Advanced Materials Research Vols. 750-752

Abstract: In this paper, Taken the methyl hydroxypropyl acrylate (HPMA) as functional monomer, a novel poly (butyl acrylate)-poly (methyl methacrylate-methyl hydroxypropyl acrylate) (PBA-P(MMA-HPMA)) core-shell latex particles were synthesized by the method of pre-emulsion semi-continuous seeded emulsion polymerization. The structure and morphology of core-shell latex particles were characterized by the way of laser particle size analyzer, transmission electron microscope (TEM), fourier transform infrared spectrometer (FTIR), nonaqueous acid-base titration, differential scanning calorimetry (DSC). Experimental results showed that the average size of PBA-P(MMA-HPMA) core-shell latex particles was 340nm and the average size of PBA core latex particles was 270nm. The functional monomer HPMA really participated in shell layer copolymerization, when the dosage of HPMA was 8% of shell monomer, HPMA content in the shell was the largest and reached 2.16%. Tg value of the copolymer P(MMA-HPMA) was firstly increased and then reduced with the increasing of HPMA content in shell.

Abstract: Double block copolymers of polyethersulfone (PES)/polycarbonate (PC) were used as a compatibilizer for a blend of PES/PC. The morphology, thermal properties, mechanical properties, etc. of the resulting ternary blend systems were investigated. The addition of the compatibizer improved the compatibility between PES and PC. It was found that the interfacial adhesion was enhanced; the size of the dispersed phase was reduced. This resulted in an improvement of elongation at break and tenacity of PES/PC blends, while the tensile modulus slightly increased, and tensile strength was almost constant.

Abstract: The synthesis of new chiral monomer 4-((4-(allyloxy) benzoyl) oxy) phenyl (S)-4-(2-methylbutoxy) benzoate (M_ch), crosslinking agent hexane-1,6-diyl diacrylate (C_A), and liquid crystal polymer elastomers (E₁-E₇) containing (S)-(-)-2-Methyl-1-butyl group is presented. The phase behavior and mesomorphism of the polymers were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and x-ray diffraction. The effect of the content of crosslinking units on the phase behavior and mesomorphism of elastomers was discussed. The chiral LCEs (E₁-E₇) exhibited elasticity, reversible phase transitions, and cholesteric Grandjean texture. The experimental results demonstrated that the glass transition temperature and isotropic temperature of Chiral LCEs decreased with increasing the content of crosslinking agent, but the cholesteric phase was not disturbed.

Abstract: The controllable preparation of nonlinear optical polymers is still one of the research hotspots on nonlinear optical field. In this paper, a triazole functional polymer was designed and achieved by high-efficiency click chemistry method. The structure and properties of the polymer was characterized and evaluated with FTIR, NMR, UV, FL, DLLS and nonlinear optical analyses. The results exhibited that the polymer was successfully synthesized and has favorable nonlinear optical property, its third-order nonlinearity up to 3.66×10^-10 esu.

Abstract: Zinc oxide (ZnO) with various morphologies consisting of nanoparticles with a diameter of approximately 20 nm have been successfully prepared by hydrothermal method from zinc nitrate (Zn (NO₃)₂)/carbamide (CO(NH₂)₂) solution. The morphologies and phase structures of the as-prepared ZnO samples were characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD). Results show that the morphologies of the as-prepared ZnO are successively present in broom-like, cabbage-like, chinese cabbage-like, honeycomb-like with the increase of the CO(NH₂)₂ concentration from 0.1 M to 1 M. The photovoltaic performances of dye-sensitized solar cells, based on ZnO with various morphologies as the photoelectrodes, are unobvious. With the morphologies of ZnO evolving, the short circuit photocurrent density (J_sc) increases from 2.35 to 3.72 mA/cm², the fill factor (FF) increases from 0.400 to 0.570, and the corresponding conversion efficiency (η) varies from 0.520 % to 1.200 %. The low η may be due to the formation of the Zn²⁺/dye polymers.

Abstract: The Zn_0.2Ca_0.8TiO₃:0.1Pr³⁺ luminescent materials were prepared by sol-gel technology. The phase transformation of gel was studied by TG-DTA and XRD in heat treatment process. The luminescent properties of phosphor in different calcination temperatures were determined by fluorescence spectrophotometer, and then the best sintering temperature was confirmed. The luminescent properties of phosphor was obtained through the emission/ excitation spectra. The surface appearance measured with SEM. The results showed that the nanoZn_0.2Ca_0.8TiO₃:0.1Pr³⁺ phosphor could be obtained by sol-gel, sintering at 900°C. It sent out red fluorescent under the Ultra Violet. This characteristic emission peak at 614nm is associated with the typical ¹D₂³H₄ transition of Pr³⁺ion.

Abstract: Due to the existence of photonic bandgap derived from the periodical dielectric structure in wavelength scale, many novel optical phenomena can be demonstrated in photonic crystals (PhCs). Anomalous propagation of electromagnetic waves in X-band is demonstrated experimentally in a two-dimensional triangular lattice PhC. The experimental measurements of electric field are carried out in a near-field scanning system. The phenomena of anomalous refractions are observed and analyzed in respect of anisotropy of equal frequency surfaces in the PhC. The analysis results of numerical simulation are compared with the experimental measurements and good agreements are obtained.

Abstract: According to the law of light propagation, this thesis analyzed that added reflective particles in the material can improve materials reflectivity properties. Established the model by the optical design software Light Tools to simulate, predicted the law of materials reflectivity properties changing with particle parameters. Chosen TiO₂ as the reflective particles to test, the result shown that when the TiO₂ content reached a certain proportion, the reflectivity and diffuse reflection of diffuse reflection composites can reach 91% and 88% respectively, the illumination uniformity can reach 60%.

Abstract: For the demand of high color rendering W-LED, we chose (SrCaBa)₃(PO₄)₂SrCl₂:Eu²⁺ blue-emitting phosphor powder as the object of our study, and use high-temperature solid-state reaction method to prepare the phosphor powders in a weak reducing atmosphere. A detailed investigation on the reaction parameters, including kinds and relative ratio of raw materials, sintering temperature and Eu²⁺ activator concentration was conducted in terms of luminescent properties of phosphors powder. Research findings show that optimal reaction parameters are: sintering temperature is 1200°C, Eu²⁺ doping level is 0.15mol. By these parameters, the (SrCaBa)₃(PO₄)₂SrCl₂:Eu²⁺ phosphor powder show bright blue emission around 450nm and can be efficiently excited by violet and ultraviolet light (200nm-440nm). Further we employed the energy transfer between Tb³⁺ and Eu²⁺ and prepared a series of phosphors using (SrCaBa)₃(PO₄)₂SrCl₂ as host material_. Research findings show that emission color can be adjusted from blue to blue green by the ratio of Tb³⁺ to Eu²⁺, with line-like Tb³⁺ green emission overlapped on band-like Eu²⁺ blue emission.

Abstract: Hierarchical porous materials with improved properties due to enhanced mass transport through the material and a high surface area and pore volume have been used in numerous applications such as catalysts or catalyst supports, energy storage and conversion, filtration, medical diagnostics, and medical therapies. This paper presents a review of recent progress in hierarchical porous materials for supercapacitor electrodes. Hierarchical porous materials comprise of hierarchical porous carbon, hierarchical porous metal oxides and hierarchical porous composites. An emphasis is placed on the performance of hierarchical porous materials for supercapacitor electrodes in terms of specific capacitance, power density, energy density, rate capability and cyclic stability.