Preparation Of Flame-retardanted Jute Fiber Composites By Incorporation Of Cyclodextrin And Nitrogen Phosphorus Flame Retardant

The nonwoven felts made by natural fibers and plastic fibers have been widely used in automotive interior parts due to the advantages of natural fibers,i.e.low density,high cost performance,good sound absorption performance,and impact resistance.The flame retardancy of the nonwoven felts is affected by the flame retardant process and the type of flame retardant.Fiber became brittle after presoaked by flame retardation,which decrease the adhesion of fibers with the matrix,and the mechanical properties of the composite.In this paper,the surface powder spraying process is used for the overall flame retardant treatment of fiber felts,and the jute/polypropylene(PP)composite containing β-cyclodextrin(β-CD)flame retardant system is prepared.The main research contents of this paper are as follows:1.Jute/PP composites containing β-CD were prepared by surface powder spraying.The results show that the use of β-CD alone has a very low flame retardancy for composites,and the flame retardancy of composites decreases with increasing β-CD content.When the content of β-CD was 20%,the limiting oxygen index(LOI)value of the composite decreased 0.8%,the horizontal burning rate increased 20% compared with jute/PP composites without flame retardant.However,the peak heat release rate(PHRR)and average effective heat of combustion(Av-EHC)of the composites were reduced 35% and 22% respectively,and the amount of carbon residue at 700°C increased 3.17%.The tensile strength and flexural strength of the composite materials were reduced.From the above results,it can be seen that the flame retardant effect of β-CD as the only carbon source is not good.To promote the char formation of β-CD,the catalytic action of the acid source is indispensible.2.This paper chooses the ammonium polyphosphate(APP)as the acid source gas source in the flame retardant system of the jute/PP composites.The flame retardancy and thermal stability of jute/PP composites are improved by adding β-CD and APP.When the ratio of β-CD and APP is 1:2 and keeping the 20 wt% total content of flame retardants,the composite become extinguished after 58 s combustion.The limiting oxygen index(LOI)value is 26.6%,which reaches the third fire resistance according to Japan’s JISD 1201-77 standard.The heat release rate and effective combustion calorific show the lowest value and carbon residual at 700℃ is increased 11.68%.The tensile strength and flexural strength increased 8% and 23%,respectively.3.Jute/PP composites containing β-CD/APP/MA and β-CD/APP/MPP flame retardant systems were prepared.The results show that the flame retardant and mechanical properties of composites containing MA flame retardant system are significantly improved with the increase of APP ratio in the system.The composite with 20 wt% flame retardants contained β-CD,APP and MA(1:2:1)shows the better flame retardant properties.The LOI value of the composite increased to 27.8%,and the self-extinguishing time reached to 37 s.Compared with pure jute/PP,the PHRR value and Av-EHC value of the composites were reduced 50% and 21% respectively,and the tensile strength and bending strength were increased 5% and 19%.In the MPP flame retardant system,both APP and MPP can promote β-CD char formation,and micron-sized APP and MPP will not easily agglomerate,so it can improve the mechanical properties of the composite.The composite with 20 wt% flame retardants comtained β-CD,APP and MA(1:2:1)shows the best flame retardant properties.The LOI value increased to 28.4%,and the self-extinguishing time reached to 20 s.Compared with the Jute/PP composites,the PHRR and Av-EHC values of the composites were reduced by 52% and 22% respectively,and the tensile strength and flexural strength were improved by 10% and 22%,respectively.