翻訳と辞書
Words near each other
・ Coordination failure (economics)
・ Coordination failure (political science)
・ Coordination game
・ Coordination geometry
・ Coordination good
・ Coordination isomerism
・ Coordination number
・ Coordination of Access to Information Requests System
・ Coordination of Democratic Rights Organisations
・ Coordination of Information on the Environment
・ Coordination of New Forces
・ Coordination of the Indigenous Organizations of the Brazilian Amazon
・ Coordination of United Revolutionary Organizations
・ Coordination Office for the Preservation of the Written Cultural Heritage
・ Coordination polymer
Coordination polymerization
・ Coordination sphere
・ Coordination Syndicale Haïtienne
・ Coordinative definition
・ Coordinatograph
・ Coordinator
・ Coordinator for Counterterrorism
・ Coordinator for International Information Programs
・ Coordinator for International Relations
・ Coordinator of Government Activities in the Territories
・ Coordinator of Indigenous Organizations of the Amazon River Basin
・ Coore
・ Coorg frog
・ Coorg Green Cardamom
・ Coorg Institute of Dental Sciences


Dictionary Lists
翻訳と辞書 辞書検索 [ 開発暫定版 ]
スポンサード リンク

Coordination polymerization : ウィキペディア英語版
Coordination polymerization
Coordination polymerisation is a form of addition polymerization in which monomer adds to a growing macromolecule through an organometallic active center.〔''Polymer science and technology'' (2000) Robert Oboigbaotor Ebewele〕〔''Kent and Riegel's handbook of industrial chemistry and biotechnology'', Volume 1 2007 Emil Raymond Riegel,James Albert Kent〕 The development of this polymerization technique started in the 1950s with heterogeneous Ziegler-Natta catalysts based on titanium tetrachloride and an aluminium co-catalyst such as methylaluminoxane.
Coordination polymerization has a great impact on the physical properties of vinyl polymers such as polyethylene and polypropylene compared to the same polymers prepared by other techniques such as free radical polymerization. The polymers tend to be linear and not branched and have much higher molar mass. Coordination type polymers are also stereoregular and can be isotactic or syndiotactic instead of just atactic. This tacticity introduces crystallinity in otherwise amorphous polymers. From these differences in polymerization type the distinction originates between low-density polyethylene (LDPE), high-density polyethylene (HDPE) or even ultra-high-molecular-weight polyethylene (UHMWPE).
Polymerizations catalysed by metallocenes occur via the Cossee-Arlman mechanism. The active site is usually anionic but cationic coordination polymerization also exists.
In many applications Ziegler-Natta polymerization is succeeded by metallocene catalysis polymerization. This method is based on homogeneous metallocene catalysts such as the Kaminsky catalyst discovered in the 1970s. The 1990s brought forward a new range of post-metallocene catalysts.
Typical monomers are nonpolar ethylene and propylene. The development of coordination polymerization that enables copolymerization with polar monomers is more recent. Examples of monomers that can be incorporated are methyl vinyl ketones methyl acrylate and acrylonitrile.
== See also ==

* Cossee-Arlman mechanism
* Ziegler–Natta catalyst
* Polymerization
* Coordination bond

抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)
ウィキペディアで「Coordination polymerization」の詳細全文を読む



スポンサード リンク
翻訳と辞書 : 翻訳のためのインターネットリソース

Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.