Structure evolution and orientation mechanism of isotactic polypropylene during the two‐stage solid die drawing process |
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Authors: | Pingping Wu Qi Yang Zhongguo Zhao Hongwen Sun Tongying Zhang Yajiang Huang Xia Liao |
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Affiliation: | College of Polymer Science and Engineering, the State Key Laboratory for Polymer Materials Engineering, Sichuan University, Chengdu 610065, People's Republic of China |
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Abstract: | High oriented isotactic polypropylene prepared by self‐designed two‐stage die drawing apparatus was explored through kinds of methods, including differential scanning calorimetry, two‐dimensional wide‐angle X‐ray diffraction, polarized light microscope, and tensile test. The results showed that there was a great difference between the orientation mechanism and structure evolution of two‐stage solid die drawing process and single‐stage solid die drawing process. All samples would undergo free drawing process after die drawing process. Die drawing and free drawing process were of equal importance to single‐stage die drawing process while die drawing process showed an prominent contribution to the two‐stage die drawing process. Drawing speed showed beneficial influence on die drawing process for both single‐ and two‐stage die drawing process routes. Under the same processing condition, tensile strength and modulus of samples prepared by two‐stage die drawing process were higher than those prepared by single‐stage die drawing process and the maximum value could reach 241.93 MPa and 3.57 GPa, respectively. Moreover, two‐stage die drawing samples showed better dimensional stability than single‐stage die drawing samples especially under low draw rate. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46581. |
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Keywords: | crystallization differential scanning calorimetry structure– property relationships theory and modeling X‐ray |
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