Preparation, characterization, and mechanical properties of some microcellular polysulfone foams

Abstract

Several polymers were evaluated as candidates for the production of high-performance microcellular closed-cell foams. The polymers involved were a polysulfone, a polyethersulfone, a polyphenylsulfone, a polyetherimide, and a poly(ether ketone ketone), and their suitability was gauged by measuring rates at which they could be impregnated with carbon dioxide under pressure at room temperature. This step is essential to the subsequent step of heating the impregnated samples at various temperatures to create foamed structures. The present study focused primarily on the use of the polysulfone in this regard. Microcellular foams of this polymer were found to have average cell sizes in the range 1-10 m and cell densities on the order of 10 10 -10 14 cells/cm 3 . The microstructures of these foamed samples were controlled through careful choices of the foaming temperature and the foaming speed to produce a wide range of foam densities. Since these materials were prepared for possible use as structural materials, tensile tests were conducted to investigate the dependence of some of their mechanical properties on the foam densities (relative to those of the unfoamed polymer). The results indicated that the tensile moduli of these polysulfone foams increased with the square of their relative densities, and the tensile strengths were proportional to these densities. Both of these experimental findings are in agreement with theory.

Microcellular foaming of polymethylmethacrylate in a batch supercritical CO2 process: Effect of microstructure on compression behavior

“…Foaming temperature and foaming time are the key parameters to adjust the cellular structure of the final product. 13,14 Using this process, microcellular polymers, such as polystyrene, 15 polypropylene, 16,17 polyethersulfone and polyphenylsulfone, 18,19 polycarbonate, 20 Poly (methyl methacrylate) 21 and biodegradable poly (lactic acid) have been prepared. 22 In all the cases, one of the main objectives is reducing material bulk density, reducing cell size and/or increasing the cell number density of the cellular polymer produced.…”

Effect of Processing Parameters on the Mechanical Properties of Injection Molded Thermoplastic Polyolefin (TPO) Cellular Foams

“…Sun and Mark [15] studied the effect of cell morphology on mechanical properties of microcellular polysulfone, polyethersulfone, and polyphenylsulfone foams. They found that the tensile modulus of these polysulfone foams increased with the square of their relative densities.…”

Preparation and characterization of microcellular thin polycarbonate sheets

“…At present, microcellular foams are produced by several techniques, such as phase separation, precipitation with a compressed fluid antisolvent, polymerization, gas supersaturation, compression molding, and so forth. 9 However, earlier research concentrated on gas supersaturation, such as the batch process, continuous extrusion, and the injection process; but high costs restricted their development. Until now, the research on microcellular foams has been mainly directed at polystyrene, 10 -18 polypropylene, 19 poly(methyl methacrylate), 20 polyamide, 21 polysulfone, 9,22,23 poly(ether sulfone), 23,24 poly(ether imide), 24 or their blends.…”

“…9 However, earlier research concentrated on gas supersaturation, such as the batch process, continuous extrusion, and the injection process; but high costs restricted their development. Until now, the research on microcellular foams has been mainly directed at polystyrene, 10 -18 polypropylene, 19 poly(methyl methacrylate), 20 polyamide, 21 polysulfone, 9,22,23 poly(ether sulfone), 23,24 poly(ether imide), 24 or their blends. [25][26][27][28][29][30][31] Only a few studies have been conducted on the preparation of microcellular polycarbonate (PC) foam, 5,32,33 one of the most important engineering plastics.…”