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首页> 外文期刊>Journal of Applied Polymer Science >Effects of molecular architecture on two-step, melt-spun poly(lactic acid) fibers
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Effects of molecular architecture on two-step, melt-spun poly(lactic acid) fibers

机译：分子结构对两步熔纺聚乳酸纤维的影响

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摘要

Fibers of poly(lactic acid) (PLA) produced by two-step melt spinning have been studied. The PLA resins used contain a 96:04 ratio of L:D stereochemical centers; however, one of the materials is branched by a peroxide treatment. The thermal, mechanical, and morphological properties of the fibers are compared for the two different molecular architectures. In the branched material, at least some of the branches exceed the entanglement molecular weight. The branched material is accordingly characterized by greater shear and extensional viscosity than the linear material. Fiber properties are highly influenced by the draw ratio; both branched and linear materials reach a plateau of about 35% crystallinity. The branched polymer reaches the plateau at a lower draw ratio, and this is indicative of faster crystallization kinetics. Both materials shrink in boiling water, and the amount of shrinkage decreases with increasing draw ratio. At an intermediate draw ratio of 6, the branched material is characterized by significantly larger shrinkage. With small-angle X-ray scattering and atomic force microscopy, the morphology is found to be fibrillar. Microfibril diameters range from approximately 20 to 30 run and are almost identical for the two molecular architectures studied. (C) 2002 Wiley Periodicals, Inc. [References: 28]
机译：研究了通过两步熔融纺丝生产的聚乳酸（PLA）纤维。所用的PLA树脂的L：D立体化学中心比例为96:04;然而，其中一种材料是通过过氧化物处理而分支的。比较了两种不同分子结构的纤维的热，机械和形态特性。在支链材料中，至少一些支链超过缠结分子量。因此，支链材料的特征在于比线性材料更大的剪切和拉伸粘度。纤维性能受拉伸比的影响很大。支链和线性材料均达到约35％结晶度的平台。支链聚合物以较低的拉伸比达到平台，这表明结晶动力学较快。两种材料都在沸水中收缩，并且收缩量随着拉伸比的增加而减小。在6的中间拉伸比下，支化材料的特征在于明显更大的收缩率。通过小角度X射线散射和原子力显微镜检查，发现其形态为原纤维状。微纤维直径范围从大约20到30纳米，并且对于所研究的两种分子结构几乎相同。 （C）2002 Wiley Periodicals，Inc. [参考：28]

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