Non-halogen Flame-retardant Irradiation Cross-linking Polyolefin Cable Materials For Electronic Wire

Polyolefin(PO)has become the preferred material of cable materials for electronic wire due to its outstanding dielectric properties and easy processability.However,PO is a kind of thermoplastic material with flammability and poor heat resistance,which is the main reason for limiting its application.Irradiation crosslinked,halogen-free and flame retardant PO compound has become one of the hot spots in this field.At present,the PO cable materials used in electronic wire has the defects of low flame retardancy and poor mechanical properties.Therefore,it is of great significance to study the halogen-free flame retardant cross-linked PO cable with high flame retardancy and mechanical properties.Compounding flame retardant of ammonium polyphosphate(APP-OS),melamine cyanurate(MCA)and pentaerythritol(PER)were investigated in this paper.For the first time,PER was modified with APP-OS to determine the factors influencing the best modification process and proportion.The synergistic action of using diethylphosphinic acid aluminum salt(ADP),zinc borate(ZB)and silicone powder(GM)as synergistic flame retardant on the properties of inorganic metal hydroxide system(PO/ATH)and using ADP,organic montmorillonite(OMMT)and GM as synergistic flame retardants on the properties of expansion system(PO/IFR)were researched by oxygen index(OI),thermogravimetric analysis(TGA),mechanical property in this paper.The results revealed that flame retardation,thermal stability and carbon layer stability of PO/ATH could be improved by compounding with proper amount of ADP,ZB and GM respectively,and the mechanical properties of the system could be improved by GM.Flame retardation properties of the PO/ATH/ADP/ZB/GM was superior to above single synergistic fire retardant in this system,and the OI wasincreased from 26.8% to 30.3%.The flame retardation,carbon layer stability and thermal stability could be improved by compounding with proper amount of ADP,OMMT and GM,respectively,the mechanical property of the system could be improved also.Flame retardation property of PO/IFR/ ADP/OMMT/GM was superior to single synergistic fire retardant in this system,and the OI was increased from 26.4% to 32.1%.The effects of vinyltrimethoxysilane(VTMO)the performances of PO/ATH and PO/IFR were further investigated.The results showed that the dispersibility of PO/ATH and PO/IFR can be better improved by the addition of proper content of VTMO.When VTMO was 0.6 wt%,tensile strength was12.8 MPa,elongation at break was 177% and OI was 31.1% of PO/ATH.When VTMO was 0.6 wt%,tensile strength was 11.4 MPa,elongation at break was145% and OI was 33.9% of PO/IFR.Finally,the effects of irradiation dose on the performances of PO/ATH and PO/IFR were investigated in this paper.Optimal comprehensive performance of PO/ATH flame retardant system could be got when the irradiation dose was 120 k Gy.For PO/IFR,the optimal comprehensive performances of PO/IFR flame retardant system could be got when the irradiation dose was 90 k Gy.The formula of halogen-free,flame retardant,and irradiation cross-linked PO cable materials for electronic wire was obtained by combining and optimizing between the ATH and the IFR flame retardant system.