Studies On Structure And Properties Of Flame-retardant EPDM

EPDM has excellent performance in many aspects, such as in heat resistant, anti-aging,chemical-resistant and is widely used in electrical wire/cable, auto, and electrical field.However, EPDM exhibits flammability property, and is restricted in some application field. Inorder to improve the performance of flame-retardant of EPDM, a new flame-retardant EPDMhas been developed in the paper, in which DOPO (9,10-dihydro-oxa-10-phosphaphenanthrene-10-oxide) is used as flame retardant. DOPO is a new flame-retardant which has a goodflame-retardant performance in epoxy, but is not suitable as a flame retardant in rubber for it’sactive hydrogen in DOPO which has a greater inhibitory effect on the vulcanization of rubber.When DOPO reacts with coupling agent KH-560, it’s active hydrogen will change into anester structure which will be a effective flame-retardant (DK) in EPDM. In this research,when peroxide used as cross-linking agent for EPDM with DOPO as flame retardant, it hasbeen found that metal oxide is an effective activator, especially, magnesium oxide. Within-site reaction of DOPO with KH-560, and silica as reinforcement, when DOPO additivecontent is20phr, the limited oxygen index (LOI) of flame-retardant EPDM sample reaches23.9, and the tensile strength, elongation and tear strength of the vulcanized rubber is18MPa,592%and61.1kN/m which can meet the need of general demand of flame-retardant andmechanical properties requirement of electrical wire/cable, which shows a good prospect ofapplication. The activity mechanism of metal oxide on promoting effect to peroxidevulcanization system has been investigated in this paper, also the flame retardant mechanismof DOPO and intermediate DK in EPDM been discussed which will give some positiveresults for the development of new type flame retardant of rubber.