LLDPE/粉煤灰复合材料非等温结晶动力学研究

Nonisothermal Crystallization Kinetics of LLDPE/Fly Ash Blend

利用差示扫描量热法(DSC)结合Avrami方程研究了线性低密度聚乙烯(LLDPE)、LLDPE/Fly Ash(粉煤灰)的非等温结晶动力学。通过Jeziorny法、Ozawa法和莫志深法分别对非等温结晶过程进行处理,采用Kissinger法和Takhor法得到迁移活化能。结果显示,粉煤灰粉体的加入阻碍了LLDPE分子链的规则排列,影响了链段的结晶扩散迁移规整排列,使LLDPE的结晶速率变慢,对LLDPE晶体生长起了抑制作用。由Ozawa法分析实验数据,得到的线性关系很差,因此也很难得到可靠的动力学参数。在所有结晶速率下,样品的Avrami指数n值在1.42～2.09之间变化,说明粉煤灰的加入对LLDPE的成核与生长方式的影响有限。用莫志深法得出的结论与Jeziorny法一致,b值在0.76～1.13之间变化。

The nonisothermal crystallization behavior and kinetics of linear low-density polyethylene （LL DPE）, LLDPE/fly ash were studied with differential scanning calorimentry combined with the Avrami equa- tion. The methods of Jeziorny, Ozawa and Mo Zhi shen for nonisothermal crystallization kinetics were used to analyze the crystallization characteristics. The activation energies have been evaluated by Kissinger and Takhor method, the results demonstrate that due to partial destruction of crystal region, the crystallization rate of LL- DPE decreases with adding fly ash. The Ozawa method is also limited in obtaining the reliable kinetic parame- ters because of the substantial curvatures in the Ozawa plots. The fact that all samples had Avrami exponents in a range limited. of I. 42 - 2. 09 implies the nucleation mechanism and geometry of crystal growth of LLDPE is affected The conclusion of Mo＇s is same as that of Jeziorny＇s, the value of b changes from O. 98 to 1.55.