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Functional Polymers (functional + polymer)
Selected AbstractsFast and Enantioselective Production of 1-Aryl-1-propanols through a Single Pass, Continuous Flow ProcessADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 6 2008Miquel Abstract A functional polymer 4, obtained by reaction of (R)-2-(1-piperazinyl)-1,1,2-triphenylethanol with a Merrifield resin, has been loaded in a packed bed reactor and used as catalyst for the continuous enantioselective production of 1-arylpropanols by ethylation of aromatic aldehydes. The high catalytic activity depicted by 4 allows the complete conversion of the substrates with the use of stoichiometric reagent ratios and unprecedently short residence times (down to 2.8,min). In practice, a single-pass operation can be used for all the studied aldehydes, and productions of up to 13.0 mol/g,h are recorded. The sequential operation of the flow system for the uninterrupted synthesis of a small library of enantiopure 1-arylpropanols is also reported. [source] Synthesis, characterization and application of poly[(1-vinyl-2-pyrrolidone)- co -(2-hydroxyethyl methacrylate)] as controlled-release polymeric system for 2,4-dichlorophenoxyacetic chloride using an ultrafiltration techniquePOLYMER INTERNATIONAL, Issue 7 2008Guadalupe del C Pizarro Abstract BACKGROUND: Polymers supporting chemicals used in agriculture have recently been developed to overcome the serious environmental problems of conventional agrochemicals. The success of these formulations is based on a suitable choice of polymer support. Degradable polymeric hydrogels are of particular interest. The gradual release of the bioactive agent can be achieved by hydrolytic or enzymatic cleavage of the linking bond. RESULTS: In this context, poly[(1-vinyl-2-pyrrolidone)- co -(2-hydroxyethyl methacrylate)] [poly(NVP- co -HEMA)] has been used as a bioactive carrier reagent. Herein, we report a controlled-release system with the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) using an ultrafiltration system. Hydrolysis was studied by testing the release at various pH values. A high release with poly(NVP- co -HEMA),2,4-D was observed at pH = 7 and 10 after two days (Z = 2). The release percentage of copolymer,herbicide increased at pH = 10. It showed release values between 79.0 and 94.5%. Poly(NVP- co -HEMA),herbicide can release a bioactive compound in aqueous solution at pH = 3, 7 and 10. CONCLUSION: Based on the results of homogeneous hydrolysis, it is argued that the herbicide release rate depends on the pH of the reaction environment. This functional polymer could be employed as a biodegradable material for applications in agrichemical release. Copyright © 2008 Society of Chemical Industry [source] Polymers Move in Response to LightADVANCED MATERIALS, Issue 11 2006Y. Jiang Abstract Significant advances have recently been made in the development of functional polymers that are able to undergo light-induced shape changes. The main challenge in the development of such polymer systems is the conversion of photoinduced effects at the molecular level to macroscopic movement of working pieces. This article highlights some selected polymer architectures and their tailored functionalization processes. Examples include the contraction and bending of azobenzene-containing liquid-crystal elastomers and volume changes in gels. We focus especially on light-induced shape-memory polymers. These materials can be deformed and temporarily fixed in a new shape. They only recover their original, permanent shape when irradiated with light of appropriate wavelengths. Using light as a trigger for the shape-memory effect will extend the applications of shape-memory polymers, especially in the field of medical devices where triggers other than heat are highly desirable. [source] Stability of poly(N -propargylamide)s under ultraviolet irradiationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2008Jianping Deng Abstract This article investigates the photostability of poly(N -propargylamide)s under different conditions, on the basis of which application research for this class of highly functional polymers can be performed. With helical polymer 1 [monomer: CCCH2NHCOCH(C2H5)2] taken as a representative, some affecting factors, including the ultraviolet (UV)-light intensity, presence of oxygen, far-UV and near-UV light, and temperature, were investigated. It was found that increasing the UV-light intensity accelerated the degradation of polymer 1. When oxygen was present, it also facilitated the degradation. Far-UV light rather than near-UV light played a predominant role in initiating the degradation of polymer main chains. Elevating the temperature of the polymer solution during UV irradiation made the degradation accelerate. Storing the polymer under weak UV light, in the absence of oxygen, and at a low temperature was favorable for keeping the polymer stable. These findings are important not only from a scientific point of view but especially for developing practical applications of this type of polymer on the basis of its photodegradability. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Chemistry of 2-oxazolines: A crossing of cationic ring-opening polymerization and enzymatic ring-opening polyadditionJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2010Akira Makino Abstract Chemistry of 2-oxazolines is involved in the polymer synthesis fields of cationic ring-opening polymerization (CROP) and enzymatic ring-opening polyaddition (EROPA), although both polymerizations look like a quite different class of reaction. The key for the polymerization to proceed is combination of the catalyst (initiator) and the design of monomers. This article describes recent developments in polymer synthesis via these two kinds of polymerizations to afford various functional polymers having completely different structures, poly(N -acylethylenimine)s via CROP and 2-amino-2-deoxy sugar unit-containing oligo and polysaccharides via EROPA, respectively. From the viewpoint of reaction mode, an acid-catalyzed ring-opening polyaddition (ROPA) is considered to be a crossing where CROP and EROPA meet. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1251,1270, 2010 [source] Postpolymerization modification of poly(pentafluorophenyl methacrylate): Synthesis of a diverse water-soluble polymer libraryJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 17 2009Matthew I. Gibson Abstract This article explores the feasibility of poly(pentafluorophenyl methacrylate) (PPFMA) prepared by reversible addition fragmentation chain transfer (RAFT) polymerization as a platform for the preparation of diverse libraries of functional polymers via postpolymerization modification with primary amines. Experiments with a broad range of functional amines and PPFMA precursors of different molecular weights indicated that the postpolymerization modification reaction proceeds with good to excellent conversion for a diverse variety of functional amines and is essentially independent of the PPFMA precursor molecular weight. The RAFT end group, which was well preserved throughout the polymerization, is cleaved during postpolymerization modification to generate a thiol end group that provides possibilities for further orthogonal chain-end modification reactions. The degree of postpolymerization modification can be controlled by varying the relative amount of primary amine that is used and random polymethacrylamide copolymers can be prepared via a one-pot/two-step sequential addition procedure. Cytotoxicity experiments revealed that the postpolymerization modification strategy does not lead to any additional toxicity compared with the corresponding polymer obtained via direct polymerization, which makes this approach also of interest for the synthesis of biologically active polymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4332,4345, 2009 [source] Synthesis and characterization of a series of diverse poly(2-oxazoline)sJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2009Kristian Kempe Abstract This article describes the synthesis and characterization of a variety of new poly(2-oxazoline)s. With regard to functional polymers, 2-oxazolines represent an interesting class of monomers because of the easy variation of the substituent in 2-position. Starting from the corresponding nitriles, different 2-oxazolines were obtained containing a diverse set of 2-substituents, including thioether bonds (M11), trifluoromethyl groups (M8, M10), and alkyl- or aryl groups (M1,M7). The subsequent polymerization of the majority of these monomers proceeded in a living manner, which was demonstrated by linear first-order kinetics, a linear increase of molar mass with conversion, and relatively narrow molar mass distributions. In addition, selected thermal and surface properties of the polymers were studied utilizing DSC and contact-angle measurements to determine the effects of different 2-substituents on the macroscopic properties. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3829,3838, 2009 [source] Selective polymerization of functional monomers with Novozym 435JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 24 2007Martijn A. J. Veld Abstract Two novel monomers, ambrettolide epoxide and isopropyl aleuriteate, encompassing functional groups, were obtained in a single step from commercially available materials. Novozym 435 catalyzed ring opening polymerization of ambrettolide epoxide furnished a polymer of Mn = 9.7 kg/mol and PDI = 1.9 while the epoxide groups remained unaffected during the polymerization. Selective polymerization of the primary hydroxyl groups of isopropyl aleuriteate using Novozym 435 was feasible and a polymer with moderate molecular weight (Mn = 5.6 kg/mol, PDI = 3.2) was isolated in moderate yield (43%). Subsequently, copolymerization of isopropyl aleuriteate with ,-CL in different ratios was performed, resulting in soluble, hydroxy functional polymers with good molecular weights (Mn = 10.4,27.2 kg/mol) in good yield (71,78%). The secondary hydroxy groups in the polymer reacted easily with hexyl isocyanate, showing the potential of isopropyl aleuriteate as a comonomer for the synthesis of functional polyesters. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5968,5978, 2007 [source] New functionalized polyesters to achieve controlled architecturesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 3 2004Anna Finne Abstract Following our continued interest in the production of bioerodible and biodegradable functional polymers for biomedical applications, we synthesized and characterized new unsaturated polyesters. The presence of functional groups in the polymer backbone provided sites for chemical modification, and through a variation in the structure, the physical properties, such as the hydrophilicity and solubility, could be affected. With 1,1-di- n -butyl-stanna-2,7-dioxacyclo-4-heptene as the initiator in the ring-opening polymerization of polyesters, a new set of functionalized polyesters was created. The polymerization of ,-caprolactone resulted in poly(,-caprolactone) with a double bond incorporated into the structure. The polymers were obtained in a controlled manner with low molecular dispersities. The double bond was previously incorporated into L -lactide polymers, and the two reactions were compared in this study. The conversion of ,-caprolactone, with a degree of polymerization of 50, was completed within 140 min, whereas for L -lactide, only a 45% conversion took place in the same period of time. The dispersities were somewhat higher with ,-caprolactone because of the higher reaction rate and, therefore, lower selectivity. The incorporated CC double bond in the polyesters provided a variety of opportunities for further modifications. In this case, the double bond of the L -lactide macromonomers was oxidized into epoxides. Epoxidation was carried out with m -chloroperoxybenzoic acid as a chemical reagent. The conversion of the double bonds into epoxides was completed, and the obtained yields were good (>95%). As a result of the mild reaction conditions, the epoxidation of the double bond was carried out quantitatively without any side reactions. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 444,452, 2004 [source] Tuning the Properties of Functional Pyrrolidinium Polymers by (Co)polymerization of Diallyldimethylammonium Ionic LiquidsMACROMOLECULAR RAPID COMMUNICATIONS, Issue 18 2010V. Jovanovski Abstract The synthesis and polymerization of novel diallyldimethylammonium ionic liquid monomers is described. A free-radical polymerization follows a ring-closing cyclopolymerization mechanism similar to the one observed previously for diallyldimethylammonium halides that leads to pyrrolidinium functional polymers. As previously observed in other families of polymeric ionic liquids, their physico-chemical properties are seriously affected by the nature of the counter-anion. As an example, the thermal stability increases following the trend SCN,,<,,<,,<,bis(trifluoromethane)sulfonamide. Interestingly, this polymerization route may lead to the synthesis of a new family of random copolymers that have a similar poly(diallyldimethylammonium) backbone and a mixture of counter-anions determined by the comonomer selection. [source] The effect of lanthanum oxide (La2O3) on the structure and crystallization of poly(vinylidene fluoride)POLYMER INTERNATIONAL, Issue 7 2010Jianbin Song Abstract Rare earth polymers, due to their excellent luminescence, fluorescence, laser protective, optical and magnetic properties, have attracted much research attention in recent years. However, little attention has been paid to the effect of rare earths on the structure and crystallization of polymers, which is of important significance in the development of functional polymers. X-ray diffraction and differential scanning calorimetry were used to investigate the structure and crystallization behavior of a poly(vinylidene fluoride) (PVDF)/lanthanum oxide (La2O3) composite. The results showed that the degree of perfection, crystal size, crystallization rate and isothermal crystallization activation energy of PVDF in the composite decreased, compared with pure PVDF. The spherulite nucleation and growth for PVDF and PVDF composite were analyzed in detail using the Lauritzen-Hoffman equation. The modified Avrami equation and the Mo equation were used to study the non-isothermal crystallization kinetics. The addition of La2O3 did not change the crystal structure and nucleation process for PVDF, but it decreased markedly the crystal growth rate and led to the formation of unstable crystals. This was attributed to the fact that too much La2O3 prevented PVDF molecular chains from moving and arranging in an orderly manner into crystals. Copyright © 2010 Society of Chemical Industry [source] Structural materials underpinning functional materials: teaching old dogs new tricksPOLYMER INTERNATIONAL, Issue 5 2008William A MacDonald Abstract ,Structural' polymers are finding new applications underpinning new technology developments based on functional polymers. This paper discusses the use of polyester films as base substrates for flexible electronic applications based on conjugated polymers and low-temperature hydrogenated amorphous silica processing, and discusses the challenges involved in successfully developing substrates ,fit for purpose'. Copyright © 2008 Society of Chemical Industry [source] Synthesis and characterization of amine-functionalized amphiphilic block copolymers based on poly(ethylene glycol) and poly(caprolactone)POLYMER INTERNATIONAL, Issue 4 2007Remant Bahadur KC Abstract A series of amine-functionalized block copolymers, poly(caprolactone)- block -poly(ethylene glycol) (PCL-b-PEG), were synthesized by ring-opening bulk polymerization (ROP) of ,-caprolactone (,-CL) initiated through the hydroxyl end of the amino poly(ethylene glycol) (PEG) used as a macroinitiator in the presence of stannous 2-ethylhexonoate [Sn(Oct)2]. The polymerization and end functionality of the polymer were studied by different physicochemical techniques (1H NMR, Fourier transform infrared and X-ray photoelectron spectroscopy, gel permeation chromatography and thermogravimetric analysis). Thermal, crystalline and mechanical properties of the polymer were thoroughly analyzed using differential scanning calorimetry, wide-angle X-ray diffractometry and tensile testing, respectively. The results showed a linear improvement in crystallinity and mechanical properties of the polymer with the content of PEG. Thus the synthesized functional polymers can be used as excellent biomaterials for the delivery of polyanions, as well as macroinitiators for the synthesis of A,B,C-type block copolymers. Copyright © 2006 Society of Chemical Industry [source] Design and synthesis of functional polymers by in vitro selectionPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 1-2 2004Yoshihiro Ito Abstract Combinatorial chemistry, in which targeting molecules are selected from a random molecular library, has recently developed. Among the methods devised by combinatorial chemistry, the recent progress in functional polymers that have molecular recognition ability and catalysis ability, and in bio-device polymers based on these functionalities is reviewed. Copyright © 2004 John Wiley & Sons, Ltd. [source] Synthesis and characterization of a novel soluble reactive ladder-like polysilsesquioxane with side-chain 2-(4-chloromethyl phenyl) ethyl groupsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 8 2001Chunqing Liu Abstract A new kind of soluble structure-ordered ladder-like polysilsesquioxane with reactive side-chain 2-(4-chloromethyl phenyl) ethyl groups (L) was first synthesized by stepwise coupling polymerization. The monomer, 2-(4-chloromethyl phenyl) ethyltrichlorosilane (M), was synthesized successfully by hydrosilylation reaction with dicyclopentadienylplatinum(II) chloride (Cp2PtCl2) catalyst. Monomer and polymer structures were characterized by FT-IR, 1H -NMR, 13C -NMR, 29Si -NMR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), vapor pressure osmometry (VPO) and X-ray diffraction (XRD). This novel reactive ladder-like polymer has promise potential applications as initiator for atom transfer radical polymerization, and as precursor for a variety of advanced functional polymers. Copyright © 2001 John Wiley & Sons, Ltd. [source] Synthesis, characterization and application of soluble fullerenated polymer materialsCHINESE JOURNAL OF CHEMISTRY, Issue 5 2000Yu Chen Abstract This article only deals with the topic of intense interest to us and to a considerable extent of our own experimental results on the synthesis, characterization and application of C60 -containing functional polymers such as poly(N -vinylcarbazole), polystyrene and polyacrylonitrile-based fullerene polymers. The results demonstrate that [60]fullerene and be directly incorporated into a variety of functional polymers by copolymerization or grafting, but also can be used to modify or improve the electronic, optical and physicochemical properties of polymers. Both the stereo-electroniceffect and me steric hindrance of C60 have an important influence on the structure and physicochemical properties of the parent polymer. [source] | |||||||||||||