Tensile properties, thermal stability, and the mechanism of PVC stabilized with zinc and calcium oxolinic complexes
ABSTRACT
Two novel thermal stabilizers, zinc and calcium oxolinic complexes (Zn(Oxo)2 and Ca(Oxo)2), with superior tensile properties and notable thermal stability effect for polyvinyl chloride (PVC) are reported here. The complexes are synthesized without any organic solvents, and the structures are confirmed as Zn(C13H10NO5)2·H2O and Ca(C13H10NO5)2·3H2O by Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray fluorescence spectrometry, and elemental analysis. The PVC samples stabilized with the complexes show superior tensile strength and elongation at break compared with zinc and calcium stearates by tensile test. The results of Congo red test, dehydrochlorination test, and discoloration test show that: (1) Zn(Oxo)2 is better than zinc stearate as thermal stabilizer for PVC; (2) Zn(Oxo)2 and Ca(Oxo)2 show notable synergistic effect with calcium stearate and zinc norfloxacin respectively. The mechanism of the superior tensile properties and notable thermal stability effect is due to the ability of the complexes to absorbing HCl and reacting with PVC chains, which result in the special chain extension of PVC and the delay of autocatalytic effect and zipper-like dehydrochlorination. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47004.
