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51.
The results of some investigations into the synthesis and characterization of a new class of oligomers and polymers, the polyselenoacetals, are described. 相似文献
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54.
Adwait K. Pradhan Gadadhar Panda Nrusingha C. Patl Padma L. Nayak 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(2):501-512
The graft copolymerization of methyl methacrylate onto silk fibers initiated by the ferric chloride-eysteine redox system has been investigated in aqueous medium. The rate of grafting was calculated by varying the concentrations of monomer, initiator, acidity of the medium, cysteine, and temperature. The percentage of grafting increases with an increase of Fe3+ concentration up to 2,5 × 10?3 mol/L and thereafter it decreases. The graft yield increases steadily upon increasing the monomer concentration. The graft yield also increases with increasing cysteine concentration up to 0.5 × 10?3 mol/L and then decreases. The effect of the perchloric acid concentration, temperature, solvents, and certain neutral salts on graft yield has also been investigated and a suitable reaction scheme has been proposed. 相似文献
55.
R. K. Samal P. C. Dash B. Mishra G. V. Suryanarayana D. P. Das M. C. Nayak 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(5):805-819
Polymerization of acrylonitrile initiated by the Cr6+/thioacetamide redox system was studied in nitrogen atmosphere in the temperature range 35–45°C. The rate of polymerization and the rate of Cr6+ ion disappearance were measured. The effect of certain water-miscible organic solvents, neutral electrolytes, and complexing agents on the rate of polymerization was investigated. Chromic acid alone did not initiate the polymerization under deaerated and undeaerated conditions. Depending on the results obtained, a suitable kinetic scheme was proposed and various rate parameters were evaluated. 相似文献
56.
A series of 4-arylidenamino-5-phenyl-4H-1,2,4-triazole-3-thiols have been synthesised and their inclusion complexes have been prepared with β-cyclodextrin. The compounds and their inclusion complexes have been characterised by studying their physical and spectral properties. The thermodynamic stability constant and free energy of activation have been determined to know the stability of inclusion complexes. Finally, the compounds and their inclusion complexes are screened for antibacterial, antioxidant and anthelmintic activities. It is found that inclusion complexes of the newly synthesised compounds have appreciable stability and inclusion complex formation increases the antibacterial, antioxidant and anthelmintic activities significantly as compared to naked compound. 相似文献
57.
Vikas Verma Kuldeep Singh Ashok Kumar Devinder Kumar 《Journal of Thermal Analysis and Calorimetry》2013,112(1):339-344
The use of unconventional synthesis methods in the formation of CaO·2Al2O3 (CA2) is justified because it reduces the formation temperature of the compound. CA2 is formed by classical method at temperatures above 1,400 °C. The polymeric precursor method allows a significant temperature decrease in CA2 synthesis reaching temperatures of 1,000 °C. This paper deals with CA2 synthesis by “citrate” method which is often presented as Pechini method, starting from a mixture of citric acid, ethylene glycol and calcium, and aluminum nitrates. A method based on the formation of a polymeric precursor was also used, starting from a mixture of acrylic acid and nitrates of calcium and aluminum. The results showed a net difference in favor of samples obtained from acrylic acid, which by annealing at 800 °C for 1 h, contain pure CA2. The samples obtained from citric acid, after annealing at 800 °C are amorphous. After annealing at 900 °C in all samples CA2 is single phase. 相似文献
58.
P. J. Jandas S. Mohanty S. K. Nayak 《Journal of Thermal Analysis and Calorimetry》2013,114(3):1265-1278
Nucleation capacity of organically modified natural montmorillonite within the surface-treated banana fiber (BF)-reinforced PLA biocomposites has been studied using DSC analysis in the present investigation. Both the surface treatments and nanoclays play vital roles in the variation in nucleation process of PLA during cold crystallization process. Biocomposite made up of silane-treated BF and its bionanocomposite prepared using cloisite 30B (C30B) were showed superior nucleation parameters, n and K values, in the Avrami plots. Enhanced equilibrium melting point and lower E a suggests the reinforcing effect imparted by the BF surface treatments and C30B within the PLA matrix. Even though, Louritzen–Hoffmann theory was revealed that no change in crystallization regimes of PLA even after the biocomposite and bionanocomposite preparation. TG analysis revealed better heat barrier capacity for all the biocomposites and bionanocomposites in comparison with virgin PLA (V-PLA). Increased storage modulus values for biocomposites and bionanocomposites also confirm the reinforcing effects of the fillers. Heat deflection temperature and the flammability studies concluded better application window for newly developed materials than that V-PLA. 相似文献
59.
Epoxides are converted regioselectively to corresponding higher substituted alcohols with greater yields using diphosphorus tetraiodide (P2I4) as a reducing agent and a catalytic amount of tetraethylammonium bromide at room temperature. 相似文献
60.
Vikas N. Telvekar 《合成通讯》2013,43(21):2827-2829
tert‐Butyl hypochlorite and tert‐butyl hypobromide react with aldoximes and convert them into hydroximinoyl chloride and bromide, respectively; however, under the same reaction conditions, tert‐butyl hypoiodite deoximates aldoximes and ketoximes to give corresponding aldehydes and ketones in high yield (>94%) in a short reaction time (~20 min). 相似文献