剪切和冷却速率对长支链聚丙烯晶体结构的影响  

Influences of Shearing and Cooling Rate on the Crystal Structure of Long Chain Branched Polypropylene

作　　者：周帅[1] 辛忠[1] 赵世成[1] 

机构地区：[1]华东理工大学化工学院化学反应工程国家重点实验室,上海200237

出　　处：《石油化工》2013年第4期430-434,共5页Petrochemical Technology

基　　金：国家自然科学基金项目(21106042)

摘　　要：采用旋转流变仪在不同剪切作用下制备了长支链聚丙烯PP-g-VS/St(PP:聚丙烯;VS:乙烯基聚二甲基硅氧烷;St:苯乙烯)结晶试样,并利用WAXRD方法考察了冷却速率、剪切作用以及两者共同作用时对PP-g-VS/St晶体结构的影响。表征结果显示,PP-g-VS/St在冷却结晶过程中可形成α晶和少量γ晶;在剪切作用下,PP-g-VS/St中形成α晶和β晶,且β晶的相对含量随剪切速率的增大先急剧增大后趋于稳定、随剪切时间的延长先增大后略有降低、随剪切温度的升高而增大。当剪切速率为70 s-1、剪切时间为60 s、剪切温度为230℃时,PP-g-VS/St中β晶的相对含量为35.6%。剪切作用和快速冷却是诱导PP-g-VS/St形成β晶的关键因素。Crystalline samples of long chain branched polypropylene PP-g-VS/St （VS： vinyl polydimethylsiloxane; St： styrene） were prepared on a rheometer. The influences of cooling rate and shearing action on the crystal structure of PP-g-VS/St were investigated by means of WAXRD. The results indicated that α crystal and a little y crystal were produced in PP-g-VS/St under the cooling process and a crystal and 13 crystal were produced in PP-g-VS/St under the shearing action. The relative content of 13 crystal in PP-g-VS/St first increased sharply and then leveled off with increasing shearing rate, and first increased and then decreased slightly with increasing shearing time, and increased with the rise of shearing temperature. The relative content of 13 crystal in PP-g-VS/St was up to 35.6% when the shearing rate, shearing time and shearing temperature were 70 s-1, 60 s and 230 ℃, respectively. Shearing action and rapid cooling were key factors for the generation of 13 crystal in PPog-VS/St.

关 键 词：长支链聚丙烯 剪切 冷却速率 Β晶 

分 类 号：TQ316.6[化学工程—高聚物工业]