聚丙烯/尼龙6复合超微粉改性天然橡胶热氧老化降解动力学

Study on Thermal Oxidative Degradation Kinetics of the Blend of PA6-PP Ultra Fine Co-Powder and Natural Rubber

采用磨盘型力化学反应器制备了平均粒径为1.04 µm的PA6/PP塑料复合超微粉,将其与NR共混,制备PA6/PP/NR共混物,用TG/DTG研究共混物热氧降解动力学。结果表明,共混物的降解曲线出现失重台阶,降解反应级数n为1.8。随升温速率β增大,相应的降解温度和降解速率升高,但最大降解率CP和最终降解率Cf基本不受β的影响。与纯NR相比,共混物初始降解温度T0、表观活化能E0有所降低,但最大降解温度Tp与最终降解温度Tf 均明显提高。PA6/PP超微粉对橡胶硫化网络的形成和热氧降解自由基反应产生影响,综合结果使共混物耐热性能提高。

PA6-PP ultra fine co-powder was prepared by pan-milling method and the co-powder was blended with natural rubber latex through ultra sonic treating. The thermal oxidative degradation kinetics of the blend was studied in air atmosphere by thermo-gravimetric analysis(TG/TGA). The results show that,the thermal degradation reaction of the blend in air atmosphere is a two-stage reaction. The reaction order (n) of the thermo-oxidation reaction is 1.8. With the increment of the heating rate (β), the degradation temperature and degradation rate as well as the activation energy of reaction (E) increase linearly, but the maximum weight loss rate (CP)and the final weight loss rate (Cf) are not affected by β. Compared to pure NR, the initial degra-dation temperature (T0) and the apparent activation energy (E0) is lower but the maximum weight loss tem-perature (Tp) and final weight loss temperature (Tf) is higher. The vulcanization net and the thermo-oxidative radical reaction of the rubber are affected by the PA6-PP ultra fine co-powder added and the anti ther-mo-oxidative degradation property of the blend is improved.