The Preparation And Application Study Of Polymer Grafted Mg(OH)₂ Flame Retardant

Magnesium hydroxide (MH) is a kind of new halogen-free flame retardant developed inrecent years. Innocuity, environmental protection, cheapness and procee convenience are itsmain advantages, so MH has the wide application prospect as the preferential substitute ofhalogen flame retardant. On the other hand, the MH has some disadvantages, such as hugeaddition level, poor dispersion effect, low flame retardant efficiency and bad influence tomaterial mechanical property and the relevant modified research is the hot point in this field.Based on the previous investigations, the modified MH has been prepared through the silanecoupler and graft polymerization. The effects of process parameter on polymer flameretardant property and tensile property were studied.The silane coupler KH-550 was anchored on the MH surface and urea formaldehyde(UF) grafted MH was prepared in order to keeping the mechanical property at the sametime of enhancing the flame retardant property. The modification effect of EVA cablematerial and the effects of synthesis process on the flame retardant morphology have beeninvestigated. The results show that UF grafted MH can be well dispersed in EVA. In theflame retardant addition level of 60ï¼…, the oxygen index (OI) of EVA can hit 40, tensilestrength enhances from 10.3MPa to 13.9MPa and breaking extension increases from 118ï¼…to140ï¼….The modified ethane-octene copolymer (POE) was prepared with the UF grafted MH andurea-melamine-formaldehyde (UMF) grafted MH as the flame retardant. The effects ofprepolymer addition level and powder content on POE flame retardant and mechanicalproperty have been researched. The results show that in modified MH content of 60%, POEOI increases from 23.9 to 29.4, tensile strength augments from 7.7MPa to 13.18MPa andbreaking extension enhances from 477.1ï¼…to 716.99ï¼…. The flame retardant of POE modifiedby UMF grafted MH is close to the one of UF modified POE, but the tensile strength andbreaking extension decline in a certain extent. It proved that UMF and UF all can improve thecompatibility of MH, but the boundary layer formed with UMF is brittler than the one of UF.The EVA cable material was modified by phenolic resin (PF) grafted MH flameretardant. The effects of resol addition level and modified MH content on powder size, flameretardant property and mechanical property were studied. The results show that PF graftedMH can enhance the flame retardant greatly. In the MH content of 60ï¼…, the EVA OI increases from 34 to 42.2, tensile strength augments from 10.3MPa to 12.1MPa and breakingextension declines from 118ï¼…to 30ï¼…. The PF grafted MH can reinforce and not plasticizethe EVA.