| Polymeric inorganic nanocomposites have received considerable attention in the field of material preparation and properties,and the researches on them have great significance. Polypropylene (PP) and silica (SiO2) both are widely used basic raw materials now. In this paper, four kinds of PP/SiO2 nanocomposites were successfully prepared by novel methods of ultrasonication, irradiation, non-aqueous Sol-gel and so on, achieving improved performance.First, the grafting modification of maleic anhydride (MAH) onto PP wax (PPw) was studied. Grafted product PPw-g-MAH was successfully prepared by four methods respectively: ultrasonication in melt or suspension state, pre-irradiation in solution state and co-irradiation in suspension state. The graft degree (G) of MAH was determined by titration using a solution of organic base tetra-butyl ammonium hydroxide (TBAOH) in ethanol. The effects of ultrasonic intensity, total irradiation dose, MAH content, reaction temperature and reaction time on G value were investigated, and the effects of the second monomer styrene (St), electron donor, free radical initiator and inhibitor on G value were also researched. The products were characterized by FTIR, 13C NMR, DSC, XRD and so on. The results showed that the grafting reaction of MAH onto PPw could be induced by ultrasonication and irradiation, and the G value obtained in irradiation method was higher than that in ultrasonication method. The highest G value of 2.67% was achieved by method of co-irradiation in suspension state, and 3.40% could be reached with the aid of St.Second, PP/PPw-g-MAH/SiO2-g-KH560 (3-glycidyloxypropyltrimethoxysilane) nanocomposites and PP/PPw-g-MAH/SiO2 nanocomposites were successfully prepared by route of SiO2 nanopowders. The composites were characterized by FTIR, DSC, XRD, POM, SEM, mechanical properties and so on. The results showed that the nano-SiO2 was dispersed well in composites and the organic-inorganic interfacial compatibility and bonding were strong, obtaining good material performance; the added PPw-g-MAH played a certain role as a compatilizer, increasing the organic-inorganic interfacial bonding; the added KH560 effectively modified the nano-SiO2 and reacted with the grafted MAH, increasing the adhesive force between SiO2 and PPw and interfacial compatibility, resulting the improved material performance.Finally, PP/ethylene-propylene rubber (EPR) -g-MAH/SiO2-g-KH560 nanocomposites and PP/PPw-g-KH570 (γ-methacryloxypropyltrimethoxysilane) /SiO2 nanocomposites were successfully prepared by route of SiO2 Sol. For this, the binary non-aqueous Sol-gel reaction of tetraethoxysilane (TEOS)-formic acid was researched first. The non-aqueous Sol-gel reaction kinetics in earlier stage was simply investigated by apparent visual phenomena, UV absorption spectrophotometry, electrical conductivity and rotation viscometry, and the influential factors on non-aqueous Sol-gel reaction were researched. Then the preparation technologies for these two composites were studied, and characterizations were carried out, such as FTIR, DSC, SEM, TGA, mechanical properties and so on. The results showed that the SiO2 in nanocomposites had good dispersion, well compatibility and strong interfacial bonding with the aid of organic interlayer and chemical bonding between SiO2 and PP, making the composites having improved performance. |
