Preparation And Characterizations Of Flame-retardant Polyamide 6 Fibers With MCA

Polyamide 6(PA6)is mainly used fibre and resin.PA6 fibre is provided with many excellent properties such as high tensile strength,abrasion resistance and superior resilience,however because of the limiting oxygen index(LOI)of PA6 is about 21,it belongs to flammable materials and can produce melting drops when burning which limits its extent.In recent years,with the increasing application amount of the PA6 fibers,it is important to improve the flame retardancy of PA6 fibers has important research value.Melamine cyanurate(MCA)is a common flame retardant used for the flame retardant of PA6.which shows mainly flame retardanand in gaseous phases and we chose it as flame retardant in this study.The flame retardant PA6(FRPA6)resin were prepared successfully by three different way of introduction via in-situ polymerization,then the FRPA6 fibers were prepared by melt spinning.The main contents and conclusions of the research are as follows:(1)The after treating MCA was introduced into the melt ?-caprolactam.and then synthetize the FRPA6 resin by hydrolytic polymerization(below referred to as the direct method).By FT-IR.Molau experiment,vertical burning test(UL94 test),sound velocimeter,strength and elongation tester,WAXD,the structures and properties of FRPA6 resin and fiber via in-situ polymerization with direct mothod were characterized and investigated.The results showed that MCA could evenly distributed in PA6 matrix and existed bonds combining with PA6,the LOI of FRPA6 resin was above 28 belonging to the flame retardant material and UL94 level was V-0 rating when the content of MCA was above 6%,the FRPA6 was a kind of good fiber-forming resin and had excellent spinnability,the tensile strength,orientation,degree of crystallinity of the FRPA6 fibers by the direct method were lower than that of PA6 fibers,the heating shrinkage of FRPA6 fibre increased.In general,the FRPA6 fibers could reach the criterion of the clothing and household fabrics.(2)The MEL and CA were introduced into the melt ?-caprolactam,and then synthetize the FRPA6 resin including MCA by hydrolytic polymerization(below referred to as the monomer method).By FT-IR,TG,combustion test,tensile experiment,strength and elongation tester,WAXD,the structures and properties of FRPA6 resin and fiber via in-situ polymerization with monomer mothod were characterized and investigated.The results indicated that the self-assembly reaction between CA and MEL was completed,the curve of thermal weight loss for FRPA6 resin changed from one-step to the multistep and thermo-gravimetric process was in advance,the tensile strength was lower than PA6,the UL94 level was V-0 rating and the LOI was 31.7 when the content of MCA was 8%,the spinnability of sections was not good during the process of melt spinning;the tensile strength,orientation of FRPA6 fibers by the monomer method were lower than that of PA6 fibers,but the flame retardant effect of the textile was obvious.(3)At the first,the optimized condition of preparation of CA-HMDA salt and ADA-MEL salt were studied.On this basis,two kinds of salt were introduced into the melt ?-caprolactam,and then synthetize the FRPA6 resin including MCA by hydrolytic polymerization(below referred to as the making-salt method).By FT-IR.viscosity test,combustion test,tensile experiment,strength and elongation tester,WAXD,the structures and properties of FRPA6 resin and fiber via in-situ polymerization with making-salt mothod were characterized and investigated.The results demonstrated that the self-assembly reaction between CA and MEL was completed,the introduction of MCA reduced the relative molecular weight of PA6,the result of flame retardant test was good,the tensile strength,orientation,degree of crystallinity of the FRPA6 fibers by the making-salt method were lower than PA6 fibers,the heating shrinkage of FRPA6 fibre increased.