Two alkylol amines, which were ethanolamine (EOA) and triethanolamine (TEOA), were used to posttreat nanosized titanium silicalite‐1 (TS‐1) to improve its catalytic activity for 1‐butene epoxidation. Comparative studies were conducted to clarify the influences of the EOA and TEOA concentrations on the physicochemical properties through detailed characterization. EOA treatment can dissolve the framework Si, [SiO4], on the external surface of TS‐1, generating some macropores. TEOA serves as structure‐directing agent to form MFI topology other than the dissolution of [SiO4], and promotes the recrystallization of [SiO4], forming new TS‐1 particles over the external surface. The two treatments can both improve the catalytic activity of 1‐butene epoxidation, but the samples treated with TEOA exhibit better catalytic stability. This can be attributed to the characteristic recrystallization of [SiO4] in the case of TEOA treatment, stabilizing the structure of TS‐1 and maintaining more framework Ti and intercrystal space.

A series of novel nano-silica-alumina co-doped polyimide (PI/nano-SiO2-Al2O3) three-layer composite films were prepared via combination of sol-gel process and ultrasonic-mechanical method. The effects of different inorganic phase contents and different Si/Al weight ratio on the properties of composites were investigation. The amination process of PI composite films was analyzed by Fourier transform infrared (FT-IR), and the inorganic phases’ morphology and its distribution in composite films were observed by scanning electron microscopy (SEM). Results indicated that a homogeneous dispersion of SiO2-Al2O3 particles was obtained when the inorganic phase content was below 6 wt.%. The thermal and mechanical properties of the three-layer composite films were measured and compared to the pure PI. It was also observed that when Si/Al weight ratio was 4:1 and the total inorganic phase weight content reached 4 wt.%, the composite film had the highest tensile strength, which was 30% higher than pure PI. Moreover, the electric breakdown strength of composite films was examined and its effective factors were analysed.

No abstract

No abstract

No abstract