Influence of low molecular weight lactic acid derivatives on degradability of polylactide

Abstract

ABSTRACT:The presence of low molecular weight lactic acid derivatives in films enhanced the degradability of polylactide in a biotic medium. Two different biotic and abiotic series were investigated. The films used for the first abiotic and biotic series (a-1 and b-1 films) initially contained some lactic acid and lactoyl lactic acid, while the films used for the second abiotic and biotic series (a-2 and b-2 films) did not originally contain them. The b-1 films decreased in molecular weight during 3 weeks in the biotic medium, while no molecular weight decrease was seen in the a-1 films aged in a corresponding abiotic mineral medium. The molecular weight for the a-2 and b-2 films without lactic and lactoyl lactic acid remained almost constant. Scanning electron microscopy micrographs showed a larger amount of bacteria and fungi growing on the surface of b-1 films compared to b-2 films; thus, the presence of easily assimilated lactic acid and lactoyl lactic acid in the films improved the initial growth of microorganisms on the film surfaces. Gas chromatography and mass spectrometry analysis showed that lactic acid and lactoyl lactic acid were rapidly assimilated from the films aged in a biotic medium. New degradation products (e.g., ethyl ester of lactoyl lactic acid, acetic acid, and propanoic acid) were formed during aging in a biotic medium. Acetic acid and propanoic acid were formed as intermediate degradation products during the initial stages, but they were no longer detected after prolonged aging. The concentration of the ethyl ester of lactoyl lactic acid increased with aging time.

PY-GC/MS an effective technique to characterizing of degradation mechanism of poly (L-lactide) in the different environment

“…10 It has been demonstrated that the easily assimilated lactic acid and lactoyl lactic acid formed during the degradation process promote the bio-degradation of PLA. 11 We have developed techniques to analyze and identify the hydrolysis products from aliphatic polyesters. 12,13 Despite the extensive data reported in the literature, some aspects of PLLA biodegradation are, however, still not completely understood.…”

Poly(L‐lactide)‐Degrading Activity in Various Actinomycetes

“…[10] The other degradation products of PLA, i.e., ethyl ester of lactoyl lactic acid, propionic acid, and acetic acid, were also observed during aging with a mixed culture of microorganisms from compost. [20,21] The residual PLA films recovered from the culture broth may contain other cell lysis substances, such as a lipid layer of the cells released during chloroform extraction. However, the residual films were efficiently recovered by this extraction method.…”

Biodegradable Polymeric Nanoparticles as Templates for Biomimetic Mineralization of Calcium Phosphate

“…[3] The chemical properties of these polymers allow hydrolytic degradation through de-esterification. [4] The degradation occurs by uptake of water followed by the hydrolysis of the ester bonds. Several factors play role in the degradation kinetics of these polymers like the chemical composition, the molar mass, environmental conditions, the crystallinity, the hydrophobicity, etc.…”