effect of ethylene vinyl acetate as an impact modifier on creep behavior of wood flour- recycled polypropylene composites

the effect of impact modifier on creep behavior of wood flour- recycled polypropylene composites has been evaluated in this work. for this purpose, impact modifier (ethylene vinyl acetate) and recycled polypropylene were mixed with wood flour (50/50% w/w) as well as the impact modifier (0, 3%, 6% and 9%) by a counter-rotating twin-screw extruder to manufacture the wood flour- recycled polypropylene composites specimens. short term flexural creep test at 30% of ultimate bending load was performed by using flexural creep equipment. the total time to complete every test was 120 min (60 min creep and 60 min recovery). results revealed that recycled polypropylene reduce creep resistance of wood flour- recycled polypropylene composites. also results have shown that impact modifier increase the creep deflection, initial creep, final creep, relative creep and decrease creep modulus in composites containing impact modifier. composites containing virgin polypropylene without impact modifier exhibited higher creep resistance than other composites in this research.