热历史对β–PP结晶和熔融行为的影响  

Influence of Thermal History on Crystallization and Melting Behaviors of β–PP

作　　者：朱文利[1,2] 张文[1,2] 李和[1,2] 

机构地区：[1]湖北文理学院机械与汽车工程学院,湖北襄阳441053 [2]汽车零部件制造装备数字化湖北省协同创新中心,湖北襄阳441053

出　　处：《工程塑料应用》2015年第9期88-93,共6页Engineering Plastics Application

基　　金：国家自然科学基金资助项目(51403059);湖北省自然科学基金资助项目(2014CFB456);襄阳市科技计划研究与开发项目(襄科业[2013]66号)

摘　　要：商业化的β晶聚丙烯(PP)(β–PP)原料是通过在PP中添加β成核剂改性而得,其最终制品中的β晶含量受加工过程中热历史的显著影响。为了研究影响β晶形成的因素,选用一种市售β–PP,通过差示扫描量热(DSC)法系统研究了热历史对其结晶和熔融行为的影响。研究结果显示,β–PP在加热过程中会发生β–α相转变,导致β晶相对含量减少、α晶相对含量增加;较慢的升温速率将导致显著的β–α相转变,而较快的升温速率可在一定程度上减小产生该现象的趋势;熔体中含有的未完全熔融的α晶以及在加热过程中因β–α相转变新形成的α晶在冷却过程中会发生重结晶,形成结构更完善、熔点更高的α晶。The commercial β -PP materials are obtained by adding β nucleating agents into PR The β crystal content of final products is significantly influenced by heat history during processing procedure. In order to study the factors affect the formation of β crystal, the influence of thermal history on crystallization and melting behaviors of β -PP was systematically investigated by using a commercially available β -PP through differential scanning calorimetric （DSC） method. The study results show that ： β - α phase transition in β -PP matrix can happen during heating process, which results in a decreased β crystal relative content and an increased crystal relative content. In addition, the slower heating rate will introduce more obvious β- α phase transition, while faster heating rate is less inclined to cause this phenomenon. Recrystallization for α crystal which resulted by incompletely melt α crystal inherently existed in the matrix together with newly formed α crystal due to β - α phase transition upon heating will happen during cooling process. The eventually-formed α crystals possess more perfect crystalline structures and higher melting points.

关 键 词：聚丙烯 Β晶 双熔融峰 重结晶 β-α相转变 

分 类 号：TQ325.14[化学工程—合成树脂塑料工业]