Crystalline, mobile amorphous and rigid amorphous fractions in poly(L-lactic acid) by TMDSC

Righetti, Maria Cristina; Tombari, E.

doi:10.1016/j.tca.2010.12.024

Cited by 93 publications

(108 citation statements)

References 49 publications

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“…This seems consistent with the results of Guinault et al [14] who described that important formation of RAF was linked to imperfect crystallization of PLA. It is assumed that at low crystallization temperature, typically 85 C, the lack of chain mobility hinders the reorganization of polymeric segments in crystals and induces many chain segments subjected to geometrical restrictions in the amorphous phase [47]. Most interestingly, we show here that this observation could be extended to imperfect conditions of crystallization in general, including the predominance of germination over growth that led to the formation of low-size spherulites.…”

supporting

confidence: 58%

Multi-scale analysis of the impact of polylactide morphology on gas barrier properties

Nassar

Guinault

Delpouve

et al. 2017

Polymer

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scale analysis of the impact of polylactide morphology on gas barrier properties. Polymer, Elsevier, 2017, 108, pp.163-172. 10.1016/j.polymer.2016 Multi-scale analysis of the impact of polylactide morphology on gas barrier properties Samira Fernandes Nassar t r a c tSemicrystalline polylactide (PLA) films with controlled morphology were produced by thermal crystallization to optimize the oxygen barrier properties. The crystalline morphology of PLA at the scales of the lamella and the spherulite was investigated and the mobile amorphous phase dynamics were studied. The crystalline morphology had a negligible impact on the oxygen diffusion coefficient. The occurrence of a rigid amorphous fraction (RAF) in the amorphous phase due to its insufficient decoupling from the crystalline phase provided an accelerated pathway for diffusion, though. As a conclusion, for reaching optimal barrier properties, semicrystalline PLA should be pre-nucleated and rapidly crystallized from the glass in the a-polymorph in the aim to reach a high crystallinity degree and decoupling of the amorphous and the crystalline phase. These recommendations can benefit to industry for the optimization of PLA annealing treatments.

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supporting

confidence: 58%

Multi-scale analysis of the impact of polylactide morphology on gas barrier properties

Nassar

Guinault

Delpouve

et al. 2017

Polymer

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“…However, as can be seen from Fig. 1a, b, they revealed a small endothermic peak due to cold crystallization of amorphous PLA chains (Fortunati et al 2012;Liao et al 2007;Mano et al 2004;Righetti and Tombari 2011;Salmerón Sánchez et al 2007;Wu et al 2007;Zhang et al 2004). Cold crystallization occurs due to rearrangement of the amorphous region of PLA into a crystalline phase during heating at low heating rates.…”

Section: Resultsmentioning

confidence: 89%

Dynamics of partially miscible polylactide-poly(ε-caprolactone) blends in the presence of cold crystallization

et al. 2016

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Previous studies on polylactide (PLA)/poly(ε-caprolactone) (PCL) biodegradable blends revealed enhanced nucleation of PLA. The mechanism by which this enhancement of nuclei density occurs attracted significant interest. In this study, precursors' transportation from PCL into PLA phase is invoked in order to interpret the experimental findings related to phase separation and crystallization. This mechanism is supported by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The DSC data revealed that PCL crystallinity within the blends is decreased with PLA content. In addition, POM data showed more nuclei within PLA as the PCL weight fraction is increased. The linear viscoelastic properties of these blends in the vicinity of the phase separation and cold crystallization boundary are examined. It is shown that the combination of POM and rheometry allows determining the phase diagram of the blend and identifying changes occurring due to phase separation and crystallization. Thus, the complete phase diagram of such systems can be fully determined, essential in process design and optimization.

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“…The drying process of the pellets at 80°C for 22 h results in a broadening of glass transition and a slight increase of the T g up to 64.0°C, without modifying the melting temperature and crystallinity degree (Figure 5a). According to Mago) et al [49] and Zuza et al [50], this increase in the T g value may be due to the confinement of the mobile amorphous phase fraction (MAF) [51,52]. Indeed, a three phases model (mobile amorphous, rigid amorphous and crystalline phases) can be used to explain the glass transition dynamics.…”

Section: Thermal Propertiesmentioning

confidence: 97%

Characterisation of low-odour emissive polylactide/cellulose fibre biocomposites for car interior

Courgneau¹,

Rusu²,

Henneuse³

et al. 2013

Express Polym. Lett.

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Abstract. Low odour-emissive polylactide/cellulose fibre biocomposites, intended for car interior, were prepared and characterised. The impact of the different stages of processing (drying cycles, compounding, injection moulding) on the extent of polylactide degradation and on biocomposites properties was investigated by size exclusion chromatography, thermogravimetry, differential scanning calorimetry. In parallel, the odour emission of these materials was quantified via dynamic dilution olfactometry and Field of odours ® method. The changes in molecular weight and global odour emission indicated that compounding had a strong impact on polylactide degradation and odour emission, while injection moulding had no significant impact. Adding 0.5 wt% of an absorbent agent based on poly(1-methylpyrrol-2-ylsquaraine could) divide the global odour concentration by a factor 2. The morphology, mechanical and thermal properties of injection moulded PLAbiocomposites were not affected by the presence of the absorbent agent.

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Crystalline, mobile amorphous and rigid amorphous fractions in poly(L-lactic acid) by TMDSC

Cited by 93 publications

References 49 publications

Multi-scale analysis of the impact of polylactide morphology on gas barrier properties

Multi-scale analysis of the impact of polylactide morphology on gas barrier properties

Dynamics of partially miscible polylactide-poly(ε-caprolactone) blends in the presence of cold crystallization

Characterisation of low-odour emissive polylactide/cellulose fibre biocomposites for car interior

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