Advanced Materials Research Vol. 441

Abstract: In the paper, synthesis of 1,2:5,6-di-O-isopropylidene-D-glucofranose (DAG) assisted by ultrasound were performed in the presence of ferric chloride as catalyst. The effects of some reaction parameters (e.g. power and frequency of ultrasound, reaction temperature, mass ratio of the reactant) on the yield were investigated. It was found that the reaction is greatly accelerated by the ultrasound in comparison to the control runs under mechanical stirring. The optimal ultrasound output power and frequency were found to be 200 W and 24 kHz at 40 °C with a 1:30 mass ratio of glucose to acetone. Under these optimal conditions, the yield of DAG reached 75.8%.

Abstract: Hyperbranched poly (amino amine) s (HPAMAMs), synthesized by Michael addition of 1-(2-aminoethyl) piperazine (AEPZ) and methyl acrylate (MA), can emit blue fluorescence under excitation wavelength. However, the relatively weak fluorescence of HPAMAMs is still an obstacle for its practical applications. Gold is one of the most frequently used metals for fluorescence enhancement. In this research, the influence of gold nanoparticles on fluorescence property of HPAMAMs was investigated by fluorometry. It was found that gold nanoparticles (GNPs) with smaller size (< 5 nm) presented greatly enhanced emission. The GNPs with larger size (~10 nm in diameter) and definite surface plasmon absorption can quench the fluorescence of HPAMAMs.

Abstract: N,N-alkylidene bisamides were synthesized with good to excellent yields from aliphatic or aromatic aldehydes and amides in the presence of 2 mol % of anhydrous zinc chloride. The synthesis successfully employed Lewis acid as catalyst.

Abstract: Cotton is the most widely used fiber. However, cotton fabric has a relatively high UV radiation permeability. Compared with some synthetic fabrics, cotton fabrics anti-UV ability is lower. nanotitanium dioxide has a good catalytic and ultraviolet light shielding effect, so it can be used as anti UV finishing agent. Using modified nanotitanium dioxide to finish the cotton fabrics, one can get the function of anti-UV performance. Therefore, in this paper, nanotitanium dioxide was first modified with 1,6-hexamethylene diisocyanate and polyethylene glycol in order to improve their size stability. And then by way of finishing, the modified nanotitanium dioxide dispersion was soaked into cotton fiber. During a baking process, modified nanotitanium dioxide was combined with cotton fibers via covalent bonds.

Abstract: In this study, monochlorotriazinyl-β-cyclodextrin (MCT-β-CD) was prepared from the reaction between cyanuric chloride and β-cyclodextrin (β-CD). The structure of the product was confirmed by FTIR, 1HNMR and ESI-MS. It is found that the yield of the MCT-β-CD was 61.72% and the average substitution degree (DS) of-OH in MCT-β-CD was 1.43. The water solubility of MCT-β-CD is 0.40 g/mL at room temperature.

Abstract: A novel Si/P flame retardant was prepared using tetraethyl orthosilicate (TEOS) and phosphoric acid (H₃PO₄). Cotton fabric treated with the flame retardant was characterized by cone calorimetry, thermogravimetric analysis (TGA), X-ray fluorescence spectroscopy, and Fourier transform infrared spectroscopy. The peak heat release rate (pHRR) and total heat release (THR) of the fabric treated with TEOS/H₃PO₄ are lower than those of the fabric treated with TEOS or H₃PO₄ alone. The HRR and THR of the treated fabric decrease from 145.66 kW/m² and 1.68 MJ/m² to 70.76 kW/m² and 0.67 MJ/m², respectively. Total smoke production decreases from 0.080 to 0.014 m²/m². TGA revealed that cellulose dehydration increases at low temperatures because of the addition of phosphoric acid and the production of charcoal. The generated charcoal is dense. The P and Si contents markedly increase, and exist in the charcoal in the form of P-O-C and Si-O bonds, respectively. On the basis of these results, we conclude that the main mechanism of TEOS/H₃PO₄ is that of a condensed-phase flame retardant. Good flame retardant synergism occurs between TEOS and H₃PO₄.

Abstract: A general methodology to prepare reagentless biosensor was developed based on self-assembly and electrodeposition. Redox active inorganic multilayers consisting of copper hexacyanoferrate (CuHCF) multilayers were formed by successive self-assembly. A simple and controllable electrodeposition approach was established for one-step fabrication of chitosan-enzyme layer on CuHCF modified electrode. Horseradish peroxidase was selected as the model enzyme. With CuHCF as the electroactive mediator, the developed reagentless biosensor exhibited a fast amperometric response for the determination of hydrogen peroxide (H₂O₂). The linear response ranged from 1.4 × 10^-5 to 2.0 × 10^-4 M with a detection limit of 1.2 × 10^-6 M. The biosensor exhibited high reproducibility and long-time storage stability. The proposed methodology could serve as a versatile platform for fabrication of electrochemical biosensors.

Abstract: In this paper, a flame retardant methacryloyl ethyl diethyl phosphoric amide (PN) containing nitrogen-phosphor for textiles was synthesized from phosphorus trichloride, absolute ethylalcohol, carbon tetrachloride, monoethanol amine, methacryloyl chloride. PN oil-in-water emulsion was grafted onto silk fabric by Atom Transfer Radical Polymerization (ATRP) method. The grafting technological parameters were investigated. The flame retardancy property of the treated silk fabric was indicated by LOI value, char length, after flame and after glow time.

Abstract: A simple means was demonstrated to control the functional group on surface and use this surface as a model support to investigate the effect of surface chemistry on lipase adsorption and its activity. It was based on mixing polystyrene (PS) solution with small molecular weight functional group-terminated polystyrenes (PS-Fs, functional groups such as-CH₃, -CF₃, -NH₂, -COOH and-OH) and casting them on glass plates to fabricate the functional group controlled surfaces. The amount of adsorbed lipase on the surface with similar functional group density was-CH₃ > PS > -CF₃ > -NH₂ > -COOH > -OH. The activity retention of the immobilized lipase was-OH > -NH₂ > -COOH > -CF₃ > -CH₃ > PS.

Abstract: An extracellular pectate lyase was purified from the culture supernatant of Paenibacillus sp. WZ008 grown in the pectin-containing medium. The enzyme was purified to homogeneity in three steps and found to have a molecular weight of around 45 kDa. Highly methylated pectin was the optimum substrate in the case of no Ca²⁺ addition while the enzyme exhibited the maximal activity on polygalacturonic acid in the presence of 4 mM Ca²⁺. The purified enzyme demonstrated the optimum activity at a temperature range of 55-60°C and pH 9.6. The Ca²⁺ ion enhanced the enzyme activity but Mn²⁺, Ba²⁺ and EDTA strongly inhibited it.