Properties of poly(lactic acid) nanocomposites based on montmorillonite, sepiolite and zirconium phosphonate

Abstract

Abstract. Poly(lactic acid) (PLA) based nanocomposites based on 5 wt.% of an organically modified montmorillonite (CLO), unmodified sepiolite (SEP) and organically modified zirconium phosphonate (ZrP) were obtained by melt blending. Wide angle X-ray scattering (WAXS) and scanning electron microscopy (SEM) analysis showed a different dispersion level depending on the type and functionalisation of nanoparticles. Differenctial scanning calorimetric (DSC) analysis showed that PLA was able to crystallize on heating, and that the addition of ZrP could promote extent of PLA crystallization, whereas the presence of CLO and SEP did not significantly affect the crystallization on heating and melting behaviour of PLA matrix. Dynamic Mechanical Thermoanalysis (DMTA) results showed that addition of all nanoparticles brought considerable improvements in E! of PLA, resulting in a remarkable increase of elastic properties for PLA nanocomposites. The melt viscosity and dynamic shear moduli (G!,G") of PLA nanocomposites were also enhanced significantly by the presence of CLO and SEP, and attributed to the formation of a PLA/nanoparticle interconnected structure within the polymer matrix. The oxygen permeability of PLA did not significantly vary upon addition of SEP and ZrP nanoparticles. Only addition of CLO led to about 30% decrease compared to PLA permeability, due to the good clay dispersion and clay platelet-like morphology. The characteristic high transparency of PLA in the visible region was kept upon addition of the nanoparticles. Based on these achievements, a high potential of these PLA nanocomposites in sustainable packaging applications could be envisaged.

Comparative study of filler influence on polylactide photooxidation

“…Moreover, there is no sensible effect of clay concentration on X-rays diffractograms either in the case of Cl20A or in that of Cl30B in the range of concentration of Table 3. As expected there are no traces of PLA crystalline structure both for PLA ( Figure 2) and for PLA nanocomposites based on clay nanoparticles, as already reported in literature for PLA/organically modified montmorillonite nanocomposites [19,[26][27][28]. These observations are in perfect agreement with the previously published data [5,19,[27][28][29] on similar materials.…”

Investigation of injection moulded poly(lactic acid) reinforced with long basalt fibres

“…PLA has good mechanical properties, high strength and stiffness; however, it is considered as a brittle polymer with a strain at break around 3-5% and a notched and unnotched Charpy impact strength of around 3 and 23 kJ/m 2 respectively. Moreover, the very slow crystallisation of PLA [4][5][6][7][8] prevents it to be used in high temperature applications due its low glass transition temperature (Tg) around 50-55°C. Since PLA is a thermoplastic polymer, it can be processed by using conventional plastic processing equipments like injection moulding, extrusion, thermoforming, blow, sheet, or compression moulding [9] into products like cutleries, cups, flower pots, food containers, films, toothbrush handles or biomedical implants [10].…”

Sheets of branched poly(lactic acid) obtained by one step reactive extrusion calendering process: Melt rheology analysis

“…In the beginning, it was mainly used for medical applications due to its high fabrication costs but now PD,L-LA polymers have finally found a commercial application in single use disposal items due to its low price compared with other biodegradable polymers. However, its brittle nature reduces its use to very limited applications and its poor melt strength limits specific processes such as film blowing or foaming [1].…”