نتایج جستجو برای: direct polycondensation

تعداد نتایج: 425759  

Journal: :ACS applied materials & interfaces 2016
Junpei Kuwabara Takeshi Yasuda Naoto Takase Takaki Kanbara

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 ...

2010
A. RAVI

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...

2013
Sergey G. Vasil’ev Vitaly I. Volkov Elena A. Tatarinova Aziz M. Muzafarov

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...

2010
Eric Besson Ahmad Mehdi Catherine Rey Robert J. P. Corriu

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...

Journal: :Langmuir : the ACS journal of surfaces and colloids 2004
Dong Jin Kim Kyung-Bok Lee Young Shik Chi Wan-Joong Kim Hyun-Jong Paik Insung S Choi

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-(...

2016
Yunzi Hu Walid A. Daoud Kevin Ka Leung Cheuk Carol Sze Ki Lin

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...

2010
Hisham Essawy Klaus Tauer

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...

Journal: :Journal of the American Chemical Society 2008
Wei Li Hung H Pham Zhihong Nie Brendan MacDonald Axel Güenther Eugenia Kumacheva

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...

2007
Lei Li Xiao-dong Zhao Jing-lun Zhou Xing-he Fan Xiao-fang Chen Xin-hua Wan Qi-feng Zhou

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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