Radiation stability of some thermally stable inorganic ion exchangers

Effect of various doses of gamma radiation on the ion-exchange capacity, distribution coefficient values, elution behaviour, pH titration and infrared spectra of some thermally stable inorganic ion exchangers has been studied systematically. No change has been observed in the ion-exchange capacity, elution behaviour and the infrared spectra of the materials irradiated up to a total dose of 3·10⁸ rad, while, a change has been observed in their pH-titration and distribution behaviour.     

Adsorptive voltammetric behaviour of immunoglobulin M

The adsorptive voltammetric behaviour of immunoglobulin M (IgM) has been investigated at the static mercury drop electrode. The stripping process yields an analytically useful signal and the detection limit is 1.2 x 10(-10)M. The adsorptive voltammetric behaviour of IgM has been compared with that of IgG and streptavidin.     

紫外光固化PDLC膜性能的温度效应

考察了紫外光固化PDLC膜的电光性能及其温度依赖性,阐述了其作为显示器件的工作稳定性。指出确定PDLC工作温度范围的方法,对PDLC膜中液晶相的N-I转变行为及其与膜的内部结构的关系进行了讨论。     

Chromatographic behaviour of alkaloids on thin layers of anion and cation exhangers. I. AG 1-X4 and cellex D.

The chromatographic behaviour of 48 alkaloids has been studied on Bio-Rad AG 1-X4, Cellex D and microcrystalline cellulose, eluting with solutions of different pH but constant ionic strength (0.5). Many interesting separations were effected on both AG 1-X4 and Cellex D layers. The influence of pH on the chromatographic behaviour of alkaloids has been quantitatively studied and an equation was used that expresses the behaviour of the alkaloids on both AG 1-X4 (AcO-) and microcrystalling cellulose layers. The nonapplicability of this equation to Cellex D layers is discussed.     

Normal- and Reversed-Phase Behaviour of 16,17-Secoestrone Derivatives on Cyanopropyl-Bonded Silica Gel

The retention behaviour of a number of 16,17-secoestrone derivatives has been studied by LC and HPTLC on a polar cyanopropyl-bonded stationary phase using non-aqueous and aqueous-organic mobile phases. The retention behaviour has been discussed in terms of nature of the solute, eluent and stationary phase. The correlation between retention constants of 16,17-secoestrone derivatives obtained from reversed-phases and commercially available ACD log P software (Advanced Chemistry, Toronto, Canada) has also been examined.     

Die Addition von Fluorcarbenen an Norbornadien: Eine Homo-1,4-addition

It has been found that difluorocarbene undergoes extensive addition to the endo-face of norbornadiene, yeilding the cheletropic adduct, 4.4-difluorotetracyclo[3.3.0.0^2,8.0^3,6]-octane. Similar behaviour has been observed for fluorochlorocarbene. Possible mechanisms to rationalize this novel behaviour of carbenes are discussed.     

Normal- and Reversed-Phase Behaviour of 16,17-Secoestrone Derivatives on Cyanopropyl-Bonded Silica Gel

The retention behaviour of a number of 16,17-secoestrone derivatives has been studied by LC and HPTLC on a polar cyanopropyl-bonded stationary phase using non-aqueous and aqueous-organic mobile phases. The retention behaviour has been discussed in terms of nature of the solute, eluent and stationary phase. The correlation between retention constants of 16,17-secoestrone derivatives obtained from reversed-phases and commercially available ACD log P software (Advanced Chemistry, Toronto, Canada) has also been examined.

     

聚酯-聚醚多嵌段共聚物的球晶生长

采用SALS等方法研究了低硬段含量的聚酯-聚醚多嵌段共聚物中硬段结晶时的球晶生长规律。发现球晶的生长取决于分相形成硬段密集微区的速率与晶体生长速率两种影响因素之间的竞争。硬段结晶形态上的差异对低拉伸此时的力学特性的影响不大,但能明显地影响断裂强度等高拉伸比时的行为。     

Polar smectogens: polymorphism of some cyanoalkoxybiphenylalkoxybenzoates and related compounds

A series of new cyanoalkoxybiphenylalkoxybenzoates containing a highly dipolar end group electrically and mechanically decoupled from the rigid moiety has been synthesized. The thermal behaviour of these compounds and their precursors (cyanoalkoxyhydroxybiphenyls) has been investigated by means of differential scanning calorimetry and optical polarizing microscopy. It has been found that such compounds often exhibit double melting behaviour through isotropic or smectic phases. A rather rich polymorphism (N, S_A, S_B and S_E phases) is observed at high temperature (100-200°C).     

Chromatographic behaviour of closely related aromatic amines on phenol-impregnated thin-layers

Summary The TLC behaviour of closely related aromatic amines on silica gel plates impregnated with phenol, o-cresol, p-nitrophenol, quinol, catechol and pyrogallol has been studied. An attempt has been made to correlate the chromatographic behaviour of amines with the equilibrium constants of the adducts formed by the interaction of amines with absorbed phenol. Suitable adsorbent system and solvent systems for an efficient separation of closely related isomers of this class of compound of physiological importance have been developed.     

TLC on mixed adsorbents-separation of closely related aromatic amines

Summary The TLC behaviour of closely related aromatic amines on silica gel plates impregnated with sodium oxalate, potassium oxalate, ammonium oxalate, sodium chloride, sodium acetate and sodium sulphate has been studied and it has been concluded that, unlike earlier findings the TLC behaviour is primarily influenced by the anion and not by the cation impregnation. Suitable adsorbent and solvent systems for an efficient separation of closely related isomers of this class of physiologically important compounds have been developed.     

The use of thermogravimetry to analyze a mixed plastic waste stream

The thermogravimetry of a mixed polymer waste stream has been studied and the weight-loss behaviour of this heterogeneous mixture has been compared with results obtained from the weight-loss curves of some individual polymers. The results suggest that the behaviour of the mixture cannot be predicted by the simple additive behaviour of the individual polymers since interactions can occur which influence the degradation weight-loss profiles. The heterogeneous polymeric waste studied was that generated from the shredding of old discarded automobiles. The results of the study indicate that while it is possible to determine what is present in a sample, the relevance of the data to a very heterogeneous waste stream is questionable.     

Analytical aspects of absorption spectroelectrochemistry at a platinum electrode-II Quantitative basis and study of organic compounds

The theoretical basis for a new spectroelectrochemical technique, in which a narrow light-beam is passed at grazing incidence over a plane electrode surface, has been derived. Agreement between theoretical and experimental behaviour has been obtained for a number of organic molecules with well-defined redox behaviour. The advantages of this technique over other spectroelectrochemical techniques are discussed with respect to potential applications in quantitative analysis and electrochemical studies.     

On the heterogeneity of fluorescence lifetime of room temperature ionic liquids: onset of a journey for exploring red emitting dyes

An excitation and emission wavelength dependent non-exponential fluorescence decay behaviour of room temperature ionic liquids (RTILs) has been noted. Average fluorescence lifetimes have been found to vary by a factor of three or more. Red emitting dyes dissolved in RTILs are found to follow hitherto unobserved single exponential fluorescence decay behaviour.     

DSC-Untersuchungen an Butadien/olefin-CO- und Terpolymeren sowie an ihren Hydrierprodukten

Poly(butadiene-alt-1-olefin) copolymers and poly[(butadiene-alt-ethene)-co-(butadiene-alt-1lefin)] terpolymers, and the hydrogenated products too, has been characterized with the aid of differential scanning calorimetry (DSC). Both the glass transition and the melting behaviour of the partial crystallized products has been investigated. From the peak area the degree of crystallinity has been calculated in a first approximation. The results allow to draw conclusions about the crystallization behaviour in relation to the number and length of the side chains and about the course of the synthesis in question.     

Selective adsorption of PMMA in polar binary mixtures—I. Benzyl alcohol/n-bytyl alcohol and benzyl alcohol/sec-butyl alcohol mixtures

The behaviour of PMMA in two binary mixtures (benzyl alcohol/n-butyl alcohol and benzyl alcohol/sec-butyl alcohol) has been studied. There is an inversion in the solvation for the second mixture but not for the first. This behaviour has been explained by considering self-association of the alcohols of the binary mixture as well as the existence of specific interactions between sec-butyl alcohol and the polymer.     

The mass spectra of N-acyliminopyridinium and isoquinolinium betaines

The mass spectral fragmentation behaviour of N-acyliminopyridinium and isoquinolinium betaines has been investigated. Major fragmentations of the pyridinium betaines can be rationalized in terms of charge localization on the pyridinium nitrogen. The most prominent process is α-cleavage followed by loss of NCO to furnish a pyridine ion. The electron-impact induced fragmentation of N-benzoyliminopyridinium betaine (I) was compared with that of thermolysis. The completely analogous behaviour has been observed in the corresponding isoquinolinium betaines.     

Thermal degradation of silane crosslinked unplasticized PVC

The thermal decomposition behaviour of rigid PVC, crosslinked using bis(γ-trimethoxysilylpropyl)amine as crosslinking agent has been studied. Different thermal stabilizers (tin and lead based) have been used with different crosslinking agent concentrations, and the influence of these factors on the decomposition behaviour in inert atmosphere studied. Results obtained have shown that the main effect of aminosilane is an advance of the first stage of the PVC degradation (i.e. the dehydrochlorination process). Moreover, samples with different concentrations of silane, and at different stages of their processing (i.e. after milling, pressing, crosslinking) have also been used in order to elucidate the influence of these factors on their thermal behaviour. A quantitative kinetic model has been developed and the corresponding kinetic constants have been obtained by modelling the experimental thermogravimetric data. The kinetic parameters obtained have revealed a reduction in the apparent activation energy of the hydrogen chloride loss process, which has shown to be markedly dependent on the thermal stabilizer used.     

The viscoelastic behaviour of elastin in aqueous ethylene glycol

The viscoelastic behaviour of arterial elastin in aqueous ethylene glycol has been studied to compare the effects of two solvents of differing polarity. The behaviour of elastin in low concentrations of ethylene glycol was similar to that of elastin that had been indirectly dehydrated using polyethylene glycol as an osmotic agent. That is, at low concentrations the dominant effect of ethylene glycol was to reduce the activity of the water molecules. However, at high concentrations, ethylene glycol appeared to interact directly with the elastin, altering both the swelling and the viscoelastic behaviour of the network.     

Modelling the influence of nanoparticles in the phase behaviour of an epoxy/polystyrene mixture

The cloud point temperatures of four series of epoxy/polystyrene blends have been experimentally determined as a function of polymer mass and system composition. The phase diagrams show an UCST behaviour, increasing incompatibility as the molar mass increases. The Flory-Huggins theory with a concentration-dependent interaction parameter has been developed to study the compatibility of two polymers in presence of spherical nanoparticles. This theory has been first compared with the experimental cloud point curve in absence of nanoparticles, and secondly it has been used to predict the thermodynamic behaviour in presence of different volume fraction of nanoparticles. Nanoparticles coated with two types of functional groups have been tested. It can be concluded that the inclusion of nanoparticles increases compatibility. Moreover concentration-dependent interaction parameters have been obtained in these systems for the first time.