Toughening semicrystalline poly(lactic acid) by morphology alteration

Rathi, Sahas

doi:10.1016/j.polymer.2011.07.032

Cited by 68 publications

(51 citation statements)

References 42 publications

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“…The strain at break before annealing is not reported in this figure since its value is close to 20%. It is noteworthy that this value, though higher than what is usually reported in the literature for PLA [35], has already been observed by several groups especially for extruded samples [36,37]. During the oxidation process, strain at break values drop with increasing exposure time and reach a value close to zero after a time depending on the exposure temperature, about 150, 250 and 500 hours for 150, 130 and 100°C respectively.…”

Section: ) Ageing Conditionsmentioning

confidence: 46%

Oxidative degradation of polylactide (PLA) and its effects on physical and mechanical properties

Rasselet¹,

Ruellan²,

Guinault³

et al. 2014

European Polymer Journal

142

102

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. AbstractThe thermo-oxidative degradation of polylactide (PLA) films was studied between 70 and 150°C. It was shown that the oxidative degradation of PLA leads to a random chain scission responsible for a reduction of the molar mass. These molar mass changes affect Tg and the degree of crystalllinity, and it was found that Tg decreases according to the Fox-Flory theory whereas the degree of crystalllinity increases due to a chemicrystallization process. A correlation between molar mass and strain at break during oxidation has been established:PLA displays a brittle behaviour when M n falls below 40 kg.mol -1 in agreement with relationships linking the critical value for embrittlement with the molar mass between entanglements.

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Section: ) Ageing Conditionsmentioning

confidence: 46%

Oxidative degradation of polylactide (PLA) and its effects on physical and mechanical properties

Rasselet¹,

Ruellan²,

Guinault³

et al. 2014

European Polymer Journal

142

102

View full text Add to dashboard Cite

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“…By introducing a polymer consisting of all D isomer (PDLA) based triblock copolymer it is possible to convert PLLA from a stiff, brittle material to a soft, flexible rubbery material [15][16][17]. In these blends the slow quiescent crystallization of poly(L-lactic acid) (PLLA) and the preferential crystallization of the PLA stereocomplex resulted in the formation of a morphology that can be described as stereocomplex crystals dispersed in a soft continuous amorphous phase when the softblock used in the triblock copolymer was miscible with PLLA [15].…”

Section: Introductionmentioning

confidence: 99%

“…In these blends the slow quiescent crystallization of poly(L-lactic acid) (PLLA) and the preferential crystallization of the PLA stereocomplex resulted in the formation of a morphology that can be described as stereocomplex crystals dispersed in a soft continuous amorphous phase when the softblock used in the triblock copolymer was miscible with PLLA [15]. In addition it was found that on addition of a molecular plasticizer to these blends, further improvement in the rubbery property of the blend was obtained [17]. Despite the attractive mechanical properties achieved, it was found that because of the hydrophilic nature of the soft mid-block used in the triblock copolymer, the degradation of PLLA was accelerated in these blends during melt processing leading to a significant drop in the molecular weight of PLLA.…”

Section: Introductionmentioning

confidence: 99%

Maintaining Structural Stability of Poly(lactic acid): Effects of Multifunctional Epoxy based Reactive Oligomers

et al. 2014

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Abstract:In order to reduce the effects of hydrolytic degradation and to maintain sufficient viscosity during processing of biomass based poly(L-lactic acid) (PLLA), various epoxy functional reactive oligomers have been characterized and incorporated into the degraded fragments as chain extenders. The molecular weight of PLLA increased with the increase in functionality of the reactive oligomers. No further increase in molecular weight was observed for oligomers with functionality of greater than five. Under our experimental conditions, no gelation was found even when the highest functionality reactive oligomers were used. This is attributed to the preferential reaction of the carboxylic acid versus the negligible reactivity of the hydroxyl groups, present at the two ends of the degraded PLLA chains, with the epoxy groups. The study provides a clear understanding of the degradation and chain extension reaction of poly(lactic acid) (PLA) with epoxy functional reactive oligomers. It is also shown that a higher functionality and concentration of the reactive oligomers is needed, to bring about a sufficient increase in the molecular weight and hence the hydrolytic stability in circumstances when PLA chains suffer significant degradation during processing.

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“…Many modifications have been made to improve the mechanical properties of PLA, more specifically its toughness. Thus, there are numerous approaches to modify the mechanical properties of PLA, such as plasticization [5], block-copolymerization [6] and blending with flexible polymers or rubber toughening [7,8]. Blending is the preferred way to improve the mechanical properties of PLA because it is less cost and more practical [9,10].…”

Section: Introductionmentioning

confidence: 99%

Preparation and characterization of reactive blends of poly(lactic acid), poly(ethylene-co-vinyl alcohol), and poly(ethylene-co-glycidyl methacrylate)

Phromma

Jana

Magaraphan

2015

AIP Conference Proceedings

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Toughening semicrystalline poly(lactic acid) by morphology alteration

Cited by 68 publications

References 42 publications

Oxidative degradation of polylactide (PLA) and its effects on physical and mechanical properties

Oxidative degradation of polylactide (PLA) and its effects on physical and mechanical properties

Maintaining Structural Stability of Poly(lactic acid): Effects of Multifunctional Epoxy based Reactive Oligomers

Preparation and characterization of reactive blends of poly(lactic acid), poly(ethylene-co-vinyl alcohol), and poly(ethylene-co-glycidyl methacrylate)

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