نتایج جستجو برای: direct polycondensation
تعداد نتایج: 425759 فیلتر نتایج به سال:
The photovoltaic characteristics of an amorphous polymer containing EDOT and fluorene units were investigated. In particular, the effects of the terminal structure, residual amount of Pd, and molecular weight were systematically investigated. Direct arylation polycondensation of EDOT followed by an established purification method readily afforded polymers with different terminal structures, Pd ...
Biodegradable aliphatic random copolyesters poly(butylene succinate-co-butylene adipate), PBSA and poly(butylene succinate-co-butylene azelate), PBSAz were synthesized from 1,4 butane diol, succinic acid and adipic acid/azelaic acid through direct melt polycondensation with Titanium Tetra isopropoxide (TTiPO) as a catalyst. These polyesters were characterized by Viscosity measurements, 1H NMR s...
The structure of MQ copolymers of the general chemical formula [(CH3)3SiO0.5]m [SiO2]n was characterized by means of solid-state magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. The MQ copolymers are highly branched polycyclic compounds (densely cross-linked nanosized networks). MQ copolymers were prepared by hydrolytic polycondensation in active medium. 29Si NMR spectr...
In this paper, we report a soft route leading to small gold nanoparticles confined within the framework of 2D-hexagonal mesoporous SH-functionalised silicas. For that purpose, a hydrophilic bis-silylated precursor containing a disulfide unit was prepared. Framework-functionalised materials were obtained in one step by the ‘‘direct synthesis’’ method which consists of a co-hydrolysis and polycon...
Biosilicification in diatoms is achieved by specific interactions between silaffins, composed of polypeptides and long-chain polyamines, and silicic acid derivatives. The polycondensation of silicic acids is reported to be catalyzed by the long-chain polyamines that mainly contain tertiary N-methylpropyleneimine moieties. In this report, we utilized a tertiary amine-containing polymer, poly(2-(...
Polycondensation and ring-opening polymerization are two important polymer synthesis methods. Poly(lactic acid), the most typical biodegradable polymer, has been researched extensively from 1900s. It is of significant importance to have an up-to-date review on the recent improvement in techniques for biodegradable polymers. This review takes poly(lactic acid) as the example to present newly dev...
Poly(terephthalamide) microcapsules can be reproducibly and easily prepared by interfacial polycondensation around emulsion droplets in water. Oil drops of cyclohexane/chloroform mixture stabilized with poly(vinyl alcohol) containing terephthaloylchloride serve as soft template. The interfacial polycondensation starts immediately after addition of an amine mixture (hexamethylenediamine/diethyle...
We report the application of the "internal trigger" approach to multistep microfluidic polymerization reactions conducted in droplets, namely, polyaddition and polycondensation. We hypothesized and experimentally established that heat generated in an exothermic free radical polymerization of an acrylate monomer (Reaction 1) triggers the polycondensation of the urethane oligomer (Reaction 2). Co...
Aromatic polybenzoxazole (PBO) precursor, hydroxy-substituted polyenaminonitrile, was prepared by direct polycondensation of 1,4-bis(1-chloro-2,2-dicyanovinyl)benzene (CCB) and 4,6-diaminoresorcinol dihydrochloride (DAR) using pyridine and N,N-dimethylacetamide as condensing agent and solvent. The precursor has good solubility in polar aprotic solvent which is due to the strong dipolar nature o...
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