Hydrolytic Degradation of Poly DL-(Lactide)

Mason, N. S.; Miles, C. S.; Sparks, Robert

doi:10.1007/978-1-4757-9510-3_20

Cited by 22 publications

(10 citation statements)

References 9 publications

(11 reference statements)

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“…The v c was evaluated from the heat of fusion measured by DSC in reference to the heat of fusion reported for the 100% crystalline PLLA. [11,13] The plots are almost on the linear dotted line that is based on the assumption that v c of the blends should be proportional to the composition of the crystalline PLA99.0. Tsuji reported that v c of the blends of PLLA and PDLLA is proportional to the composition of PLLA as shown by the half-dotted line.…”

Section: Properties Of Blend Specimensmentioning

confidence: 99%

Properties and Biodegradability of Polymer Blends of Poly(L-lactide)s with Different Optical Purity of the Lactate Units

Urayama

Kanamori

Kimura

2002

Macromol. Mater. Eng.

139

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Section: Properties Of Blend Specimensmentioning

confidence: 99%

Properties and Biodegradability of Polymer Blends of Poly(L-lactide)s with Different Optical Purity of the Lactate Units

Urayama

Kanamori

Kimura

2002

Macromol. Mater. Eng.

139

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“…[16] Fischer et al investigated the effects of l-lactide content and L c on the alkaline hydrolysis of the single crystals of l-lactide-rich PLAs with different l-lactide contents, [22] while Cam et al studied the X c effects on the alkaline hydrolysis of as-cast PLLA films with different molecular weights. [23] The effects of temperature on the hydrolysis of PLLA and poly(dl-lactide) (PDLLA) were studied by Mason et al [24] and Makino et al [25] and they estimated the activation energy for their hydrolysis from the decrease rates in viscosity and weight-average molecular weight, respectively, at different temperatures. Buchholz [26] and Dauner et al [27] studied the hydrolysis of tablets, fibers, nonwovens, and sheets of PLLA and PDLLA at 80 8C in phosphate-buffered solution using gravimetry and viscometry, while Jamshidi et al [28] investigated the hydrolysis of PLLA fibers at 100 8C in phosphate-buffered solution with gravimetry and tensile testing.…”

Section: Introductionmentioning

confidence: 99%

Poly(L-Lactide), 8. High-Temperature Hydrolysis of Poly(L-Lactide) Films with Different Crystallinities and Crystalline Thicknesses in Phosphate-Buffered Solution

Tsuji¹,

Nakahara

Ikarashi

2001

Macromol. Mater. Eng.

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“…21 They found that the acid media slightly accelerates the hydrolysis of PDLLA 17,18 and the water absorption of PDLLA hydrolyzed at pH 3.7 was much lower than that hydrolyzed at pH 7.4. 21 Shih revealed that in acid media the hydrolytic scission at the PDLLA chain ends is faster than that of the internal ester bonds and in alkaline media the hydrolysis proceeds by random chain scission.…”

mentioning

confidence: 97%

“…The effects of pH on the hydrolysis of poly(dllactide) [i.e., poly(dl-lactic acid) (PDLLA)] were studied by Mason et al, 17 Makino et al, 18 Shih,19,20 and Li and McCarthy. 21 They found that the acid media slightly accelerates the hydrolysis of PDLLA 17,18 and the water absorption of PDLLA hydrolyzed at pH 3.7 was much lower than that hydrolyzed at pH 7.4.…”

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confidence: 99%

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

Tsuji

Nakahara

2002

J of Applied Polymer Sci

113

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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.

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Hydrolytic Degradation of Poly DL-(Lactide)

Cited by 22 publications

References 9 publications

Properties and Biodegradability of Polymer Blends of Poly(L-lactide)s with Different Optical Purity of the Lactate Units

Properties and Biodegradability of Polymer Blends of Poly(L-lactide)s with Different Optical Purity of the Lactate Units

Poly(L-Lactide), 8. High-Temperature Hydrolysis of Poly(L-Lactide) Films with Different Crystallinities and Crystalline Thicknesses in Phosphate-Buffered Solution

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

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