高组分纳米碳酸钙填充聚丙烯及增韧机理  

Toughening Mechanism of Polypropylene with High Components of Nano-Calcium Carbonate

作　　者：石璞[1] 陈浪[1] 钟苗苗[1] 刘跃军[1] 

机构地区：[1]湖南工业大学包装新材料与技术重点实验室,湖南株洲412007

出　　处：《高分子材料科学与工程》2015年第10期69-74,共6页Polymer Materials Science & Engineering

基　　金：国家自然科学基金资助项目(11372108);湖南省自然科学基金资助项目(14JJ5021);湖南省高校创新平台开放基金资助项目(14K032;13K098);湖南省研究生科研创新项目(CX2015B561)

摘　　要：采用工业级的纳米碳酸钙（nano-CaCO3）,通过双螺杆挤出机制备了一系列nano-CaCO3填充的聚丙烯（PP）复合材料。力学性能实验表明,高组分nano-CaCO3填充PP复合材料的拉伸强度略有下降,而弯曲模量有较大提高;nano-CaCO3在低组分时对PP没有明显的增韧效果,但在20~40phr时对PP都有较好的增韧效果。当填充40phr时,其CHARPY冲击强度达到17.0kJ/m2。通过偏光显微镜（POM）、差示扫描量热仪（DSC）、X射线衍射仪（XRD）、扫描电子显微镜（SEM）等研究了高含量nano-CaCO3对复合材料结晶的影响。POM观察表明nano-CaCO3使PP的球晶尺寸变小;DSC和XRD研究表明复合材料从单纯的α晶型向α和β晶型共同存在转变,并且结晶峰温升高了约7.0℃（8#样）,结晶度增加到62.7%;SEM观察表明PP/高组分nano-CaCO3复合材料内仅有少量的银纹-剪切带和刚性粒子脱粘。但有大量120~300nm的孔洞,估计原因是较蓬松的纳米碳酸钙粒子之间含有大量的微小气体,在加工剪切后保留于复合材料内,形成一种带亚微米级孔洞的复合材料。这些孔洞最有可能是导致材料韧性大幅度上升的主要原因。PP/nano-calcium carbonate（nano-CaCO3）composites filled with industrial nano-CaCO3 were prepared by a twin-screw extruder at filler loadings of a series of copies.The mechanical properties,thermal behaviors and morphology structure of PP/nano-CaCO3 composites were investigated to explore toughening mechanism.The mechanical tests results show that the tensile strength of high components of PP/nano-CaCO3 composites decreases slightly,while the flexural modulus is improved greatly.What is more,it has a toughening effect on PP when the content of nano-CaCO3 is 20~40phr.And the CHARPY impact strength is 17.0kJ/m2 at a 40 phr filled content.Polarized light microscopy（POM）measurement indicates that the spherulite size of the materials becomes smaller because of nano-CaCO3.DSC studies reveal that crystallization peak temperature of composites increase about 7.0℃（8#sample）,DSC and XRD results show thatαcrystal form of PP transforms into bothαandβco-crystal form.SEM observations show that only small amount of silver streaks-cut tape and rigid particles debonding exist in the PP/nano-CaCO3 composites.And a large number of sub-micron holes which are about 120~300nm size are found in PP matrix,and these holes are probably originated from huge mount of gases which exist in fluffy nano-CaCO3 particles,after processing the gases preserved in the PP matrix,they form composite material with sub-micron holes.These sub-micron holes are most likely to be the main cause of a substantial increase in material toughness.

关 键 词：高组分nano-CaCO3 聚丙烯 增韧机理 亚微米级孔洞 

分 类 号：TQ325.14[化学工程—合成树脂塑料工业]