预辐射聚丙烯反应挤出接枝丙烯酸的研究

利用电子束(EB)预辐照方法和反应挤出技术制备了聚丙烯接枝丙烯酸共聚物PP-g-AA. 采用化学滴定、红外光谱、偏光显微镜(PLM)、DSC和广角X射线衍射(WAXD)对接枝产物进行了表征. 研究结果表明, 接枝率随辐照剂量增加而增大并逐渐达到平台值, 但随单体浓度增大而表现为线性增加, 接枝链能起到异相成核作用, 从而提高了结晶速率并细化了球晶. 同时, 熔体流动速率(MFR)和力学性能测试结果表明, 预辐射和挤出过程造成了PP严重降解, 据此可认为接枝反应主要发生在聚丙烯断裂分子链的末端.

Grafting Acrylic Acid onto Pre-irradiated Polypropylene by Reactive Extrusion

Polypropylene functionalized with acrylic acid(PP-g-AA)was prepared by coupling electron beam(EB)pre-irradiation treatment with reactive extrusion process.The grafting samples were characterized by chemical titration,FTIR,polarized light microphotographs,DSC and WAXD.The study showed that grafting degree(Gd)increased with increasing irradiation dose and then leveled off;the Gd increased linearly with the AA concentration rising.It was observed that crystallization temperature of the grafted sample increased and crystallite size decreased,which can be attributed to the heterogeneous nucleating action of grafting chain.The MFR and mechanical properties measurements proved that serious degradation of PP occured in the stage of pre-irradiation and extruding process.Meanwhile,a mechanism of grafting reactions was proposed tentatively.