New monomers

In ebook "Metal catalysts in olefin polymerization" the most recent major breakthroughs in the development of new olefin polymerization catalysts, including early metal metallocene and non-metallocene complexes and late transition metal complexes, are discussed by leading experts. The authors highlight the most important discoveries in catalysts and their applications in designing new polyolefin-based functional materials.

260p coduathanh1122 27-03-2024 1 1   Download

Ebook "Polymer science: A comprehensive reference - Volume 3: Chain polymerization of vinyl monomers" presents the great progress achieved in precise synthetic polymerization techniques for vinyl monomers to control macromolecular architecture: the development of metallocene and post-metallocene catalysis for olefin polymerization, new ionic polymerization procedures, and atom transfer radical polymerization, nitroxide mediated polymerization, and reversible addition-fragmentation chain transfer systems as the most often used controlled/living radical polymerization methods.

978p loivantrinh 29-10-2023 5 3   Download

This work reports the surface modification of polyacrylonitrile (PAN) fibers by graft copolymerization to ensure the decoration of homogenous and dense Ag nanoparticles. Two facile and subsequent modification processes resulted in a PAN fiber composite with an intact fibrous structure, sufficiently conductive for antistatic application and antibacterial activity. In the first step, some chemically attractive monomers and monomer mixtures, such as acrylic acid (AA), AA-itaconic acid (AA-IA), AA-acrylamide (AA-AAm), were introduced to the fiber surface by grafting.

15p lyhuyenthu 31-01-2023 6 2   Download

A new method is developed for calculating the vibration-rotation-tunneling spectra of molecular clusters consisting of rigid monomers. The method is based on generation of optimized bases for each monomer. First, a sequential symmetry adaptation procedure is developed for relating the symmetries of monomer basis functions with the symmetries of the eigenstates of the cluster. Then this symmetry adaptation procedure is used in the generation of optimized bases and combining them for finding the eigenstates.

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A new monomer was prepared from (1R,3S)-(+) -camphoric acid. Novel polyimide and polyimide–clay hybrid composites were developed from one-pot condensation reactions of this monomer and pyromellitic dianhyride. Polyimidemontmorillonite nanocomposites were prepared from solution of polyimide and with different weight percentages (1, 5, 10 wt %) of organo-modified montmorillonite (OM-MMT) using N -methyl-2-pyrrolidone (NMP) as aprotic solvent. The reactive organoclay was formed by using hexadecylpyridinium chloride as a swelling agent for silicate layers of montmorillonite.

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A new chromium(III) ion-imprinted polymer (IIP) was prepared from a Cr(III)-nicotinate complex (template), acrylamide (functional monomer), and ethylene glycol dimethacrylate (cross-linking agent) using 2,2’-azobisisobutyronitrile as the radical initiator. IIP was characterised and used as a selective sorbent for the solid-phase extraction of Cr(III) ions. The conditions for dynamic separation of Cr(III) on IIP were optimised.

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Boron methacrylate (BAc) monomer was synthesized via an esterification reaction. Boric acid, neopentyl glycol, and 2-hydroxyethyl methacrylate (HEMA) were reacted to obtain boron-containing acrylic monomer. Characterization was achieved by FT-IR, 13 C NMR, 1 H NMR, and 11 B NMR and the results for the synthesized monomer were compared to those for HEMA. Homopolymer and copolymers with styrene (St) were synthesized via free radical polymerization. The properties of the synthesized styrene copolymers were investigated using several techniques.

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In the present study, two new donor–acceptor–donor-type molecules were synthesized and the electro-optical properties of the resulting monomers and their corresponding polymers were investigated. Thiophene was selected as the donor unit and cycloheptyl- and cyclooctyl- substituted benzimidazoles were used as the acceptor units. The synthesized monomers and their electrochemically obtained polymers were characterized using cyclic voltammetry and UV-Vis spectrometry. The optical band gap values of the polymers were 1.

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It was demonstrated that Poly(p-Xylylene) (PPX) could be prepared from α,α’-Bis(Alkoxy or Aryloxy) –p-Xylenes via chemical vapor decomposition (CVD)- method. This is one-step process and there are side products by the CVD-process. This effect depends both on the CVD- condition and the properties of the starting monomer. The structure and thermal behavior of the material were characterized by FTIR, UVvis spectroscopy, elemental analysis, wide-angle X-ray diffraction, DTA and DSC.

14p 12120609 01-06-2020 13 1   Download

The incorporation of two different monomers, having different properties, in the same polymer molecule leads to the formation of new materials with great scientific and commercial importance.

9p vijiraiya2711 27-05-2020 9 1   Download

Although poly(N-acyl dithieno[3,2-b:2′,3′-d]pyrrole)s have attracted great attention as a new class of conducting polymers with highly stabilized energy levels, hyperbranched polymers based on this monomer type have not yet been studied.

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A new method of amidation of Carboxy Multi Walled Carbon Nanotubes (MWCNT-COOH) with diamine monomer such as ethylene diamine (EDA) and O-Phenylenediamine (OPDA) was applied by using a solution blending technique.

10p tocectocec 25-05-2020 16 1   Download

In this research, the new fluorescent conjugated polymers based on 10-(Perylene-3-yl-10HPhenoxazine (PyP) and 9,9-dioctyl-9h-fluorene (PF) have been synthesized via direct arylation polymerization using Pd(OAc)2, PivOH and PCy3.HBF4 as catalyst system. The monomer based on phenothiazine has been synthesized via C-N coupling to obtain the 4-(10H-phenothiazine-10-yl)- N,N-diphenylaniline (PyP). The synthesized novel conjugated polymers based on PyP and PF have been characterized via 1 H NMR, GPC, FTIR, DSC, XRD, PL, and UV-Vis spectrum.

10p 035522894 26-03-2020 49 2   Download

In the present study, we report the identification of a new gene from the Bacillus subtilisB3 strain (aatB3), which comprises 1308 bp encoding a 436 amino acid protein with a monomer molecular weight of 49.1 kDa. Phylo-genetic analyses suggested that this enzyme is a member of the Ib subgroup of aspartate aminotransferases

13p cosis54 05-01-2013 48 2   Download

The state-of-the-art of controlled radical polymerization (CRP) in 2011 is presented. Atom transfer radical polymerization, stable radical mediated polymerization, and degenerate transfer processes, including reversible addition fragmentation chain transfer are the most often used CRP procedures. CRP opens new avenues to novel materials from a large range of monomers. Detailed structure-reactivity relationships and mechanistic understanding not only helps attain a better controlled polymerization but enables preparation of polymers with complex architectures.

339p bachduong1311 12-12-2012 56 7   Download