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Polymerization
About: Polymerization is a research topic. Over the lifetime, 147983 publications have been published within this topic receiving 2711902 citations.
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01 Jan 1985
TL;DR: In this paper, the authors describe a chain transfer characterisation of polymers charge-transfer complexes, charge transfer complexes and charge transfer complexes of charge transfer and charge-Transfer complexes.
Abstract: Cellular Materials Cellulose Cellulose, Biosynthesis Cellulose, Graft Copolymers Cellulose, Microcrystalline Cellulose Derivatives Cellulose Esters, Inorganic Cellulose Esters, Organic Cellulose Ethers Cement Additives Chain-Reaction Polymerization Chain Transfer Characterization of Polymers Charge-Transfer Complexes Chelate- Forming Polymers Chemical Analysis Chemically Resistant Polymers Chitin Chloroprene Polymers Chlorotrifluorethylene Polymers Chromatography Classification of Polymerization Reactions Coating Methods Coatings Coatings, Electrodeposition Cold Forming.
7,256 citations
TL;DR: In this article, a review of polymer-layered silicate nanocomposites is presented, where the polymer chains are sandwiched in between silicate layers and exfoliated layers are more or less uniformly dispersed in the polymer matrix.
Abstract: This review aims at reporting on very recent developments in syntheses, properties and (future) applications of polymer-layered silicate nanocomposites. This new type of materials, based on smectite clays usually rendered hydrophobic through ionic exchange of the sodium interlayer cation with an onium cation, may be prepared via various synthetic routes comprising exfoliation adsorption, in situ intercalative polymerization and melt intercalation. The whole range of polymer matrices is covered, i.e. thermoplastics, thermosets and elastomers. Two types of structure may be obtained, namely intercalated nanocomposites where the polymer chains are sandwiched in between silicate layers and exfoliated nanocomposites where the separated, individual silicate layers are more or less uniformly dispersed in the polymer matrix. This new family of materials exhibits enhanced properties at very low filler level, usually inferior to 5 wt.%, such as increased Young’s modulus and storage modulus, increase in thermal stability and gas barrier properties and good flame retardancy.
5,901 citations
Book•
01 Jan 1981TL;DR: In this paper, the authors present an overview of the properties of polymers and their applications in the literature, including the following: 1.1 Types of Polymers and Polymerization. 2.3 Linear, Branched, and Crosslinked Polymers.
Abstract: Preface. 1. Introduction. 1.1 Types of Polymers and Polymerizations. 1.2 Nomenclature of Polymers. 1.3 Linear, Branched, and Crosslinked Polymers. 1.4 Molecular Weight. 1.5 Physical State. 1.6 Applications of Polymers. 2. Step Polymerization. 2.1 Reactivity of Functional Groups. 2.2 Kinetics of Step Polymerization. 2.3 Accessibility of Functional Groups. 2.4 Equilibrium Considerations. 2.5 Cyclization versus Linear Polymerization. 2.6 Molecular Weight Control in Linear Polymerization. 2.7 Molecular Weight Distribution in Linear Polymerization. 2.8 Process Condition. 2.9 Multichain Polymerization. 2.10 Crosslinking. 2.11 Molecular Weight Distributions in Nonlinear Polymerizations. 2.12 Crosslinking Technology. 2.13 Step Copolymerization. 2.14 High-Performance Polymers. 2.15 Inorganic and Organometallic Polymers. 2.16 Dendric (Highly Branched) Polymers. 3. Radical Chain Polymerization. 3.1 Nature and Radical Chain Polymerization. 3.2 Structural Arrangement of Monomer Units. 3.3 Rate of Radical Chain Polymerization. 3.4 Initiation. 3.5 Molecular Weight. 3.6 Chain Transfer. 3.7 Inhibition and Retardation. 3.8 Determination of Absolute Rate Constants. 3.9 Energetic Characteristics. 3.10 Autoacceleration. 3.11 Molecular Weight Distribution. 3.12 Effect of Pressure. 3.13 Process Conditions. 3.14 Specific Commercial Polymers. 3.15 Living Radical Polymerization. 3.16 Other Polymerizations. 4. Emulsion Polymerization. 4.1 Description of Process. 4.2 Quantitative Aspects. 4.3 Other Characteristics of Emulsion Polymerization. 5. Ionic Chain Polymerization. 5.1 Comparison of Radical and Ionic Polymerization. 5.2 Cationic Polymerization of the Carbon-Carbon Double Bond. 5.3 Anionic Polymerization of the Carbon-Carbon Double. 5.4 Block and Other Polymer Architecture. 5.5 Distinguishing Between Radical, Cationic, and Anionic Polymerizations. 5.6 Carbonyl Polymerization. 5.7 Miscellaneous Polymerizations. 6. Chain Copolymerization. 6.1 General Considerations. 6.2 Copolymer Composition. 6.3 Radical Copolymerization. 6.4 Ionic Copolymerization. 6.5 Deviations from Terminal Copolymerization Model. 6.6 Copolymerizations Involving Dienes. 6.7 Other Copolymerizations. 6.8 Applications of Copolymerizations. 7. Ring-Opening Polymerization. 7.1 General Characteristics. 7.2 Cyclic Ethers. 7.3 Lactams. 7.4 N-Carboxy-alphaAmino Acid Anhydrides. 7.5 Lactones. 7.6 Nitrogen Heterocyclics. 7.7 Sulfur Heterocyclics. 7.8 Cycloalkenes. 7.9 Miscellaneous Oxygen Heterocyclics. 7.10 Other Ring-Opening Polymerizations. 7.11 Inorganic and Partially Inorganic Polymers. 7.12 Copolymerization. 8. Stereochemistry of Polymerizaton. 8.1 Types of Stereoisomerism in Polymers. 8.2 Properties of Stereoregular Polymers. 8.3 Forces of Stereoregulation in Alkene Polymerization. 8.4 Traditional Ziegler-Natta Polymerization of Nonpolar Alkene Monomers. 8.5 Metallocene Polymerization of Nonpolar Alkene Monomers. 8.6 Other Hydrocarbon Monomers. 8.7 Copolymerization. 8.8 Postmetallocene: Chelate Initiators. 8.9 Living Polymerization. 8.10 Polymerization of 1,3-Dienes. 8.11 Commercial Applications. 8.12 Polymerization of Polar Vinyl Monomers. 8.13 Alehydes. 8.14 Optical Activity in Polymers. 8.15 Ring-Opening Polymerization. 8.16 Statistical Models of Propagation. 9. Reactions of Polymers. 9.1 Principles of Polymers Reactivity. 9.2 Crosslinking. 9.3 Reactions of Cellulose. 9.4 Reactions of Poly(vinyl) acetate). 9.5 Halogenation. 9.6 Aromatic Substitution. 9.7 Cyclization. 9.8 Other Reactions. 9.9 Graft Copolymers. 9.10 Block Copolymers. 9.11 Polymers as Carriers or Supports. 9.12 Polymer Reagents. 9.13 Polymer Catalysts. 9.14 Polymer Substrates. Index.
4,933 citations
TL;DR: The authors proposed a reversible additive-fragmentation chain transfer (RAFT) method for living free-radical polymerization, which can be used with a wide range of monomers and reaction conditions and in each case it provides controlled molecular weight polymers with very narrow polydispersities.
Abstract: mechanism involves Reversible Addition-Fragmentation chain Transfer, and we have designated the process the RAFT polymerization. What distinguishes RAFT polymerization from all other methods of controlled/living free-radical polymerization is that it can be used with a wide range of monomers and reaction conditions and in each case it provides controlled molecular weight polymers with very narrow polydispersities (usually <1.2; sometimes <1.1). Living polymerization processes offer many benefits. These include the ability to control molecular weight and polydispersity and to prepare block copolymers and other polymers of complex architecturesmaterials which are not readily synthesized using other methodologies. Therefore, one can understand the current drive to develop a truly effective process which would combine the virtues of living polymerization with versatility and convenience of free-radical polymerization.2-4 However, existing processes described under the banner “living free-radical polymerization” suffer from a number of disadvantages. In particular, they may be applicable to only a limited range of monomers, require reagents that are expensive or difficult to remove, require special polymerization conditions (e.g. high reaction temperatures), and/or show sensitivity to acid or protic monomers. These factors have provided the impetus to search for new and better methods. There are three principal mechanisms that have been put forward to achieve living free-radical polymerization.2,5 The first is polymerization with reversible termination by coupling. Currently, the best example in this class is alkoxyamine-initiated or nitroxidemediated polymerization as first described by Rizzardo et al.6,7 and recently exploited by a number of groups in syntheses of narrow polydispersity polystyrene and related materials.4,8 The second mechanism is radical polymerization with reversible termination by ligand transfer to a metal complex (usually abbreviated as ATRP).9,10 This method has been successfully applied to the polymerization of various acrylic and styrenic monomers. The third mechanism for achieving living character is free-radical polymerization with reversible chain transfer (also termed degenerative chain transfer2). A simplified mechanism for this process is shown in
4,561 citations
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