The Study Of EPDM/PP Thermoplastic Elastomer Cable

The ethylene-propylene-diene terpolymer (EPDM)/polyprop'ylene (PP) thermoplastic elastomer (TPE) were prepared by melt blend dynamic vulcanization method, the nano-Mg(OH)2 particles have been used as environmentally friend halogen-free flame retardant in EPDM/PP TPE.The effects of vulcanization agents, sulfur and peroxides, preparation technology on properties of dynamically vulcanized EPDM/PP TPE were investigated. The results showed that the TPE have excellent mechanical properties using peroxides vulcanizing system. When ratio of EPDM/PP was 70/30, the amount of vulcanizing agent dicumyl peroxide (DCP) was 1.5phr, co-agents TAIC was 0.5phr, and the dynamically vulcanized through on step, the optimal mechanical properties of EPDM/PP TPE can be obtained. The tensile strength, elongation at break and Shore A of the EPDM/PP TPE were 13.0MPa, 320% and 87, respectively.The effects of nano-Mg(OH)₂ particles reinforced EPDM/PP TPE were studied. The results showed that the dispersion effect and reinforcing effect of nano-Mg(OH)2 particles treated by silane coupling agent KH560 was better than that of the untreated nano-Mg(OH)₂ particles. The tensile strength, elongation at break of reached to maximum 18.5MPa and 350%, respectively, when the content of nano-Mg(OH)2 particles was 10 wt%. Moreover, the differential scanning calorimetry (DSC) test results showed that the crystallinity degree of composites decrease slightly with the content of nano-Mg(OH)2 particles increased. The dielectric constant and dielectric loss of EPDM/PP/nano-Mg(OH)₂ composites increased slightly with the increase of nano-Mg(OH)₂ particles.The flammability of EPDM/PP/nano-Mg(OH)₂ composites were studied by Limiting oxygen index (LOI),UL-94 and Thermogrvimetric analysis(TGA).The results showed that the flame retardancy of EPDM/PP/Mg(OH)₂ composites is improved with the increase of the Mg(OH)₂ content. The flame retardancy of nano-Mg(OH)₂ particles is better than that of micro-Mg(OH)₂ . When the content of nano-Mg(OH)₂ in the composites is up to 120%, The LOI value of composites was 26 and the flame retardancy can get UL94 V-0 grade. It was found that microencapsulated red phosphorus (MRP) have synergistic flame retardant effects with nano-Mg(OH)₂ particles, and the LOI value of composites increases to 28 and can get UL94 V-0 grade when then content of nano-Mg(OH)₂ is 30wt% and MRP is 15wt%.