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Anionic synthesis of arborescent pol...

Yuan, Zhongshun.

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Anionic synthesis of arborescent polymers.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Anionic synthesis of arborescent polymers./
Author:	Yuan, Zhongshun.
Description:	176 p.
Notes:	Source: Dissertation Abstracts International, Volume: 66-06, Section: B, page: 3158.
Contained By:	Dissertation Abstracts International66-06B.
Subject:	Chemistry, Polymer. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=NR02960
ISBN:	0494029609

Anionic synthesis of arborescent polymers.
Yuan, Zhongshun.

Anionic synthesis of arborescent polymers. - 176 p.

Source: Dissertation Abstracts International, Volume: 66-06, Section: B, page: 3158.

Thesis (Ph.D.)--University of Waterloo (Canada), 2005.

Arborescent polymers are branched macromolecules obtained from successive grafting reactions. Their main distinguishing feature is a dendritic architecture, characterized by multiple branching levels. Two new methods developed for the synthesis of arborescent polymers are reported in this thesis. The first technique provided arborescent homopolymers based on polyisoprene chain segments with a high cis-1,4-microstructure content. A linear polyisoprene substrate was first epoxidized and then reacted with polyisoprenyl anions to obtain a comb-branched (generation G0) polyisoprene. Several promoters were identified for the coupling reaction, LiCl and LiBr being most effective and increasing the yield from 78% (without additive) to 92% for a linear epoxidized substrate. The epoxidation and grafting cycles were repeated to obtain generation G1 and G2 arborescent polyisoprenes, with molecular weights and branching functionalities increasing geometrically for successive generations. The graft polymers had narrow molecular weight distributions (Mw/M n ≤ 1.05) and high cis-1,4-contents. The second method developed allowed the one-pot synthesis of arborescent styrene homo- and copolymers. Linear and G0 styrene-1,3-diisopropenylbenzene copolymers were synthesized and the pendent isopropenyl moieties were activated with sec-butyllithium to obtain macroinitiators for the polymerization of styrene, tert-butyl methacrylate, or 2-vinylpyridine. The branching density and side chain molecular weight were controlled by varying the styrene/1,3-diisopropenylbenzene ratio in the substrate synthesis and the amount of monomer added in side chain growth, respectively. The arborescent polymers obtained had relatively narrow molecular weight distributions ( Mw/Mn = 1.1--1.5) in most cases.

ISBN: 0494029609Subjects--Topical Terms:

1018428
Chemistry, Polymer.

Anionic synthesis of arborescent polymers.
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100 1 $a Yuan, Zhongshun. $3 1904845
245 1 0 $a Anionic synthesis of arborescent polymers.
300 $a 176 p.
500 $a Source: Dissertation Abstracts International, Volume: 66-06, Section: B, page: 3158.
502 $a Thesis (Ph.D.)--University of Waterloo (Canada), 2005.
520 $a Arborescent polymers are branched macromolecules obtained from successive grafting reactions. Their main distinguishing feature is a dendritic architecture, characterized by multiple branching levels. Two new methods developed for the synthesis of arborescent polymers are reported in this thesis. The first technique provided arborescent homopolymers based on polyisoprene chain segments with a high cis-1,4-microstructure content. A linear polyisoprene substrate was first epoxidized and then reacted with polyisoprenyl anions to obtain a comb-branched (generation G0) polyisoprene. Several promoters were identified for the coupling reaction, LiCl and LiBr being most effective and increasing the yield from 78% (without additive) to 92% for a linear epoxidized substrate. The epoxidation and grafting cycles were repeated to obtain generation G1 and G2 arborescent polyisoprenes, with molecular weights and branching functionalities increasing geometrically for successive generations. The graft polymers had narrow molecular weight distributions (Mw/M n ≤ 1.05) and high cis-1,4-contents. The second method developed allowed the one-pot synthesis of arborescent styrene homo- and copolymers. Linear and G0 styrene-1,3-diisopropenylbenzene copolymers were synthesized and the pendent isopropenyl moieties were activated with sec-butyllithium to obtain macroinitiators for the polymerization of styrene, tert-butyl methacrylate, or 2-vinylpyridine. The branching density and side chain molecular weight were controlled by varying the styrene/1,3-diisopropenylbenzene ratio in the substrate synthesis and the amount of monomer added in side chain growth, respectively. The arborescent polymers obtained had relatively narrow molecular weight distributions ( Mw/Mn = 1.1--1.5) in most cases.
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650 4 $a Chemistry, Inorganic. $3 517253
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