Effect of Oscillatory Shear on the Mechanical Properties and Crystalline Morphology of Linear Low Density Polyethylene  

作　　者：Zhong-bin Xu Liang-yao Su Peng-fei Wang 彭懋 

机构地区：[1]College of Chemical and Biological Engineering,Zhejiang University [2]Department of Polymer Sci & Engn,Zhejiang University

出　　处：《Chinese Journal of Polymer Science》2015年第8期1114-1124,共11页高分子科学（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.51373153 and 51073139);the Zhejiang Provincial Natural Science Foundation of China(No.LY13E030002);the Zhejiang Leading Team of S&T Innovation(No.2011R50005)

摘　　要：In this study, effects of oscillatory shear with different frequencies （0-2.5 Hz） and amplitudes （0-20 mm） on the mechanical properties and crystalline morphology of linear low density polyethylene （LLDPE） were investigated. It was found that the mechanical properties of LLDPE are improved because of the more perfect crystalline structure when LLDPE crystallizes under low-frequency and small-amplitude （0.2 Hz/4 mm） oscillatory shear. The mechanical properties can be further improved by increasing either the frequency or the amplitude of oscillatory shear. The Young＇s modulus and tensile strength of LLDPE are improved by 27% and 20%, respectively, when the frequency is increased to 2.5 Hz and the amplitude is maintained at 4 mm; while the Young＇s modulus and tensile strength are improved by 49% and 47%, respectively, when the amplitude is increased to 20 mm and the frequency is remained as 0.2 Hz. The crystallinity and microstructure of LLDPE under different oscillatory shear conditions were investigated by using differential scanning calorimetry, wide angle X-ray diffraction and scanning electron microscopy to shed light on the mechanism for the improvement of mechanical properties.In this study, effects of oscillatory shear with different frequencies （0-2.5 Hz） and amplitudes （0-20 mm） on the mechanical properties and crystalline morphology of linear low density polyethylene （LLDPE） were investigated. It was found that the mechanical properties of LLDPE are improved because of the more perfect crystalline structure when LLDPE crystallizes under low-frequency and small-amplitude （0.2 Hz/4 mm） oscillatory shear. The mechanical properties can be further improved by increasing either the frequency or the amplitude of oscillatory shear. The Young＇s modulus and tensile strength of LLDPE are improved by 27% and 20%, respectively, when the frequency is increased to 2.5 Hz and the amplitude is maintained at 4 mm; while the Young＇s modulus and tensile strength are improved by 49% and 47%, respectively, when the amplitude is increased to 20 mm and the frequency is remained as 0.2 Hz. The crystallinity and microstructure of LLDPE under different oscillatory shear conditions were investigated by using differential scanning calorimetry, wide angle X-ray diffraction and scanning electron microscopy to shed light on the mechanism for the improvement of mechanical properties.

关 键 词：Oscillatory shear Linear low density polyethylene SHISH-KEBAB Mechanical property Crystalline morphology. 

分 类 号：O632.12[理学—高分子化学]