Microwave treatment was used to cut off the three-dimensional structure of waste rubber powder(WRP)

which increased the swelling degree of WRP in organic solvent.Then WRP modified by microwave treatment was immersed in tetraethoxysilane.During hydrolysis and condensation reaction process

SiO2 network was in situ generated on the surface of WRP by sol-gel method

which prepared modified waste rubber powder(MWRP).Natural rubber (NR)/MWRP composites were prepared by NR blended with MWRP.The properties of NR/MWRP composites were investigated.Thermogravimetry

differential scanning calorimetry and mechanical properties analysis showed that the best microwave treatment time was 20 s.The NR/MWRP composite owned the good mechanical properties

due to the improvement of compatibility between NR and WRP after microwave treatment and the reinforcement effect of in situ generated SiO2 particles.Si69 which prevented SiO2 particles aggregation and improved the dispersion of SiO2 particles was added to the rubber matrix.With Si69 content increased

the mechanical properties of NR/MWRP composites further improved and the Payne effect decreased.The storage modulus increased with increasing frequency during frequency sweep.The result of temperature sweep showed that with temperature increased

the aggregation of SiO2 particles increased and NR/MWRP composites exhibited the aging phenomenon.To improve the aging resistance properties of NR/MWRP composites

N

N-m-phenylene bismaleimide (BMI) as an antioxidant was added.BMI compensated for the lost crosslinking bonds during rubber aging process and improved the interfacial compatibility between NR and WRP by Diels-Aider reaction

which increased the aging resistance properties of NR/MWRP composites.