Topic
Polymerization
About: Polymerization is a research topic. Over the lifetime, 147983 publications have been published within this topic receiving 2711902 citations.
Papers published on a yearly basis
Papers
More filters
••
TL;DR: In this article, a couple-monomer methodology (CMM) is proposed for hyperbranched polymers, which is based on the in situ formation of ABn intermediates from specific monomer pairs.
1,896 citations
••
TL;DR: In this article, the authors review recent progress and advances that have been made on: (a) dispersion of CNTs in a polymer matrix, including optimum blending, in situ polymerization and chemical functionalization; and (b) alignment of CNNs in the matrix enhanced by ex situ techniques, force and magnetic fields, electrospinning and liquid crystalline phase-induced methods.
Abstract: Polymer/carbon nanotube (CNT) composites are expected to have good processability characteristics of the polymer and excellent functional properties of the CNTs. The critical challenge, however, is how to enhance dispersion and alignment of CNTs in the matrix. Here, we review recent progress and advances that have been made on: (a) dispersion of CNTs in a polymer matrix, including optimum blending, in situ polymerization and chemical functionalization; and (b) alignment of CNTs in the matrix enhanced by ex situ techniques, force and magnetic fields, electrospinning and liquid crystalline phase-induced methods. In addition, discussions on mechanical, thermal, electrical, electrochemical, optical and super-hydrophobic properties; and applications of polymer/CNT composites are included. Enhanced dispersion and alignment of CNTs in the polymer matrix will promote and extend the applications and developments of polymer/CNT nanocomposites.
1,848 citations
•
TL;DR: In this article, a class of π;-conjugated compounds that exhibit large δ (as high as 1, 250 × 10−50 cm4 s per photon) and enhanced two-photon sensitivity relative to ultraviolet initiators were developed and used to demonstrate a scheme for three-dimensional data storage which permits fluorescent and refractive read-out, and the fabrication of 3D micro-optical and micromechanical structures, including photonic-bandgap-type structures.
Abstract: Two-photon excitation provides a means of activating chemical or physical processes with high spatial resolution in three dimensions and has made possible the development of three-dimensional fluorescence imaging, optical data storage, and lithographic microfabrication. These applications take advantage of the fact that the two-photon absorption probability depends quadratically on intensity, so under tight-focusing conditions, the absorption is confined at the focus to a volume of order λ3 (where λ is the laser wavelength). Any subsequent process, such as fluorescence or a photoinduced chemical reaction, is also localized in this small volume. Although three-dimensional data storage and microfabrication have been illustrated using two-photon-initiated polymerization of resins incorporating conventional ultraviolet-absorbing initiators, such photopolymer systems exhibit low photosensitivity as the initiators have small two-photon absorption cross-sections (δ). Consequently, this approach requires high laser power, and its widespread use remains impractical. Here we report on a class of π;-conjugated compounds that exhibit large δ (as high as 1, 250 × 10−50 cm4 s per photon) and enhanced two-photon sensitivity relative to ultraviolet initiators. Two-photon excitable resins based on these new initiators have been developed and used to demonstrate a scheme for three-dimensional data storage which permits fluorescent and refractive read-out, and the fabrication of three-dimensional micro-optical and micromechanical structures, including photonic-bandgap-type structures.
1,833 citations
•
01 Jan 1971
TL;DR: The Science of Large Molecules POLYMERIZATION Step-Reaction (Condensation) Polymerization Radical Chain (Addition) PolyMERization Ionic and Coordination Chain (addition) Copolymerization Polymerisation Conditions and Polymer Reactions CHARACTERIZATION Polymer Solutions Measurement of Molecular Weight and Size Analysis and Testing of Polymers STRUCTURE and PROPERTIES Morphology and Order in Crystalline Polymers Rheology and the Mechanical Properties of Polymer Structure and Physical Properties as mentioned in this paper.
Abstract: The Science of Large Molecules POLYMERIZATION Step-Reaction (Condensation) Polymerization Radical Chain (Addition) Polymerization Ionic and Coordination Chain (Addition) Polymerization Copolymerization Polymerization Conditions and Polymer Reactions CHARACTERIZATION Polymer Solutions Measurement of Molecular Weight and Size Analysis and Testing of Polymers STRUCTURE AND PROPERTIES Morphology and Order in Crystalline Polymers Rheology and the Mechanical Properties of Polymers Polymer Structure and Physical Properties PROPERTIES OF COMMERICAL POLYMERS Hydrocarbon Plastics and Elastomers Other Carbon-Chain Polymers Heterochain Thermoplastics Thermosetting Resins POLYMER PROCESSING Plastics Technology Fiber Technology Elastomer Technology Appendixes Author and Subject Indexes.
1,703 citations
••
TL;DR: An extension of ATRA to atom transfer radical addition, ATRP, provided a new and efficient way to conduct controlled/living radical polymerization as mentioned in this paper, using a simple alkyl halide, R-X (X = Cl and Br), as an initiator and a transition metal species complexed by suitable ligand(s), M t n /L x, e.g., CuX/2,2'-bipyridine, as a catalyst.
Abstract: An extension of atom transfer radical addition, ATRA, to atom transfer radical polymerization, ATRP, provided a new and efficient way to conduct controlled/living radical polymerization. By using a simple alkyl halide, R-X (X = Cl and Br), as an initiator and a transition metal species complexed by suitable ligand(s), M t n /L x , e.g., CuX/2,2'-bipyridine, as a catalyst, ATRP of vinyl monomers such as styrenes and (meth)acrylates proceeded in a living fashion, yielding polymers with degrees of polymerization predetermined by Δ[M]/[I] 0 up to M n ≃ 10 5 and low polydispersities, 1.1 < M w /M n < 1.5. The participation of free radical intermediates was supported by analysis of the end groups and the stereochemistry of the polymerization. The general principle and the mechanism of ATRP are elucidated. Various factors affecting the ATRP process are discussed.
1,628 citations