Search results

In order to obtain TiO2, dissolution – precipitation mechanism where titanium arranges into different crystal structure depending on the reactant chemistry.

Key Laboratory of Fruit Waste Treatment and Resource Recycling of the Sichuan Provinicial College, College of Chemistry and Chemical Engineering, Neijiang Normal University, Neijiang, Sichuan 641100; 2.
The effect of doping concentration and calcination temperature on structure of TiO2 was discussed.
Among the fabrication techniques, the templating method has become very useful in preparation TiO2 with specific structure and morphology [11, 15].
It is well known the photocatalytic activity of a semiconductor is related to its photonic bandgap structure.
Collagen could be extended to synthesize different oxide nanocrystals with specifically structure and morphology.

Scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDS) and X-ray diffractometer (XRD) were used to analyze the surface morphology, composition and phase structure of the coating.
It was found that the composite coating after the addition of graphene has a great improvement in phase structure, surface morphology, hardness, friction and corrosion resistance.
Moreover, the addition of graphene is advantageous for the formation of dense hexagonal (100) crystal plane, (002) crystal plane and (101) crystal plane structure in the composite plating layer.
The composition and phase structure of the coating were tested by EDS spectrometer and XRD diffractometer.
Journal of Materials Chemistry A, 2013, 1(9):3101

The engineered surfaces were evaluated using Scanning Electron Microscopy and Water Contact Angle. 0.1M alkaline solution hydrolyzed microspheres at higher extends as compared to 0.01M, where partial microspheres disintegrated and porous structure was revealed.
Poly(lactic acid) (PLA, Nature Work), dichloromethane (DCM, ACS Grade, Merck), poly(vinly alcohol) (PVA, 80 % hydrolyzed, Mw 9-10 K, Aldrich Chemistry), sodium hydroxide (M=40 g/mol, Merck) , hydrochloric acid (37 %, fuming acid, Merck), filter paper (Whatman 42, diameter 125 mm).
On the other hand, porous structure of PLA microspheres and disintegrated microspheres was revealed in Fig. 2 (c) & (d) after 0.1 M alkaline hydrolysis, this indicated surface erosion and bulk degradation had occurred.
However, the results can be explained based on the statement stated by Tsuji and Ikada (1998), where the bulk degradation in alkaline treatment is possible when there have porous structure to facilitate the penetration of hydroxide ions.
Thus, the porous structure in microspheres was indirectly inducing the degradation of microspheres during surface modification.

It was then possible to observe by XRD to obtain a structure exfoliated or partially exfoliated in the studied systems.
It is noticed that the peak of the organoclay with d001 = 21.34 Å, disappears when it is incorporated into the matrix of polyamide 6 and a shoulder appears around 6.2 which can be related to a partial intercalation of the polyamide chains among the layers of clay, apparently showing that all systems present partially exfoliated and/or exfoliated structure, and which was confirmed by transmission electron microscopy, as stated in the literature [5].
Fig. 2: XRD diffractograms of polyamide 6 with two molecular weights (C216 and B400) and (b) its nanocomposites Transmission Electron Microscopy (TEM) The transmission electron microscopy to analyze locally formed in the nanocomposite morphology and thus provides a better representation of its structure.
In tests of XRD, the peak disappeared when the organoclay was incorporated in polyamide 6, apparently indicating that the systems had exfoliated and/or partially exfoliated structure.
J., Chemistry of Material, vol. 8, (1996) p. 1584-1587,

The structure of AAO can be molecular self-assembly and its pore size is consistent.
The AAO is the nanopore array template created by chemical method; and its structure has good properties, such as wear resistance, corrosion resistance and insulation and so on.
A highly ordered nanoporous structure of anodic alumina can be produced by using anodic oxidation.
Then, the second time of anodic oxidation was given for film growth on the alumina template surface to obtain an alumina template with an array list typed nanopore structure and smooth surface.
Losic:Trends in Analytical Chemistry, Vol. 44 (2013), p. 25

Study on the Preparation and Performance of Carboxymethyl Chitosan Calcium and Carboxymethyl Chitosan Zinc Composite Materials Jing Li1,a, Chang-Ping Wei1,b, Feng-Ming Wang1, Li-Dan Dong1, Shuang Sun1 and Qin-Yi Liu2,c 1School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Changchun 130022, China 2the second Hospital of Jilin University, Changchun 130022, China a245711992@qq.com, bchangpingwei@hotmail.com, c1226527208@qq.com Keywords: carboxymethyl chitosan, complex substance, preparation, performance research Abstract.
At pH<7 conditions,the obtained carboxymethy chitosan respectively were reacted with calcium chloride solution,zinc chloride solution,after fully reacted,obtained carboxymethyl chitosan calcium and carboxymethyl chitosan zinc .Through infrared spectrum,X-ray diffraction and scanning electron microscopy(sem)analysis means,the structure of the products were characterized.Through the cutting of mice tail hemostasia test ,study the performance of the product.The results showed that the water solubility of carboxymethyl chitosan is better than that of chitosan and with excellent performance,and the performance of carboxymethyl chitosan calcium and carboxymethyl chitosan zinc was better than that of carboxymethyl chitosan.
It suggested that crystallinity of chitosan replaced by carboxymethyl was significantly lower.It was due to the introduction of carboxymethyl polarity hydrophilic group which increased the distance of the molecular structure.So the crystalline state of chitosan was destroyed.
In figure (b), the morphology of carboxymethyl chitosan was a kind of relative rules of spherical link structure and the minimum size was about 23 nm.That may be due to the crystallinity of carboxymethyl chitosan much smaller than chitosan, the carboxyl was hydrophilic group, molecule could form the mutual coupling between the molecular chain, thus the whole presented this kind of structure.

Poly(lactide-co-glycolide) (PLGA) and alginate(AG) are the most promising scaffolds in the bone tissue engineering for their stable mechanical characters and three-dimensional porous structure.
Alginate (AG) and poly(lactide-co-glycolide) (PLGA) have gotten much attention as bone tissue engineering scaffold for their good biocompatibility, good three-dimensional porous structure, etc.
PLGA (polylactide/polyglycolide =4: 1) were gifts from Chemistry Institute, Chengdu branch of Chinese Science Institute, in which pores diameter range from 200 to 250μm, porosity were over 90％, percentage of open area were 98-99%.
PGLA/BMSCs group: HE staining displayed that BMSCs migrated into the inner part of the scaffold where the cells wrapped with mineralized matrix and cartilage-like structures were observed at 4 th week.

Two mechanisms about electrochemical modification of clay minerals are summarized: one of electroosmotic dewatering and stabilization and the other of cation substitutions, structures and properties change, forming new minerals.
● Cation substitutions, structures and properties change, forming new minerals.
The mechanism of electrochemical modification is: (1) electroosmotic dewatering and stabilization; (2) ionic substitutions, structures and properties change, forming new minerals.
Pozzi," Eleclrokinetic in Rocks: Laboratory Measurements in Sandstone and Volcanic Samples,〞Physics and Chemistry of the Earth,Part A: Solid Earth and Geodesy,Vol. 25,Au9.2000,pp.329-332.

Characterization of magnetic cellulose microspheres reconstituted from ionic liquid Shuai Penga, Juan Fanb,Jie Changc* State Key Laboratory of Pulp and Paper Engineering, School of Chemistry and Chemical Engineering, South China University of Technology,Guangzhou.510640,China agwzps211@126.com, b957804576@qq.com, c*changjie@scut.edu.cn Keywords: cellulose;ionic liquids; magnetic cellulose microsphere Abstract.
Their structure , properties and morphology were analysed using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and vibrating-sample magnetometer.
Its highly ordered structure is responsible for its desirable mechanical properties but makes it a challenge to find suitable solvents for its dissolution.[3]Various systems for dissolving cellulose without any chemical reaction have been studied and reported, such as DMAc/LiCl, DMSO/triethylamine/SO2,NMMO and NaOH/urea aqueous solution.
The native cellulose diffraction pattern (Fig. 4a) showed the typical cellulose I structure, with a sharp peak at 22.5°and a wide peak between 12°and18°.[10]The six characteristic XRD peaks of the Fe3O4((220), (311), (400),(422), (511), and (440)) (Fig. 4b) were consistent with the JCPDS file (PDF No. 65-3107), which was the standard pattern for crystalline magnetite with spinel structure.[11]However, the combination of Fe3O4 with cellulose resulted in obvious crystal change.
Their structure, properties and morphology have been characterized, and this type of biocompatible material is proposed to have promising potential in biomedical, drug delivery systems, enzyme immobilization, and many other related fields.