过氧化物交联UHMWPE的动力学与结晶行为的研究

Study on kinetics and crystallization behavior of peroxide crosslinked UHMWPE

采用过氧化二异丙苯(DCP)交联改性超高相对分子质量聚乙烯(UHMWPE),通过差示扫描量热和广角X射线衍射测试,研究了DCP交联UHMWPE的反应动力学以及DCP含量对交联UHMWPE片材的热性能、结晶性能和晶粒尺寸的影响。结果表明:DCP与UHMWPE交联反应为放热反应,其非等温交联反应符合一级反应,反应活化能随着DCP含量的增加而降低;随着DCP含量的增加,交联UHMWPE片材的结晶度、重结晶度、熔点和结晶温度均降低,结晶峰强度和晶粒尺寸减小,当DCP质量分数为2. 5%时,交联UHMWPE片材(110)晶面和(200)晶面所对应的晶粒尺寸分别降低至18. 6 nm和12. 1 nm。

The ultra-high relative molecular mass polyethylene(UHMWPE)was modified by crosslinking with dicumyl peroxide(DCP).The crosslinking reaction kinetics of DCP and UHMWPE and the effects of DCP content on the thermal properties,crystallization properties and grain size of crosslinked UHMWPE sheet material were investigated by differential scanning calorimetry and wide-angle X-ray diffraction.The results showed that the crosslinking reaction between DCP and UHMWPE belonged to exothermic reaction,the non-isothermal crosslinking reaction accorded with first-order reaction,and the reaction activation energy was decreased with the increase of DCP content;the crystallinity,recrystallinity,melting point and crystallization temperature of the crosslinked UHMWPE sheet material were decreased and the crystalline peak intensity and the grain size were reduced with the increase of DCP content;the grain size corresponding to crystal faces(110)and(200)of the crosslinked UHMWPE sheet material dropped to 18.6 nm and 12.1 nm,respectively,when the mass fraction of DCP was 2.5%.