Synergistic effect of intumescent flame retardant and attapulgite on mechanical properties and flame retardancy of glass fibre reinforced polyethylene composites.

The synergistic flame retardant system consisted of intumescent flame retardant (IFR) and organic modified attapulgite (OATP) synergist was used to improve the mechanical properties and flame retardancy of continuous glass fibre reinforced polyethylene composites (GFPE). The IFR was composed of ammonium polyphosphate (APP) as acid source and poly(1,3-diaminopropane-1,3,5-triazine-o-bicyclic pentaerythritol phosphate) (PDTBP) as carbon source. The mechanical properties (tensile strength) of GFPE/IFR/OATP were improved by 35%–43% after adding OATP synergist with rod-like fiber structure due to its strengthening and toughening effect on the resin matrix, and the flame retardancy increased first and then decreased with the increase of OATP synergist loading. When 4 wt% OATP synergist was added into GFPE/IFR, the LOI value increased from 29.5% to 31.3% and the flame spread rate significantly reduced. The synergistic flame retardant system of IFR/OATP could form a stable and dense char layer on the surface of glass fibre and weaken the wicking actions of glass fibre. The synergistic flame retardant system of 26 wt% IFR/4 wt% OATP could endow GFPE with best comprehensive performance. [ABSTRACT FROM AUTHOR]