Synthesis of 4A zeolite containing la from kaolinite and its effect on the flammability of polypropylene

摘要

4A zeolites (4A) and 4A zeolites containing La (4A-La) were prepared by kaolinite and their element composition, morphology, and structure were characterized by X-ray fluorescence (XRF), scanning electron microscope (SEM), X-ray diffraction (XRD) and fourier-transform infrared spectroscopy (FTIR). 4A and 4A-La zeolites were incorporated into PP composite containing intumescent flame retardant (IFR). The thermal behavior and flammability of PP composite were investigated by thermogravimetric analysis (TGA), FTIR, limiting oxygen index (LOI) and cone calorimeter test (CCT). Both 4A and 4A-La zeolites can enhance the flame retardancy of PP composites significantly. LOI for neat PP was only 18.1, it increased to 31.1 for PP/25 wt% IFR; and further increased to 34.1 and 35.5 or PP/23.5 wt% IFR/1.5 wt% 4A or 4A-La respectively. In CCT, the value of peak heat release rate (PHRR) is 1474 kW/m2 in PP, which sharply decreased to 436, 299 and 248 kW/m2 for PP/IFR, PP/IFR/4A and PP/IFR/4A-La composite. It was suggested that 4A-La zeolite could alter the thermal degradation behaviors and enhance the char formation of PP composites. POLYM. COMPOS., 39:3461-3471, 2018. (c) 2017 Society of Plastics Engineers