Effect of natural weather on the structure and properties of polylactide/Cloisite 30B nanocomposites

Zaidi, Lynda; Kaci, Mustapha; Bruzaud, Stéphane; Bourmaud, Alain; Grohens, Yves

doi:10.1016/j.polymdegradstab.2010.05.014

Cited by 137 publications

(101 citation statements)

References 30 publications

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“…They observed a decrease in the molecular weight of the PE/MMT nanocomposites that was attributed to the occurrence of chain scission reactions during photo-oxidation. In addition, Zaidi, L. et al [15] showed that the photo-oxidation rates of PLA were increased in the presence of C30B. Also, the same effect of the MMT into PLA matrix on the degradation rate was found by Araujo, A. et al [28].…”

Section: Number Average Molecular Weight Decay Due To Artificial Weatmentioning

confidence: 66%

“…Previous studies of PLA nanocomposites indicate that chain scission was the most prominent phenomenon in natural weathering [14]. Zaidi, L. et al (2010) [15] found that the weathering effect on the morphology of exposed samples observed by SEM (Scanning electron microscope) revealed fractured surfaces exhibiting many voids and cracks. These defects were much more pronounced for the PLA nanocomposites.…”

Section: Introductionmentioning

confidence: 94%

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Effect of Artificial Weathering on PLA/Nanocomposite Molecular Weight Distribution

et al. 2015

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Abstract:The reduction of polylactide acid (PLA) molecular weight for amorphous and semicrystalline grade nanocomposites with 5 wt% load of organomodified montmorillonite Cloisite30B (C30B) was investigated in periods of up to 360 h under artificial weathering. A correlation between artificial and natural weathering was established. The nanocomposites were prepared by mixing the C30B in PLA matrix using two stages of extrusion followed by injection molding. In addition, we also studied materials without C30B in PLA matrix prepared by a single stage of injection, as well as with two stages of extrusion followed by injection, in order to assess thermal effects. XRD (X-ray diffraction) and TEM (Transmission electron microscope) were used to determine the layer dispersion of the C30B within the PLA. An increase in the interlayer spacing of a sandwich structure corresponding to a partial exfoliation of the C30B was found, leading to the creation of OPEN ACCESSPolymers 2015, 7 761 small particles at nanoscale of one (1.29 nm) to eight (11.76 nm) platelets. Also, GPC (Gel permeation chromatography) was used to evaluate the molecular weight decay of neat PLA and its nanocomposites due to thermal processing and subsequent artificial weathering exposure. From thermal processing, a more significant decrease of polydispersity in amorphous PLA than in semicrystalline PLA counterparts could be observed. First order fitting of molecular weight decay of samples versus time of exposure under artificial weathering was found for all materials tested. It was observed that the addition of clay favored PLA degradation in amorphous PLA, in comparison with semicrystalline PLA in both thermal processing and artificial weathering. Moreover, a possible effect of C30B interactions with PLA chains under artificial weathering could be postulated.

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Section: Number Average Molecular Weight Decay Due To Artificial Weatmentioning

confidence: 66%

Section: Introductionmentioning

confidence: 94%

Effect of Artificial Weathering on PLA/Nanocomposite Molecular Weight Distribution

et al. 2015

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“…Although PLA is unsuited to exterior application [29], the PLA samples were subjected to accelerated weathering as a means to artificially age the plastic and evaluate any retention of PLA properties due to the presence of tannin esters. This test included both water condensation and UV irradiation (Table 2) with samples expected to exhibit some degradation due to PLA hydrolysis and UV-promoted oxidation [7,29].…”

Section: Artificial Weatheringmentioning

confidence: 99%

Esterification of Condensed Tannins and Their Impact on the Properties of Poly(Lactic Acid)

et al. 2013

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Abstract:Reported is a study evaluating the potential of esterified tannins as plastic additives in poly(lactic acid) (PLA). Tannin esterification using anhydrides was investigated as a route to synthesize tannin esters possessing varying ester chain length and degree of substitution (DS). Esterification decreased the tannin UV absorbance, predominately in the UVB region. However, tannin materials with longer ester chain lengths exhibited melt behaviors suitable for processing in plastics. On compounding into PLA, tannin hexanoate esters lowered the PLA glass transition by 5-6 °C. Shorter chain length tannin esters had a reduced effect on PLA polymer properties. The PLA flexural properties were significantly altered with stiffness decreases of up to 15% depending on ester chain length and loading. Artificial weathering of modified the PLA samples suggests the presence of tannin esters may confer a protection role to PLA on extended exposure. Overall, results suggest scope for the use of tannin esters possessing longer ester chain length as plastic additives.

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“…PLA performance in terms of durability are limited by multiple chemical ageing mechanisms such as thermal decomposition [3][4][5], hydrolysis [6][7][8], photo oxidation [9,10], natural weathering [11] and thermo oxidation at high temperature [12,13]. Due to biodegradable applications, numerous studies dealing with hydrolytic ageing are available (see for instance reference [8]).…”

Section: Introductionmentioning

confidence: 99%

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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Effect of natural weather on the structure and properties of polylactide/Cloisite 30B nanocomposites

Cited by 137 publications

References 30 publications

Effect of Artificial Weathering on PLA/Nanocomposite Molecular Weight Distribution

Effect of Artificial Weathering on PLA/Nanocomposite Molecular Weight Distribution

Esterification of Condensed Tannins and Their Impact on the Properties of Poly(Lactic Acid)

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

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