Advanced Materials Research Vols. 239-242

Abstract: The main factors affecting the properties of veneer—rice straw composite board have been investigated, including the quality fraction ratio of SBR to PVA, spreading and the amount of PMDI. The results showed that: the ratio of SBR/PVA：80:20, spreading 15%, the amount of PMDI 20%( accounting for the weight of main agent). Using this adhesive the veneer—rice straw composite board could meet the requirement of GB/T 21723-2008.

Abstract: This study focuses on the effect of impregnation process on the main mechanical properties in the production of veneer composite plank. The results showed that:①Under the normal pressure and temperature the drug absorption of impregnated veneer shall extend the volume with the growth in impregnation time, but growing faster early, the later change slowly. In the impregnation process under pressure, its absorption rate and speed are greatly increased. ②The Modulus of rupture (MOR) and modulus of elasticity (MOE) of veneer composite plank are gradually increased with the drug absorption increased, but after reached a certain peak value they gradually decrease, and the variation of MOE is smaller than MOR.

Abstract: An unsymmetrical photochromic diarylethene, 1-[2-methyl-5-(3,5-difluorophenyl)-3-thienyl]-2-(2-cyano-1,5-dimethyl-4-pyrryl)perfluorocyclopentene (1o), was synthesized, and its optoelectronic properties were also investigated. The results showed that this compound exhibited reversible photochromism changing from colorless to blue after irradiation with UV light both in solution and in PMMA amorphous film. The open-ring isomer of the diarylethene 1 exhibited relatively strong fluorescence both in hexane solution and in PMMA amorphous film. The fluorescence intensity decreased along with the photochromism upon irradiation with 297 nm light and its closed-ring isomer showed almost no fluorescence.

Abstract: A newunsymmetrical photochromic diarylethene 1-(2-cyanophenyl)-2-[2-methy-5-(3-fluorophenyl)-3-thienyl]perfluorocyclopentene (1a) has been synthesized. Its photochromic properties in solution and PMMA film were investigated. Diarylethene 1a changed the color from colorless to purple upon irradiation with 297 nm UV light, in which absorption maxima were observed at 540 nm in hexane and at 545 nm in PMMA film, respectively. This new photochromic system also exhibited remarkable fluorescence switching in the solid state. The results demonstrated that it can be potentially used as polarization holographic optical recording medium.

Abstract: Molecularly imprinted polymers (MIPs) were synthesized by precipitation polymerization using salvianolic acid A (Sal A), acrylamide (AA), ethylene glycol dimethacrylate (EGDMA) and acetonitrile as template molecule, functional monomer, cross-linker and solvent, respectively. The morphology of the obtained polymers was characterized by scanning electron microscopy (SEM). The effect of different polymerization conditions (solvent volume, solvent and template amount) on the size and shape of particles was investigated. The binding properties of the imprinted polymers were evaluated through the equilibrium rebinding experiments. Scatchard analysis revealed that two classes of binding sites were formed in the imprinted polymers with equilibrium dissociation constants of 0.33 μmol·mL^-1 and 0.07 μmol·mL^-1, respectively. Besides Sal A, two structurally related compounds, protocatechuic aldehyde (Pra) and salvianolic acid B (Sal B), were employed for molecular selectivity tests. The results indicated that the imprinted polymers exhibited good selectivity and specificity toward Sal A.

Abstract: A new photochromic diarylethene 1-(3,5-dimethyl-4-isoxazolyl)-2-[2-methyl-5- (3-chlorophenyl)-3-thienyl]perfluorocyclopentene (1o) has been synthesized. Its properties, including photochromism and fluorescence were investigated in detail. It underwent reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light both in hexane and in PMMA. The results showed that this compound exhibited reversible photochromism and good fluorescent switching after irradiation with UV light and visible light.

Abstract: In this study, a core-shell structure acrylate elastomer with UV stabilization core–shell poly[methyl methacrylate-butyl acrylate-2-hydroxy-4-(3-methacryloxy-2-hydroxylproroxy) benzophenone] [poly(MMA-BA-BPMA)] was synthesized by methyl methacrylate (MMA), butyl acrylate (BA) and a polymerizable UV-stabilizer 2-hydroxy-4-(3-methacryloxy-2-hydroxylproroxy) benzophenone (BPMA) via semicontinuous seeding emulsion polymerization. The composition and characteristics of core-shell Poly (MMA-BA-BPMA) were determined by using Fourier transform infrared spectroscopy (FTIR), Ultraviolet-visible absorption spectroscopy (UV-vis) and transmission electron microscope (TEM). Further, the obtained core-shell poly (MMA-BA-BPMA) was blended with polyoxymethylene (POM) to modify its photostabilization. The mechanical properties of POM composite were tested before and after UV-irradiation. The result showed that core-shell poly (MMA-BA-BPMA) can be dispersed well in the POM matrix, which could play a role of improving compatibility with POM and the mechanical properties of modified POM were kept well, which leaded higher impact strength and elongation at break after UV-irradiation.

Abstract: Based on the platform ABAQUS, a 3-D FEM model of spirogyrate ring rolling process has been developed to investigate the ring’s deformation behavior and the expansion law of the diameter. According to the FEM analysis, this kind of profile ring rolling process can be divided into two phases, i.e. the profile forming phase and the diameter increasing phase. During the former phase, the deformation of spirogyrate ring focuses on the profile formation and the diameter increases slowly. In the latter phase, the ring diameter expands rapidly. FEA illustrates that the material flowing to the outer diameter areas is greater than that towards the inner diameter areas in the profile forming phase. The maximum PEEQ is in the pit of the outer profile, whereas the minimum PEEQ locates near the end face. The variation of outer and inner diameter of the spirogyrate ring shows monotonic increasing trend during the whole ring rolling process, in which the expanding rate of inner areas is greater than that of the outer areas.

Abstract: War-broken parts can be repaired quickly without electricity and gas in the wild by use of the thermit welding technology, so it is of great significance to study on welded quality of thermit welding parts for its military application. As the crack resistance of welded parts is an important target to estimate the welded performance, crack resistance test and microstructure analysis have been conducted on test specimens made of Q235 welded parts. Results showed that as the crack ratio was less than 20% in the Y-groove crack test, the crack propagation would not occur in the practical welding structure and that the crack resistance of welded joints could meet the welded demand.

Abstract: A new unsymmetrical photochromic diarylethene 1-(2-methyl-benzothiophenyl)- 2-(2-methyl-5-(2-chlorophenyl))perfluoroncyclopentene (1a), was synthesized and its optoelectronic properties, such as photochromism in solution as well as in poly-methylmethacrylate (PMMA) amorphous films, fluorescences and the fluorescence spectra of diarylethene 1a depended on the concentration were investigated. Using diarylethene 1/PMMA film as recording medium and a linearly polarized 633 nm laser diode for recording and readout, polarization multiplexed image recording can be carried out in this film, which illustrated that the diarylethene can be potentially used as holographic optical recording medium.