FTIR studies of β-phase crystal formation in stretched PVDF films
FTIR studies of β-phase crystal formation in stretched PVDF films
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DOI：
10.1016/s0142-9418(03)00003-5
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发表时间：
2003-09-01
期刊：
影响因子：
5.1
通讯作者：
Yousefi, AA
中科院分区：
文献类型：
--
作者：
Salimi, A;Yousefi, AA
聚偏氟乙烯（PVDF）是一种具有多晶性的半结晶聚合物，通常以非极性晶相结晶。在过去的几十年里，它已经找到了各种各样的应用，最重要的应用在于它的热和压电性能。在这些应用中，β相的含量是最重要的，因此提高聚合物的β相含量一直是该领域关注的焦点。量热研究和红外光谱显示了两种不同等级PVDF树脂的压缩成型薄膜中β相的出现。拉伸膜中β相的形成更为明显，是通过拉伸过程中颈缩区形成的α相到β相的转变机制。利用FTIR技术计算出β相的最大含量为74%。这是在90度拉伸时实现的，拉伸比在4.5到5之间。FTIIR光谱为检测聚合物薄膜中β相的变化提供了一种精确的方法。2003爱思唯尔科学有限公司版权所有。
Poly vinylidene fluoride (PVDF) is a semi-crystalline polymer which shows polymorphism and is commonly crystallized in non-polar crystalline alpha-phase. It has found various applications during the last decades and the most important applications lies in its pyro- and piezoelectric properties. The beta-phase content is of prime importance in these applications so that increasing beta-phase content of the polymer has always been of great concern in this field. Calorimetric studies and FTIR spectra show the appearance of beta-phase in compression molded films of two different grades of PVDF resin. beta-phase formation is more evident in stretched films by a transformation mechanism of alpha to beta-phase via the formation of a necking region during stretching. By using FTIR techniques, a maximum content of 74% for beta-phase was calculated. This was achieved during stretching at 90 degreesC and for a stretch ratio between 4.5 and 5. FTIIR spectra offer a precise method for detecting the variations of beta-phase in polymer films. (C) 2003 Elsevier Science Ltd. All rights reserved.