Effect of crystallinity and loading-rate on mode I fracture behavior of poly(lactic acid)
Effect of crystallinity and loading-rate on mode I fracture behavior of poly(lactic acid)
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DOI：
10.1016/j.polymer.2005.12.046
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发表时间：
2006-02-08
期刊：
影响因子：
4.6
通讯作者：
Koganemaru, M
中科院分区：
文献类型：
--
作者：
Park, SD;Todo, M;Koganemaru, M
本研究的目的是表征可生物降解聚乳酸（PLA）的断裂行为。特别强调了结晶度和加载速率对断裂行为的影响。对所制备的PLA样品进行退火以控制结晶度，然后在准静态和冲击载荷条件下测量其断裂韧性值。结果表明，PLA的准静态断裂韧性随着结晶度的增加而降低；另一方面，冲击断裂韧性往往随着结晶度的增加而增加。通过偏光显微镜和扫描电子显微镜观察了不同结晶度的PLA试样的裂纹扩展行为。微观结果表明，在准静态加载下，裂纹尖端区域的多个裂纹消失导致断裂韧性随着结晶度的降低而降低。反之，在冲击载荷作用下。断裂韧性随结晶度的增加被认为与原纤维形成的增加有关。 (c) 2005 Elsevier Ltd. 保留所有权利。
The aim of this study is to characterize the fracture behavior of biodegradable poly(lactic acid) (PLA). Especially, the effects of crystallinity and loading-rate on the fracture behavior are emphasized. Annealing was performed to control the crystallinity of the PLA samples prepared, and then their fracture toughness values were measured under quasi-static and impact loading conditions. The results showed that the quasi-static fracture toughness of PLA decreases with increase of crystallinity; on the other hand, the impact fracture toughness tends to increase with crystallinity. The crack growth behaviors of the PLA specimens having different crystallinity were also observed by polarizing and scanning electron microscopies. The microscopic results exhibited that under quasi-static loading, disappearance of multiple crazes in the crack-tip region results in the decrease of the fracture toughness with crystallinity. On the contrary, under impact loading. the increase of the fracture toughness with crystallinity is considered to be related to the increase of fibril formation. (c) 2005 Elsevier Ltd. All rights reserved.