scispace - formally typeset
Search or ask a question
Topic

Copolymer

About: Copolymer is a research topic. Over the lifetime, 84093 publications have been published within this topic receiving 1296738 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: Block copolymers are macromolecules composed of sequences, or blocks, of chemically distinct repeat units that make possible the sequential addition of monomers to various carbanion-ter­ minated ("living") linear polymer chains.
Abstract: Block copolymers are macromolecules composed of sequences, or blocks, of chemically distinct repeat units. The development of this field originated with the discovery of termination-free anionic polymerization, which made possible the sequential addition of monomers to various carbanion-ter­ minated ("living") linear polymer chains. Polymerization of just two dis­ tinct monomer types (e.g. styrene and isoprene) leads to a class of materials referred to as AB block copolymers. Within this class, a variety of molec­ ular architectures is possible. For example, the simplest combination, obtained by the two-step anionic polymerization of A and B monomers, is an (A-B) dioblock copolymer. A three-step reaction provides for the preparation of (ABA) or (BAB) triblock copolymer. Alternatively, "living" diblock copolymers can be reacted with an n-functional coupling agent to produce (A-B)n star-block copolymers, where n = 2 constitutes a triblock copolymer. Several representative (A-B)n block copolymer architectures

3,475 citations

Journal ArticleDOI
TL;DR: In contrast to heterogeneous Ziegler-Natta catalysts, homogeneous metallocene-based catalysts as discussed by the authors allow efficient control of regio-and stereoregularities, molecular weights and molecular weight distributions, and comonomer incorporation.
Abstract: Current studies on novel, metallocenebased catalysts for the polymerization of α-olefins have far-reaching implications for the development of new materials as well as for the understanding of basic reaction mechanisms responsible for the growth of a polymer chain at a catalyst center and the control of its stereoregularity. In contrast to heterogeneous Ziegler–Natta catalysts, polymerization by a homogeneous, metallocene-based catalyst occurs principally at a single type of metal center with a defined coordination environment. This makes it possible to correlate metallocene structures with polymer properties such as molecular weight, stereochemical microstructure, crystallization behavior, and mechanical properties. Homogeneous catalyst systems now afford efficient control of regio- and stereoregularities, molecular weights and molecular weight distributions, and comonomer incorporation. By providing a means for the homo- and copolymerization of cyclic olefins, the cyclopolymerization of dienes, and access even to functionalized polyolefins, these catalysts greatly expand the range and versatility of technically feasible types of polyolefin materials. For corrigendum see DOI:10.1002/anie.199513681

2,436 citations

Journal ArticleDOI
TL;DR: A general overview of the preparation, characterization and theories of block copolymer micellar systems is presented in this paper, with examples of micelle formation in aqueous and organic medium are given for di-and triblock copolymers, as well as for more complex architectures.

1,856 citations

Journal ArticleDOI
TL;DR: In this article, the association properties of poly(ethylene oxide)-block-poly(propyleneoxide)-blockpoly(methylene oxide) (PEO) copolymers in aqueous solutions, and the adsorption at interfaces are reviewed.

1,730 citations


Network Information
Related Topics (5)
Polymer
131.4K papers, 2.6M citations
97% related
Polymerization
147.9K papers, 2.7M citations
97% related
Nanocomposite
71.3K papers, 1.9M citations
90% related
Phase (matter)
115.6K papers, 2.1M citations
90% related
Nanoparticle
85.9K papers, 2.6M citations
85% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,959
20224,148
20211,326
20201,828
20192,146
20182,181