新型膨胀阻燃聚丙烯的热分解动力学研究

Thermal Degradation Kinetics of Novel Intumescent Flame Retardant Polypropylene

通过极限氧指数法(LOI)和锥形量热仪(Cone)考察了膨胀阻燃聚丙烯体系(PP/IFR)的阻燃性能;利用热重分析法(TG)研究了聚丙烯(PP)及PP/IFR体系在不同升温速率下的热稳定性及热分解动力学,采用Kissinger及Flynn-Wall-Ozawa方法分析PP和PP/IFR的热分解表观活化能;利用Coats-Redfern方法确定了PP和PP/IFR热分解动力学机理及其模型,得出了聚合物主降解阶段的非等温动力学方程,结果表明,IFR的添加提高了聚丙烯的阻燃性能,添加30%IFR的聚丙烯复合材料,极限氧指数达到27.5%,热释放速率平均值相对未阻燃聚丙烯降低31.2%,PP和PP/IFR热分解反应机理函数为g(α)=-ln(1-α),反应级数n=1,其热分解机理均属于随机成核和随后增长反应。

Thermal stability and thermal degradation kinetics of polypropylene （PP） and flame retardant polypropylene （PP/IFR） were investigated by a conventional dynamic thermogravimetric analysis （TG） under highly purity N2 atmosphere at different heating rates between 5 and 35 ℃/min^-1. The flame retardant properties of PP and PP/IFR were studied by limiting oxygen index （LOI） and Cone method. The thermal degradation activation energies of PP and PP/IFR were determined using Kissinger and Flynn-Wall-Ozawa methods. The thermal degradation kinetic mechanism and the isothermal kinetic equations of PP and PP/IFR were determined by Coast- Redfern method. When the content of IFR in PP was 30 wt%, the limited oxygen index value reached 27.5 % and the av-HRR was 31. 2 % lower than neat PP. The kinetic equation can be expressed as g（a）=-ln（1=a）, and the reaction order was n=1, and the thermal decomposition mechanism of PP and PP/IFR was random nucleation reaction.