Study And Preparation On The Properties Of New Halogen Free Flame Retardant Dynamic Crosslinking PP/EVA Composites

Firstly,the different ratio of PP/EVA composites was prepared using polypropylene(PP),ethylene/vinyl acetate copolymer(EVA)by blending through two-roller mill in this paper.The mechanical properties and processability of the different PP/EVA composites was also discussed.The results showed that the EVA can not only enhance the impact strength of PP,but also can improve the processing flow performance.When the ratio of PP/EVA is 80/20(mass ratio),the PP/EVA composites is better.Compared with the pure PP,the impact strength and melt index of PP/EVA composites increased by 271.8%and 82.9%respectively.Secondly,the dynamic crosslinked PP/EVA composites was prepared by dynamic vulcanization system composed of the dicumyl peroxide DCP,vulcanizing agent TAIC,antioxidant 1010.The mechanical properties and processability of dynamic crosslinked PP/EVA composites with different proportion(DCP)and TAIC was explored.The results showed that the dosage of DCP,TAIC and antioxidant 1010 was 0.10,0.15 and 0.20%respectively,the dynamic crosslinked PP/EVA composites has better comprehensive performance.When the ratio of PP/EVA is 80/20,the bending strength and impact strength of dynamic crosslinked PP/EVA composites is 25.2MPa,53.6kJ/m2 respectively,increasing by 2.99MPa,0.8kJ/m2 compared to the non-crosslinked PP/EVA composites.Finally,the modifier DOPO-OA for treatment magnesium hydroxide(MH)was synthesized using DOPO and oleinic acid(OA).Meanwhile,the dynamic crosslinked PP/EVA/MH composites and PP/EVA/modified magnesium hydroxide(MMH)composites was also prepared on the basis of the 80/20 ratio of PP/EVA,DCP of 0.10%,TAIC of 0.15%,antioxidant 1010 of 0.20%.The results showed that the MH content of 60%was added into PP/EVA composites,the class V-O of dynamic crosslinked PP/EVA composites was passed,its bending strength and carbon residue increased by 5.86 MPa and 57.1%at the same time,its thermal stability and processing flow performance were obviously also improved compared with non-crosslinked PP/EVA/MMH composites.In addition,a new type of flame retardant NSiB was synthesized using the silane coupling agent and boric acid.The effect of DOPO add alone,DOPO/NSiB and DOPO/NSiB/MMH on flame retardant performance of the dynamic crosslinked PP/EVA composites was discussed.The results showed that the LOI of dynamic crosslinked PP/EVA/DOPO/NSiB composites was 29.6%,and the class V-0 was passed.Compared with the dynamic crosslinked PP/EVA/DOPO composites,the bending strength of dynamic crosslinked PP/EVA/DOPO/NSiB composites increased by 4.8MPa,melt index increased to 16.798 g/10min,and the initial decomposition temperature and weightlessness 50%temperature increased by nearly 70?.The effect of different DOPO/NSiB content on the flame retardancy of dynamic crosslinked PP/EVA/MMH composites was explored in adding MMH amount of 50%.The results showed that the tensile strength and impact strength of dynamic crosslinked PP/EVA/DOPO/NSiB/MMH composites increased to 16.72 MPa and 37.3 kJ/m2 respectively.Meanwhile,the LOI value of dynamic crosslinked PP/EVA/DOPO/NSiB/MMH composites increased to 33.5%,the class V-0 was passed,its thermal stability and processability were obviously also improved compared to the dynamic crosslinked PP/EVA/MMH composites.The result was an excellent flame retardant properties and mechanical properties of dynamic crosslinked of PP/EVA composites...