Abstract: The influence of silane coupling agent KH-550 and KH-560 on the structure and properties ofpolypropylene(PP)/intumcsccnt flame-rctardant(KDIFR) composites was studied. X-ray diffraction(XRD)indicated that KDIFR promoted the formation of俘一form PP，which was strengthened by KH-550，but weakened by KH-560.SEM showed that the adhesion between KDIFR and PP was enhanced by the silanes. POM showed that the size of the spherulites of PP and the dispersion of KDIFR particles became more uniform with the increasing silane content. The mechanical properties of the composites were also improved.八recipe of PP/KDIFR/KH-560二70}30}5 was found to be optimal，the impact and tensile strengths were increased by 24. 2%and 9. 6%，rc}spectivcly, compared with neat PP/KDIFR eompcasites. The flame retardancy of the eompcasites was also improvcxl when silane was added.

Key words: polypropylene, intumescent flame-retardant, silane coupling agent, (3-nucleation, sphcrulitc