Nano-composites Of Polyolefin/Silica Prepared Via In Situ Sol-gel Reaction

The polyolefin are important synthetic materials, and their global production hasmore than one hundred million tons. Polyolefin/inorganic nanocomposites withexcellent mechanical properties and the synergy of the two materials, thecomprehensive performance of a single can not be compared. The nanocompositesannual growth rate of over30%, it shows that the nanocomposites applicationprospects. In this paper, polyolefin grafted product were prepared by co-irradiation,and two kinds of nanocomposites were successfully prepared by situ Sol-gel.Firstly, the EPR-g-KH570was prepared by co-irradiation in solid-phase and theeffect of the co-irradiation dose on the grafting yield of KH570on EPR was studied.Then the graft product was soaked into tetraethylorthosilicate （TEOS）. Finally, theswollen material was put into butylamine solution to catalyze the sol-gel reaction ofthe precursor TEOS. The influences of different solvents and concentrations ofbutylamine on sol-gel reaction of TEOS and the size of the silica which was obtainedby situ sol-gel were studied. The composites were characterized by FTIR, SEM,mechanical properties and so on. The results showed that the maximum graftingefficiency was obtained when the co-irradiation dose was2kGy. The averagediameters of SiO₂were100-200nm and they were well dispersed. Because of theKH570, the organic-inorganic interfacial compatibility and chemical bonding werestrong, obtaining good material performanceSecond, PP/EPR-g-KH570/SiO₂nanocomposites were successfully prepared bysol-gel in situ. Firstly, EPR-g-KH570/SiO₂nanocomposites material were prepared bysol-gel in situ, And then nanocomposites were prepared by blending method. Thecrystallization procession of PP/EPR-g-KH570/SiO₂composite was investigatedusing DSC, and the composites were characterized by SEM, mechanical properties,rhiological behavior and so on. The results showed that EPR and SiO₂acted as theheterogeneous nucleating agent and increased the crystallization rate of PP. And thecomposite melt was pseudo-plastic and exhibited shear-thinning and easy molding;the SiO₂in nanocomposites had good dispersion, well compatibility and stronginterfacial bonding with the aid of organic interlayer and chemical bonding betweenSiO₂and PP. Compared to the pure PP, the tensile strength of the composite wasincreased by20.9%, the young’s modulus was increased by70.4%and the elongationat break was increased by95.3%.