The effect of the distance between neighboring vinyl groups on template polymerization

Intra-molecular polymerization of methacrylate type multi-vinyl monomer of Noria (Noria-MVM) was investigated from the viewpoint of the structure of Noria-MVM. Noria-MVM was polymerized by atom transfer radical polymerization (ATRP) with different reaction time, temperature, and monomer concentration. Polymerized sequences were derived from polymerized Noria-MVM by hydrolysis and methylation. The degree of polymerization (DP) of polymerized sequence was determined by matrix-assisted laser desorption/ionization time-of-flight mass (MALDI-TOF mass) analyses. The DP values were odd value in a range of 3-23. The distance from radical to the next vinyl group was influenced by the structure of Noria. When the distance was shorter than 5 Å, the polymerization did not terminate. When the distance was longer than 5 Å, the termination tended to occur.     

P(BS-co-DGA)共聚物的合成和降解性的研究

改变二乙醇酸(DCA)的添加量和聚丁二酸丁二醇酯PBS缩合聚合,得到了数均分子质量达6.5万以上的P(BS-co-DGA)二元无规共聚物.使用核磁共振表征了共聚物的化学结构,根据不同DGA的添加量对共聚物的相对分子质量、热性质、力学性能、降解性的影响等进行了研究.结果表明P(BS-co-DGA)共聚物在较短的反应时间内具有相对高的数均分子质量,分子量分布在2左右;随着DGA添加量的增加,共聚物的Tm和△Hm呈降低趋势;但是所有共聚物的热稳定性没有大的改变,热分解温度均在300℃以上;DGA添加量为2%时在堆肥中的降解速度最快.     

Constraint loss correction for assessment of CTOD fracture toughness under welding residual stress - Part II: Application of toughness correction methodology

This part II paper presents the verified results of the toughness correction methodology for welded joints of wide plates. The equivalent CTOD ratio, β_r, is applied to the fracture data of the welded joints from lower to upper ductile-brittle transition temperature region. In the part I paper, β_r is defined as the ratio of CTOD in the standard fracture toughness specimen to CTOD in the wide plate with welding residual stress at the same level of the Weibull stress. In this part II paper, the equivalent CTOD ratio, β_r, under the welding residual stress field has been verified for assessment of constraint loss effects on CTOD fracture toughness of wide plate. Fracture assessments have been conducted by applying the methodology for “After Weld Notch” and “Before Weld Notch” type welded joints. It has been found that an excessive conservatism observed in the conventional procedure is reasonably reduced by applying the proposed methodology.     

A new antifouling paint based on a zinc acrylate copolymer

A series of novel acrylic copolymers, which contains zinc atom in a form of polymeric salt and can be exchanged with e.g. sodium ions in sea water, has been developed. As the ion exchange reaction proceeds, the polymers become soluble and leach out by flow of sea water. The polymers are considered to be suitable for antifouling paints, since erosion rates of antifouling paints formulated with the polymers could easily be controlled by varying the polymers’ characteristics such as molecular weight, hydrophilicity, etc., without spoiling the paints’ overall water resistance. After dynamic immersion the copper release rates, which represent efficacy of the main biocide, increased in most of the paint samples, and the copper release rates also depended upon the leaching out behaviors of the polymers.     

Endo‐α‐Mannosidase‐Catalyzed Transglycosylation

In order for facilitating the synthesis of oligosaccharides, transglycosylation reactions mediated by glycoside hydrolases have been studied in various contexts. In this study, we examined the transglycosylating activity of a Golgi endo ‐ α‐mannosidase. We prepared various glycosyl donors and acceptors, and recombinant human Golgi endo‐α‐mannosidase and its various mutants were expressed. The enzyme was able to mediate transglycosylation from α‐glycosyl‐fluorides. Systematic screening of various point mutants revealed that the E407D mutant had excellent transglycosylation activity and extremely low hydrolytic activity. Substrate specificity analysis revealed that minimum motif required for glycosyl acceptor is Manα1– 2Man. The synthetic utility of the enzyme was demonstrated by generation of a high‐mannose‐type undecasaccharide (Glc₁Man₉GlcNAc₂).     

The Effects of Wet-Milled Wood Flour on the Mechanical Properties of Wood Flour/Polypropylene Composites

The sizes and shapes of wet ball-milled wood flour were investigated based on their average particle size, size distribution, their solution viscosity, and scanning electron microscopy images. The ball-milling conditions were combinations of rotational speed (150, 200, and 250 rpm) and milling time (1 to 16 h). The average diameter of the wood flours decreased and the degree of fibrillation of the wood fibers increased with the ball-milling time at each rotational speed. Ball-milled wood flours having the same average particle size had similar surface fibrils that were tens to hundreds of nanometers wide. Ball-milling at 200 or 250 rpm could pulverize just as effectively as that at 150 rpm because the size reduction and fibrillation progressed more quickly. Tensile and bending properties of the composites prepared from the ball-milled wood flour (4 wt% in polypropylene) were evaluated. Morphological changes in the wood fillers had little effect on the properties of the composites. The tensile and bending properties of the composites containing the wood filler were 10% higher than those for the unfilled resin.     

Electrical Conduction Properties of LaP3O9 Glass and Glass–Ceramics

Electrical conduction properties of undoped and 1 mol% Sr-doped LaP₃O₉ glasses and glass–ceramics were investigated over the temperature range of 673–1123 K. Both the materials showed relatively low conductivities in the glassy state. However, the conductivity of the Sr-doped LaP₃O₉ glass significantly increased with a heat treatment above the crystallization temperature, while the conductivity of the undoped LaP₃O₉ glass did not improve even after the heat treatment. It was concluded that crystallization of the Sr-doped LaP₃O₉ glass induced protonic conduction and thus enhanced the conductivity. Electrical conduction properties of the Sr-doped LaP₃O₉ glass–ceramic fundamentally resembled those of the sintered crystalline Sr-doped LaP₃O₉.     

Proton Conductivity in Zr4+-Ion-Doped P2O5–SiO2 Porous Glasses

The effect of zirconium ions on glass structure and proton conductivity was investigated for sol-gel-derived P₂O₅–SiO₂ glasses. Porous glasses were prepared through hydrolysis of PO(OCH₃)₃, Zr(OC₄H₉)₄, and Si(OC₂H₅)₄. Chemical bonding of the P⁵⁺ ions was characterized using ³¹P-NMR spectra. The phosphorous ions, occurring as PO(OH)₃ in the ZrO₂-free glass, were polymerized with one or two bridging oxygen ions per PO₄ unit with increased ZrO₂ content. The chemical stability of these glasses was increased significantly on the addition of ZrO₂, but the conductivity gradually decreased from 26 to 12 mS/cm at room temperature for 10P₂O₅·7ZrO₂·83SiO₂ glass. A fuel cell was constructed using 10P₂O₅·5ZrO₂·85SiO₂ glass as the electrolyte; a power of ∼4.5 mW/cm² was attained.     

Fabrication and characterization of cuprous oxide: fullerene solar cells

Cuprous oxide (Cu₂O)-based solar cells with fullerene (C₆₀) were fabricated on indium tin oxide (ITO) by a spin-coating method. The microstructure and cell performance of the solar cells with the Cu₂O:C₆₀ structure was investigated. A photovoltaic device based on an ITO/Cu₂O:C₆₀ bulk heterojunction structure fabricated by the spin-coating method provided short-circuit current density of 0.11 mA cm^?2 and open-circuit voltage of 0.17 V under an Air Mass 1.5 illumination. The microstructures of the Cu₂O active layer were examined by using X-ray diffraction and transmission electron microscopy. The energy levels of the present solar cells are also discussed.