Studies on the properties of a new hybrid materials containing chain-extended urea and SiO2-TiO2 particles

EP/SiO2-TiO2 hybrid materials, which contained chain-extended urea, were prepared through sol-gel process of triethoxylsilyl functionalized polyethylene oxide (PEO)-2000, i.e. chain-extended urea -PEO-[Si(OC2H5)(3)](2), tetraethoxysilane (TEOS) and tetrabutyltitanate (TBT) using HCl as catalyst. The PEO-[Si(OC2H5)(3)](2) was obtained by endcapping PEO-2000 with tolylene 2,4-diisocyanate (TDI), followed by a reaction with 3-aminopropyltriethoxylsilane (WD-50). The chemical structure of the products was confirmed by IR measurements. The curing reactivity, the apparent activation energy (Ea), and the mechanical properties of composites such as impact strength, flexural strength, dynamic mechanical thermal properties were investigated. The results showed that the addition of PEO[Si(OC2H5)(3)](2) to epoxy resin and DDS curing system could reduce the apparent activation energy (E-a) of the curing reaction and accelerate the curing reaction. In addition, the glass transition temperatures were little alteration, while the modulus maintained high value, and the impact strength was enhanced by 2-3 times compared with that of the neat epoxy. The morphological structure of impact fracture surface and the surface of the hybrid materials were observed by scanning electron microscope (SEM) and atomic force microscopy (AFM), respectively. (c) 2005 Elsevier Ltd. All rights reserved.