Thermal-oxidative aging kinetics of montmorillonite/polypropylene nanocomposites

Organ montmorillonite (OMMT1)/polypropylene (PP) nanocomposites were prepared by the melt intercalation method. After thermal-oxidative aging for 0 ~ 12d at the temperature of 100℃, 110℃ and 120℃, the thermal property, thermal stability, the attenuation of tensile strength and kinetics were studied. The results of TG, DSC and FTIR show that, compared with PP, the thermal decomposition temperature of OMMT1/PP increases by 37℃, the crystallinity increases from 51% to 71%, and there is stronger interaction between nano-OMMT lamellar and PP.So CO vibration absorption peaks of OMMT1/PP weaken significantly in FTIR spectra and surface cracks slightly during thermal-oxidative aging. After aging at 100~120℃, strength retention of OMMT1/PP is much superior to pure polypropylene material (8~22 times), and its tensile strength was 54% after 12 d aging at 110℃. The first-order kinetics equation of OMMT1/PP thermal-oxidative aging was established with tensile strength as parameter, its activation energy was 52.3kJ/mol (1.7 times of PP). The higher the activation energy values and excellent resistance to thermal-oxidative aging of OMMT1/PP can be contributed to the mechanical protection of exfoliated nano-MMT lamella, physical barrier effect to PP and the chemical interaction between MMT and PP.