高等学校化学学报

高等学校化学学报 ›› 2001, Vol. 22 ›› Issue (2): 298.

• 研究论文 • 上一篇    下一篇

茂金属聚乙烯和低密度聚乙烯共混物的流变行为

刘琛阳1, 李育英1, 王进1, 何嘉松1, 张林2   

  1. 1. 中国科学院化学研究所分子科学中心, 工程塑料国家重点实验室, 北京 100080;
    2. 北京燕山石油化工有限公司树脂应用研究所, 北京 102500
  • 收稿日期:1999-07-13 出版日期:2001-02-24 发布日期:2001-02-24
  • 通讯作者: 何嘉松(1944年出生),男,研究员,博士生导师,主要从事聚合物共混物与复合材料基础研究.

Rheological Behavior of Metallocene Catalyzed PE and LDPE Blends

LIU Chen-Yang1, LI Yu-Ying1, WANG Jin1, HE Jia-Song1, ZHANG Lin2   

  1. 1. State Key Laboratory of Engineering Plastics, Centerf or Molecular Science, Institute of Chemistry, The Chinese Academy of Sciences, Beijing 100080;
    2. Resin Application Research Institute, Beijing Yanshan Petrochemical Co.Ltd., Beijing 102500, China
  • Received:1999-07-13 Online:2001-02-24 Published:2001-02-24

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被引次数

42

摘要： 研究了茂金属催化乙烯丁烯1共聚物mPE和LDPE共混物的流变行为.测定了一系列共混物的稳态剪切粘度和动态粘弹性,用改进Cross模型拟合实验数据.mPE的零切粘度η0较小,从牛顿型转变为非牛顿型所需的剪切速率较大,转变应力较高,在挤出加工剪切速率范围内熔体粘度高,对剪切敏感性差,这是由于它有较低的重均分子量、窄的分子量分布(Mw/Mn=21)所致.对于对数加和规律,共混物η0在mPE/LDPE为50/50和25/75时有强烈的正偏差,这是由于共混物自由体积减小所致.共混物的转变应力τ*和非牛顿指数n随LDPE加入量增大而降低,表明共混物对剪切的敏感性提高,加工性得到改善.G'和G”的一致性说明mPE和LDPE共混是相容的.

关键词: 茂金属聚乙烯, 低密度聚乙烯, 流变行为, 共混

Abstract: The rheological behavior was studied for blends of metallocene catalyzed ethylene/1-butene copolymer(mPE) and low density polyethylene(LDPE). Steady-state viscosity and dynamic viscoelasticity were measured by using a DSR-200 rheometer with parallel plate geometry. Non-linear fitting with the modified cross model was conducted successfully. Due to lower molecular weight and narrower molecular weight distribution(Mw/Mn=21),mPEhas a lower sensitivity to shear, shown by a lower zero shear viscosity, higher values of shear rate and shear stress at the transition from Newtonian to non-Newtonian behavior, higher viscosities in shear rate range from 100 s-1 to 102 s-11. Zero shear viscosities of mPE/LDPE 50/50 and 25/75(mass ratio) blends have a large positive deviation from log-additivity rule, due to a decrease of the free volume fraction in these blends. The transition stress and non-Newtonian index decrease with increasing LDPEfraction in blends, which indicate that the blends have high sensitivity to shear and improved processability. The single correlation betweenG' andG" corresponds to the behavior expected for a miscible blend.

Key words: Metallocene catalyzed polyethylene, Low density polyethylene(LDPE), Rheological behavior, Blend

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