Chem. J. Chinese Universities ›› 2019, Vol. 40 ›› Issue (4): 832.doi: 10.7503/cjcu20180685

• Polymer Chemistry • Previous Articles     Next Articles

Long-term Stress Relaxation Prediction for Nylon 1010 Using Time-temperature Superposition Method

CAI Lihai, GUO Baohua*(), ZHANG Cheng, XU Jun, HUANG Zhongyao   

  1. Department of Chemical Engineering, Key Lab of Advanced Materials of Ministry of Education, Tsinghua University, Beijing 100084, China
  • Received:2018-10-10 Online:2019-04-03 Published:2019-04-10
  • Contact: GUO Baohua E-mail:bhguo@mail.tsinghua.edu.cn
  • Supported by:
    † Supported by the National Natural Science Foundation of China(Nos.51473085, 51673110), the Joint Funds of the National Natural Science Foundation of China(No.U1862205)and the Tsinghua University-Suzhou Innovation Leading Program, China(No.2016SZ0315).

Abstract:

Stress relaxation behavior of plastic has great influence on its service life and safety. The master curves were generated by horizontal and vertical shifts of the short term curves of stress relaxation for Nylon 1010 at temperatures ranging from 293 K to 353 K using proposed time-temperature superposition equivalence method. The apparent activation energy was calculated from the Arrhenius plots of shift factor, and the values of activation volume and stress-assisted work were calculated from the master curves. The time-temperature superposition principle was found to be available for the stress relaxation curves. During the superposition interval of the experimental temperature from 293 K to 323 K, the apparent activation energy and stress-assisted work show a tendency to decrease gradually, which is helpful for the relaxation of the moving units in the polymer over the energy barrier. During the superposition interval of the experimental temperature from 333 K to 353 K, the apparent activation energy of different initial strain samples is about the same value of 260 kJ/mol and the stress-aided work is basically unchanged at the value of 60 MPa·nm3, which indicates that the energy barrier of the moving unit is independent of the stress effect. According to the mater curves of Nylon 1010, the relationship between stress decay and relaxation time in a long time range can be obtained under the strain of 1.0%, 2.8% and 5.1%, which provides a reference for predicting stress relaxation behavior in practical use.

Key words: Nylon 1010, Stress relaxation, Time-temperature superposition, Apparent activation energy, Activation volume, Stress-aided work

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