Preparation and structure of multiwalled carbon nanotubes

The structure of oxidized multiwalled carbon nanotubes has been studied by transmission electron microscopy and X-ray diffraction. The results demonstrate that oxidation disrupts nanotubes. Subsequent heat treatment at 300°C also changes the structure of the nanotubes, increasing their inner diameter and reducing their outer diameter.     

Influence of carbon fibre on formation kinetics of crosslinked copolymer from bisphenol A dicyanate and epoxy oligomer

The influence of carbon fibre on the curing kinetics of the prepolymer based on bisphenol A cyanurate and epoxy resin has been studied using infra-red spectroscopy. It was found that the curing process of the prepolymer is very complicated. It is shown that in curing the prepolymer a number of the sequential transformations of one ring structure into others occurs. An introduction of the carbon fibre (CF) of two types, original CF and modified CF (MCF) containing phosphate groups, affects strongly the prepolymer curing. Both CF and MCF accelerate the conversion rate of epoxy groups. In the case of cyanate groups, the former has practically no effect on their conversion whereas the latter decelerates strongly this process. In the present paper the influence of CF on the mechanism of the copolymer formation is considered.     

Dynamic mechanical study of filled semi-interpenetrating polymer networks: Influence of γ-Fe2O3 on microphase structure

The preparation of filled two-component semi-interpenetrating polymer networks (semi-IPNs) is described and the results of an investigation of their morphology by means of dynamic mechanical spectroscopy are considered. The influence of an active dispersed filler (γ-Fe₂O₃) on the semi-IPNs phase structure is studied. A comparison is made between filled and unfilled semi-IPNs consisting of compatible or incompatible polymers. In the case of a semi-IPN of compatible polymers, the introduction of γ-Fe₂O₃ was observed to cause phase separation. With a two-phase semi-IPN the introduction of the filler enhanced the phase separation. The presence of two distinct peaks (the dynamic glass transition temperatures) corresponding to those of the two initial homopolymers shows the semi-IPN to have a two-phase structure.     

New platforms for 3-D microarrays: Synthesis of hydrophilic polymethacrylate monoliths using macromolecular porogens

Hydrophilic macroporous monolithic material based on poly(glycidyl methacrylate-co-glycerol dimethacrylate) was synthesized by photo-initiated free-radical polymerization. Different pore-forming agents, including low molecular mass cyclohexanol and dodecanol, as well as the solutions of hydrophobic polymers, namely, polystyrene in toluene and poly(dimethyl siloxane) in hexane, were used to obtain the macroporous polymer platforms intended for new type of 3-D microarrays (biochips). The porous characteristics of functional copolymers obtained were investigated by mercury intrusion porosimetry and scanning electron microscopy. Some of developed materials were tested for protein microarray construction. Demonstration of potential of suggested materials, as well as optimization of protein covalent immobilization conditions, were realized using model mouse IgG – goat anti-mouse IgG affinity pair.     

Evaluation of corrections due to local deformations in contact measurements of the thickness of low-modulus articles

Translated from Izmeritel'naya Tekhnika, No. 3, pp. 17–18, March, 1990.     

Photoelectric properties of surface-barrier structures based on Zn<Subscript>2−2<Emphasis Type="Italic">x</Emphasis></Subscript>Cu<Subscript>x</Subscript>In<Subscript>x</Subscript>Se<Subscript>2</Subscript> films obtained by selenization

p-Zn_2?2xCu_xIn_xSe₂ (ZCIS) polycrystalline films 1–2 ¼m thick have been obtained by selenization. Photosensitive surface-barrier In/p-ZCIS structures are fabricated based on the films. The spectra of relative quantum efficiency of the structures obtained by selenization of the initial ZnSe/(Cu-In) and (Zn-Cu-In) films are examined. The optical band gap of the Zn_2?2xCu_xIn_xSe₂ films is determined. Conclusions are reached on the prospects for the use of the obtained films as broadband photoconverters of natural optical radiation.