Impact behavior of microcellular foams of polystyrene and styrene‐acrylonitrile copolymer, and single‐edge‐notched tensile toughness of microcellular foams of polystyrene, styrene‐acrylonitrile copolymer, and palycarbonate

Abstract

In the first part of this series of papers, the tensile properties of microcellular foams of polystyrene (PS), styrene‐acrylonitrile copolymer (SAN), and polycarbonate (PC) were reported. In this part, the impact properties of unnotched, sharply and bluntly notched samples of microcellularly foamed PS and SAN samples were studied. Furthermore, the effects of the sharpness of the notch as well as of the speed of the test were studied by comparing the impact tests with the single‐edge‐notched (SEN) tensile tests, which were carried out for the PS, SAN, and PC sample. Some limited improvement in impact and SEN tensile properties was exhibited in some experimental conditions. The impact properties of microcellularly foamed PC samples are reported elsewhere.

Polymer Blends: Introduction

“…For example, microfoamed blends of HDPE with PP (using CO 2 in an autoclave) showed significantly improved impact strength (Dorudiani et al 1998). Similar enhancement of mechanical performance was reported earlier for N 2 -microfoamed PS, SAN, or PC (Collias and Baird 1995). Now, microfoaming is being used to reduce the material consumption, part weight (by 30-50 %) (Kumar and Suh 1990), but it can also help to improve the mechanical performance, especially of the injection molded parts.…”

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

“…The tensile strengths were proportional to foam densities. More research also proved that the relative foam density is by far, the most influential parameter over mechanical properties of cellular liner low-density polyethylene (LLDPE), [16] poly-(methyl methacrylate) (PMMA), [17] polyurethane, [18] polycarbonate, [19][20][21] glass fiber reinforced polycarbonate, [22] polystyrene, [23] poly(phenylene oxide), [24] and poly(vinyl chloride) (PVC). [25,26] Matuana et al [27] found that the impact resistance increases as the relative density of the cellular PVC foams decreased.…”

Preparation and characterization of microcellular thin polycarbonate sheets

“…[1][2][3] The cell size in microcellular foams is on the order of microns, generally between 1 and 10 m, which is below the critical flaw size of polymer materials, so it will absorb the energy and increase the strength as additives (fillers) do when force is applied to microcellular foam. 4 It is more interesting that, in many cases, these novel materials display high performance, [5][6][7] implying that they have much potential for applications in daily life. Moreover, the tiny size and uniform distribution of the microcells make it possible to produce small-profile foaming parts for insulating purposes, such as microelectronic circuit board insulators, electronic signal-wire insulation, and read-only memory storage, which cannot be produced with traditional foaming processes.…”