Thermal Transitions of ε Crystalline Phases of Syndiotactic Polystyrene
Thermal Transitions of ε Crystalline Phases of Syndiotactic Polystyrene
复制标题
间规聚苯乙烯ε晶相的热转变
DOI：
10.1021/ma071640q
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发表时间：
2007
期刊：
影响因子：
5.5
通讯作者：
G. Guerra
中科院分区：
文献类型：
--
作者：
Paola Rizzo;C. D'Aniello;Anna De Girolamo Del Mauro;G. Guerra
用X射线衍射仪、差示扫描量热仪和动态力学分析比较了间规聚苯乙烯(S-PS)的三个结晶相(γ，δ和e)的热转变，它们呈现S(2/1)2螺旋结构。这些分析是在结晶(δ和e)薄膜上进行的，这些薄膜是从相同的γ形式的薄膜开始，通过类似的溶剂吸附和解吸过程获得的。并对三种薄膜的傅里叶变换红外光谱进行了比较。所得结果表明，最近发现的e相，即已知的δ相，在100℃以上加热就转变成γ相。然而，e→γ相变直接发生，在中温下没有形成螺旋介晶相，而不是δ→γ相变。差示扫描量热法和傅里叶变换红外光谱分析还表明，电子形式的结晶填充可能与γ形式的晶体填充非常相似。
Thermal transitions of the three crystalline phases (γ, δ, and e) of syndiotactic polystyrene (s-PS), presenting s(2/1)2 helices, have been compared by X-ray diffraction, differential scanning calorimetry (DSC), and dynamic-mechanical analyses. These analyses have been conducted on crystalline (δ and e) films, obtained by similar solvent sorption and desorption procedures, starting from a same γ-form film. The Fourier transform Infrared (FTIR) spectra of the three films have also been compared. The obtained results indicate that the recently discovered e-phase, as the already known δ-phase, is transformed in γ-phase by heating above 100 °C. However, the e → γ transition occurs directly without the formation, for intermediate temperatures, of a helical mesomorphic phase, as instead observed for the δ → γ transition. DSC studies and FTIR measurements also suggest that the crystalline packing of the e-form could be rather similar to that one of the γ-form.