摘要
以聚丙烯(PP)为原料制备了PP微颗粒,再以CO2为发泡剂,采用釜压发泡工艺将PP微颗粒进行发泡得到PP发泡珠粒。利用DSC和XRD方法对PP发泡珠粒的熔融行为及晶型特征进行了研究。实验结果表明,PP发泡珠粒具有独特的熔融双峰,随发泡温度的升高或压力的增大,熔融双峰向高温区移动,且高温峰焓值减小,低温峰焓值增大;高温峰为PP微颗粒在发泡温度下的不熔晶体或以不熔晶体为"核"生长的新晶体的熔融峰,低温峰为PP熔体在淬冷作用下结晶所得晶体的熔融峰;熔融双峰的形成是由于在发泡升温过程中,PP的部分结晶被消除了所致。
Expanded polypropylene（EPP） beads were prepared from PP micropellets with CO2 as the foaming agent through an autoclave foaming process.The melting behavior and crystal type of EPP beads were investigated by means of DSC and XRD.The results indicated that EPP had double melting peaks.With increasing foaming temperature or pressure,the double melting peaks shifted to high temperature area,the enthalpy of high-temperature peak decreased and the enthalpy of lowtemperature peak increased.High-temperature peak belongs to unmelting crystals of PP micropellets under the foaming temperature and the new crystals formed with unmelting crystal as ＂core＂,and low-temperature peak belongs to the recrystallization of partial melted crystals after the foaming process.The double melting peaks are formed because some PP crystals are eliminated when foaming temperature rises.
出处
《石油化工》
CAS
CSCD
北大核心
2013年第9期1019-1022,共4页
Petrochemical Technology
基金
中国石化科技开发项目(211065)
关键词
熔融行为
釜式发泡
聚丙烯
结晶
熔融双峰
melting behavior
autoclave foaming process
polypropylene
crystal
double melting peak
