Solid Phase Synthesis Of MCA And Its Application In PA6

Nylon 6 was used widely in varies fields for its excellent mechanical,antiwear and high temperature properties.However,its limit oxygen index(LOI)is around 23,which belongs to one of burning plastics.Its application is also limited for this shortage.Hence,for Nylon 6 it is necessary to be modified with flame retaradants(FRs).Melamine cyanurate(MCA),a non-halogen FRs with high nitrogen content,was widely used in polyamide plastics.Traditionally,MCA was prepared in a large amount of hot water media,and thus amount of energies were costed and wastewater was discharged.The mechanical properties would be reduced for the poor interfaces between MCA particles and polyamide 6 matrixes,which were caused by the poor interactions between MCA and PA 6 for high FRs content.A novel solid-phase-synthesis method was used to prepare MCA,besides silica sol was introduced during the preparation to modify the MCA.The flame retardant PA 6/modified MCA(m MCA)was prepared by molten blending.The resultant materials were characterized by FTIR,XRD,TG and SEM.The results showed that the structure of m MCA was the same with MCA,the max weight-lose temperature of m MCA was larger than pure MCA and reached at 465.2?.As the FRs content was 13wt%,the LOI of PA 6 composites was 33% and the flame retardancy reached UL-94 V0.The peak heat release rate(PHRR)of the composites decreased by 26.3%,and the mechanical properties were improved at some FRs content.Besides,another modified MCA(u MCA)was prepared by heating urea,and silica sol was introducd during the preparation process.u MCA was molten blended with PA6 and flame retardant nylon 6 composites were obtained.The resultant materials were characterized by FTIR,XRD,TG and SEM.Mechanical properties were also characterized.The results showed that the yield of u MCA increased from 52.3% to 73.2%,the max weight-lose temperature of u MCA increased from 400.6?to 437?,it indicated the thermal performance was improved.As the FRs content was 13wt%,the LOI of PA 6 composite reached 30% and the flame retardancy was UL-94 V0.with the FRs content increase the mechanical properties of PA 6 composites reduced.