Entity

Time filter

Source Type


Yang S.,Kagawa University | Tang W.,Research Institute for Solvothermal Technology | Ishikawa Y.,Kagawa University | Feng Q.,Kagawa University
Materials Research Bulletin | Year: 2011

A novel active carbon reducing process was developed for the synthesis of titanium dioxide with oxygen vacancy. In this process a nanocomposite of hydrolyzed titanium(IV) tetra-isopropoxide and the active carbon was annealed in air. The formation reaction, visible-light absorption, and visible-light sensitive photocatalytic activity of the titanium dioxide with oxygen vacancy samples were investigated using XRD, TG-DTA analyses, FE-SEM, EDS, and measurements of electric conductivity, BET specific surface area and photocatalytic activity. The nonstoichiometric titanium dioxide with oxygen vacancy sample has a rutile structure and its chemical formula can be written as Ti(IV) 1-xTi(III) xO (2-x/2)□ x/2, where □ is oxygen vacancy. The oxygen vacancy was introduced into the rutile structure by reducing reaction of the active carbon in a phase transformation process from anatase to rutile. The samples showed visible-light absorption with an absorption edge around 570 nm and high surface visible-light sensitive photocatalytic activity. © 2011 Elsevier Ltd © 2011 Elsevier Ltd. All rights reserved. Source


Tsutsumi C.,Niihama National College of Technology | Hara T.,Niihama National College of Technology | Fukukawa N.,Niihama National College of Technology | Oro K.,Research Institute for Solvothermal Technology | And 3 more authors.
Green Chemistry | Year: 2012

This study involved the incorporation of useful compounds, such as repellents and antibacterial agents, at high concentrations in l-lactide (l-LA) random copolymers. The amount of α-pinene released in gas from the copolymers was also evaluated. Outstanding controlled release properties were developed using random copolymers of l-lactide (l-LA) with γ-valerolactone (VL), ε-caprolactone (CL), tetramethylene carbonate (TEMC) (1,3-dioxepan-2-one), and 1,5-dioxepan-2-one (DXO) using tin 2-ethyl-hexanoate [Sn(oct) 2] as a catalyst at 150 °C for 24 h without solvent. Preparation of controlled release materials was accomplished using α-pinene from Japanese cypress oil and synthetic random copolymers of l-LA with cyclic monomers as base materials under supercritical carbon dioxide (scCO 2). Poly(l-LA-ran-VL), poly(l-LA-ran-CL), poly(l-LA-ran-TEMC), and poly(l-LA-ran-DXO), which have lower T m and ΔH m values than poly(l-LA) were used for the impregnation experiments. The oil content of the copolymers was greater than that in poly(l-LA). The content of oil into poly(l-LA-ran-TEMC) (80:20) was 8.1%, 2.1-fold greater than that in poly(l-LA) (Lacea H-100) (H-100), and 1.5-fold greater than that in poly(l-LA) (Lacea H-440) (H-440). Although a previous study showed that 3.2% d-limonene could be incorporated into poly(l-LA-ran-CL) (85:15) under the same conditions, results of this experiment showed that 5.8% and 6.6% oil could be incorporated into poly(l-LA-ran-CL) (81:19 or 91:9), respectively. Results from controlled release experiments demonstrated that the oil content in the polymer decreased upon copolymer degradation for all copolymers. In gas release tests, polymers H-440 and poly(l-LA-ran-VL) (85:15) released gas upon hydrolysis. Although the weight loss of H-440 was only 9% at 56 days, the calculated loss of oil in H-440 was 28%. © 2012 The Royal Society of Chemistry. Source


Tsutsumi C.,Niihama National College of Technology | Fukukawa N.,Niihama National College of Technology | Sakafuji J.,Niihama National College of Technology | Oro K.,Research Institute for Solvothermal Technology | And 3 more authors.
Journal of Applied Polymer Science | Year: 2011

In this article, we cover the development of L-lactide (L-LA) random copolymers into which useful compounds, such as repellents and antibacterial agents, were impregnated by high concentration. Outstanding controlled release materials were developed with statistical random copolymers of L-LA with cyclic carbonate (CC) [2,2-dimethyltrimethylene carbonate (2,2-DTMC) or tetramethylene carbonate (TEMC)] with tin 2-ethyL-hexanoate as a catalyst at 150°C (2,2-DTMC) or 120°C (TEMC) for 24 h without solvent. The preparation of improved controlled release materials was performed with useful organic compounds with low boiling points and synthetic L-LA random copolymers containing CCs as base materials under supercritical carbon dioxide (scCO 2). Low-boiling-point compounds, such as d-limonene and hinokitiol, were used. In impregnation experiments with scCO 2, the amounts of low-boiling-point compounds increased with increasings L-LA content. The compound content impregnated into poly(L-lactide-ran-cyclic carbonate) [poly(L-LA-ran-CC)] was greater than that of the experiment with poly(L-lactide-ran-ε-caprolactone) previously studied. When the enzymatic degradation of poly(L-LA-ran-CC) was performed with proteinase K, copolymers with a greater L-LA content degraded more rapidly than did copolymers with a greater CC content. In a controlled release experiment with poly(L-lactide-ran- 2,2-dimethyltrimethylene carbonate) (76/24) or poly(L-lactide-ran-tetramethylene carbonate) (81/19), the rate of polymer degradation and the rate of impregnated compound release were almost the same. © 2011 Wiley Periodicals, Inc. Source

Discover hidden collaborations