论文部分内容阅读
通过对等规聚丙烯(iPP)过冷熔体施加不同应变的正弦振荡剪切场,研究了大应变振荡剪切流场作用下,等温iPP的流动诱导结晶过程.研究结果表明,施加大应变振荡剪切流场可以明显加速iPP的结晶动力学,且施加的应变越大可以促使iPP结晶动力学加速现象越明显.通过对iPP熔体的应力波形进行傅立叶变换分析发现,由于结晶会引起熔体内部非线性行为改变,傅里叶变化峰值的3倍基频峰值I3与基频峰值I1之比I3/I1可以敏感反映iPP的流动诱导结晶过程.当流变仪施加的应变幅度从10%提高到30%时,I3/I1比值发生突跃的时间则从2500 s迅速减小为600 s.
The flow induced crystallization process of isothermal iPP under the action of the large strain oscillatory shear flow field was studied by applying different strains of sine oscillating shear field to the supercooled melt of iPP.The results show that the application of large strain The oscillatory shearing flow field can obviously accelerate the crystallization kinetics of iPP, and the larger the applied strain, the more pronounced the acceleration of iPP crystallization kinetics.Fourier transform analysis of the stress waveforms of iPP melt shows that due to the crystallization, The internal nonlinear behavior change, the Fourier transform peak I3 fundamental frequency peak I3 and the peak I1 ratio I3 / I1 can sensitively reflect iPP flow induced crystallization process when the rheometer strain amplitude applied from 10% At 30%, the time of the I3 / I1 jump suddenly decreased from 2500 s to 600 s.