Advanced Materials Research Vols. 554-556

Abstract: Amino functional silica gel was synthesized by in-situ hydrolysis method in the present of silane coupling agent. Then dendrimer-like polyamidoamines based on the silica gel surface (PAMAM-SG) were prepared using Micheal addition of the amino and methyl acrylate, and ester-exchange of ethylene diamine and the ester group. The effects of solution pH, concentration and temperature on the adsorption capacity of PAMAM-SG for Cr ³⁺ were studied. The optimum pH range is 4.0-7.0. The adsorption rate decreased with increasing the time, but increased with increasing the temperature. The adsorption capacity increased with increase of the concentration until the adsorption reached equilibrium. The adsorption capacity increased with the generations of PAMAM-SG.

Abstract: Polypyrrole (PPy) nanowires and bundles were successfully synthesized by changing the concentration of the monomer in sodium dodecyl sulfate (SDS) solution. The obtained PPy was characterized by SEM, FT-IR and XRD. The results showed that the PPy was amorphous although their morphology was different and some surfactant molecules were doped into the polymer chains as counterions.

Abstract: Konjac glucomannan is a kind of natural polysaccharides with excellent biocompatibility and biodegradable activities. In this paper, a series of Konjac glucomannan-graft-methacrylic acid copolymers were prepared by the free-radical initiation grafting Konjac Glucomannan (KGM) with methacrylic acid(MA). The reaction conditions such as reaction temperature, KGM and MA ratio and initiator concentration, were investigated, and chemistry of KGM and its MA grafted copolymers were characterized using FTIR.

Abstract: D-glucose was used to react with methyl methacrylate (MMA) (and methyl acrylate(MA) as comparison) to generate new biomass-based materials in presence of free radical initiator. Potassium peroxydisulfate was used as free-radical initiator in the reaction. The final chemical structure and thermal stability were analyzed by FT-IR and TGA. The results showed that the Glucose-co-MMA (G-MMA) and Glucose-co-MA (G-MA) copolymers had better thermal performance than PMMA and PMA.

Abstract: For purpose of recycle and environmental protection, recycled Kevlar selvages and spunlace PP selvages, blended with low-melting polyester, were used to prepare composite nonwovens. In addition, the effect of hot-pressing and lay-up orientation on tensile strength and tearing strength was evaluated. The result shows that, after hot-pressing, laying respectively 0°/90°and -45°/45°PP selvages, tensile strength and tearing strength of composite nonwovens exhibits the highest, reaching 1000 N and 1370.2 N separately.

Abstract: The aggregates size, plugging and propagation properties for supramolecular aggregates based on phenol-formaldehyde resin have been investigated by measurement of hydrodynamic diameter, filtration with nuclear pore film and plugging test with sand-pack core. The results show at the condition tested, supramolecular aggreates have an average hydrodynamic diameter of about 450 nm, and can sufficiently plug 1.2 μm-nuclear pore film. The aggregates can plug, propagate, replug and repropagate in porous media, which is an obligatory property of an in-depth profile modifier for oil reservoir.

Abstract: Radiation effects on polyimide (PI) films were studied with different irradiation doses by 60Co. The PI film were synthesized from 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (Bis-AP-AF) with 3,3',4,4'-Benzophenone tetracarboxylic dianhydride (BTDA). The tensile strength, tensile modulus and elongation at break of the irradiation PI films were measured and compared in order to determine the effect of the irradiation doses on the tensile properties. The results showed that the tensile strength, tensile modulus and elongation at break of the irradiation PI film can be significantly improved by irradiation of 60Co source. The optimum irradiation doses were 50 kGy. The maximum increment of tensile strength, tensile modulus and elongation at break of the irradiation PI film is 37.8%, 45.0% and 95.2%, respectively.

Abstract: In this study, Metakaolin was used as source material, NaOH and sodium silicate were used as alkali activators.Preparation of three sets of geopolymer samples subject different NaOH concentration from 8 to16mol/L. The effect of alkaline concentration on compressive strength was analyzed. NaOH concentrations at 12mol/L and 16mol/L resulted in high 7-day compressive strengths. And the compressive strength of geopolymeric cement reached the maximum when adding 24mL sodium silicate at SiO₂:Na₂O ratio 3.3.

Abstract: The composite was prepared with montmorillonite (MMT) and poly(γ-glutamic acid) (γ-PGA). Applied the composite as the sorbent, methylene blue as the adsorbate, the influences of the initial concentrations of methylene blue, adsorption time and pH values of the solution on the adsorption capacity of methylene blue by the composite were studied. The experimental results showed that the adsorption capacity of methylene blue by MMT/γ-PGA composite both increased with the increasing of initial concentration of methylene blue and the prolonging of adsorption time, and then approached saturation respectively. The adsorption capacity of methylene blue by MMT/γ-PGA composite increased with the increasing of pH values of methylene blue solution. Meanwhile, the study of adsorption mechanism demonstrated that the adsorption of methylene blue by MMT/γ-PGA composite was Langmuir type, and the adsorption equation wasΓ=0.204c/(1+0.381C).

Abstract: Four vanadium phosphate catalysts were synthesized via vanadyl hydrogen phosphate sesquihydrate (VOHPO₄•1.5H₂O) route and activated at different duration (6, 18, 30 and 75 hours) in 1% oxygen/ nitrogen (1% O₂/N₂) mixture at 733K. The increased activation duration led to a decreased in the specific surface area of the catalysts. The increased activation duration increased the average oxidation state of vanadium. The surface morphologies of the catalysts exhibited plate-like crystals that agglomerated into clusters with folded edges. Temperature-programmed reduction (TPR) showed that increasing activation duration led to an increased in total amount of oxygen removed from the catalysts. Temperature-programmed desorption (TPD) showed that the total amount of oxygen desorbed from the catalysts increased as the activation duration increased. Catalytic performance revealed that all the catalysts produced possessed rather low in terms of activity but high in terms of selectivity.