Premium
Research on viscoelastic behavior of semi‐crystalline polymers using instrumented indentation
Author(s) -
Liu Erqiang,
Wu Jianguo,
Li Huaying,
Liu Haitao,
Xiao Gesheng,
Shen Qiang,
Kong Lingyu,
Lin Jinbao
Publication year - 2021
Publication title -
journal of polymer science
Language(s) - English
Resource type - Journals
eISSN - 2642-4169
pISSN - 2642-4150
DOI - 10.1002/pol.20210075
Subject(s) - viscoelasticity , creep , materials science , rheology , indentation , composite material , stiffness , softening , polymer , relaxation (psychology) , polyamide , psychology , social psychology
Abstract In this study, the viscoelastic behavior of a polyamide 12 (PA12) polymer was evaluated using instrumented indentation technology based on a rheological model. The creep compliance and retardation spectra were obtained to analyze the viscoelastic response during the holding stage according to the rheological model under different preloading conditions. The results showed that the viscoelastic responses were independent of the indentation depth or load under step loading conditions. However, the creep compliance increases, and the peak intensity of the retardation spectrum decreases with a decrease in the preloading rate owing to the structural relaxation observed during the preloading stage under ramp loading conditions. Furthermore, softening dispersion can be completed during the loading stage under continuous stiffness measurement (CSM) conditions. As the preloading strain rate changes, the peak of the retardation spectrum gradually decreases until it disappears completely. Moreover, studies on indentation creep using the CSM method are challenging because of the complicated viscoelastic response observed during the preloading stage.