Enhancement on physical properties of flame retarded ethylene-vinyl acetate copolymer/ferric pyrophosphate composites through electron beam irradiation

Ferric pyrophosphate (FePP) with silica-gel microencapsulated ammonium polyphosphate (MCAPP) and char forming agent (CFA) in the flame retardation of ethylene-vinyl acetate copolymer has been studied through LOI and UL-94 test. The UL-94 data show that EVA with 20 wt.% IFR only has V-2 rating. However, with the addition of 1 wt.% FePP and 19 wt.% IFR, it can reach V-0 rating. The properties of the composites before and after the electron beam irradiation are compared. The volume resistivity, mechanical and thermal properties of the irradiated EVA composites are also evidently improved at appropriate irradiation dose as compared with those of un-irradiated ones. The tensile strength of EVA/IFR/FePP composites with 160 kGy irradiation is 21.8 Mpa, which is much higher than that of un-irradiated one (12.7 MPa). Furthermore, the thermal aged test and water resistance test results demonstrate that EVA/IFR/FePP composites have good thermal aging property and water durability. (C) 2011 Elsevier Ltd. All rights reserved.