widths o f >CH-Cl show a sharp increase due to the strong hydrogen-bonding inte raction between the >C=O (ester) group of DOP and >CHCl of PVC with va rious concentrations of DOP. The spin-lattice relaxation time T-1(C) a lso confirms the presence of a strong interaction due to hydrogen bond ing. The less mobile intermediate phase is mostly affected by the pres ence of plasticizer The spin-spin relaxation time T-2(C) shows that DO P,is a mixed type plasticizer showing the features of both molecular a nd structural type plasticization.