نتایج جستجو برای: direct polycondensation

تعداد نتایج: 425759  

2010
Khalil Faghihi Meisam Shabanian Maryam Faraz

In this paper six new copoly(amide-imide)s (7a-f) were synthesized through the direct polycondensation reaction of N,N'-(4,4'-diphenylsulfone)bistrimellitimide (1) with 4,4'-diamino diphenylsulfone (2), 4,4'-diamino diphenylether (3), in the presence of adipic acid (4), fumaric acid (5) or terephthalic acid (6) as the second diacid in a medium consisting of N-methyl-2-pyrrolidone, triphenyl pho...

Journal: :Journal of the American Chemical Society 2006
Keith Huynh Alan J Lough Ian Manners

A series of phosphine donor-stabilized N-silylphosphoranimine salts [R'3P.PR2=NSiMe3]+Br- were prepared from the direct reaction between the phosphoranimines BrR2P=NSiMe3 (R = Me, OCH2CF3) and the tertiary phosphines nBu3P and Me3P. The 1JPP values of these salts exhibit an unusual dependence on the substituents at the phosphoranimine acceptor and appear to reflect an electronic push-pull mecha...

Journal: :Biomedicine and chemical sciences 2022

Nine copolyesters were prepared from a dicarboxylic acid, curcumin analogues (monocarbonyl) and phenophthalene dye in the mole ratio of 2:1:1 by direct polycondensation using triethylamine (Et3N) as condensation agent. The used is 2,6-Pyridine dicarbonyl dichloride acid. acid catalyzed Aldol reaction. These characterized FT-IR. fluorescence synthesized was also investigated. Furthermore, Thermo...

2012
J. Woenckhaus

The polycondensation kinetics of silicic acid was measured cryoscopically in a temperature interval between 5 ◦C and 35 ◦C. Unlike polyamines such as polyallylamine, polylysine or polyarginine, catalitical amounts of Cytochrom c have a distinct retarding influence on the polycondensation kinetics. The Arrhenius analysis of the experimental reaction rates with and without Cytochrome c determines...

Journal: :Journal of the American Chemical Society 2004
Nobuyoshi Nomura Ko Tsurugi T V RajanBabu Tadao Kondo

Carothers and Flory established the fundamental principles of homogeneous two-component polycondensation reactions by which a variety of commonly used polymers such as polyesters and polyamides (nylons) are synthesized even now. One of the most critical factors to achieve a high degree of polymerization is a strict adherence of stoichiometric balance of the two components. An imbalanced ratio o...

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