Abstract: A novel PEG200 lauric acid diester was synthesized high yield by direct esterification using polyethylene glycol and lauric acid respectively was presented in this work. The product of PEG200 lauric acid diester was characterized by a fourier transform infrared spectrometer(FTIR). The effects of catalyst, reaction time, reaction temperature and molar ratio on the reaction were discussed. The optimum synthetic condition of PEG200 lauric acid diester: esynthesis is based on protection of N2 and the ressure is 0.08Mpa. Using mass fraction 0.45% in p-toluene sulphonic acid as catalyst, molar ratio of polyethylene glycol and oleic acid 1:1.95, reaction temperature about 130-140°C, and reaction time 9-10h. The results of testing of diester products showed that the yield of PEG200 lauric acid diester is 98.2%.And this article reviewed the effect of concentration on viscosity. The characteristic curve of Viscosity-Concentration showed the viscosity increased with increase of the concentration which brought about the increase of particle size. Especially focusing on the maximum viscosity appeard on 80% because of the phenomenon of reverse micelles. Then the viscosity decreased with increase of the concentration.
Abstract: Polyamic acids (PAA) were synthesized by solution polycondensation of aromatic diamine with dianhydride and PAA were readily soluble in polar organic solvents (N-methylpyrrolidinone, N, N-dimethylacetamide and DMF). It was found that the most appropriated reaction conditions of synthesis of PAA solution were the ratio of dianhydride with diamine being 1.02:1and 3h reaction time at ambient temperature in both N-methylpyrrolidinone and N, N-dimethylacetamide polar organic solvents. PAA thin films were prepared by PAA solution spread on the glass plate and PI thin films were obtained by the casted thin films which underwent a special high-temperature (300°C, 2h) heat curing. The structures of PAA and PI films were characterized by FT-IR spectra and degree of imidization of PAA solution was indicated from IR spectra. The thermal stability was studied by thermogravimetric analysis (TGA) and the thermal behaviors were investigated by differential scanning calorimetry (DSC) in this paper. It was shown that PAA solution were imidization at 200°C mostly and PI had higher thermal stability.
Abstract: Terbium doped tantalum oxide (Tb-Ta2O5) particles were synthesized with a low hydrothermal method. The phase structure of Tb-Ta2O5 obtained was performed by X-ray diffraction (XRD). The result revealed that the terbium doped Ta2O5 belongs to orthorhombic crystal. The electrochemical property of methylene blue (MB) at Tb-Ta2O5 film electrode in 0.5 mol dm-3 KCl aqueous solution was investigated with cyclic voltgrammetry (CV). The CV result indicated that the electrochemical kinetics of MB was diffusion controlling at Tb-Ta2O5 film electrode. Tb dopping imporved the electrochemical property of Ta2O5 film electrode. Tb-Ta2O5 is used as a kind of electrode material which has some new potential applications.
Abstract: C/C composites were prepared by low temperature and hot pressure moulding process from T300 carbon fibre and medium temperature pitch(MTP) or MP with nematic liquid crystalline. The effect of the content of carbon fibre and different proportion of MTP to MP on interlaminar bonding strength (ILBS) of C/C composites was investigated. C/C composites were characterized by ILBS test and scanning electron microscope. Results showed that the ILBS increased with the increase of the content of carbon fibre and proportion of MTP. When the content of carbon fibre was 60.5%, the ILBS of composites prepared from MP reached up to 1.498MPa, and to 3.031MPa from MTP.
Abstract: This first part of this paper will introduce the mechanical-dynamical properties of polysiloxane defoamer thoroughly. Defoamers or foam breakers are added to eliminate the existing foam and usually act on the outer surface of the foam because a bubble is a closed system and the defoamer can only reach the outer surfaces. Then, some of synthesis methods and compounds under real application conditions are given, such as synthesis of methyl hydrogen silicone oil, synthesis methods of polyether and compounds of polyether modified polysiloxane defoamer.
Abstract: China has more than seven-thousand-year history of ceramics, in the course of which it forms distinctive style of ceramics culture. Ceramics has been more and more attractive as one artistic school with special style. The paper studies on ceramics technique in order to help people know of and extend the culture of ceramics.
Abstract: Some kinds of solvents were utilized to investigate the influences of the compatibility between the polymers and their solvent on formation of honeycomb patterns. Polyphenylene Oxide (PPO), Poly (D, L-lactic-co-glycolic acid) (PLGA) and Poly (L-lactic-co-glycolic acid) (PLLGA) were dissolved in different solvents to form porous films. It was found that the good compatibility between the polymers and their solvents was beneficial to the formation of regular structures. Moreover, several solvents were fixed to form a serial of mixed-solvents which had different compatibility with the polymer, such as C2HCl3-CH2Cl2 mixed-solvent. These mixed-solvents were used to investigate in detail how the change of the compatibility between the polymer and its solvent influence the morphography of the polymer film. The result showed that, excluding the affection of the solvents’ evaporation rate, the pattern became more regular along with the improvement of the compatibility between the polymer and its solvent.
Abstract: In this paper, we propose an analysis method for examining yarn cross-sectional structure. After obtaing yarn cross section photos, annular equal area yarn model and binary operation were used for image analysis and treatment. Then, statistic method was applied to analyze the distribution of fiber area in equal areas. The centroid position of the fiber and yarn were calculated, and the percentage values of the fiber area in each equal division against its circle (ring) area were obtained by using an ImageJ software. Finally a yarn sample was examined, and results show that this method is useful.
Abstract: A novel photonic crystal fiber (PCF) design with two rings of hybrid elliptical air-holes for single-polarization single-mode (SPSM) operation is presented. The proposed SPSM-PCF characteristics are investigated by using a full-vector finite element method (FEM) with perfect matched layer (PML) boundary conditions. The proposed SPSM-PCF can perform a single-polarization single-mode propagation. The modal birefringence of the proposed SPSM-PCF is as high as 0.00284 at the wavelength of 1.55 µm, the beat length is 0.546 mm. The confinement loss of the x-polarized mode is lower than 0.5 dB/km, whereas the loss of the y-polarized one is larger than 15 dB/km. Compared with the case of x-polarized mode, the y-polarized mode can be suppressed with a shorter fiber length. Variations of the mode field characteristics with input wavelength are given. For considering loss ratio and loss difference, the proposed PCF can perform SPSM operation with wide bandwidth of 600 nm. It indicates that this is a good solution to realize single-mode single-polarization operation.