Crystallization of polyamide 11 during injection molding
Crystallization of polyamide 11 during injection molding
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DOI：
10.1002/pen.24665
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发表时间：
2018-07
影响因子：
3.2
通讯作者：
Katalee Jariyavidyanont;Jason J. Williams;A. Rhoades;I. Kühnert;W. Focke;R. Androsch
中科院分区：
文献类型：
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作者：
Katalee Jariyavidyanont;Jason J. Williams;A. Rhoades;I. Kühnert;W. Focke;R. Androsch
研究了在25、50和80°C模具温度下制备的聚酰胺11（PA 11）注塑制品的半结晶形态。无论模具温度如何，位置分辨X射线衍射（XRD）和偏光光学显微镜（POM）显示，在表皮的非球晶超结构中存在分子茎几乎呈六边形排列的不良/不完美α晶体，在芯中形成α晶体和球晶。随着模具温度的升高，皮层厚度减小，芯部α晶的完整性和球晶尺寸增大。根据预测的结晶温度讨论了实验观察结果，预测基于使用Moldflow®对注塑成型的各个部分的冷却速率模拟，以及使用快速扫描芯片量热法、XRD和POM对松弛熔体的结晶进行分析。结果表明，对于PA 11这种特殊的聚合物，在不考虑剪切作用的情况下，可以预测其注射成型中的结构梯度。Polym.工程索引，2017.© 2017塑料工程师协会
The semicrystalline morphology of injection moldings of polyamide 11 (PA 11) prepared using mold temperatures of 25, 50, and 80°C was investigated. Regardless of the mold temperature, position-resolved X-ray diffraction (XRD) and polarized-light optical microscopy (POM) revealed presence of poor/imperfect α-crystals with an almost hexagonal arrangement of molecular stems in a nonspherulitic superstructure in the skin, and formation of α-crystals and spherulites in the core. With increasing mold temperature, the thickness of the skin layer decreased, and the perfection of α-crystals and the spherulite size in the core increased. The experimental observations are discussed in terms of predicted crystallization temperatures, with the prediction based on cooling-rate simulations for the various parts of the injection moldings using Moldflow® and analysis of crystallization of the relaxed melt using fast scanning chip calorimetry, XRD, and POM. It is shown that the structure gradient in PA 11 injection moldings can be forecast without considering the effects of shear for this particular polymer. POLYM. ENG. SCI., 2017. © 2017 Society of Plastics Engineers