单向和双向拉伸聚乙烯薄膜的残余应力分析

［摘要］采用 2D-XRD 单倾斜角方法分析了单向拉伸聚乙烯和双向拉伸聚乙烯（BOPE）薄膜的残余应力，研究了聚乙烯薄膜
的晶体结构对其残余应力的影响。表征结果显示，单向拉伸聚乙烯薄膜的残余主应力表现为沿纵向的拉应力；而 BOPE 薄膜
的残余主应力与纵向成一定的夹角，且为压应力。残余应力与薄膜晶体的取向、晶粒尺寸有较好的相关性。单向拉伸聚乙烯
［中图分类号］TQ 325.12
［文献标志码］A
Residual stress analysis of uniaxially and biaxially oriented polyethylene films
Ren Minqiao，Tang Yujing，Shi Hongwei，Gao Dali，Zhang Taoyi
双向拉伸聚乙烯（BOPE）薄膜是一种新型的 聚乙烯（PE）薄膜，它采用平膜法双轴取向分步 拉伸加工工艺制备而成。近年来，佛山佛塑科技集 团股份有限公司等采用进口茂金属 PE 催化剂成功 生产出了 BOPE 薄膜［1-2］。中国石油化工股份有限 公司通过分子结构设计成功开发出了工业化非茂
金属催化剂生产的 BOPE 薄膜专用树脂［3-4］，用于 高速生产 BOPE 薄膜。所生产的 BOPE 薄膜的拉 伸强度高、透明性好、耐低温、抗穿刺、抗冲击、 针孔缺陷极少，可用于农用棚膜、多层复合膜、低 温食品包装膜等高性能制品。
残余应力是指消除外力或不均匀的温度场等
［收稿日期］2018 - 11 - 08；［修改稿日期］2019 - 01 - 01。 ［作者简介］任敏巧（1974—），女，河北省无极县人，博士，高级工程师，电话 010 - 59202918，电邮 renmq.bjhy@sinopec.com。
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石油化工 PETROCHEMICAL TECHNOLOGY
2019 年第 48 卷第 3 期
石油化工 PETROCHEMICAL TECHNOLOGY
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DOI：10.3969/j.issn.1000-8144.2019.03.006
单向和双向拉伸聚乙烯薄膜的残余应力分析
任敏巧，唐毓婧，施红伟，高达利，张韬毅
（中国石化 北京化工研究院，北京 100013）
（Sinopec Beijing Research Institute of Chemical Industry，Beijing 100013，China）
［Abstract］Single tilt method for residual stress evaluation with two-dimensional XRD was used to analyze the residual stress of uniaxially and biaxially oriented polyethylene films. The effect of crystalline structure on the residual stress of the polyethylene films was also investigated. The results showed that the direction of the maximum principal tensile residual stress was approximately along machine direction(MD) for the uniaxially oriented polyethylene film，while it deviated from MD and turned into the principal compressive residual stress in the case of the biaxially oriented polyethylene film. Good correlations of the direction of the maximum principal residual stress with the orientation of the crystallite and the crystallite size were found for the uniaxially and biaxially oriented polyethylene films. The crystallite size increased with the increase of draw ratio for the uniaxially oriented polyethylene films，while the crystallinity increased but the crystallite size changed little with the increase of draw ratio when the films were further stretched along transverse direction. It was inferred that a fraction of crystallites with similar size was randomly distributed for the biaxially oriented polyethylene films. ［Keywords］uniaxially oriented；biaxially oriented；polyethylene film；residual stress；twodimensional X-ray diffraction
薄膜的晶粒尺寸随拉伸比的增加而增大。BOPE 薄膜在 TD 方向拉伸时，随拉伸比的增加，薄膜的结晶度增大，但晶粒尺寸
变化不明显。BOPE 中可能存在一部分无规分布的具有相近晶粒尺寸的晶体。
Hale Waihona Puke Baidu
［关键词］单向拉伸；双向拉伸；聚乙烯薄膜；残余应力；二维 X 射线衍射
［文章编号］1000 - 8144（2019）03 - 0261 - 06