Search

In this work, a promising method for production of high value-added aromatic aldehydes from lignin was proposed. The concept is based on the use of metalloporphyin as catalyst and hydrogen peroxide as oxidant under alkaline condition. The biomimetic catalyst Co (TPPS4) (TPPS4=meso-tetra (p-sulphonatophenyl) porphyrin) was prepared and characterized by1H-NMR spectroscopy, FT-IR spectroscopy and UVvisible spectroscopy. It exhibited high activity in the catalytic oxidation of lignin. The main products were p-hydroxybenzaldehyde, vanillin, and syringaldehyde from catalytic oxidation of lignin, which in total were up to 75.09% of the identified compounds by GC-MS. The yield of the three aromatic aldehydes was 12.84 wt.%, compared to a poor 2.63 wt.% yield of the three aromatic aldehydes without Co (TPPS4).

A new 3D unit cell model is developed for homogenization calculation of composites containing randomly dispersed ellipsoid inclusions. The new unit cell is constructed using the Ansys Parameter Design Language (APDL), taking the inclusion volume fraction, inclusion orientation and spatial dispersion as variables. A series of unit cells containing multiple ellipsoids, showing random distributions in particle size and position, were constructed and used for finite element calculation at microscale, the effective modulus of the composites with periodic microstructures, which modeled by the unite cells, were then estimated by homogenization. The influences of particle volume fraction and the particle stiffness on the effective elastic modulus of the composites were examined. The estimated results were compared with different particle volume fractions were calculated, and the calculated data was compared with other classic models.

The character of ilmenite was modified by pretreatment, the effect of pre-oxidation temperature and time on structure of ilmenite were investigated by X-ray diffraction(XRD) and Thermo-gravimetric/differential thermal analysis. The results indicated that new microcrystal rutile and FeTiO3·Fe2O3 solid solution were appeared on the surface of mineral below 800°C, but evident rutile crystals and pseudobrookite Fe2O3·TiO2 were appeared above 850°C with the structure of ilmenite disrupting simultaneously. The preoxidation time increased from 15min to 60min, evident microcrystal rutile and FeTiO3·Fe2O3 solid solution were appeared by degrees without structure of ilmenite breaking.

The tensile stress-strain relationship of rubbers is fairly linear and can be used for obtaining tensile modulusE. In this work we analyzed the tensile stress-strain relationship of filled rubber experimentally and employed the extended 2D homogenization method to compute the modulus of the carbon black (CB) filled rubbers with various CB volume fractions ranging from 5% to 25%. The results reveal that the modulus of CB-filled rubbers increased with the increase in CB volume fraction and in CB aggregation.