Study On The Processing And Properties Of Halogen Free Flame Retardant Ethylene Propylene Diene Monomer

Ethylene propylene diene monomer (EPDM) is one of the most currently used syntheticrubbers with excellent heat aging resistance, mechanical properties at low temperature, vapourresistance and electric insolate properties. However, EPDM has bad flame retardant properties,and need to add a large amount of flame retardants to improve its flame retardancy. But thiswill make a decrease of mechanical properties and limit the application of EPDM.In this work, the effect of vulcanizing system, flame retardants, combination of flameretardants and soften agents on curing properties, mechanical properties, thermal resistance,electric insolate properties and dynamic mechanical properties of EPDM strengthened bywhite carbon black were systematically investigated. The results showed that sulfur/peroxideand peroxide/ (sulfur supplier) combinated vulcanizing system perform well in kinds ofproperties of EPDM. Its tensile strength is above 13.0 MPa, the retention of tensile strengthand elongationg at break are about 90 percent, LOI is about 30.0, vertical burning is FV-0grade, volume resistivity is 10¹³Î©Â·cm and surface resistivity is 10¹³Î©.ATH can keep a fine balance between mechanical properties and flame retardancy. Whencombinated with 20-25phr ZnB₄O₇, Sb₂O₃ or MP, 80phr ATH will cooperate well with themon flame retardant effect, LOI can reach 30.0 or above, and vertical burning is FV-0 grade.Soften agent TCP is the best soften agent for flame retardant EPDM.The properties of halogen free flame retardant EPDM highly filled with ATH with theaddition of acrylic aluminum as well as white carbon black were studied in this paper. Theresults showed that acrylic aluminum formed in-situ can improve the mechanical properties ofhalogen free flame retardant EPDM filled with ATH. When EPDM was 100phr, ATH was 120phr, AA was 10 phr, DCP was 2.5 phr, the EPDM vulcanizate has good mechanical propertyand flameretardancy, tensile strength is 16.7MPa,elongation at break is 260%,limited oxygenindex is 30.0,vertical burning is FV-0 grade, volume resistivity is 2.3×10¹⁵Ω·cm and surfaceresistivity is 1.8×10¹⁴Ω. The addition of DTDM or soften agent TCP make a decrease intensile strength, but provide an improvement on tear resistance, elongation at break andhardness. Also do little harm to flame retardant properties.