聚对苯二甲酸乙二醇酯的拉伸应力波动行为研究

Study on Stress-oscillation Behavior of Poly (ethylene terephthalate) During Tensile Test

研究了不同相对分子质量聚对苯二甲酸乙二醇酯(PET)在不同拉伸速率下的应力波动行为。通过拉伸测试、差示扫描量热仪和扫描电子显微镜等方法对PET样条不同区域的应力波动行为、结晶度、宏观及微观形貌进行了分析。结果表明,PET应力波动行为对相对分子质量和拉伸速率具有依赖性;PET试样内部空洞不均匀现象只是应力波动行为的微观结果;拉伸诱导结晶过程中,明带暗带的结晶度大小不同是应力波动产生的原因。

This paper reported a study on the effect of molecular weight on stress-oscillation behavior of poly（ethylene terephthalate）（PET）during the tensile experiment.Tensile test,differential scanning calorimetry and scanning electron microscopy were performed to investigate the stress-oscillation behavior,crystallinity,and macroscopic and microscopic morphologies in different regions of PET specimen.The results indicated that the stress-oscillation behavior of PET specimen was dependent on the relative molecular weight of PET resin and the tensile rate.Inhomogeneous voids observed inside the PET specimen were derived from the stress oscillation and considered as a microscopic result.The occurrence of stress oscillation was due to the difference of crystallinity degree within the bright-dark alternating bands during the process of stretch-induced crystallization.