Superior Impact Toughness and Excellent Storage Modulus of Poly(lactic acid) Foams Reinforced by Shish-Kebab Nanoporous Structure

Abstract

Poly(lactic acid) (PLA) foams, with the combination of shish-kebab and spherulite nanoporous structure in skin and core layer respectively, was prepared using a novel technique comprising loop oscillating push-pull molding (LOPPM) and supercritical carbon dioxide low-temperature foaming process (SC-COLTFP). The foams present superior impact toughness which is 6-fold higher than that of neat PLA, and no significant decrease was observed for the storage modulus. Moreover, SC-COLTFP at soaking temperature ranging from 110 to 150 °C were performed to determine the evolution of pore morphology. The ultratough and supermoduli are unprecedented for PLA, and are in great need for broader applications.

Toward endothelialization via vascular endothelial growth factor immobilization on cell‐repelling functional polyurethanes

“…The promising candidates for small diameter vascular grafts belong to PCUs, because of their superior biostability and their mechanical compliance similar to natural arteries . In comparison, biodegradable scaffolds usually suffer from the mismatch between the tissue ingrowth and the material degradation, and thus are less mechanically reliable. The functional PCUs we developed in this study cannot serve as bulk materials for small‐diameter grafts either, because the relatively high water uptake due to their hydrophilic PEG segments can weaken the materials.…”

Large-scale formation of shish-kebab in water-assisted injection-moulded high-density polyethylene with a high-molecular weight

“…From the time, the shish-kebab was first reported, it has attracted immense research interest because of its remarkable improvement of some physical properties and significant theoretical values [1][2][3][4][5][6][7][8][9][10]. However, although conventional injection moulding (CIM) is the most common and convenient polymer processing method for the fabrication of polymer products with different geometric profiles, it is still a great challenge to form rich shish-kebabs in injection-moulded products due to the relaxation of oriented molecular chains and the 'weak' shear flow [1][2][3][4].…”

“…A relatively small number of shish-kebabs can be found in the thin shear (skin) region of the sample. In this respect, several novel injection moulding techniques, including oscillation shear injection moulding, loop oscillating push-pull moulding and multi-melt injection moulding have been developed to prepare injection-moulded samples with highly oriented or numerous shish-kebabs [4][5][6][7][8][9][10][11].…”

Effect of octa(epoxycyclohexyl) POSS on thermal, rheology property, and foaming behavior of PLA composites

“…The study on mechanism of low‐density PLA composite foams is hence an important and popular subject. In the sc‐CO 2 foaming process of PLA composites, NPs were generally considered as cell nucleation agent, which were beneficial for increasing the cell nucleation density, and in turn optimized cellular structure as well as the final performances of PLA foam . However, in most cases, the poor dispersibility of non‐reactive NPs would result in the non‐uniform cell size distribution.…”