Effects of phosphate and polysiloxane on flame retardancy and impact toughening behavior of poly(2,6‐dimethyl‐1,4‐phenylene oxide)

Abstract

Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)-based compounds containing resorcinol bis(diphenyl phosphate) (RDP) and poly(dimethyl-diphenyl siloxane) (PDMDPS) were prepared through melt extrusion, and their flammability characteristics and mechanical properties were evaluated. The incorporation of RDP enhanced the flame retardancy of PPO compounds, but hardly made them obtain the UL 94 V-0 rating unless RDP and PDMDPS were combined. Studies on the residual chars after vertical burning test suggested that the excellent flame retardancy be correlated with the retention from the combination effects of silica and phosphate in the char, whose cross-linked silica enhanced the formation of a compact char to retard combustion. Thermogravimetric analysis indicated that the presence of PDMDPS and RDP improved the char yielding as well as the decomposition temperature of PPO compounds. Moreover, the Izod impact strength was improved significantly in the presence of RDP and PDMDPS, and this toughening effect was attributed to the deformation and multiple cracks induced by PDMDPS, which enhances the impact energy absorption of the matrix. This work provides a very effective flame retarding formulation for PPO compounds with improved impact toughness. POLYM. ENG. SCI., 52:927-936,

SEBS-based thermoplastic elastomers containing aluminum hypophosphite and melamine cyanurate: Thermal degradation, flame retardancy, and mechanical properties

“…Additives containing phosphorus flame retardants can promote carbonaceous char and inorganic residue formation on the polymer surface to inhibit the polymer surface from heat and air in condensed phase and inhibit flame spread due to radical trapping in gas phase. Among them, aryl phosphates, notably bisphenol A bis (diphenyl) phosphate ester (BDP), 8,9 resorcinol bis(diphenyl phosphate) (RDP), 13 and triphenyl phosphate (TPP), were found to be effective flame retardants in SEBS-based TPE (TPE-S). Aryl phosphates usually act like acid precursors and the produced acids join the charring through esterification and dehydration with polymer and other additives.…”

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

“…PPO/HIPS‐0 with 9 wt% RDP and 3 wt% AP presented an increased LOI value of 31.5%, suggesting that RDP and AP was the efficient external flame retardant. It was reported that RDP could produce phosphorus‐containing compounds to promote the carbon formation of PPO, which was benefited for stabilizing the degradation products, and improving the quality of the char layer 31 . In contrast, the pure HIPS was highly combustible with an LOI value of just 18.5%.…”