The surface of natural talc was modified with organosilanes (H3 CO)3 SiR, for R = -(CH2 )3 NH2 , -(CH2 )3 NH(CH2 )2 NH2 and -(CH2 )3 NH(CH2 )2 NH(CH2 )2 NH2 , resulting in the inorganic-organic hybrids TC1, TC2 and TC3 . These aminated talcs contain 4.38, 2.56 and 2.03 mmol g-1 of immobilized organic chains for TCx (x =1 to 3), respectively. The chemisorption isotherm data obtained by a batch wise process were adjusted to a modified Langmuir
equation, to give the maximum adsorption capacity TC1 >TC2 >TC3 . The chelate effect was illustrated through calorimetric titration, giving the highest enthalpic values for TC2 and TC3 hybrids and favoured for sulfate counter anion. The enthalpic and entropic values indicated favourable reaction between copper-basic
nitrogen center atoms on pendant chain covalently bonded to the inorganic backbone.
Authors:R. Kotsilkova, V. Petkova, and Y. Pelovski
The thermal behavior of epoxy-smectite nanocomposites (hybrids) is examined by non-isothermal thermogravimetry (TG, DTG and
DTA) in air atmosphere. It has been shown that the thermal stability of hybrids is much greater than that of epoxy resin and
strongly depends on both the smectite loading and the type of the gallery cations of organically modified smectites. The kinetics
of degradation of nanocomposites is significantly influenced by the presence of smectites and proceeds in three stages. Stage
I is attributed to the effect of quaternized ammonium ion exchanged smectite, as stages II and III are associated with the
decomposition of the bulk epoxy resin. Because of the interfacial interactions and thesilicate-polymer multilayered nanoscale
organization, the nanocomposites act as excellent heat insulator and mass transport barrier, which shift the thermal decomposition
peaks towards much higher temperatures.
Excitation function measurements are reported for reactions induced in natural nickel with 9–86 Mev -particles. Cumulative cross sections were obtained for the production of60(m+g)Co,58(m+g)Co,57Co and56Co. The stacked-foil method was used to measure product yields by gamma-spectrometry with a Ge intrinsic detector. The experimental data (supplemented with previously reported cross sections by other authors were compared with the calculated values obtained by means of the hybrid model.
Authors:C. Ramírez, M. Rico, J. M. L. Vilariño, L. Barral, M. Ladra, and B. Montero
Summary Cubic silsesquioxanes offer access to organic/inorganic hybrids. A system formed by a polyhedral oligomeric silsesquioxane (POSS) with eight epoxy reactive groups per molecule, octaepoxycyclohexyldimethylsilyl-POSS, cured with an aliphatic diamine (bisaniline) was studied in different ratios. The characterization of the POSS was carried out by differential scanning calorimetry (DSC) and thermogravimetry (TG). The distribution of species in the reaction of the mixtures POSS/diamine was followed by gel permeation chromatography (GPC). The degradation was studied by thermogravimetric analysis.
Analytical equations related
adiabatic runaway reactions to programmed scanning thermal curves from differential
scanning calorimetry (DSC) were proposed. Thermal or pressure hazards can
be assessed from the adiabatic trajectories expressed in the analytical equations.
These industrially energetic materials include polymerizable monomers, unstable
organic peroxides and nitro-compounds. Various emergency relief behaviors,
such as tempered vapor, gassy, and hybrid were re-evaluated for calculating
vent sizing or mass flow rates from DSC thermal curves and the related physical
A hybrid stable iodine/radioiodine (131I) atmospheric photochemistry box model, including 27 reactions, has been developed and solved using algorithmic programme
with the application of the Runge-Kutta method of the order 4(5). This modelling offers a clearer view of relationship among
aerosol-associated (inorganic iodine compounds, mostly I2O2), gaseous inorganic (mostly IONO2, HOI) and organic (CH3I) iodine compounds in ambient atmosphere. Summing up the data of the Chernobyl accident, the problem of the standardised
method for atmospheric aerosol-associated and gaseous (inorganic and organic) radioiodine activity measurements in the case
of the nuclear power plant accident is discussed.
Excitation functions for the production of194Au,195(m+g)Au,196(m+g)Au,198mAu,195gAu and199Au were determined experimentally. In addition, the yields of thick targets of these products were calculated and a comparison between the cross sections obtained using the hybrid model of pre-equilibrium reactions in combination with the statistical model of compound nucleus is presented. The method of activation of metallic foils was employed. The irradiations were performed in the internal beam of the isochronous cyclotron at Karlsruhe (FRG) with -particles at 90 MeV. Gamma-spectrometry by means of an intrinsic Ge detector was used to determine the nuclides produced.
Authors:G. Bannach, R. Arcaro, D. Ferroni, A. Siqueira, O. Treu-Filho, M. Ionashiro, and E. Schnitzler
Thermogravimetry (TG), differential thermal analysis (DTA), differential scanning calorimetry (DSC) as well as X-ray diffraction
powder (DRX) patterns and Fourier transformed infrared spectroscopy (FTIR) were used to study ketoprofen, ibuprofen, and naproxen.
The chemical or physical properties of the studied compounds were established and when possible by X-ray powder diffractometry
and/or infrared spectroscopy were used. In this investigation, quantum chemical approach was used to determine the molecular
structures using Becke three-parameter hybrid method and the Lee–Yang–Par (LYP) correlation functional. The performed molecular
calculations in this work were done using the Gaussian 03 routine. Theoretical calculations help in interpretations of FTIR
spectra supplying structural and physicochemical parameters.
Adaptive or smart hybrid
composites consisting of a polymer matrix reinforced by aramid fibres and
incorporating pre-strained Shape Memory Alloy (SMA) wires are able to tune
some of their properties, such as their shape, the natural vibration frequency
or the damping coefficient, in response to an external stimulus. The functional
properties of these systems are directly related to the reversible martensitic
transformation in the SMA elements. In this work the transformational behaviour
of both free SMA wires and SMA wires embedded in polymer matrix is investigated
by means of DSC. The martensitic transformation of the constrained wires is
impeded by the polymer matrix, while the interface integrity plays a crucial
Authors:J. Chruściel, Grażyna Janowska, P. Rybiński, and L. Ślusarski
Thermal properties, ageing
resistance and flammability of peroxide vulcanizates of butadiene-acrylonitrile
rubber Perbunan NT 1845 (NBR) of Bayer, modified in bulk and on a surface
with synthesized hybrid functional poly(methylsiloxanes) were investigated.
The derivatographic, DSC, oxygen index and FTIR methods were applied. It was
stated that addition of poly(methylsiloxanes) caused distinct increase of
ageing resistance and of NBR vulcanizates and decrease of their thermal decomposition
rate and flammability, providing self-extinguishing samples. The mechanism
of addition reactions of Si–H bond to multiple bonds of NBR has been