Research On The Non-halogen Flame Retardant Polyethylene/Ethylene-vinyl Acetate Cable Material

In this research, LLDPE and EVA were used as the matrix, MH and modified vermiculite as the synergistic flame retardant, LLDPE/EVA/MH/modified vermiculite composite were made by melt blending. Do the grafted modification of the matrix, add the graft polymer and change the processing technology to improve the comprehensive properties of the composites. The effect of MH surface treatment on the mechanical properties and processing performance has also been investigated.The modification of the vermiculite has been studied by the analysis of XRD, FTIR. The flame retardant property has been studied by the methods of CCT, LOI, UL 94 and TGA. Universal testing machine and impact tester were used to test the mechanical properties of the composites. SEM test were used to investigate the dispersion of MH in the matrix.The research results are as follows:the results of XRD and FTIR showing, HDTMA has been inserted between the lamellars of the vermiculite successfully. Compared with the primary vermiculite, the mechanical and flame retardant properties of the LLDPE/EVA/MH composite synergistic flame retardant with the modified vermiculite have been improved, as the carbon residue ratio, heat release rate and total heat release have been decreased, with little effect on the thermal property. For the LLDPE-2/EVA system, the composite made by two-step process and with the addition of PE-MAH prove to be better, and when the addition of modified vermiculite reach 3%and MH 57%, the mechanical and flame retardant properties of the composite is the best:tensile strength (19.2MPa), elongation at break (123%) and LOI (29.7%). The SEM pictures showing, the MH modified by silane coupling agent can disperse more homogeneously, so the elongation at break and the impact strength of the composite have been improved remarkably.