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通过熔融纺丝及随后的热处理制备了具有不同初始结构的间规聚丙烯纤维(sPP).采用差示扫描量热仪(DSC)和变温广角X-射线衍射仪详细研究了sPP纤维在升温过程中的结构转变和熔融行为.结果表明,不同初始结构sPP纤维的晶型不同,卷绕纤维和退火处理纤维以Ⅰ型和Ⅱ型晶型为主,牵伸纤维介晶相占优;升高温度导致Ⅰ型和Ⅱ型两种晶型直接熔融,没有出现Ⅱ型向Ⅰ型的晶型转变;初始结构为介晶相的纤维在升温过程中部分介晶相直接转变为Ⅱ型晶型,还有一部分介晶相直接熔融,并在随后的升温过程中,形成Ⅰ型晶型.sPP纤维的多重熔融行为与其初始结构和纤维制备条件密切相关.
The syndiotactic polypropylene fibers (sPP) with different initial structures were prepared by melt spinning and subsequent heat treatment.The effects of sPP fiber temperature during heating process were investigated in detail by means of differential scanning calorimetry (DSC) and wide temperature wide angle X-ray diffractometer The results show that the crystal structure of sPP fibers with different initial structure is different, the type I and type II crystal fibers are the main components of the wound and annealed fibers, and the mesophase of the draw fibers is dominant and elevated The temperature leads to the direct melting of type I and type II, and the type I to type I do not appear. The transition from the initial mesogenic phase to the type II is heating at the initial stage, There is also a part of mesogen phase melted directly, and the formation of crystal form I during the subsequent heating.Multiple melting behavior of sPP fiber is closely related to its initial structure and fiber preparation conditions.