Materials Research Express (Jan 2022)

Dehydrochlorination study of plasticized poly(vinyl chloride) contianing modified titanium dioxide, cerium stearate, organotin and β-diketone complex after long-term storage

  • Long-juan Ma,
  • Yi-heng Lu,
  • Yan Chen,
  • Yu-wei Lu,
  • Gang Yuan

DOI
https://doi.org/10.1088/2053-1591/ac4f87
Journal volume & issue
Vol. 9, no. 2
p. 025305

Abstract

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Understanding the influence of additives on the dehydrochlorination of plasticized poly(vinyl chloride) (PVC) from the source and long-term storage is an attractive topic. In this work, the effects of folic acid modified nano titanium dioxide (FANT), cerium stearate, organotin and β -diketone compound additives on the dehydrochlorination of plasticized PVC and long-term storage were investigated using conductivity measurements. The results showed that the induction time of hydrogen chloride removal of plasticized PVC (C-1) containing composite stabilizer at 200 °C were 243% higher than those of the control (S1). After storage, the heat stability of the control decreased significantly. Instead, the induction time and stability time of plasticized PVC containing FANT, cerium stearate, organotin and β - diketone composites were significantly enhanced at 200 °C. The thermal stability sequence from difficult to easy for removal of hydrogen chloride was : 3.0 phr (1.90% wt) (C2) >1.0 phr (0.64% wt) (C1) > 5.0 phr (3.17% wt) (C3) with FANT. It is inferred that this is due to the FANT’s hydrogen bonding van der Waals force and the complexation reaction of variable valence metal Ce ^+3 /Ce ^+4 with C-Cl bond in PVC polymer molecule. The induction time (min) of hydrogen chloride removal at 200 °C before and after storage is as follows: C-20 (71.9) > C-10 (70.6) > C-1 (60.7) > C-3 (57.2) > C-30 (52.7) > C-2 (49.9) > S1 (25.3) > S10 (19.7). The critical temperature for hydrogen chloride removal by the composite film is around 210 °C. If the content of FANT increased to 3.17%, the intermolecular force and repulsive force in PVC system offset each other, indicating that the increase of FANT content will lead to the increase of repulsive force with PVC. A certain amount of FANT, cerium stearate, organotin and β - diketone composites has a significant synergistic effect on the thermal stability of PVC.

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