نتایج جستجو برای: direct polycondensation
تعداد نتایج: 425759 فیلتر نتایج به سال:
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...
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...
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...
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...
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...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید