Thermal and crystallization behaviour of gamma irradiated PLLA

Miličević, Dejan; Trifunović, S.; Galović, S.; Suljovrujić, E.

doi:10.1016/j.radphyschem.2007.02.035

Cited by 43 publications

(36 citation statements)

References 14 publications

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“…Also, residues of PLLA in vivo have been observed after 7 years of implantation. Also worth noting for biomedical uses of PLLA is the increase in crystallinity due to gamma ray irradiation with the formation of new thin crystal lamellae [86].…”

Section: Hydrolytic Degradationmentioning

confidence: 99%

Crystallization and Thermal Properties

Fambri

Migliaresi

2010

Poly(Lactic Acid)

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Section: Hydrolytic Degradationmentioning

confidence: 99%

Crystallization and Thermal Properties

Fambri

Migliaresi

2010

Poly(Lactic Acid)

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“…Moreover, it also can be used as drug release, operative suture, antiadhesion membrane and so on in the medical field. However, its low heat resistance is the main shortcoming in its use as commodity material [1][2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Thermal degradation behavior and kinetic analysis of poly(L-lactide) in nitrogen and air atmosphere

Run

Yao

2010

Front. Mater. Sci. China

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The non-isothermal and isothermal degradation behaviors and kinetics of poly(L-lactide) (PLLA) were studied by using thermogravimetry analysis (TGA) in nitrogen and air atmosphere, respectively. At lower heating rate ((5-10)°C/min), PLLA starts to decompose in air at lower temperature than those in nitrogen atmosphere; however, at higher heating rate ((20-40)°C/min), the starting decomposition temperature in air are similar to those in nitrogen atmosphere, not only showing that PLLA has better thermal stability in nitrogen than in air atmosphere, but also suggesting that the faster heating rate will decrease the decomposition of PLLA in thermal processing. Whether in air or in nitrogen atmosphere, the decomposition of PLLA has only one-stage degradation with a first-order decomposed reaction, suggesting that the molecular chains of PLLA have the similar decomposed kinetics. The average apparent activation energy of nonisothermal thermal degradation (Ē non ) calculated by Ozawa theory are 231.7 kJ$mol -1 in air and 181.6 kJ$mol -1 in nitrogen; while the average apparent activation energy of isothermal degradation (Ē iso ) calculated by Flynn method are 144.0 kJ$mol -1 in air and 129.2 kJ$mol -1 in nitrogen, also suggesting that PLLA is easier to decompose in air than in nitrogen. Moreover, the decomposed products of PLLA are also investigated by using thermogravimetrydifferential scanning calorimetry-mass spectrometry (TG-DSC-MS). In air atmosphere the volatilization products are more complex than those in nitrogen because the oxidation reaction occurring produces some oxides groups.

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“…Besides, EB irradiation can cause in parallel sterilization of the materials,16 which is important for medical applications. Some people have studied the degradation behavior of gamma irradiated PLLA, reporting that PLLA has a high sensitivity to gamma radiation, whose thermal and mechanical properties decrease significantly due to the drastic decrease in the molecular weight 17–20. Recently, some studies report an approach to control the degradation rate of PLLA and poly(lactide‐ co ‐glycolide) (PLGA) using EB irradiation under air atmosphere 6, 15, 21‐23.…”

Section: Introductionmentioning

confidence: 99%

Degradation of poly(D,L‐lactic acid)‐b‐poly(ethylene glycol) copolymer and poly(L‐lactic acid) by electron beam irradiation

Miao

Zeng

et al. 2010

J of Applied Polymer Sci

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This article investigated the effects of electron beam (EB) irradiation on poly(D,L-lactic acid)-b-poly-(ethylene glycol) copolymer (PLEG) and poly(L-lactic acid) (PLLA). The dominant effect of EB irradiation on both PLEG and PLLA was chain scission. With increasing dose, recombination reactions or partial crosslinking of PLEG can occur in addition to chain scission, but there was no obvious crosslinking for PLLA at doses below 200 kGy. The chain scission degree of irradiated PLEG and PLLA was calculated to be 0.213 and 0.403, respectively. The linear relationships were also established between the decrease in molecular weight with increasing dose. Elongation at break of the irradiated PLEG and PLLA decreased significantly, whereas the tensile strength and glass transition temperature of PLLA decreased much more significantly compared with PLEG. The presence of poly(ethylene glycol) (PEG) chain segment in PLEG was the key factor in its greater stability to EB irradiation compared with PLLA.

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Thermal and crystallization behaviour of gamma irradiated PLLA

Cited by 43 publications

References 14 publications

Crystallization and Thermal Properties

Crystallization and Thermal Properties

Thermal degradation behavior and kinetic analysis of poly(L-lactide) in nitrogen and air atmosphere

Degradation of poly(D,L‐lactic acid)‐b‐poly(ethylene glycol) copolymer and poly(L‐lactic acid) by electron beam irradiation

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