过氧化二异丙苯(DCP)交联聚乙烯的非等温结晶动力学研究

采用扩散的方法,在低于PE熔点的温度下,使过氧化二异丙苯(DCP)均匀扩散进入PE切片内部,并在180°C交联0.5 h得到交联PE。通过DSC测试对其结晶行为及其非等温结晶动力学进行了研究,研究表明,DCP交联对PE的结晶行为影响较大,与纯PE相比,在DCP用量较低时,交联PE的结晶峰向低温方向移动,结晶温度随着DCP用量的增加而降低,但继续增加DCP的用量,结晶温度反而会增加;纯PE及交联PE的结晶温度Avrami指数n介于3.2~4.2之间,DCP用量较低时,随着DCP含量的增加而增加,n呈增长趋势,继续增加DCP含量,n反而降低,交联PE的结晶速率常数Zc与n呈相同变化趋势。

Non-isothermal Crystallization Kinetics of Dicumyl Peroxide (DCP)Cross-linked Polyethylenes

Dicumyl peroxide(DCP)was blended and diffused into polyethylene(PE)at the temperature below the melting point of PE.The cross-linking reaction was carried out at 180℃ for 0.5 h.The nonisothermal crystallization kinetics of dicumyl peroxide(DCP)modified PE was studied by differential scanning calorimetry.The values of Avrami index(n)was between 3.2 and 4.2 which characterized the coexistence of homogeneous nucleation and heterogeneous nucleation during the crystallization process in this system.When the dosage of DCP was lower than a certain value.with the increase of DCP content the crystallization temperature(Tc)was lowered while n became larger.When the dosage of DCP was more than that,Tc was higher and n was smaller.The trend of Zc was the same as that of the value n.