INHIBITION OF DETERIORATION OF PLASTICS BY HYDROAROMATICS

Based on our previous works concluding that the addition of hydrogen-donating hydroaromatics is effective in inhibiting the deterioration of hydrocarbons, heavy hydroaromatics from petroleum (HHAP) that were produced by hydrogenating highly aromatic heavy oil containing partly hydrogenated condensed aromatic rings were examined by the addition to high-density polyethylene (PE), isotactic polypropylene (PP), and poly(vinyl chloride) (PVC, MW: 1300) after confirming its prominent hydrogen-donating ability. The following results were obtained by the deterioration tests and melt-flow tests: (1) Clear inhibiting effects could be found on preservation of elongation and tensile tests: (1) Clear inhibiting effects could be found on preservation of elongation and tensile strength by the addition of 0.1% and 0.5% of HHAP to PE. (2) Cross-linking of PE was restricted by the addition of HHAP. (3) Obvious effects could be found on preservation of elongation and tensile strength by the addition of 0.5% of HHAP to PP, but 0.1% of HHAP was not so effective. (4) Melt-flow rate of PP at 270-degrees-C supported the results of the deterioration tests at 120-degrees-C. (5) Color changes were remarkably improved by the addition of HHAP to PVC (at 160-degrees-C, 140 min). From these results, hydrogen donation from hydroaromatics can be considered effective in inhibiting the deterioration of PE, PP, and PVC.