Effect of β-cyclodextrin and ammonium polyphosphate on flame retardancy of jute/polypropylene composites

The jute and polypropylene fiber (PP) were formed into jute/PP composite by carding, netting and needling. Using surface dusting process, β-cyclodextrin (β-CD), β-CD and ammonium phosphate (APP) were combined and hot pressed to form a flame-retardant layer on the surface of jute/PP composite. The flame-retardant properties, mechanical properties, carbonization properties and surface microstructure of the jute/PP composites were tested by FTIR, limit oxygen index tester, horizontal combustion tester, cone calorimeter, thermogravimetric analysis tester, SEM and universal testing machine. The results show that the thermal compression film formation on the surface of jute/PP composite after β-CD and APP compounding can significantly improve the flame retardancy and thermal stability of the jute/PP composite. When the mass ratio of β-CD to APP is 1:2 and keeping the 20wt% total content of the flame retardants, the jute/PP composite becomes 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 the carbon residual at 700℃ is increased by 11.68%. The mechanical properties test of the jute/PP composites show that the flexible strength increases while the tensile strength shows little change by adding flame-retardant layer on the surface of the jute/PP composites.