Cross-linking of borosiloxane oligomers and properties of materials with vulcanized borosiloxane coating

Cross-linking of liquid borosiloxane oligomers was studied. The reaction is described by a first-order rate equation for irreversible reactions. The effective cross-linking rate constants and activation energies of the reaction were calculated. The properties of materials with the vulcanized borosiloxane coating were studied. The physicomechanical properties of materials with borosiloxane coating are higher than those of materials with coatings based on vulcanized liquid siloxane rubbers.     

聚乳酸/肝素缓释微囊复合材料组织相容性研究

研究了三种不同包覆材料的肝素微胶囊／聚乳酸(PLA)复合材料的组织相容性。结果表明，随着胶囊中壳聚糖浓度的增大，肝素的释放速率变慢。皮肤刺激、皮内刺激、热原、全身急性毒性和细胞培养等试验表明，制备的复合材料在生物学评价试验中均呈阴性反应，材料无明显毒性，材料中不存在潜在致敏性物质，所含热原含量符合生物体的要求。由此表明，肝素缓释微胶囊／PLA复合材料符合三维多孔材料的要求，且具有优良的组织相容性。     

The sorption properties of chitosan-carbon fibrous materials

The kinetics and equilibrium of sorption of copper(II) ions on natural biopolymer chitosan, activated carbon fiber, and composite materials prepared by electrochemical modification of activated carbon fibers with chitosan were studied. The influence of the conditions of modification of the microporous carbon matrix on the sorption properties of composite materials with respect to copper(II) was investigated. It was shown that changes in modification conditions could be used to control the sorption properties of chitosan-carbon materials. The mechanisms of copper(II) ion absorption by the sorption materials studied were considered.     

Preparation of polymeric nanostructured materials

A procedure for forming nanostructured materials by impregnation filling of pores of poly(ethylene terephthalate) track membranes with polymeric compounds was examined. The relationships of formation of these materials were elucidated, and the structural and surface properties of these materials were studied.     

Nonhydrothermal Synthesis and Properties of Saponite-Like Materials

Main features of nonhydrothermal synthesis of saponite-like materials containing Zn(II) and Mg(II) cations in octahedral networks were studied. Optimal conditions for the synthesis were determined. The influence exerted by the double-charged structure-forming cation on the rate of structure formation in the synthesized materials and also on their pore structure and thermal stability was studied.     

Preparation and characterization of 3D collagen materials with magnetic properties

In this study 3D collagen materials with magnetic properties were prepared by lyophilization technique. Magnetic particles were synthesized by precipitation of iron (II) sulfate heptahydrate and iron (III) chloride hexahydrate in an aqueous solution of chitosan and then added to a collagen solution. Starch dialdehyde (DAS) was used as a cross-linking agent for the materials. The properties of the obtained materials were studied using infrared spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Additionally, mechanical properties, porosity, density, swelling and moisture content were measured.It was found that 3D composites made from collagen with magnetic particles are hydrophilic with a high swelling ability. Cross-linking of such collagen materials with dialdehyde starch (DAS) alters the swelling degree, porosity and density of materials. The addition of magnetic particles to collagen materials decreases its porosity, and increases the density of the studied materials. Collagen 3D materials with magnetic particles are rigid and inflexible. Magnetic properties of the 3D collagen materials containing magnetic particles were confirmed by the interaction of this material with a magnet.     

Chiral HPLC and physical characterisation of orthoconic antiferroelectric liquid crystals

New orthoconic antiferroelectric liquid crystalline materials were synthesised and characterised in their racemic forms and as (S) enantiomers. The materials possess oligo-methylene spacers of different lengths in semi-fluorinated achiral chains and lateral substitution by fluorine at two different positions of the molecular core. For comparison purposes, analogical materials without fluorine lateral substitutions were also prepared. Polysaccharide chiral stationary phases based on two different chiral selectors were used for the separation of the enantiomers of the individual racemic mixtures by high-performance liquid chromatography. A baseline separation of (S) and (R) enantiomers was obtained for four of the six studied liquid crystalline materials. Two of the materials were partially separated under the optimised separation conditions. The elution order of the individual enantiomers in the racemic mixtures was successfully assigned, as pure (S) enantiomers of all the studied materials were available. Both the position of the fluorine atom within the molecular core and the size of the achiral moiety had significant effects on the separation of the individual enantiomers of the studied compounds. Moreover, it was also found that the structure of the chiral stationary phase selector significantly influenced the enantiomeric resolution.     

Cross-linking of titanosiloxane oligomers and properties of materials with vulcanized titanosiloxane coatings

The structuring of the liquid titansiloxan oligomer at higher temperatures is studied. The properties of cover materials were investigated. It is shown that the materials have a high fire resistance and physical and mechanical properties compared to materials with vulcanized cover on the base of liquid siloxane rubbers.     

甲酸和草酸盐掺杂的AgBr乳剂对亲水型PTG材料感光性能的影响

研究了甲酸盐掺杂和草酸盐掺杂对AgBr乳剂和亲水型PTG材料感光性能的影响.实验结果表明,掺杂后的AgBr乳剂在PTG材料中作为光敏元显著提高了其相对感光度,而不引起灰雾的增加;掺杂增感与硫增感、金增感、硫加金增感在PTG材料中同样表现出协同增感效果,使PTG材料的感光度得到进一步的提高;掺杂后的AgBr乳剂在PTG材料中具有一个最佳使用量,即Ag-Br与硬脂酸银的摩尔比为1:4.     

The optical and gas-sensitive properties of opal-like structures based on SnO<Subscript>2</Subscript>

Opal-like materials based on tin dioxide were prepared, and their structural and sensor characteristics were studied. The optical transmission spectra of opal-like structures based on SnO₂ were recorded, and the volume fraction occupied in them by tin dioxide was estimated. It was shown that structures based on SnO₂ contained a photon stop-zone in the visible spectrum range. The sensor properties of the materials toward CO and H₂ were studied over the temperature range 375−425°C. The SnO₂ samples studied had much higher sensitivity to CO compared with SnO₂ materials without opal-like structures.     

极化聚合物电光材料研究进展

极化聚合物由于其在集成光电子学领域的潜在应用前景已经引起了广泛关注。本文在简要介绍电光调制器及其材料有关知识的基础上,综述了近几年来极化聚合物电光材料的研究进展,主要介绍发色团和聚合物的设计、合成、并对这类材料将来的发展方向作了探讨。     

Supramolecular hydrogels of self-assembled zwitterionic-peptides

Zwitterionic polymer materials have been extensively studied, but zwitterionic peptides supramolecular hydrogel materials are rarely studied. In this study, the preparation of two zwitterionic hydrogels using self-assembled peptides were reported. The hydrogels could be fabricated easily by changing the temperature or enzyme catalysis in a short time. And the differences in structure and function of the zwitterion peptide hydrogels caused by the two preparation methods were also be compared. We found that the hydrogel prepared by enzyme induced self-assembly has better solubility and lower cytotoxicity than that prepared by the heating-cooling process. The result showed the enzyme induced self-assembly way to form zwitterionic peptides supramolecular hydrogel materials could have further biomedical applications.     

锂离子电池纳米N iO负极材料的研究

分别应用溶胶凝胶法和室温固相法合成纳米N iO材料,运用DSC、TG等热分析技术分析了合成的样品,通过选择不同的溶剂和调节溶液的pH值,优化溶胶凝胶法合成纳米N iO负极材料.XRD、TEM技术表征材料的结构和形貌,并对所得材料作了电化学性能测试.     

Study of physical and mechanical properties and combustibility of filled acrylate compositions

Compositions based on cross-linked acrylate copolymers and bentonites were obtained. Physical-mechanical and absorption characteristics of bentonite-polymeric composite materials were studied. The effect of a filling agent on the final product properties was demonstrated. The possibility of using these compositions for creating materials with reduced combustibility was shown.     

Crosslinking of mixtures of DGEBA with 1,6-dioxaspiro[4.4]nonan-2,7-dione initiated by tertiary amines, Part II: Thermo-mechanical properties and reworkability

The copolymerization of a DGEBA epoxy resin and a bislactone was studied using different anionic initiators. In the previous work, the kinetics of the process was studied and the differences were observed which could affect the thermal and mechanical properties of the materials. In the present work, the thermo-mechanical properties of these materials have been investigated. An important influence of the final curing temperature on the thermal properties of the materials was detected. The addition of bislactone improved the thermal degradation of the materials due to the introduction of ester groups into the network, which in turn allowed partial or complete recovery and reworkability of the coated material via hydrolysis of the thermoset. In addition, the materials exhibited superior flexibility and toughness, in comparison to the pure DGEBA material.     

Development of Procedures for Synthesis of Carbon Materials with Molecular-Sieve Properties

New methods for synthesis of uniformly porous carbon materials with sieve properties and small apparent density from phenol-formaldehyde resins were developed; the optimal conditions of their synthesis were determined. New types of finely dispersed carbon powders were prepared using various treatment procedures at different stages; the structural and sorption properties of the resulting materials were studied.     

Properties of cellulose solutions in methylmorpholine N-oxide containing montmorillonite nanoparticles and of composite films thereof

Rheological properties of moderately concentrated solutions of cellulose in methylmorpholine N-oxide-dimethylformamide mixtures containing hydrophilic montmorillonite nanoparticles were studied. Film composite materials were prepared, and their physicomechanical properties and structural organization were studied.     

Properties of aqueous solutions containing blends of poly-N-vinylformamide with carboxymethyl cellulose of various degrees of ionization and of composite films of these polymers

Rheological properties of mixtures of dilute and moderately concentrated aqueous solutions of poly-N-vinylformamide and carboxymethyl cellulose of various degrees of ionization were studied. Composite film materials were prepared, and their physicomechanical properties and structural organization were studied.     

Synthesis of graphene-like materials by graphite oxide reduction

Graphene-like materials were produced by the reduction of graphite oxide with a series of chemical reagents and high-temperature treatment. Hydrazine hydrate, hydroxylamine hydro-chloride, sodium borohydride, and sodium sulfite were used as reducing agents. The obtained materials were studied by elemental and thermal gravimetric analyses, scanning electron microscopy, X-ray diffraction, and IR and Raman spectroscopy. Depending on the used reducing agents, the graphene-like materials contained different amounts of residual oxygen.     

Small-angle x-ray scattering studies of thermally-induced morphological changes in segmented polyurethane elastomers

The effect of temperature on the morphology of a series of polyether and polyester polyurethanes has been studied using small-angle x-ray scattering. Scattering curves were obtained in situ at high temperature (90 and 150°C) and also later at room temperature to study the effects of thermal history on the materials. In general, annealing improves the degree of phase separation and increases the hard domain size in the materials studied. Annealing improves the degree of phase separation in more compatible systems to a greater degree than in less compatible systems. Increased interfacial mixing is apparent in the materials studied in situ at high temperatures. Thicker interfacial regions are also present in the annealed material relative to the control.