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931.
Kang Dai Lei Song Saihua Jiang Bin Yu Wei Yang Richard K.K. Yuen Yuan Hu 《Polymer Degradation and Stability》2013
A novel reactive phosphorus-containing monomer [1-oxo-2,6,7-trioxa-1- phosphabicyclo-[2.2.2]octane-methyl diallyl phosphate, PDAP] was synthesized, and various amounts of PDAP were combined with unsaturated polyester by radical bulk polymerization. The resulting flame-retardant unsaturated polyester resin (FR-UPR) samples were investigated by thermogravimetric analysis (TGA), microscale combustion calorimetry (MCC), and limiting oxygen index (LOI) tests. Due to the relatively high phosphorus content of PDAP (18.2 wt%), incorporation of this monomer into unsaturated polyester resin (UPR) led to a marked decrease in the heat release capacity (HRC), the total heat release (THR), an increase in the LOI and the char yield upon combustion. In order to elaborate the interactions between the UPR and PDAP in degradation, differences between the experimental and theoretical mass losses of a FR-UPR sample were evaluated. Furthermore, thermogravimetry-Fourier transform infrared (TG-FTIR) and real-time Fourier transform infrared (RTIR) spectroscopy were employed to investigate the degradation behavior of UPRs, providing insight into the degradation mechanism. 相似文献
932.
The main goal of this work is to identify two polyamides (PA11 and PA1012) by mass spectrometry including pyrolysis-GC/MS and MALDI-TOF MS. PA11 and PA1012 have similar properties and cannot be distinguished by many other methods. Using pyrolysis-GC/MS, the pyrograms of PA11 and PA1012 at 600 °C were compared. Specific pyrolyzates for PA11 and PA1012 were obtained, 2-azacyclotridecanone for PA11 and 1,10-diaminodecane, 1,10-dicyanodecane for PA1012, respectively, which was the basis to distinguish them. Meanwhile, MALDI-TOF MS can give specific repeat unit for these two polyamides, dehydrated 11-aminoundecanoic acid (M = 183) for PA11, acetylate of dodecanedioic acid and diaminodecane (M = 366) for PA1012, which can be another means of identifying them. 相似文献
933.
Water is an important component in living systems and deserves better understanding in chemistry and biology. However, due to the difficulty of investigating the water functions in protein structures, it is usually ignored in computational modeling, especially in the field of computer‐aided drug design. Here, using the potential of mean forces (PMFs) approach, we constructed a water PMF (wPMF) based on 3946 non‐redundant high resolution crystal structures. The extracted wPMF potential was first used to investigate the structure pattern of water and analyze the residue hydrophilicity. Then, the relationship between wPMF score and the B factor value of crystal waters was studied. It was found that wPMF agrees well with some previously reported experimental observations. In addition, the wPMF score was also tested in parallel with 3D‐RISM to measure the ability of retrieving experimentally observed waters, and showed comparable performance but with much less computational cost. In the end, we proposed a grid‐based clustering scheme together with a distance weighted wPMF score to further extend wPMF to predict the potential hydration sites of protein structure. From the test, this approach can predict the hydration site at the accuracy about 80% when the calculated score lower than ?4.0. It also allows the assessment of whether or not a given water molecule should be targeted for displacement in ligand design. Overall, the wPMF presented here provides an optional solution to many water related computational modeling problems, some of which can be highly valuable as part of a rational drug design strategy. © 2012 Wiley Periodicals, Inc. 相似文献
934.
A water-soluble derivative of chitosan, carboxymethylchitosan (CMCH), was mixed with alkyltrimethylammoniumbromides (CmTAB) and was studied on the adsorption at air/water interface using equilibrium and dynamic surface tension method. The effects of surfactant and polymer concentrations, surfactant chain length, as well as pH of solution were investigated. Addition of the surfactants remarkably promotes the polymer adsorption. Increasing any one of surfactant concentration, surfactant chain length, and pH will facilitate the adsorption of the mixture whereas little effects of polymer concentration were observed. The results are explained in terms of the interaction between CMCH and CmTAB under different conditions. 相似文献
935.
Jian-Zhong Jiang Li-Ting Lu Zheng-Yong Liang Zheng-Gang Cui 《Journal of Dispersion Science and Technology》2013,34(1):125-127
Highly regiospecific mononitration of phenols and substituted phenols was carried out in TX100-based microemulsion. The use of inexpensive and relatively nontoxic acidic reagent is an advantage of this method. The effect of various parameters such as concentration of NaNO3, temperature, and agitation speed on reaction system have been investigated. Exclusive ortho-selectivity was observed for all the phenols subjected to this protocol. 相似文献
936.
Jianqiang Zhang Jijiang Ge Anzhou Feng Ping Jiang Ruidong Li 《Journal of Dispersion Science and Technology》2013,34(11):1589-1595
To solve the problem of high pressure of water injection in low permeability reservoirs, a high concentration of surfactant system was developed in this article. With the solubilization of oil in aqueous surfactant solution as a criterion, a formula was screened from anionic and nonionic-anionic surfactants, and the optimal depressurized system was obtained as follows, 13.3% surfactant HEX +2.23% n-propanol +4.47% n-butanol, the solubilization capability being up to 0.66 g/g. This system had good salt tolerance, and it exhibited water external microemulsion in the range of of 1 to 200 g/L NaCl. Core flooding results show that this high concentration of surfactant system formed water external microemulsion with the residual oil in the core, reducing the displacement pressure over 35%. Meanwhile, the effects of concentration and injection volume on depressurization were also investigated. It is indicated that a good depressurization effect was achieved after injecting 1 pore volume of the system with the salt concentration of 100 g/L. 相似文献
937.
Song Wang Liqiang Tan Jinlong Jiang Jing Chen Liangdong Feng 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(2):1305-1312
In this research TiO2 sample was synthesized by a simple sol–gel method and was characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET) techniques. The XRD result indicated that the obtained product was anatase titanium dioxide with high purity, the TEM image clearly showed that the particle sizes of TiO2 nanoparticles were in the range of 30–70 nm, and the measured BET surface area of the heated TiO2 nanoparticles was 147.14 m2/g. In this work, the prepared TiO2 sample was used as a new adsorbent for the adsorption of radionuclide Co(II) ions from aqueous solutions, and the influence of pH, contact time, ionic strength and temperature in the presence or absence of humic acid/fulvic acid (HA/FA) were also investigated. The experimental results indicated that the adsorption of Co(II) ions onto TiO2 was strongly pH-dependent. Based on the surface complexation, the presence of HSs enhanced the adsorption of Co(II) ions and the influence of Co(II) adsorption onto FA–TiO2 hybrids was much stronger than that of HA–TiO2 at pH values of 2.0–9.0. Adsorption of Co(II) ions onto TiO2 powder was strongly dependent on ionic strength. The adsorption process mainly occured in the first contact time of 2 h and could be fitted by a pseudo-second-order rate model. The calculated thermodynamic data indicated that the adsorption of Co(II) ions onto TiO2 was a spontaneous process and favorable at high temperatures. 相似文献
938.
Jian‐zhong Jiang 《Journal of Dispersion Science and Technology》2013,34(8):1137-1140
Heterogeneous Heck reaction catalyzed by Pd (NH3)4 2+‐Na‐Y zeolite in the presence of K2CO3 as the base has been carried out in an oil‐in‐water microemulsion based on Triton X10 at 80°C. 相似文献
939.
The dynamic surface elasticity of the solution of carboxymethylchitosan (CMCH) and cetyltrimethylammonium bromide (C16TAB) was measured as a function of the surfactant concentration and the surface age by the oscillating drop method. The results showed that the surface layer of the CMCH/C16TAB solution transformed from loose to structured with the increase in the surfactant concentration. The surface elasticity versus the surface pressure curve during the adsorption showed different features at different surfactant concentration ranges, which was connected with the structural transformation of the surface layer. Our results show that the measurement of dynamic surface dilational properties is a powerful tool for studying the surface kinetics, which is helpful for dealing non-equilibrium systems in industry. 相似文献
940.
Yongbing Pei Yuling Jiang Hong Huang Huanqin Chen 《Journal of Dispersion Science and Technology》2013,34(9):1279-1284
The acrylate redispersible polymer powder (RPP) was produced from acrylate latex via spray drying, which was synthesized by latex polymerization with the configuration of soft core and hard shell. The powder's redispersibility and stability of its reconstituted latex were achieved through incorporating monomer methacrylic acid (MAA), which has functional carboxyl group and can provide an ionization effect in alkaline range. The influence of pH value and MAA amount on the redispersibility and stability were studied. The stabilization mechanism for reconstituted latex was also investigated. The acrylate RPP has good redispersibility at MAA of 4–5% and pH values between 9.0 and 10.0. The reconstituted latex is stable at these conditions due to high zeta potential and strong electrostatic repulsion force. 相似文献