High speed injection molding of high density polyethylene - Effects of injection speed on structure and properties
High speed injection molding of high density polyethylene - Effects of injection speed on structure and properties
复制标题
高密度聚乙烯高速注射成型-注射速度对结构和性能的影响
DOI：
10.1007/s10118-011-1049-3
复制
发表时间：
2011-07-01
影响因子：
4.3
通讯作者：
Fu, Qiang
中科院分区：
文献类型：
--
作者：
Jiang, Kun;Yu, Fei-long;Fu, Qiang
采用不同注射速度（100 ~ 1200 mm/s）注射成型高密度聚乙烯（HDPE）薄壁试样。随着注射速度的增加，观察到拉伸强度和杨氏模量的显着下降。为了探讨这种下降背后的机制，取向，分子量，分子量分布，熔体流动速率，结晶度和结晶形态的HDPE进行了表征，采用二维广角X射线衍射（2D-WAXD），凝胶渗透色谱（GPC），毛细管流变仪和差示扫描量热法（DSC），分别。结果表明，随着注射速度的增加，熔体的取向度、分子量、分子量分布、熔体流动速率和结晶度均无明显变化。然而，延长链晶体或大折叠链晶体的含量被发现随着注射速度的增加而减少。拉伸性能的下降主要是由于拉伸链晶体或大的折叠链晶体含量的减少。本研究为高速注射成型技术的应用提供了有价值的参考。
Thin wall samples of high density polyethylene (HDPE) were prepared via injection molding with different injection speeds ranging from 100 mm/s to 1200 mm/s. A significant decrease in the tensile strength and Young's modulus was observed with increasing injection speed. In order to investigate the mechanism behind this decrease, the orientation, molecular weight, molecular weight distribution, melt flow rate, crystallinity and crystal morphology of HDPE were characterized using two-dimensional wide-angle X-ray diffraction (2D-WAXD), gel permeation chromatography (GPC), capillary rheometry and differential scanning calorimetry (DSC), respectively. It is demonstrated that the orientation, molecular weight, molecular weight distribution, melt flow rate and crystallinity have no obvious change with increasing injection speed. Nevertheless, the content of extended chain crystals or large folded chain crystals was found to decrease with increasing injection speed. Therefore, it is concluded that the decrease in tensile properties is mainly contributed by the reduced content of extended chain crystals or large folded chain crystals. This study provides industry with valuable information for the application of high speed injection molding.