MECHANISM OF ORGANOTIN STABILIZATION OF POLY(VINYL CHLORIDE). 6: COMPATIBILITY OF ORGANOTIN STABILIZERS WITH PVC

摘要

Compatibility of PVC with liquid alkyltin alkylthioglycolates stabilizers was studied by thermal methods including isothermal calorimetry of mixing, DSC, DMA, and dielectric relaxation. The enthalpy of mixing of PVC with the series of alkyltin alkyl thioglycolates was measured over the entire concentration range at ambient conditions. It was found that all compounds are compatible with PVC in a broad concentration range and form homogeneous mixtures. The results are discussed in terms of superposition of glassy-state and molecular interaction contributions to the enthalpy of mixing of glassy polymer with liquid additives. The influence of organotin stabilizers on the glassy structure of PVC films was studied by means of DSC and the dielectric relaxation spectrum. The alkyltin alkyl thioglycolates enhancement of the glassy structure of PVC is interpreted as the result of strong multi-site molecular complexes between organotin molecules and PVC chains, which act like additional clips in the entanglement network of polymer chains.