Biodegradability of Poly (L-lactic Acid) Functionally Graded Materials with Hardness Gradient
Biodegradability of Poly (L-lactic Acid) Functionally Graded Materials with Hardness Gradient
复制标题
具有硬度梯度的聚(L-乳酸)功能梯度材料的生物降解性
DOI：
10.2320/matertrans.45.1005
复制
发表时间：
2004
影响因子：
1.2
通讯作者：
Y. Ohkoshi
中科院分区：
文献类型：
--
作者：
Yoshimi Watanabe;T. Iwamoto;A. Teramoto;K. Abe;Y. Ohkoshi
本研究的目的是开发一种具有硬度梯度的可生物降解聚（L-乳酸）（PLLA）功能梯度材料（FGM）。为此，在高温下挤出 PLLA 以引入分子取向。进行了两种类型的挤压：直接挤压和等通道角（ECA）挤压。还在 50°C、60°C 和 70°C 下进行了无挤压的热处理。为了表征机械性能，使用维氏显微硬度计研究了硬度分布。通过评估在 37℃ 生理盐水溶液中孵育后的质量减少率来测量 PLLA FGM 的生物降解性。结果发现，分别通过直接挤出和高温 ECA 挤出可以制备具有对称和不对称硬度梯度的 PLLA FGM。虽然在初始状态下PLLA的质量随着FGM的软化而逐渐增加，但两周后开始减少。
The aim of this study is to develop a functionally graded material (FGM) of biodegradable poly (L-lactic acid) (PLLA) with a hardness gradient. For this purpose, the PLLA was extruded at elevated temperatures to introduce molecular orientation. Two types of extrusion, direct extrusion and equal channel angular (ECA) extrusion, were carried out. Heat treatment without extrusion was also carried out at 50 � C, 60 � C and 70 � C. For the mechanical property characterization, the hardness distributions were investigated using a Vickers microhardness tester. Biodegradability of PLLA FGM was measured by evaluating the mass decreasing ratio after incubation in a physiological saline solution at 37 � C. It was found that the PLLA FGMs with symmetric and asymmetric hardness gradients could be fabricated by direct extrusion and ECA extrusion at elevated temperature, respectively. Although in the initial state the mass of PLLA gradually increased with the softening of the FGM, it started to decrease after two weeks.