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Title: Hydrolytic kinetics of biodegradable polyester monolayers

Journal Article · · Langmuir
DOI:https://doi.org/10.1021/la990800r· OSTI ID:20075524

The rate of hydrolysis of Langmuir monolayer films of a series of biodegradable polyesters was investigated at the air/water interface. The present study investigated parameters such as degradation medium, pH, and time. The hydrolysis of polyester monolayers strongly depended on both the degradation medium used to control subphase pH and the concentration of active ions. Under the conditions studied here, polymer monolayers showed faster hydrolysis when they were exposed to a basic subphase rather than that of acidic or neutral subphase. The basic (pH = 10) hydrolysis of [poly(l-lactide)/polycaprolactone](l-PLA/PCL 1/1 by mole) blend was faster than that of each homopolymer at the initial stage. This result is explained by increasing numbers of base attack sites per unit area owing to the very slow hydrolysis of PCL, a dilution effect on the concentration of l-PLA monolayers. Conversely the hydrolytic behavior of l-lactide-co-caprolactone (1/1 by mole) was similar to that of PCL even though the chemical compositions of the blend and the copolymer are very similar to each other. The resistance of the copolymer to hydrolysis might be attributed to the hydrophobicity and the steric hindrance of caprolactone unit in the copolymer.

Research Organization:
State Univ. of New York, Buffalo, NY (US)
OSTI ID:
20075524
Journal Information:
Langmuir, Vol. 16, Issue 7; Other Information: PBD: 4 Apr 2000; ISSN 0743-7463
Country of Publication:
United States
Language:
English