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Graft Copolymerization of Styrene from Poly(vinyl alcohol) via RAFT Process  [PDF]
Gholam Ali Koohmareh,Morteza Hajian,Hazhir Fallahi
International Journal of Polymer Science , 2011, DOI: 10.1155/2011/190349
Abstract: Polystyrene, PS, was grafted from poly(vinyl alcohol), PVA, backbone by reversible addition-fragmentation chain transfer (RAFT) polymerization. The hydroxyl groups of the PVA were converted into aromatic dithioester RAFT agent and polymerization began in the presence of this agent. The structure of compounds was confirmed by FT-IR and 1HNMR spectroscopy. The graft copolymer was characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Grafted polystyrene chains were cleaved from the PVA backbone by acidic hydrolysis of the PVA-g-PS, and its polydispersity index, PDI, was determined by gel permeation chromatography (GPC) showing narrow molecular weight distribution. 1. Introduction Poly(vinyl alcohol) (PVA) has excellent film forming, emulsifying, and adhesive properties. It is odorless, nontoxic and has high tensile strength and flexibility as well as high oxygen and aroma barrier properties. PVA is a water-soluble semicrystalline polymer with good chemical and thermal stability and has biomedical applications [1–4]. Functionalized modification of PVA at the side groups is easy by utilizing various reactions of hydroxyl groups with small molecules or polymers. Such modification may provide PVA with pendant functional groups or graft polymer chains, and thus expand their applications in biological fields [5–8]. There are plenty of hydroxyl groups present as side groups on the backbone chain of poly(vinyl alcohol). The hydroxyl groups bring about good solubility in water but, on the other hand, lead to its high resistance to oil and poor mechanical properties. Because the modified PVA possesses hydrophilic backbone chain and hydrophobic branched chains synchronously after being modified by vinyl monomers, it can serve as amphiphilic compatibility-reagent between a hydrophobic polymer and a hydrophilic polymer. Graft copolymerization is one of the most important methods to modify PVA [9]. The synthesis of polymers with predetermined molecular weight and low polydispersity index can possible with controlled free-radical polymerization techniques, such as nitroxide-mediated polymerization (NMP), [10] atom transfer radical polymerization (ATRP), [11] and reversible addition fragmentation chain transfer (RAFT) polymerization [12–15] for a great variety of vinyl polymers. The last one, (RAFT), is one of the promising living radical methods for synthesizing well-defined graft polymers. A wide range of monomers can be polymerized in a controlled manner under nondemanding reaction conditions via this
RAFT polymers for protein recognition  [cached]
Alan F. Tominey,Julia Liese,Sun Wei,Klaus Kowski
Beilstein Journal of Organic Chemistry , 2010, DOI: 10.3762/bjoc.6.66
Abstract: A new family of linear polymers with pronounced affinity for arginine- and lysine-rich proteins has been created. To this end, N-isopropylacrylamide (NIPAM) was copolymerized in water with a binding monomer and a hydrophobic comonomer using a living radical polymerization (RAFT). The resulting copolymers were water-soluble and displayed narrow polydispersities. They formed tight complexes with basic proteins depending on the nature and amount of the binding monomer as well as on the choice of the added hydrophobic comonomer.
Synthesis, properties and aplications of functionalized polyanilines
Acevedo, Diego F.;Salavagione, Horacio J.;Miras, María C.;Barbero, César A.;
Journal of the Brazilian Chemical Society , 2005, DOI: 10.1590/S0103-50532005000200020
Abstract: novel functionalized conductive polymers are synthesised using modification reactions of polyaniline: diazonium coupling, nucleophilic addition and n-nitrosation. diazonium salt coupling with polyaniline renders modified polymers which are soluble in common solvents and electroactive. nucleophilic addition could also be used to modify polyaniline. modified polymers produced by addition of thiols, carbanions and arylsulphinic acids are described. the nucleophilic addition of arylsulphinic acids to oxidized polyaniline is shown to be controlled by the oxidation and/or protonation state of the polymer. it is also possible to n-nitrosate polyaniline producing a material soluble in common solvents. the reaction could be reversed by acid treatment. the reversible nitrosation reaction is used to design lithographic and photolithographic processes to deposit pani patterns.
On locally defined formations of soluble Lie and Leibniz algebras  [PDF]
Donald W. Barnes
Mathematics , 2011,
Abstract: It is well-known that all saturated formations of finite soluble groups are locally defined and, except for the trivial formation, have many different local definitions. I show that for Lie and Leibniz algebras over a field of characteristic 0, the formations of all nilpotent algebras and of all soluble algebras are the only locally defined formations and that the latter has many local definitions. Over a field of non-zero characteristic, a saturated formation of soluble Lie algebras has at most one local definition but a locally defined saturated formation of soluble Leibniz algebras other than that of nilpotent algebras has more than one local definition.
Photocrosslinkable Star Polymers via RAFT-Copolymerizations with N-Ethylacrylate-3,4-dimethylmaleimide  [PDF]
Nadja F?rster,Ann-Christin P?ppler,Dietmar Stalke,Philipp Vana
Polymers , 2013, DOI: 10.3390/polym5020706
Abstract: This paper describes the Z-RAFT-star copolymerization of n-butyl acrylate (BA) and N-isopropyl acrylamide (NIPAm), respectively, with N-ethylacrylate-3,4-dimethylmaleimide ( 1.1), a monomer carrying a UV-reactive unit that undergoes photocrosslinking. Addition of 1.1 slows down the polymerization rate both for BA and for NIPAm polymerization. Double star formation due to radical attack to the 3,4-dimethylmaleimide moiety was found in the case of BA. Dead polymer formation, presumably due to aminolysis as side-reaction, was pronounced in the NIPAm system. These two effects broadened the molar mass distributions, but did not impede the formation of functional star polymers. The composition of the copolymers as well as the reactivity ratios for the applied comonomers were determined via NMR spectroscopy (BA- co- 1.1 r 1.1 = 2.24 r BA = 0.95; NIPAm- co- 1.1 r 1.1 = 0.96 r NIPAm = 0.05). In both cases, the comonomer is consumed preferably in the beginning of the polymerization, thus forming gradient copolymer stars with the UV-reactive units being located in the outer sphere.

ZHANG Xiaojuan,GAO Jing,LUO Yingwu,LI Bogeng,

高分子学报 , 2008,
Abstract: 采用Z基团为—CH2C6H5的RAFT试剂为链转移剂,AIBN为引发剂,60℃下进行甲基丙烯酸甲酯/丙烯酸丁酯(MMA/BA)的本体RAFT共聚合,并用GPC法测算不同单体组成下低聚物RAFT的链转移常数(Ctr).实验表明,对BA的均聚合,Ctr高达116,但对MMA的均聚合,Ctr约为0.1.在共聚体系中,Ctr与fMMA之间为非线性关系,随着fMMA的增加呈下降趋势.Ctr随单体组成的变化规律可以很好地解释不同单体组成下RAFT共聚合中分子量及其分布随转化率变化的规律.
Self-Assembly of Cholesterol-Containing Water-Soluble Polymers  [PDF]
Shin-ichi Yusa
International Journal of Polymer Science , 2012, DOI: 10.1155/2012/609767
Abstract: Self-assembly of amphiphilic polymers containing cholesteryl groups has proved to be attractive in the field of nanotechnology research. Some cholesterol derivatives are known to form ordered structures which indicate thermotropic and lyotropic liquid-crystalline, monolayers, multilayers, micelles, and liposomes. This paper involves the synthesis and characterization of various kinds of amphiphilic polymers bearing cholesteryl moieties. 1. Introduction Self-assembling water-soluble polymers are of current scientific and technological interest because of their relevance to biological macromolecular systems and also to various industrial applications [1–3]. Macromolecular self-assemblies can be driven by noncovalent interactions including Coulombic, hydrogen bonding, van der Waals, exchange repulsive, and hydrophobic interactions. Among others, hydrophobic interaction is a major driving force for the self-organization of amphiphilic polymers in water. Various types of self-assembling amphiphilic polymers have so far been synthesized by various methods. A practical approach to the synthesis of such polymers is to covalently introduce hydrophobes into water-soluble polymers. A large number of hydrophobes can be incorporated into a water-soluble polymer chain by copolymerization of hydrophilic and hydrophobic monomers with a block, alternating, or random sequence distribution. The incorporation of hydrophobic groups into a hydrophilic polymer can alter its solution properties in an aqueous solution. Water forms an organized, ice-like structure around hydrophobic molecules, which is entropically unfavorable [4, 5]. Therefore, water forces hydrophobic molecules together so that the amount of water structuring is minimized. If the hydrophobic groups are covalently attached to a hydrophilic polymer, associations of hydrophobes either within or between polymer chains occur in water. The micelle formation of amphiphilic block copolymers in aqueous solutions has been the focus of great interest in a number of excellent reviews [6–8]. It is well established that block copolymers dissolved in a selective solvent—a solvent good for one block and poor for the other—undergo self-organization, leading to the formation of various morphologies, for example, spheres, rods, or lamellae. Water is a selective solvent for amphiphilic block copolymers, allowing for the formation of spherical micelles. Typically, they are formed with hydrophobic cores and hydrophilic outer layers (i.e., shells). On the other hand, a great deal of effort has also been devoted to the investigations

XU Xiaocong,LIU Meihua,LU Yanbing,XU Weijian,

高分子学报 , 2007,
Abstract: A series of soluble aromatic polyamide copolymers were prepared by the one-step polymerization or two-step polymerization of p-phenylene diamine (A_2 monomer),trimesic acid (B_3 monomer),and p-aminobenzoic acid (AB monomer).The structure of resulting polymers was confirmed by IR, ~1H-,and ~13C-NMR measurements.The copolymerization behavior was investigated by IR and ~1H-NMR. ~1H-NMR spectra of the polymers indicated that the AB monomer reacted by inches with the increasing of reaction time.The copolymers synthesized by two-step polymerization had different structures as compared with the one-step copolymer.The influence of three different monomers on the polymerization was investigated.

ZHU Xuezhen,YIN Qingming,ZHAO Jiruo,YIN Jinghua,FENG Ying,WANG Yuling,

高分子学报 , 2007,
Abstract: A grafting copolymer(CPE-g-HEA),composed of poly(2-hydroxy ethyl acrylate)(PHEA)as branched chains and chlorinated polyethylene(CPE)as backbone,was synthesized by in situ chlorinating graft copolymerization.No any initiator was added in the system.The process of in situ chlorinating graft copolymerization comes from continuously introducing chlorine gas into the reaction mixtures composed of only high-density polyethylene powder and a little amount of 2-hydroxy ethyl acrylate(HEA).When heated,a chlorine molecule decomposed into two chlorine radicals,which can lead to chlorination of PE,grafting of HEA to PE and homopolymerization of HEA as well.The structure of CPE-g-HEA was characterized by FT-IR,1H-NMR,GPC and WAXD.The results of FT-IR,1H-NMR and GPC indicated the existence of grafting copolymer of CPE-g-HEA.It can be found that the side chains of the copolymer were very short compared with those of HEA by bulk polymerization according to the GPC trace,and also the copolymer had more branches compared with the aqueous suspension graft system(CPE-g-MMA).
A Synthetic Route to Quaternary Pyridinium Salt-Functionalized Silsesquioxanes  [PDF]
Nataliya Kostenko,Jochen Gottfriedsen,Liane Hilfert,Frank T. Edelmann
International Journal of Polymer Science , 2012, DOI: 10.1155/2012/586594
Abstract: A synthetic route to potentially biocidal silsesquioxanes functionalized by quaternary pyridinium functionalities has been developed. N-Alkylation reactions of the precursor compounds 4-(2-(trimethoxysilyl)ethyl)-pyridine (5) and 4-(2-trichloro-silylethyl)pyridine (6) with iodomethane, n-hexylbromide, and n-hexadecylbromide cleanly afforded the corresponding N-alkylpyridinium salts (7–10). The synthesis of a 4-(2-ethyl)pyridine POSS derivative (2) was achieved by capping of the silsesquioxane trisilanol Cy7Si7O9(OH)3 (1) via two different preparative routes. Attempts to use compound 2 as precursor for quaternary pyridinium salt-functionalized POSS derivatives were met with only partial success. Only the reaction with iodomethane cleanly afforded the new N-methylpyridinium salt 12 in high yield, whereas n-hexylbromide and n-hexadecylbromide failed to react with 2 even under forcing conditions. 1. Introduction Over the past fifty years a broad variety of new classes of polymers have been prepared and studied which should provide advances in developing a new family of compounds for antibacterial surface treatments [1]. Such polymeric materials or films which kill or inactivate microorganisms upon their direct contact are known as biocidal (antimicrobial) polymers or also polymeric biocides. During the 1990s the interest in biocidal polymers arose rapidly due to their potential ability to keep surfaces and materials permanently antiseptic. This continues to be of current importance for a wide range of applications. Biocidal polymers are used, for example, in cartridge filters for the disinfection of potable and recreational water supplies, in filter units for air disinfection, as sterile bandages, clothing, surgical gloves for medical uses, as biocidal polymeric coatings on surfaces of ship hulls, shower walls and many other kinds of tubing. The ideal biocidal polymer should possess at least the following characteristics: (1) it should be easily and inexpensively synthesized; (2) it should be stable in long-term usage and storage at the temperature of its intended application; (3) it should be not soluble in water in the case of water disinfection applications; (4) it should not decompose to and emit toxic products; (5) it should not be toxic or irritating to those handling it; (6) it should be regenerable upon loss of activity; and (7) it should be biocidal to a broad spectrum of pathogenic microorganisms in brief times of contact [1–4]. By now various biocidal polymers have been produced and tested in different fields, but the achievement of a polymer
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