Influences of high‐impact polystyrene loading on the foaming behavior andflame‐retardantproperties of polyphenylene oxide composites blown withCO₂

Abstract

Polymeric foam with high expansion ratio, well-defined cell structure, and excellent flame retardant properties is essential for broadening its applications. Polyphenylene oxide (PPO) is a kind of cost-effective engineering plastic with excellent flame retardancy, anti-dripping behavior, and good mechanical strength, but suffers from its poor processability. In this study, microcellular PPO composite foams were fabricated by applying a solid-state foaming technology using compressed CO 2 as the blowing agent. High-impact polystyrene (HIPS) phase was introduced with the aim to improve the fluidity and foaming ability of PPO composites. It was interesting to find that the 18-48% HIPS loading significantly increased the expansion ratio, that is, 1.8-3.3 versus, 10.8-14.3, and broadened the optimum foaming temperature of PPO composite foams, attributing to the miscible character between PPO and HIPS and excellent foaming ability of HIPS. Furthermore, the as-prepared PPO/HIPS composite foams exhibited high limited oxygen index (LOI) of 22.0-29.9%, low

Synergistic effects of in situ fibrillated polytetrafluoroethylene and polystyrene–butadiene block on the microcellular foaming behaviors of polyphenylene oxide modified by high‐impact polystyrene

“…Their results showed that the foam expansion rate of the PPO/HIPS blends increased, and the optimum foaming temperature range widened after HIPS addition. Furthermore, these foams exhibited exceptional thermal insulation and tensile properties 8 . Jiang et al Successfully produced PPO/HIPS bead foams with excellent compression, tensile, and flame retardant properties, using in‐mold foaming and mold forming technologies 9 …”

Fabrication of Lightweight Polyphenylene Oxide/High‐Impact Polystyrene Composite Bead Foam Parts via In‐Mold Foaming and Molding Technology

“…A second compound, such as PA [ 16 ] , PBT [ 17 ] , and high‐impact PS (HIPS), [ 18 ] is usually used to blend with PPO to improve melt viscosity. Using temperature rising foaming method, Zhai et al [ 19 ] systematically studied the influence of the addition of HIPS on thermal behavior, foaming behavior, and flame‐retardant properties of PPO. It was found that 18−48% loading of HIPS greatly increased the expansion ratio of PPO/HIPS foams from 1.8−3.3 to 10.8−14.3.…”