Antioxidation and mechanism of phosphites including the free phenolic hydroxyl group in polypropylene

作者：Meng, Xin; Jiang, Zewen; Xin, Zhong^*; Chen, Weijie; Sheng, Yan; Wu, Chushi

来源：Journal of Applied Polymer Science, 2017, 134(15): 44696.

DOI：10.1002/app.44696

• degradation
• polyolefins
• structure-property relationships

Inhibiting the degradation of polypropylene (PP) in melt processing and usage is an important issue in the plastic industry. It is becoming more and more urgent to increase the antioxidation of phosphites alone while maintaining the water resistance. In this study, one phosphite antioxidant, named bis-2,2'-methyl-4,6-di-tert-butylphenyl phosphite (BM46TBPP), which contains a water-resistant inner ring and a free phenolic hydroxyl group together, was synthesized. Then, antioxidation in PP was characterized with multiple extrusions and oxidation induction times (OITs). Finally, the hydrogen-donating ability of this antioxidant was tested with 2,2-diphenyl-1-picrylhydrazyl radical colorimetry to explain the antioxidation mechanism. The results show that the phosphite BM46TBPP displays better antioxidation than tris(2,4-di-tert-butylphenyl) phosphite (Irgafos 168) in melt processing and OIT testing. Furthermore, the priority of this antioxidant was more obvious when it was used in the presence of oxygen, so the antioxidant even made the PP stabilized by it alone show a longer OIT value than the PP stabilized by the complex system including Irgafos 168 and 2,4-di-tert-butylphenol because there was a free phenolic hydroxyl group in the BM46TBPP antioxidant molecule and the hydroxyl group made the antioxidant show intermolecular synergistic antioxidation through hydrogen donation to radicals.

• 出版日期2017-4-15
• 单位华东理工大学