Preparation And Properties Of Thermally Conductive Flame Retardant PA6 Composites

At present,the trend of"small,light and thin"of electronic components puts forward high requirements for heat dissipation of materials.In addition,the safety requirements for electronic components are getting higher and higher,the development of non-toxic,environmentally friendly,low smoke flame-retardant and thermal conductive polymer materials has become a hot direction of future development.In this paper,PA6 was modified by using thermally conductive flame retardant fillers,and the effects of these fillers on the thermal conductivity,flame retardancy,mechanics,crystallization,rheology,thermal stability and the synergistic effect of thermal conductive flame retardant fillers were studied.The main work of this project is to give PA6 good thermal conductivity,excellent flame retardancy,excellent mechanical performance and other functions at the same time.The main research work of this paper is as follows:Firstly,PA6 based thermal condutive composite was prepared by mixing PA6 with A1₂O₃ and CNT.The effects of the amount,the type,modification and hybrid fillers on the composite properties were systematicall studied.The results showed that the thermal conductivity of A1₂O₃ was better than that of CNT.When the content of A1₂O₃ was50wt%,the thermal conductivity of the composite was the best.The smaller particle size of A1₂O₃ has outstanding effects on the thermal conductivity and mechanical properties.SEM showed that the compatibility between the filler and the matrix was improved after adding KH550,and the thermal conductivity and mechanical properties of the composite modified by KH550 were improved.The thermal conductivity of 3B50K was0.459W/?m·K?,the tensile strength and bending strength were 82.4MPa and 118.9MPa respectively.The combination of A1₂O₃ and CNT played a good synergistic role and greatly improved the thermal conductivity and mechanical properties of the composite.Among them,the thermal conductivity of B50C1 and B50C2 were 0.501W/?m·K?and0.557W/?m·K?,and the tensile strength was 85.6MPa and 89.5MPa respectively.The fluidity of the composite changed little and the processability was good.Secondly,PA6 based composite was prepared with PA6 as matrix and Mg?OH?₂and ADP as flame retardant fillers.The effects of the amount,the modification of Mg?OH?₂ and ADP on the composite properties were discussed.The results showed that the flame retardant effect of PA6 filled with Mg?OH?₂ was obvious,among which M60PN2 had the best performance,its LOI value was 31.4%,and passed the UL94 V-0flame retardant level.The tensile strength was 62.8MPa,slightly higher than that of pure PA6.Among the three modifiers SA,PN80 and KH550,PN80 had the best effect.Among all the formulas,ADP15P had the best flame retardant performance,with LOI value of 31.5%,and it had passed UL94 V-0 flame retardant level.Compared with ADP15P and M60PN2,which had the same flame retardant performance,their tensile strength had little difference,but the impact strength of ADP15P was better than M60PN2,and the effect of Mg?OH?₂ flame retardant could be achieved by using a small amount of ADP,with high cost performance and good processability.Finally,thermal conductive and flame retardant composites based on PA6 were prepared with A1₂O₃,CNT and ADP as fillers.The influence of hybrid fillers on the composite properties was discussed.The results showed that the thermal conductivity of B50A15 was 0.4 W/?m·K?,VST and HDT were 205.9?and 90.9?respectively,and the flame retardancy of B50A15 was greatly improved.The LOI value of B50A15 was34.8%,and it was better than that of CNT and had passed UL94 V-0 flame retardant level.TG showed that the carbon residue of the composite in air atmosphere was higher than that in nitrogen atmosphere,which showed that the thermal stability of the composite was improved;the tensile strength and bending strength were increased by the combination of A1₂O₃ and ADP,which were 80.3MPa and 110.4MPa respectively.With the increase of extrusion rate,the surface of the composite extrusion becomed rough,but there was no melt fracture,and the processability was good;Mo method described the non-isothermal crystallization process of B50A15 well,which had certain guiding significance of composite materials for the actual production and processing.