Probing the Early Stages of Melt Crystallization in Polypropylene by Simultaneous Small- and Wide-Angle X-ray Scattering and Laser Light Scattering
Probing the Early Stages of Melt Crystallization in Polypropylene by Simultaneous Small- and Wide-Angle X-ray Scattering and Laser Light Scattering
复制标题
DOI：
10.1021/ma991468t
复制
发表时间：
2000-01
期刊：
影响因子：
5.5
通讯作者：
Zhi-Gang Wang;B. Hsiao;E. Sirota;P. Agarwal;S. Srinivas
中科院分区：
文献类型：
--
作者：
Zhi-Gang Wang;B. Hsiao;E. Sirota;P. Agarwal;S. Srinivas
采用同步辐射小角X射线散射（SAXS）/广角X射线衍射（WAXD）和激光光散射（LS）技术，以分级等规聚丙烯（iPP）为模型体系，研究了聚合物熔体结晶的早期阶段。由于早期阶段的结晶度非常低，因此解决了WAXD的结晶度检测限问题。这是通过使用不同浓度（低至1%）的正链烷烃（C33 H68）在十二烷（C12 H26）中的溶液来完成的。沉淀部分模拟聚乙烯中的结晶度，因为在测量温度下正链烷烃基本上完全结晶并且十二烷保持液体。还使用建模方法来模拟WAXD曲线，以检查在低结晶度下晶体尺寸的影响。通过这两种方法，我们得出结论，我们的WAXD程序能够检测0.5%至1%的结晶度。在iPP等温结晶的早期阶段，值得注意的是，
The early stages of polymer melt crystallization using fractionated isotactic polypropylene (iPP) as a model system were investigated via simultaneous synchrotron small-angle X-ray scattering (SAXS)/wide-angle X-ray diffraction (WAXD) and laser light scattering (LS) techniques. Since the crystallinity in the early stages is very low, the issue of the crystallinity detection limit of WAXD was addressed. This was done by using solutions of n-paraffin (C33H68) in dodecane (C12H26) at different concentrations (as low as 1%). The precipitated fraction simulated the degree of crystallinity in polyethylene since n-paraffin essentially completely crystallized and dodecane remained liquid at the measurement temperature. A modeling method was also used to simulate the WAXD profiles to check the effect of crystal size at low crystallinity. With these two methods, we conclude that our WAXD procedure is capable of detecting crystallinity from 0.5% to 1%. During the early stages of iPP isothermal crystallization, notic...