A number of aqueous polyurethane dispersions were synthesized by the reaction of poly(ε-caprolactone) and isophorone diisocyanate, extended with different mass ratios of chitosan and dimethylol propionic acid.
Their chemical structures were characterized by using FTIR, 1H NMR, and 13C NMR spectroscopy, and thermal properties were determined by TGA. Incorporation of chitosan into the polyurethane backbone
improved thermal stability. The hydrophilicity of the prepared polymers was also examined by contact angle measurements. For
all samples, the contact angles increased by increasing the amount of chitosan. The increased contact angle is ascribed to
the decrease of the hydrophilicity of the polyurethanes, which is reduced by the increasing amount of chitosan with respect
to dimethylol propionic acid chain extender. 相似文献
A simple, efficient, and green method for synthesis of 2,4,6-triarylpyridines by one-pot three-component reaction of acetophenones,
aryl aldehydes, and ammonium acetate using 3-methyl-1-(4-sulfonylbutyl)imidazolium hydrogen sulfate [HO3S(CH2)4MIM][HSO4], a Br?nsted-acidic ionic liquid, as an effective and reusable catalyst under solvent-free conditions is described. This
method has several advantages, for example simple procedure with an easy work-up, shorter reaction times, and high yields. 相似文献
Synthesis of five phosphonato esters has been accomplished via reaction between dimethyl acetylenedicarboxylate and triphenyl
phosphite in the presence of biological compounds such as theophylline, 4-hydroxypyrimidine, 2H-3,1-benzoxazine-2,4(1H)-dione, 2-chloroaniline, or 3-nitroaniline at ambient temperature. The configuration of the compounds was determined on the
basis of coupling constants emerging from the Karplus equation. 相似文献
Hyperbranched polyester-grafted poly(vinylidene fluoride) (HBPE-g-PVDF) was synthesized and used as additive in preparation of PVDF blend membranes. HBPE-g-PVDF copolymer was characterized with FTIR and TGA techniques. The prepared membranes were also characterized with SEM, AFM and contact angle measurement. The performance of prepared membranes as nanofiltration membrane was studied by pure water flux (PWF), salt rejection, dynamic and static fouling tests. The results showed that hydrophilicity of prepared membranes greatly increased after blending, and their pore size and pore size distribution and so PWF of blend membranes increased. 相似文献
The tricyclic isatin, 5,6‐dihydro‐4H‐pyrrolo[3,2,1‐ij]quinoline‐1,2‐dione, undergoes three‐component, one‐pot reactions with 1‐aryl‐3‐methylpyrazole‐5‐amines and cyclohexane‐1,3‐diones producing hexacyclic spiro products, hexahydrospiro[pyrazolo[3,4‐b]quinoline‐4,1‐pyrrolo[3,2,1‐ij]quinoline‐2′,5(1H,4′H)‐diones]. Comparable spiro condensation products are also obtained using 4‐hydroxy‐2H‐1‐benzopyran‐2‐one in place of cyclohexane‐1,3‐diones. 相似文献
The present work deals with numerical investigations on heat transfer characteristics and friction factor of aqueous CuO nanofluids flow in a set of four microchannels connected in parallel under laminar regime. For each single phase, volume of fluid, mixture and Eulerian models, a particular computer code is developed to carefully simulate this problem. The three-dimensional steady-state governing equations are solved through finite volume method. The primary aim of this study is to comparatively distinguish the most appropriate and accurate model for numerical studies of nanofluids in microchannels. The results are compared with one another and the data obtained from an experimental work. Regarding the results, an acceptable consistency is observed for all models with the experimental data. The current study truly demonstrates that applying single-phase model to simulate and evaluate the laminar flow of CuO–water nanofluid inside microchannels with uniform wall temperature is more modest, precise and reliable compared with two-phase models.
Nano‐Zn‐[2‐boromophenyl‐salicylaldimine‐methylpyranopyrazole]Cl2 (nano‐[Zn‐2BSMP]Cl2) as a nanoparticle Schiff base complex and a catalyst was introduced for the solvent‐free synthesis of 4‐((2‐hydroxynaphthalen‐1‐yl)(aryl)methyl)‐5‐methyl‐2‐phenyl‐1H‐pyrazol‐3(2H)‐ones by the multicomponent condensation reaction of various aromatic aldehydes, β‐naphthol, ethyl acetoacetate, and phenyl hydrazine at room temperature. 相似文献
Microfluidic system, or lab-on-a-chip, has grown explosively. This system has been used in research for the first time and then entered in the clinical section. Due to economic reasons, this technique has been used for screening of laboratory and clinical indices. The microfluidic system solves some difficulties accompanied by clinical and biological applications. In this review, the interpretation and analysis of some recent developments in microfluidic systems in biomedical applications with more emphasis on tissue engineering and cancer will be discussed. Moreover, we try to discuss the features and functions of microfluidic systems. 相似文献
A new Schiff base ligand of 5-bromo-2-hydroxybenzaldehyde S-ethyl-isothiosemicarbazone (H2L) was synthesized and its mixed-ligand Cu(II) complex was also prepared by reaction of Cu(NO3)2·3H2O with H2L and imidazole. Their structures were fully characterized by elemental analysis, FT-IR, molar conductivity and UV-Vis methods. The analytical data suggest that the metal, H2L and imidazole ratios in the Schiff base complex are 1:1:1. Single crystal diffraction was also used to better understand the molecular structure of the Cu(II) complex. The results of physico-chemical analyses of the Schiff base complex reveal the coordination geometry around the central atom is square planar. The H2L ligand (NNO donor) is coordinated to the metal center as a tridentate bionegatively agent. Another position of the square planar geometry is occupied by the imidazole ligand. Furthermore, computational studies of the new complex were performed by carrying out DFT calculations. Geometry optimization and natural band analysis of the complex is discussed in further detail. 相似文献