母料法制备LDPE/EVA/粘土纳米复合材料及其性能研究

Study on the Preparation of LDPE/EVA/Clay Nanocomposites by Masterbatch Method and Structure-Property Relationship

采用熔融插层工艺制备低密度聚乙烯(LDPE)/乙烯-醋酸乙烯酯共聚物(EVA)/粘土纳米复合材料,比较了母料法与一步共混法对粘土的分散状态和材料性能的影响。通过X射线衍射仪(XRD)和透射电镜(TEM)表征了粘土在基体中的分散状态。结果表明,母料法制备得到的纳米复合材料粘土片层已均匀剥离于基体中。呈剥离状的5%粘土更好地促进了材料燃烧过程中的成炭,形成的致密连续的炭层起到了很好地隔热隔氧效果,使材料的热释放速率峰值降低了54%。热失重分析表明,粘土的加入促进了体系成炭,提高了高温下的残炭量。母料法制备的LDPE/EVA/5%粘土纳米复合材料的弹性模量为324.98MPa,比LDPE/EVA基体增加了45.8%。

Polyethylene clay nanocomposites were prepared from melt intercalation process. Influence of two kinds of preparation methods including masterbateh and one-step process on the dispersion state and prop- erties of nanocomposites were compared. The dispersion state of the clay layers in matrix were evaluated u- sing X-ray diffraction and transmission electron microscopy. The results showed that masterbatch method is favorable to exfoliation of clay layer in LDPE/EVA matrix. The homogeneous dispersion of clay layer in polymer matrix promotes the char formation greatly. The resulting compact and continuous char layer sup- press the transfer of heat and oxygen effectively. The peak heat release rate （pHRR） of nanocomposites prepared by masterbatch method was decreased by 54% relative to LDPE/EVA matrix. Thermogravimetric analysis results indicate that clay can play a catalytic role on the promotion of char forming reactions and so increase the residual char. The elastic modulus of LDPE/EVA/5% Clay nano- eomDosite is 324. 98MPa, increased by 45.8% relative to LDPE/EVA matrix.