Study on Stress Relaxation and Creep Properties of PTFE Membrane

The relaxation modulus and creep compliance curves of PTFE membrane against time were obtained by the uni-axial stress relaxation and creep tests.The generalized linear viscoelastic model,fractional model and fractional exponential model were adopted to simulate the test curves and make precision comparisons.The analysis results show that all the above models can be used to describe the relaxation modulus and creep compliance of PTFE membrane in the short time.For the generalized linear viscoelastic model,the relaxation modulus and creep compliance in the long time do not agree with the test results,this model has a low precision in the long-term prediction.For the fractional model,the long-term relaxation modulus and creep compliance can be predicted well.The fractional exponential model can predict the warp creep compliance in the long time,but it has a low precision for the long-term prediction for the relaxation modulus and weft creep compliance.