Dynamic viscoelasticity of PUF under small strain and prediction of dynamic viscoelasticity in a wide frequency range

摘要

The dynamic viscoelasticity of polyurethane fiber (PUF) under small strain was studied with dynamic mechanical analysis and differential scanning calorimetry, and its viscoelasticity was predicted in a wide frequency range. The results revealed that the loss factor (tan delta) was about 0.05 and the phase angle (delta) was 2.86 degrees, very close to the delta of a perfect elastomer in the range from -100 degrees C to -80 degrees C. The master curves superimposed by time-temperature superposition (TTS), the frequency range of the storage modulus master curve spanned 17 orders of magnitude from 10(-7) Hz to 10(10) Hz, and the loss modulus master curve spanned 13 orders of magnitude from 10(-3) Hz to 10(10) Hz. The apparent activation energy of the soft segment relaxation decreased with increasing temperature in the range from -70 to -26 degrees C. (c) 2018 Wiley Periodicals, Inc.