Polylactide/montmorillonite nanocomposites and microcomposites prepared by melt blending: Structure and some physical properties

Abstract

Polylactide (PLA)/clay nanocomposites loaded with 3 wt % organomodified montmorillonite and PLA/clay microcomposites containing 3 wt % sodium montmorillonite were prepared by melt blending. We investigated the morphology and thermal properties of the nanocomposites and microcomposites and compared them with unfilled PLA, keeping the same thermomechanical history. The influence of the processing temperature on the structural characteristics of the investigated systems was determined. The investigations were performed with differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), size exclusion chromatography (SEC), and polarized light microscopy (LM). XRD showed that the good affinity between the organomodified clay and the PLA was sufficient to form intercalated structure in the nanocomposite. The microcomposite featured a phase-separated constitution. DSC and LM studies showed that the nature of the filler affected the ordering of the PLA matrix at the molecular and supermolecular levels. According to TGA, the PLAbased nanocomposites exhibited improvement in their thermal stability in air. Reduced flammability, together with char formation, was also observed for nanocomposites, compared to the microcomposites and pure PLA.

Comparative study of filler influence on polylactide photooxidation

“…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. The WAXS pattern of PLA is characterized by a broad band with maximum at 2" % 17º, indicating a completely amorphous structure (Figure 2).…”

Preparation and characterization of tapioca starch‐poly(lactic acid)‐Cloisite NA+ nanocomposite foams

“…This could have been due to the PLA reacting readily with the starch matrix to form strong interactions between them. [38] Addition of different amounts of clay to the nanocomposites reduced the bulk compressibility significantly (P < 0.05). The 1, 3, and 5 wt % clay contents produced bulk compressibilities which were not significantly different from each other at 7.32, 5.87, and 7.39 MPa, respectively.…”

Barrier Properties of Polylactic Acid in Cellulose Based Packages Using Montmorillonite as Filler

“…The variation of T g , by the incorporation of fillers is explained by a plasticizing effect of the PLA polymeric matrix by the organic filler [35,52]. Pluta et al [52], reported a T g reduction 54.1 °C to 53.2 °C with 3 wt% of montmorillonite. In the case of PLA-SC the difference among its composite is very slight (in 0.5 °C).…”