نتایج جستجو برای: chemical polymerization

تعداد نتایج: 405925  

2013
ASHOK K. SHARMA YASHPAL SHARMA

Composites of polyaniline and carbon nanotube (CNT) were prepared by in-situ chemical polymerization method using various aniline concentrations in the initial polymerization solution with p-toluene sulfonic acid (PTS) as secondary dopant and mechanical mixing of the PANI and CNT using different weight ratios of PANI and CNTs. The structural characterizations of the composites were done by Four...

Journal: :The Journal of biological chemistry 1989
G M Omann M M Porasik L A Sklar

Leukotriene B4 and platelet-activating factor induced a rapidly oscillating actin polymerization/depolymerization response in human polymorphonuclear leukocytes. N-Formylpeptides were deficient in the ability to induce these oscillations. Flow cytometric analysis of filamentous actin verified that all cells were synchronously responding in this cyclic manner. The hypothesis was tested that thes...

Journal: :علوم و تکنولوژی پلیمر 0
علیرضا شاکری احسان کبیری سید ضیاءالدین حسینی

this research was performed to study the effect of murray red gum tree age (4, 6, 8 years) on the chemical components, viscosity and the cellulose degree of polymerization. the eucalyptus trees were cut at the ages of 4, 6, and 8 from hand planted forests. the contents of cellulose, hemicellulose, lignin, extractives and ash for each age were then determined. the results show that with increasi...

2008

Polymers can be prepared using chemical and/or electrochemical methods of polymerization (see Chap. 2), although most redox polymers have been synthesized by chemical polymerization. Electrochemically active groups are either incorporated into the polymer structure inside the chain or included as a pendant group (prefunctionalized polymers), added to the polymer phase during polymerization, or ...

2007
Ibrahim M. Maafa João B. P. Soares Ali Elkamel

The objective of this paper is to present a dynamic Monte Carlo model that is able to simulate the polymerization of styrene with bifunctional free-radical initiators in a batch reactor. The model can predict the dynamic evolution of the chain length distribution of polystyrene in the reactor. The model includes all relevant polymerization mechanistic steps, including chemical and thermal radic...

Journal: :Environmental Health Perspectives 1975
H K Reimschuessel

The term, synthetic polymer, denotes a macromolecule composed of simple structural units and usually derived from monomers by a process of polymerization. This process is possible only if certain chemical, thermodynamical, and mechanistic conditions are satisfied. The monomer must have a functionality of two or higher. The polymerization process must be characterized by a negative free energy c...

Journal: :Ultrasonics sonochemistry 2015
Simone Pinto Carneiro Ricardo Machado Cruz Orlando David Henrique Dos Santos

Ultrasound is widely used in several chemical reactions and other process, including production of nanocapsules by in situ polymerization. In this work, the main objective was to evaluate the impacts and viability of successive ultrasound application in nanoemulsions to obtain nanocapsules. Initiator potassium persulfate (KPS) concentration, number of ultrasound cycles and reaction time influen...

Journal: :Chemical communications 2011
Zhen Liu Yang Liu Selcuk Poyraz Xinyu Zhang

Bulk quantities of polypyrrole nanofibers and nanospheres can be synthesized with a facile, one-step "green-nano" chemical oxidative polymerization approach, by simply using different reaction media.

2016
Jesper Edberg Donata Iandolo Robert Brooke Xianjie Liu Chiara Musumeci Jens Wenzel Andreasen Daniel Simon Drew Evans Isak Engquist Magnus Berggren Jens Wenzel Daniel T. Simon

We demonstrate a novel patterning technique of conductive polymers produced by vapor phase polymerization. The method involves exposing an oxidant film to UV light which changes the local chemical environment of the oxidant and subsequently the polymerization kinetics. This procedure is used to control the conductivity in the conjugated polymer poly(3,4ethylenedioxythiophene):tosylate (PEDOT:To...

2009
Richard C. Foitzik Elspeth K. Bowen Amelia M. Taylor Frederick M. Pfeffer Akif Kaynak

The synthesis of 3-(-)and 3-(+)-menthyl carboxylate pyrrole was achieved in four high yielding steps, including the triisopropylsilyl (TIPS) protection of the pyrrole nitrogen, bromination of the 3-position, lithium halogen exchange followed by reaction with menthyl chloroformate, and finally de-protection. Chemical polymerization of both the TIPS protected, and non-protected, menthyl carboxyla...

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