4-甲基苯酚低聚物对聚丙烯热氧稳定性的影响

Influences of p-Cresol Oligomer on Thermal Oxidation Stability of Polypropylene

采用酶催化聚合反应制备了含有受阻酚结构的4-甲基苯酚低聚物,利用热失重、差示扫描量热分析、热老化等方法研究了该低聚物对聚丙烯热氧稳定性的影响。结果表明,与纯聚丙烯相比,4-甲基苯酚低聚物(0.5%)/聚丙烯复合物的起始氧化温度提高了32℃,氧化诱导时间提高了27min。4-甲基苯酚低聚物/聚丙烯复合物具有良好的长期耐热氧稳定性,在140℃的空气氛围中老化240h,拉伸强度没有明显下降。利用Flynn-Wall-Ozawa法研究了聚丙烯和4-甲基苯酚低聚物/聚丙烯复合物的热分解动力学,结果表明,加入4-甲基苯酚低聚物可提高聚丙烯的热分解表观活化能。

Sterically hindered p-cresol oligomer was prepared by enzymatic polymerization m aqueous mmene system. Influences of p-cresol oligomer on thermaloxidation stability of polypropylene were investigated by TG, DSC and thermal aging test. In contrast with virgin PP, the initial oxidation temperature of PP stabilized with p-cresol oligomer increases by 32℃ and oxidation induction time increases by 27 min. Blend of p-cresol oligomerAPP shows good long-term thermal oxidation stability and hardly any decrease in the tensile strength is observed even after thermal aging at 140 ℃ under air atmosphere for 240 h. Investigations of thermal decomposition kinetics of PP and p-cresol oligomer/PP was performed by Flynn-WaU-Ozawa method. Result shows that the apparent activation energy of thermal degradation of PP is enhanced after blending with p-cresol oligomer.