Cyanoethylation of several fiber materials and their utilization as adhesive in wood-based panels
This study examines the cyanoethylation and thermoplasticity of several cyanoethylated fiber materials. Cyanoethylated pulps with a degree of substitution of 1.43 have the lowest Vicat softening point. Cyanoethylated poplar with a weight gain of 18.2 % has the lowest melting temperature. Instead of traditional adhesives, cyanoethylated materials can be used to produce wood-based panels because of their good thermoplasticity. Plywood bonded with cyanoethylated pulp has a bonding strength of 2.06 MPa and an average wood failure of 62.7 %. Wheat straw particle board containing 40 % cyanoethylated pulp has an internal bonding strength of 0.49 MPa, a modulus of rupture (MOR) of 33 MPa, and a density between 0.5 and 0.6 g cm−3. Fiberboard containing 40 % cyanoethylated pulp has an internal bonding strength of 0.53 MPa, MOR of 38 MPa, modulus of elasticity of 4,200 MPa, and a density between 0.7 and 0.8 g cm−3. Its swelling in thickness is 41 %.
Wetting/drying cyclic effects on mechanical and physicochemical properties of quasi-isotopic flax/epoxy composites
Abstract The aim of this work is to investigate the effects of wet/dry aging cycles on flax/epoxy composite properties for long-term structural applications. The mechanical performance of flax/epoxy exposed to wet/dry cycles during 104 days was evaluated. The physicochemical changes induced by wet/dry cycles were also studied. Unaged and cyclic aged samples were characterized by tensile test, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The tensile test results showed good aging performance of this composite. FTIR chemical investigation revealed the disappearance of the characteristic peaks of the cyanoethylation treatment at the fiber/matrix interface during cyclic aging. TGA data showed an improvement in thermal properties of the composite after the hydrolysis of cyanoethyl group, as well as the increase of the crystallinity index, as measured from XRD during cyclic wet/dry aging. This explains the limitation of mechanical degradation of this composite despite the severe wetting-drying cycles aging conditions. The results also show the positive effects of the cyanoethylation fiber treatment on the long-term durability of flax/epoxy composite.
Thermodynamics on the Carbochlorination of Titanium-bearing Ores
The equilibrium compositions of the multi-component, multi-phase and multi-reaction system of carbochlorination of titanium-bearing ores are calculated with HSC, a computational chemistry software. The thermodynamic equilibrium calculation of the reaction system shows that a complete conversion of titanium-bearing ores is feasible at a temperature near 200oC. At temperatures ranging from 800 to 1600oC, the products of the reaction system are all in gaseous phase. Thermodynamic analysis accords with the industrial practice. The simulated results provide reasonable scientific basis for improving suitable technological conditions of the carbochlorination reduction.