Poly(l-lactide): 7. Enzymatic hydrolysis of free and restricted amorphous regions in poly(l-lactide) films with different crystallinities and a fixed crystalline thickness

Tsuji, Hideto; Miyauchi, Shinya

doi:10.1016/s0032-3861(00)00792-8

Cited by 115 publications

(110 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Proteinase K works by irreversibly adsorbing on the surface of the PLA film before catalysing the hydrolysis of the ester bond. Tsuji and Miyauchi [41] studied the effect of crystallinity on the enzymatic degradation of PLLA films in the presence of proteinase K and found that the amorphous region outside of the spherulite was predominantly degraded rather than that inside. However, proteinase K can still access to the intra-spherulite amorphous phase and hydrolyse the spherulitic superstructure.…”

Section: Pla Crystallization Kineticsmentioning

confidence: 99%

Multi-scale analysis of the impact of polylactide morphology on gas barrier properties

Nassar

Guinault

Delpouve

et al. 2017

Polymer

View full text Add to dashboard Cite

scale analysis of the impact of polylactide morphology on gas barrier properties. Polymer, Elsevier, 2017, 108, pp.163-172. 10.1016/j.polymer.2016 Multi-scale analysis of the impact of polylactide morphology on gas barrier properties Samira Fernandes Nassar t r a c tSemicrystalline polylactide (PLA) films with controlled morphology were produced by thermal crystallization to optimize the oxygen barrier properties. The crystalline morphology of PLA at the scales of the lamella and the spherulite was investigated and the mobile amorphous phase dynamics were studied. The crystalline morphology had a negligible impact on the oxygen diffusion coefficient. The occurrence of a rigid amorphous fraction (RAF) in the amorphous phase due to its insufficient decoupling from the crystalline phase provided an accelerated pathway for diffusion, though. As a conclusion, for reaching optimal barrier properties, semicrystalline PLA should be pre-nucleated and rapidly crystallized from the glass in the a-polymorph in the aim to reach a high crystallinity degree and decoupling of the amorphous and the crystalline phase. These recommendations can benefit to industry for the optimization of PLA annealing treatments.

show abstract

Section: Pla Crystallization Kineticsmentioning

confidence: 99%

Multi-scale analysis of the impact of polylactide morphology on gas barrier properties

Nassar

Guinault

Delpouve

et al. 2017

Polymer

View full text Add to dashboard Cite

show abstract

“…14, 15 The hydrolysis mechanisms of PLLA films under different conditions are summarized in Table IV. The LMW specific peak ascribed to the crystalline residues, 10 -15 which are formed by predominant hydrolysis and removal of the chains in the amorphous region, appears for the crystallized PLLA140 film at a molecular weight of around 6 ϫ 10 3 when hydrolyzed at pH 12 for 120 days [ Fig. 2(d)].…”

Section: Molecular Weight Changementioning

confidence: 99%

“…Hydrolysis of PLLA films proceeds via mainly a surface erosion mechanism in the alkaline solution (pH 12) 13 and the proteinase K/Tris-HCl buffer solution system, 14,15 whereas in phosphate-buffered solution it proceeds homogeneously along the film cross section via mainly a bulk erosion mechanism. 10 -12 2.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Poly(L‐lactide). IX. Hydrolysis in acid media

Tsuji

Nakahara

2002

J of Applied Polymer Sci

Self Cite

113

View full text Add to dashboard Cite

Amorphous and crystallized poly(l-lactide) (PLLA) films are prepared by quenching and annealing at 140°C for 600 min, respectively, from the melt. Their hydrolysis is investigated at pH 2.0 in HCl and dl-lactic acid (DLLA) solutions (37°C) for up to 300 days, and the results are compared with those obtained for PLLA films hydrolyzed at pH 7.4 (phosphate-buffered solution) and pH 12 (NaOH solution). The changes in the weight loss and molecular weight distribution of the PLLA films during hydrolysis in the acid media reveals that their hydrolysis proceeds homogeneously along the film cross section by mainly a bulk erosion mechanism. Moreover, the durability of PLLA films in the acid media is very similar to that in the neutral medium but higher than that in the alkaline medium. The hydrolysis rate constant values (k) of the initially amorphous PLLA0 film evaluated from the changes in the numberaverage molecular weight were 3.0 and 2.4 ϫ 10 Ϫ3 day Ϫ1 at pH 2.0 in the HCl and DLLA solutions, respectively. These k values are very similar to 2.6 ϫ 10 Ϫ3 day Ϫ1 at pH 7.4 in the phosphate-buffered solution. The similar k values and the negligible weight loss after the hydrolysis for 300 days reflect that the hydronium ions and the lactic acid oligomers and monomers have insignificant catalytic effects on the hydrolysis of the PLLA films. Increasing the initial crystallinity of the PLLA film increases the hydrolysis rate in the HCl solution, whereas increasing the initial crystallinity of the PLLA film does not alter the hydrolysis rate in the DLLA solution. The differential scanning calorimetry results show that the crystallization of PLLA chains occurs during the hydrolysis, irrespective of the hydrolysis acid media and the initial crystallinity.

show abstract

“…It was shown that the thermal stability of aliphatic polyesters is small regarding: (1) a hydrolysis as a result of small amount of water existing; (2) zipper-like de-polymerization catalyzed by the residual catalyst; (3) oxidative degradation leading to the random scission of the main backbone; (4) intramolecular transesterification of monomers and oligomers; and (5) intermolecular transesterification creating small molecular weight compounds (monomers and oligomers) [9]. The application of polyesters for biomedical purposes requires the fundamental knowledge of their stability in biomedical environment, but still there is poor information available regarding this type of hydrolysis [11].…”

Section: Introductionmentioning

confidence: 99%

Thermal Aging Study of Biodegradable Polymer Materials by Dielectric Thermal Analysis

Kujundziski

Chamovska

2018

JEPM

View full text Add to dashboard Cite

show abstract

Poly(l-lactide): 7. Enzymatic hydrolysis of free and restricted amorphous regions in poly(l-lactide) films with different crystallinities and a fixed crystalline thickness

Cited by 115 publications

References 16 publications

Multi-scale analysis of the impact of polylactide morphology on gas barrier properties

Multi-scale analysis of the impact of polylactide morphology on gas barrier properties

Poly(L‐lactide). IX. Hydrolysis in acid media

Thermal Aging Study of Biodegradable Polymer Materials by Dielectric Thermal Analysis

Contact Info

Product

Resources

About