久久精品免费观看_欧美日韩精品电影_91看片一区_日日夜夜天天综合

據悉，MIT研究人員通過凝膠電紡工藝獲得超強又韌的超高分子量聚乙烯納米纖維，力學性能超過凱夫拉。最大的特點是又強又韌，從下圖中可以看出，其它很多超強材料強度和韌性不可兼顧。而且制備成本不高，可實現產業化，作為超強纖維，可預見其未來的應用前景。這么牛逼的材料可能是由于高結晶度、結晶取向和纖維內部缺陷少等綜合因素造成。有興趣的朋友請閱讀參考文獻。

不同直徑超高分子量聚乙烯纖維力學與本體材料力學數據如下：

凝膠電紡示意圖：

文獻資料：Ultrafine high performance polyethylene fibers，

Abstract
Stiff, strong and tough ultrafine polyethylene fibers that rival the best high performance fibers, but with diameters less than one micron, are fabricated for the first time by “gel-electrospinning.” In this process, solution concentration and process temperatures are chosen to induce the formation of gel filaments “in flight,” which are subsequently drawn at high rates as a consequence of the whipping instability. The resulting submicron-diameter fibers exhibited Young’s moduli of 73 ± 13 GPa, yield strengths of 3.5 ± 0.6 GPa, and toughnesses of 1.8 ± 0.3 GPa, on average. Among the smallest fibers examined, one with a diameter of 490 ± 50 nm showed a Young’s modulus of 110 ± 16 GPa, ultimate tensile strength of 6.3 ± 0.9 GPa, and toughness of 2.1 ± 0.3 GPa, a combination of mechanical properties that is unparalleled among polymer fibers to date. The correlation of stiffness, strength and toughness with fiber diameter is attributed to high crystallinity and crystallite orientation, combined with fewer defects and enhanced chain slip associated with small diameter and high specific surface area. Gel-electrospinning improves the prospects for production of such fibers at scale.