Effect of lithium salt and plasticizer on processing and flammability of PA6/sulfamate/nanoclay composites

The focus of the present study is to lower the processing temperature of PA6 so as to avoid the degradation of polymer matrix due to aminolysis caused by ammonium sulfamate (AS) during processing for the development of flame retarded PA6 composites. Nanoclay and straw were used to see their synergistic effects on flammability and mechanical properties of the polymer. Thermal, flammability and mechanical properties were studied using thermogravimetry, differential thermal analysis, UL-94, limiting oxygen index and tensile tester, respectively. FTIR spectra of char residues were obtained to analyze the structural changes of polymer on heating of samples. Inclusion of 2 wt% of lithium chloride (LC) & N-butyl benzene sulfonamide (NBS) each enabled to reduce the processing temperature by about 10 oC for extruding the flame retarded PA6 composite with sulfamate system. PA6/sulfamate/nanoclay composite containing LC, NBS and rice straw gave LOI value of 32% and passed UL-94 vertical test with V-2 rating.