Biaxial Stretching of Ultra-High Strength Polyolefin Gel Films

本项目主要研究超高相对分子质量聚烯烃凝胶薄膜，特别是超高相对分子质量聚乙烯(UHMWPE)和超高相对分子质量PP(UHMWPP)的双向拉伸。单轴拉伸UHMWPE凝胶显示出超高强度，可与钢或芳纶纤维等同类产品相媲美。然而，由于纤化，这种单轴驱动的光纤在横向方向上固有地较弱。通过在凝胶中引入双向取向，可以显著提高凝胶的横向强度。PI将在双向拉伸之前对UHMWPE凝胶进行交叉滚动，以限制在双向拉伸过程中样品厚度的显著减少。另一个要解决的领域是通过探测标记分子来研究凝胶吸引的机制。第三个要解决的领域是用常规的时间分辨光散射、SAXS、WAXD和光学显微镜研究UHMWPE凝胶的熔融和结晶行为以及凝胶球晶的变形机制。

The project deals with the study of biaxial stretching of ultra- high molecular weight polyolefin gel films, especially UHMWPE and UHMWPP. Uniaxially drawn UHMWPE gels have shown ultra-high strength comparable to its counterparts such as steel or KevlarR fibers. However, such uniaxially driven fibers are inherently weak in transverse direction due to fibrillation. The lateral strength may be significantly improved by introducing biaxial orientation in the gels. The PI will perform cross-rolling of UHMWPE gels prior to biaxial stretching to limit significant reduction of sample thickness during biaxial stretching. Another area that will be addressed is to study the mechanisms of gel drawing by probing labelled molecules. A third area that will be addressed is a study of melting and crystallization behavior of UHMWPE gels and the deformation mechanisms of gel spherulites by conventional time-resolved light scattering, SAXS, WAXD and optical microscopy.