Enzymatic degradation of poly(L‐lactic acid) fibers: Effects of small drawing
Enzymatic degradation of poly(L‐lactic acid) fibers: Effects of small drawing
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DOI：
10.1002/app.25366
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发表时间：
2007-02
影响因子：
3
通讯作者：
H. Tsuji;Yuki Kidokoro;M. Mochizuki
中科院分区：
文献类型：
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作者：
H. Tsuji;Yuki Kidokoro;M. Mochizuki
采用重量法、扫描电镜（SEM）、凝胶渗透色谱（GPC）、差示扫描量热法（DSC）和拉伸试验研究了不同低拉伸倍数（1.0、1.2和1.4倍）的聚L-乳酸（PLLA）纤维在pH = 8.6的Tris-HCl缓冲溶液中的酶降解行为。令人惊讶的是，即使是很小的拉伸（1.2和1.4倍）也会扰乱蛋白酶K催化的PLLA纤维的酶促降解。这应该是因为酶不能附着在单轴取向PLLA纤维的无定形区域中的延伸（应变）链上，或者不能催化应变链的裂解。没有观察到由于选择性裂解而形成的结晶残留物的积累和无定形链的去除，即使对于初生PLLA纤维也是如此。这表明在酶降解过程中，所形成的结晶残留物从初生PLLA纤维的表面容易释放。这种释放可能是因为初生PLLA纤维的结晶区域以其c轴平行于机器方向取向，如双轴取向PLLA膜所报道的。重量分析法、SEM和拉伸测试可以追踪PLLA纤维的酶降解，但GPC和DSC无法追踪PLLA纤维的酶降解。© 2006 Wiley Periodicals，Inc.应用聚合物科学杂志103：2064-2071，2007
The enzymatic degradation of poly(L-lactic acid) (PLLA) fibers with different low draw ratios (1.0, 1.2, and 1.4 times) was investigated in tris-HCl buffer solution (pH = 8.6) with proteinase K by the use of gravimetry, scanning electron microscopy (SEM), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and tensile testing. Surprisingly, even the small drawings (1.2 and 1.4 times) disturbed the proteinase K catalyzed enzymatic degradation of the PLLA fibers. This should have been because the enzyme could not attach to the extended (strained) chains in the amorphous regions of the uniaxially oriented PLLA fibers or could not catalyze the cleavage of the strained chains. The accumulation of crystalline residues formed as a result of selective cleavage, and removal of the amorphous chains was not observed, even for as-spun PLLA fibers. This indicated the facile release of formed crystalline residues from the surface of the as-spun PLLA fibers during enzymatic degradation. Such release may have been because the crystalline regions of the as-spun PLLA fibers were oriented with their c axis parallel to the machine direction, as reported for biaxially oriented PLLA films. Gravimetry, SEM, and tensile testing could trace the enzymatic degradation of the PLLA fibers, although the enzymatic degradation of the PLLA fibers was untraceable by GPC and DSC. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2064–2071, 2007