In this article, synthesis, characterization, and thermal properties of diacrylic/divinylbenzene copolymers based on the new
aromatic tetrafunctional acrylate monomers are presented. The new monomers were generated by treatment of epoxides derived
from various aromatic diols: naphthalene-2,3-diol (NAF), biphenyl-4,4′-diol (BIF), bis(4-hydroxyphenyl)methanone (BEP) or
4,4′-thiodiphenol (BES), and epichlorohydrin with acrylic acid. The addition reaction was carried out by a ratio of 0.5 mol
of suitable epoxy derivative and 1 mol of acrylic acid in the presence of 0.7 wt% of triethylbenzylammonia chloride (TEBAC)
as a catalyst and 0.045 wt% of hydroquinone as a polymerization inhibitor. The chemical structure of the prepared acrylate
monomers was confirmed by 13C NMR and GC MS spectra. The emulsion–suspension polymerization of acrylate monomers with divinylbenzene (DVB) in the presence
of pore-forming diluents (toluene + decan-1-ol) allowed obtaining microspheres containing pendant functional groups (hydroxyl
groups). This process was carried out at constant mol ratio of acrylate monomers: DVB (1:1), and constant volume ratio of
pore-forming diluents to monomers (1:1). The different concentrations of toluene in the mixture with decan-1-ol were used
for qualifying the effect of the diluents on the microsphere characteristics. The influence of synthesis’s parameters on the
properties of copolymer beads, e.g., pore size and surface area by BET method, the surface texture by AFM, swelling behavior
in polar and non-polar solvents as well as thermal stability by differential scanning calorimetry (DSC), and thermogravimetric
analysis (TG) was studied and discussed.
Authors:Monika Waksmundzka-Hajnos, Mieczyslaw Hajnos, Ryszard Świeboda, and Anna Hawrył
Experimental results for the wicking process in a solid thin porous layer by liquids of different polarity with defined surface free energy components and viscosity has been considered theoretically. The method was used for determination of the solid surface free energy of the adsorbents used in thin layer chromatography. Experiments were performed on commercial glass plates precoated with silica, CN-silica, diol-silica, NH
-silica, and silanized silica with
-alkanes, diiodomethane, water, and formamide as mobile phases. Surface free energy components determined for investigated adsorbents were used for characterization and comparison of their surface properties.
Authors:K. Jerie, A. Baranowski, J. Gliński, and K. Orzechowski
The structure of aqueous solutions of 1,2-butanediol and 1,4-butanediol was investigated using adiabatic compressibility measurements
and positron annihilation methods. In the case of 1,2-butanediol the experimental results are very similar to those obtained
earlier for systems where hydrophobic hydration dominates. In both cases there are evidences for increased rigidity of the
water network, which arises from the formation of hydrogen bonds between diols and water. The usefulness of both the methods
applied in investigating the structure of liquid solutions was proved.
Authors:K. Kawai, Y. Tanaka, Y. Nakano, W. Ehrlich, and M. Akaboshi
An experimental method is described for the synthesis of195mPt-radiolabeled cis-diammine (glycolato) platinum (II) (254-S). Ten mg of 95% enriched194Pt was irradiated for 75 h in the hydraulic conveyer of KUR at a thermal neutron flux of ca. 8.15×1013 n·cm–2·s–1, and the195mPt-radiolabeled 254-S was synthesized and purified using HPLC (column: Dichrosorb Diol, elution: 80% CH3CN). The chemical yield was approximately 45%, with chemical purity greater than 98.4%. The radionuclidic purity was nearly 100% and the specific activity, 7.2 MBq·mg–1 254-S.
Authors:J. Narbutt, J. Olza, Z. Przybyłowicz, and S. Siekierski
Extractive purification of boric acid from radioactive corrosion and fission products dissolved in aqueous solutions modelling
nuclear reactor coolants has been studied. Aliphatic 1,3-diols containing 8 and 9 carbon atoms per molecule were used as extractants
fro boric acid. The behaviour of some representative corrosion and fission products as well as various factors affecting their
distribution between the organic and aqueous phases have been investigated under the conditions of boric acid extraction.
Conditions for the effective separation of boric acid from most of the radioactive contaminants are presented.
Natural phenolic compounds, e.g. ellagitannins, gallotannins, and flavonoid glycosides, from the aerial parts of
) have been isolated and identified. The structures of these compounds were determined by conventional methods of analysis and confirmed by MS and NMR spectral analysis. The distribution of tannins and flavonoids in
E. ciconium, E. cicutarium, E. manescavi
were examined by TLC on unmodified silica gel and on silica gel chemically modified with polar and nonpolar groups (HPTLC Si 60, HPTLC Si 60 LiChrospher, HPTLC diol, HPTLC CN, and HPTLC RP-18W).
Authors:M. Ştefănescu, O. Ştefănescu, M. Stoia, and C. Lazau
paper we present a study on the synthesis of Fe(III) oxide, by thermal decomposition
of some complex combinations of Fe(III) with carboxylate type ligands, obtained
in the redox reaction between some polyols (ethylene glycol (EG), 1,2-propane
diol (1,2PG), 1,3-propane diol (1,3PG) and glycerol (GL)) and NO3–
ions (from ferric nitrate). Fe2O3
was obtained by thermal decomposition of the synthesized metal-organic precursors
at low temperatures. γ-Fe2O3
was obtained as nanoparticles at 300C, while at higher temperatures α-Fe2O3
starts to crystallize and becomes single phase at ~500C.
formation of the metal-organic precursors and their thermal decomposition
were studied by thermal analysis and FTIR spectroscopy.
of Fe2O3 crystalline phases
with the thermal treatment of iron complexes was followed by RX diffractometry.
The size of γ-Fe2O3 nanoparticles
was estimated by transmission electron microscopy (TEM).
Authors:M. Daszykowski, M. Hawrył, M. Waksmundzka-Hajnos, and B. Walczak
In this paper a broad overview of the retention behaviour of twenty flavonoids and their analogues in 74 TLC systems is reported. The compounds were chromatographed on different stationary phases (non-polar and polar-bonded stationary phases — wettable RP18W, silica, and aminopropyl-modified and diol-modified plates) developed with a variety of binary mobile phases (aqueous and non-aqueous). The chemometric techniques principal component analysis and hierarchical clustering were used to evaluate similarities and differences among the chromatographic systems. For selection of the most suitable systems either to perform two-dimensional separation or to enhance overall resolution by merging two stationary phases, indices scoring the separating power of a given system or pair of systems were applied. When separation of all pairs of chromatographic systems was evaluated with the index considered, the theoretical separation achieved in these systems could be visualized as a colour map. This colour map enabled rapid examination of resolution and selection of orthogonal systems enabling acceptable separation of the compounds. On the basis of the colour map it was found that relatively efficient two-dimensional separation of the compounds could be achieved on amino-modified plates developed using 9:1 tetrahydrofuran-water in the first dimension then 9:1, 4:1, 3:1, or 7:3 acetonitrile-water in the second dimension. Theoretically, the best separation could be achieved by combining diol-modified and amino-modified stationary phases and using 3:2 methanol-water and 9:1 acetonitrile-water, respectively, as mobile phases.
In this paper, the non-isothermal differential scanning calorimetry
(DSC) was employed to investigate the cure process and to determine the kinetic
parameters of the curing reaction of the unsaturated polyester resin catalyzed
with promoter-cobalt(II)octoate and free-radical initiators. The initiators
were formed by the oxidation process of acetylacetone with 60% hydrogen peroxide
in the presence of the catalyst-sulphuric acid and the solvents: propano-1,2-diol
or the mixture of propano-1,2-diol and hydroxypolyether TG 500. As a reference,
the typical curing system containing ethyl methyl ketone hydroperoxide (Luperox)
and promoter was used.
It was found that the cure process of the
unsaturated polyester resin with the new initiators/cobalt(II)octoate was
described through lower maximum peak temperatures (Tmax)
and lower values of the total heat of the curing reaction (ΔHR) in comparison with Luperox/cobalt(II)octoate.
The computed values of activation energies were in the range of 40.8–44.9
and 80.4–87.6 kJ mol–1 for unsaturated
polyester resin cured with the new initiators/cobalt(II)octoate. The values
of activation energies were little lower or comparable to those obtained when
Luperox/cobalt(II)octoate system was used (45.8 and 82.3 kJ mol–1).
Authors:G. Chuah, S. Jaenicke, K. Chan, S. Khor, and J. Hill
Thermal decomposition of metal-organic precursors for the mixed oxide BaBiO3 was studied using TG and EGA. Precursors produced by polyesterification of bifunctional acids with ethylene glycol (Pechini
process) decomposed about 100°C higher than those without the diol. BaCO3 was identified by IR and XRD as a reaction intermediate. EGA proved that the amount of BaCO3 was below 10% of the total barium, and that the barium exists mainly as a nitro-compound up to 650°C. Phase-pure BaBiO3 with a moderately high surface area (1.4 m2/g) could be synthesised from a citrate precursor by the Pechini process at around 850°C.