Batch-foamed biodegradable polylactide acid/organic modified montmorillonite clays and polylactide/sericite powder nanocomposites

Abstract

The properties of microcellular polylactic acid (PLA)/organic modifi ed montmorillonite (OMMT) clays and PLA/sericite powder (SP) nanocomposites were investigated and compared in terms of thermal property, rheological property, particles dispersability, and cell microstructure. The batch-foaming process uses carbon dioxide as the physical blowing agent. According to the transmission electron microscopy and X-ray diffraction characterization, fi llers (i.e., OMMT and SP) have good dispersions in PLA matrices. The thermal and rheological properties of solid PLA composites are demonstrated by differential scanning calorimetry and capillary rheometer, respectively. The microcellular morphology of fractured cross-sectional surfaces is characterized by scanning electron microscope. The batch-foamed PLA composites have more uniform cells in comparison with foamed pure PLA parts due to the mineral particles.

Foaming of PLA Composites by Supercritical Fluid-Assisted Processes: A Review

“…Potential fillers can vary in origin from lignocellulosic fibers from different sources [103,104] to mineral ones, especially talc [105,106], clays [90,107], and silicates [108,109], as well as in terms of size, from micro- [110] to nanoparticles [109,111,112], and shape. The presence of a filler in the polymer melt can increase the cell nucleation rate during foaming, acting as a heterogeneous nucleation agent [44][45][46], and also can increase the melt strength [105,106] and the crystallization rate of PLA [113,114].…”

Thermal Behavior of the Porous Polymer Composites Based on LDPE and Natural Fillers Studied by Real Time Thermal Microscopy

“…Consequently, the foaming process is a fundamental step in the production of porous functional polymer materials allowing to control their properties. This is true for many different natural and synthetic compounds and compositions or raw materials -from synthetic polyethylene to microbiologically synthesized PHB [4][5][6][7], from compositions with inorganic components (such as TiO2 [8], graphite [9], dispersed clay minerals [10,11]) to biomaterial-containing ones (for example, cellulose or wood [12,13]) and even combined (bio-)organic-inorganic composite fillers in polymeric matrix (such as clay-reinforced wood-based foamed composites, foamed wood flour / polyethylene / clay composites [14,15], flame resistant / flame retardant foamed polyurethane / wood-flour / Fe2O3 / ammonium polyphosphate composites, etc. [16,17]).…”