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Enzymatic degradation of poly( L ‐lactic acid) fibers: Effects of small drawing
Author(s) -
Tsuji Hideto,
Kidokoro Yuki,
Mochizuki Masatsugu
Publication year - 2006
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.25366
Subject(s) - differential scanning calorimetry , ultimate tensile strength , materials science , scanning electron microscope , gel permeation chromatography , amorphous solid , degradation (telecommunications) , hydrolysis , chemical engineering , enzymatic hydrolysis , cleavage (geology) , composite material , polymer chemistry , polymer , chemistry , organic chemistry , telecommunications , physics , fracture (geology) , computer science , engineering , thermodynamics
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