-Methyldiethanolamine (MDEA), were used as synergist for the polymerization of acrylates in the presence of various type II initiators (Thioxanthone, isopropylthioxanthone, benzophenone and 5-thianapthasen-12-one).
Photopolymerization was followed by Photo
The combination of lipophilic macrocyclic oxygen donors with the extractant thenoyltrifluoroacetone /HTTA/ has been shown to have a significant synergistic effect on the extractions of trivalent actinides and lanthanides. The results show that the nitrogen containing cryptand /222BB/ is a more effective synergist than the crown ether compound /15-C-5/ with only oxygen donors.
Authors:Gy. Marosi, P. Anna, I. Balogh, Gy. Bertalan, A. Tohl, and M. A. Maatoug
Engineering application of polypropylene requires the employment of flame retardants. Reactive compounding of ammonium-polyphosphate and synergist additives with polypropylene is an effective way for forming flame retardant polypropylene. Both the ammonium-polyphosphate and the additives used for improving its performance effect the crystallization and melting behavior of polypropylene. Encapsulation of flame retardant additives with appropriate elastomer, in order to improve their water resistancy, causes further changes in degree of crystallinity and consequently in the mechanical properties.
Authors:S. Ribeiro, L. Estevão, and Regina Nascimento
The effect of two different Brazilian montmorillonitic
clays in intumescent ammonium polyphosphate and pentaerythritol formulations
was evaluated. Ethylene and butyl acrylate copolymer was used as polymeric
matrix. The clays were added both to the pure polymer and to the polymer containing
intumescent mixture. The influence of these mineral fillers on flame retardancy
was investigated by thermogravimeric analysis (TG). The results show that
these inorganic additives have a synergist effect in the polymeric composite
containing the intumescent formulation.
Some popular neutral extractants (PSO-petroleum sulfoxide, DOSO-di-n-octyl sulfoxide, TBP-tributylphosphate etc.) were chosen
as synergist to study the synergistic effect on the extraction reaction with HBMPPT (4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione)
for U(VI), and the synergistic separation ability of HBMPPT for U(VI) and Th(IV). The synergistic extraction ability shown
by the studied systems for U(VI) is as follows: PSO>DOSO>TBP, and the same sequence was also verified for the separation coefficient
of U(VI) and Th(IV). The synergistic complexes may be presented as: UO2NO3·BMPPT·S and UO2(BMPPT)2·S for U(VI) (S is PSO, DOSO or TBP).
The synergistic extraction of UO2(II) in a chloroform solution of propionic, butyric and valeric acids (HA) in the presence of some aliphatic and aromatic amines (B) has been investigated. The effect of various variables, like the concentration of hydrogen and metal ion, carboxylic acid and amine on extraction has been studied. The composition of the synergistic adducts has been determined on the basis of slope analysis and the species is proposed to be UO2A2B2 2HA. The extraction constants (Kex) have been calculated and the relative effectiveness of the amines as synergists is compared. Extraction data have been used to separate UO2(II) from lanthanides, like Ce(III), Nd(III), Gd(III), Eu(III) and Yb(III).
Authors:M. Mufazzal Saeed, Munir Ahmed, M. Cheema, and I. Qureshi
Synergic extraction of Ni/II/ at pH 1 to 10 was studied using a mixture of 2-thenoyltrifluoroacetone /HTTA/ and tribenzylamine /TBA/ in chloroform. The synergist TBA enhances the extraction of Ni/II/ by an order of 5 from pH 3 to 5 having ionic strength 0.1M /H+, ClO
/. The synergic adduct was found to be Ni/TTA/2.2TBA. The equilibrium constants K2,0 and K2,2 and stability constant
2,2 have been ascertained radiometrically. The influence of various cations and anions on the extraction of Ni/II/ has been examined under optimal conditions. Back extraction of the adduct species in different acids of varying concentrations has been studied.
Authors:Yanhong Shi, Yongde Yue, Haiqun Cao, Feng Tang, Rimao Hua, Xiangwei Wu, and Jun Tang
Octachlorodipropyl ether (OCDPE) is a chloroalkyl ether widely used as an insecticide synergist, which was considered as a widespread persistent pollutant. Photodegradation kinetics of OCDPE in selected organic solvents was studied using the high-performance thin-layer chromatography (HPTLC) method in this paper. The results showed that photochemical reaction of OCDPE in organic solvents such as n-hexane, methanol, acetonitrile, and acetone under the irradiation of ultraviolet light could well be described by the first-order kinetic equation. The photodegradation rate constants of OCDPE in methanol, acetone, acetonitrile, and n-hexane were 0.3310, 0.2382, 0.0287, and 0.0276 h−1, and the corresponding half-lives were 2.09, 2.91, 24.1, and 25.1 h, respectively. Photodegradation kinetics of OCDPE under sunlight was slower than UV light, the half-lives of which were 8.87 and 2.09 h, respectively. The main photodegradation products of OCDPE in acetone and methanol under UV light were detected by HPTLC, which included product 01 (RF = 0.19) and product 02 (RF = 0.82). Identification of the main photodegradation products of OCDPE requires further studies.
Authors:A. Bhattacharyya, P. Mohapatra, and V. Manchanda
Separation of trivalent actinides (An(III)) and lanthanides (Ln(III)) is a challenging task in the nuclear fuel cycle due
to their similar charge and chemical behaviour. Some soft donor ligands show selectivity for An(III) over Ln(III) due to the
formation of stronger covalent bonds with the former. The extraction behaviour of Am(III) and Eu(III) is studied in the present
work with a mixture of Cyanex-301 (bis(2,4,4-trimethylpentyl)di-thiophosphinic acid) with several various ‘N’, ‘O’ or ‘S’ donor neutral ligands. Comparison of the
data was done with that of the oxygen donor analogue of Cyanex-301, i.e. Cyanex-272 (bis(2,4,4-trimethylpentyl)phosphinic acid). Effect of the organic diluent on the extraction behaviour of Am(III) using Cyanex-301
in presence of ‘N’ donor synergists was also studied. Ab initio molecular orbital calculations were carried out using GAMESS
software and charges on the donor atoms were calculated which helped in understanding the co-ordination chemistry of the ligands
and explained the separation behaviour.
potential environmental hazard [ 6 ]. To address some of the problems associated with the additive route to flame retardance, we have turned our attention to synergy of flame retardancy. In the field of fire retardancy, synergists are often required in order