Material valorisation of amorphous polylactide. Influence of thermo-mechanical degradation on the morphology, segmental dynamics, thermal and mechanical performance

Abstract

The role of crystalline, mobile amorphous and rigid amorphous fractions in the performance of recycled poly (ethylene terephthalate) (PET). Polymer Degradation and Stability,97 (1) 98-107, 2012

Structure-properties relationships in melt reprocessed PLA/hydrotalcites nanocomposites

“…Cold crystallization is observed for both neat PLA and PLA + HTs samples. Regarding the cold crystallization temperature (T cc ), a progressive decrease is shown on increasing the extrusion number, in agreement with the results obtained for similar systems [5,6]. For neat PLA and PLA + U-HT the decrease is comparable while it is more remarkable for PLA + OM-HT likely due to the better dispersion of OM-HT that promotes an easier cold-crystallization.…”

“…However, the replacement of conventional polymers with biodegradable polymers cannot be the only way to reduce the accumulation of plastic materials in landfills. Several papers also investigated the possibility to recycle biodegradable polymers in order to reduce the environmental impact related to the life cycle of biodegradable polymer-based items [5][6][7][8][9][10][11]. Among the different recycling routes, mechanical reprocessing represent an easy and low cost method [12,13].…”

“…Due to the growing market of nanocomposites, the scientific literature has currently studied the effect of reprocessing of the nanocomposites based on conventional polymers [13,[16][17][18][19]. Moreover, several studies investigated the effect of the reprocessing on the properties of neat biodegradable polymers, such as PLA [5,6,8,20]. However, recycling of PLA-based biodegradable nanocomposites was not been investigated in depth so far.…”

Dielectric spectroscopy of recycled polylactide

“…Therefore, the results were fitted to VTFH model (Eq.8), as shown in Figure 4 with good linear regression coefficient, as it is given in Table 1. The α relaxation could be therefore assigned to movements of the segmental backbone, in accordance with previous experiments with DSC and DMTA [13]. Though the Tg obtained by DSC did not change with the reprocessing cycles, a deep inspection on the dielectric relaxations spectra at different frequencies can give information on the segmental rearrangements driven through the glass-rubber transition, in terms of dynamic fragility.…”

“…Previous studies showed the simulation of mechanical recycling by multiple processing to assess the effects of thermo-mechanical degradation on polylactide [12][13][14][15][16] although results showed that there were non-significant changes in the nature of the functional groups of PLA, there was a remarkable reduction in molar mass due to chain scission, which was subscribed by characterisation of the cold-crystallization phenomenon found during DSC and DMTA. The effect of chain shortening studied on the glass-rubber relaxation showed an increase in free-volume affecting the segmental dynamics of PLA.…”