Preparation Of N-P Flame Retardants And The Applications In Glass-fiber/polyamide 6 Composites

Aluminum hypophosphate(AHP)has been used widely in flame retardant polyamide 6(PA6)for its excellent performances.However,it decomposes seriously and hence causes fire when it was co-extruded with glass-fiber(GF)and PA6.In order to overcome this shortage,polymer-encapsuled AHP flame retardants were prepared.Dimethylsulphoxide was used as reaction medium,melamine,terephthalaldehyde and AHP powders were introduced,the reaction was carried out and poly(melamine-terephthalaldehyde)/AHP flame retardants(MAHP)were prepared.Besides,halogen-free flame retardant GFPA6 composites were prepared by molten extrusion.The structure,properties and flame retardant mechanism of the flame retardant composites were investigated.The results show that both the disperse-ability of AHP and the interaction between AHP and PA6 were improved for the modification.Halogen-free flame retardant GFPA6 composites have excellent flame retardancy.As the content of MAHP and MCA composite flame retardant was 19wt%,the flame retardancy of flame retardant GFPA6 composites reached UL94 V-0.Compared with GFPA6 composites,the flexural strength of flame retardant GFPA6 composites were increased,however,the tensile strength was decreased,and the ultimate oxygen index increased by 31.2%(up to 29).This methods would be helpful for modification of other flame retardants.