A systematic experimental investigation of the coupling between the extensional flow and the crystallization of a commercial grade polypropylene is presented. A modified Sentmanat extensional device allows one to generate a uniaxial extensional flow in the absence of gravity sagging and monitoring its effect on the kinetics of crystallization via in-situ visualization of the sample in polarised light. As compared to the shear induced crystallization, a three fold increase of the kinetics of the extension induced crystallization is found. The study is complemented by a post mortem analysis of the crystalline morphology by small angle X ray scattering ($SAXS$) and wide angle X ray scattering ($WAXS$).

对商品级聚丙烯的拉伸流动与结晶之间的偶联进行了系统的实验研究。改进的Sentmanat拉伸装置允许在没有重力下垂的情况下产生单轴拉伸流，并通过在偏振光下对样品进行原位观察来监测其对结晶动力学的影响。与剪切诱导结晶相比，发现延伸诱导结晶的动力学增加了三倍。这项研究得到了小角度X射线散射对晶体形态的事后分析的补充（$\mathrm{小号}\mathrm{一种}X\mathrm{小号}$）和广角X射线散射（$\mathrm{w\; ^}\mathrm{一种}X\mathrm{小号}$）。