Thermal and mechanical properties of chemical crosslinked polylactide (PLA)

Yang, Senlin; Wu, Zhihua; Yang, Wei

doi:10.1016/j.polymertesting.2008.08.009

Cited by 347 publications

(191 citation statements)

References 31 publications

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“…Overall, the %χ c of the PLA decreased with the introduction of additives. %χ c of the PLA used in this study is much lower than that reported in the literature [12], and this is attributed to the fact that to improve the biodegradability of the PLA resin, supplier has incorporated cereal starch (wheat, potato and tapioca) in this grade of resin. The influence of biological environment on the changes in chemical structure of the native and biodegraded composites can be investigated by the analysis of the infrared spectra.…”

Section: Resultsmentioning

confidence: 59%

Biodegradation of flax fiber reinforced poly lactic acid

Kumar¹,

Yakubu²,

Anandjiwala³

2010

Express Polym. Lett.

120

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Woven and nonwoven flax fiber reinforced poly lactic acid (PLA) biocomposites were prepared with amphiphilic additives as accelerator for biodegradation. The prepared composites were buried in farmland soil for biodegradability studies. Loss in weight of the biodegraded composite samples was determined at different time intervals. The surface morphology of the biodegraded composites was studied with scanning electron microscope (SEM). Results indicated that in presence of mandelic acid, the composites showed accelerated biodegradation with 20–25% loss in weight after 50–60 days. On the other hand, in presence of dicumyl peroxide (as additive), biodegradation of the composites was relatively slow as confirmed by only 5–10% loss in weight even after 80–90 days. This was further confirmed by surface morphology of the biodegraded composites. We have attempted to show that depending on the end uses, we can add different amphiphilic additives for delayed or accelerated biodegradability. This work gives us the idea of biodegradation of materials from natural fiber reinforced PLA composites when discarded carelessly in the environment instead of proper waste disposal site

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Section: Resultsmentioning

confidence: 59%

Biodegradation of flax fiber reinforced poly lactic acid

Kumar¹,

Yakubu²,

Anandjiwala³

2010

Express Polym. Lett.

120

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“…A produção do PLA apresenta inúmeras vantagens: pode ser obtido de fontes agrícolas renováveis, sua produção consome quantidades consideráveis de dióxido de carbono, é reciclável e compostável, sendo uma alternativa do ponto de vista ambiental e apresenta potencial para melhorar a economia nas propriedades agrícolas [1] . Porém este material puro apresenta algumas limitações importantes de aplicação e por isto são encontrados na literatura vários estudos para melhorar suas propriedades físicas e mecânicas tais como flexibilidade, resistência ao impacto e processamento através de aditivação [2][3][4][5] , da preparação de blendas com outros polímeros [6] ou de reticulação [7] . Embalagens termoformadas são produzidas em grande quantidade e a possibilidade em produzi-las com um polímero biodegradável seria de grande relevância do ponto de vista ambiental.…”

Section: Introductionunclassified

Estudo do comportamento térmico e mecânico do PLA modificado com aditivo nucleante e modificador de impacto

Pereira¹,

Morales²

2014

Polímeros

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Resumo: O poliácido lático (PLA) é, dentre os polímeros biodegradáveis, o que apresenta o maior potencial para substituição aos polímeros derivados do petróleo na indústria de embalagens. No entanto uma de suas principais limitações está na baixa estabilidade térmica dimensional. O presente trabalho apresenta um estudo da influência da utilização de dois aditivos: modificador térmico (nucleante) e modificador de impacto, na Temperatura de Distorção Térmica (HDT), no Ponto de Amolecimento Vicat (Vicat) e nas propriedades mecânicas do PLA. Os mecanismos de atuação destes aditivos foram estudados por alterações na temperatura de transição vítrea (Tg) e na cristalinidade medidas por calorimetria diferencial exploratória (DSC) em corpos de prova injetados sem e com tratamento de recozimento. Aplicou-se um planejamento experimental para tratamento estatístico dos dados. Os valores de HDT e de Vicat foram pouco alterados pela presença dos aditivos, embora tenha sido observado aumento nos valores do módulo elástico de tração. O tratamento de recozimento foi responsável pelo aumento tanto na HDT como na Vicat devido ao aumento no grau de cristalinidade. As curvas de DSC mostraram uma grande complexidade no comportamento térmico do PLA, sendo fortemente influenciado pelas condições de tratamento térmico. Palavras-chave: PLA, aditivos nucleantes, propriedades mecânicas, propriedades térmicas. Study of Mechanical and Thermal Behavior of PLA Modified with Nucleating Additive and Impact ModifierAbstract: Poly(lactic acid) (PLA) is the biodegradable polymer with greatest potential to replace petroleum-based polymers for the packaging industry. However one of its major limitations is the poor thermal dimensional stability. This paper presents a study of the influence of two additives: thermal modifier (nucleating) and impact modifier on the Heat Distortion Temperature (HDT), Vicat Softening Temperature (Vicat) and mechanical properties of PLA. The mechanism of these additives was evaluated by analyzing the glass transition temperature (Tg) and degree of crystallinity by Differential Scanning Calorimetry (DSC) in the samples with and without annealing treatment. An experimental design was applied for the statistical treatment of the data. The values of HDT and Vicat were slightly altered by the presence of additives, although the tensile elastic modulus increased. Annealing was responsible for the increase in HDT as well as in Vicat due to an increased degree of crystallinity. DSC curves showed a great complexity in the thermal behavior of PLA, being strongly influenced by the conditions of heat treatment.

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“…It is well known that the degree of swelling is related to the crosslink density where a low degree of swelling indicates a high crosslink density of polymer [14]. The degree of swelling, M -c and crosslink density for three selected samples are presented in Table 2.…”

Section: Resultsmentioning

confidence: 99%

“…Crosslinking could be a good strategy to overcome this disadvantage. Radiation and chemical crosslinking are two well-known methods for osslinking and have been reported in the literatures [7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Silane crosslinking of poly(lactic acid): The effect of simultaneous hydrolytic degradation

Rahmat¹,

Ghasemi²,

Karrabi³

et al. 2015

Express Polym. Lett.

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Abstract. In this work, silane crosslinking of poly (lactic acid) (PLA) was studied. PLA was grafted with vinyltrimethoxysilane (VTMO) via melt mixing in an internal mixer, followed by a crosslinking reaction in hot water for different times. The effect of simultaneous hydrolytic degradation in hot water (70°C) during crosslinking was monitored. Silane grafting of PLA was characterized using mixing torque and gel permeation chromatography (GPC) analysis. The results revealed that by increasing the silane (0-7 wt%) and peroxide (0-0.5 wt%) contents, the degree of grafting was increased. A peak corresponding to higher molecular weight in GPC chromatograms appeared in comparison to pure PLA due to the grafting reaction. Gel content, swelling test, GPC and thermal gravimetric analysis (TGA) were performed to monitor gel structure and concurrent hydrolytic degradation. Results confirmed that the occurrence of hydrolytic degradation during crosslinking and gel content of some samples tended to zero over 10 hr of immersion in hot water. The effect of hydrolytic degradation was not significant up to 10 hr and a tight gel structure was obtained. However, at longer crosslinking times, hydrolytic degradation was the dominant mechanism that leads to network defects.

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Thermal and mechanical properties of chemical crosslinked polylactide (PLA)

Cited by 347 publications

References 31 publications

Biodegradation of flax fiber reinforced poly lactic acid

Biodegradation of flax fiber reinforced poly lactic acid

Estudo do comportamento térmico e mecânico do PLA modificado com aditivo nucleante e modificador de impacto

Silane crosslinking of poly(lactic acid): The effect of simultaneous hydrolytic degradation

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