中文摘要：

通过微/纳共挤制备了α-PP/β-PP多层交替复合物,通过差示扫描量热仪（DSC）和偏光显微镜（POM）分析其熔融与结晶行为.结果表明,相同含量、相同加工条件下,β成核剂的成核效率低于α成核剂;α-PP/β-PP多层交替复合物的半结晶时间（t1/2）介于单台单螺杆挤出机得到的α-PP与β-PP之间;相同螺杆转速、不同层数时,与纯PP相比,成核剂的加入可明显提高α-PP/β-PP复合物的结晶温度（Tc）,同时Tc随层数增加而逐渐由比较明显的2个Tc演变成1个高温Tc,类似于α/β-PP共混物的结晶行为;随分层叠加单元个数增加,提供的剪切应力越大,越有利于β晶生成.

英文摘要：

The alternating multilayered compounds of α-PP/β-PP were successfully prepared through coextrusion technology.Then the melting and crystalline behaviors were investigated by differential scanning calorimeter and polarizing optical microscope.The results showed that the nucleating efficiency of β nucleating agent was lower than that of α nucleating agent under the same circumstances.The half crystallization time （t 1/2） of the alternating multilayered compounds was between that of α-PP and that of β-PP.Compared with pure PP,the crystallization temperature （Tc） of α-PP/β-PP with different layers was obviously enhanced,and the Tc curves gradually transformed from two distinct peaks into one peak with increasing the layer number.Meanwhile,the shear force provided by laminating-multiplied elements （LMEs） was conducive to the formation of β-crystals.