Solidification of syndiotactic polystyrene by a continuous cooling transformation approach
Solidification of syndiotactic polystyrene by a continuous cooling transformation approach
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间规聚苯乙烯连续冷却转化法固化
DOI：
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发表时间：
2007
期刊：
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通讯作者：
V. Brucato
中科院分区：
文献类型：
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作者：
V. Carrubba;S. Piccarolo;V. Brucato
根据作者开发的连续冷却转化方法，在剧烈条件下从熔体固化间同立构聚苯乙烯（sPS），该方法涵盖约0.03至3000 °C/s的冷却速率范围。所产生的样品，结构均匀的厚度和表面，进行了分析，宏观方法，如密度，广角X射线衍射（WAXD），和显微硬度（MH）测量。密度与相含量严格相关，如WAXD去卷积所证实的。所遇到的特殊行为（密度随着冷却速率先降低，然后增加）归因于sPS中形成的相的奇异性;也就是说，其中一个结晶相（a）的密度低于非晶相，而后者反过来又低于另一个结晶相（β）。随着冷却速率的增加，β相首先消失，然后是α相。另一方面，MH值显著地取决于β相的量，α相含量仅在较小程度上影响力学性能。采用修正的多相Kolmogoroff-Avrami-Evans非等温结晶动力学模型描述了结晶动力学行为。
Syndiotactic polystyrene (sPS) was solidified from the melt under drastic conditions according to a continuous cooling transformation methodology developed by the authors, which covered a cooling rate range spanning from approximately 0.03 to 3000 °C/s. The samples produced, structurally homogeneous across both their thickness and surface, were analyzed by macroscopic methods, such as density, wide-angle X-ray diffraction (WAXD), and microhardness (MH) measurements. The density was strictly related to the phase content, as confirmed by WAXD deconvolution. The peculiar behavior encountered (the density first decreasing and then increasing with the cooling rate) was attributed to the singularity of the phases formed in sPS; that is, one of the crystalline phases (a) was less dense than the amorphous phase, and the latter, in turn, was less dense than the other crystalline phase (β). With an increasing cooling rate, the thermodynamically stable phase (β) disappeared first, and it was followed by the a phase. On the other hand, the MH values remarkably depended on the amount of the β phase, the α-phase content influencing the mechanical properties only to a minor extent. The behavior of the crystallization kinetics was described through a modified multiphase Kolmogoroff-Avrami-Evans model for nonisothermal crystallization.