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Anionic Initiators (anionic + initiator)
Selected AbstractsMorphology and temperature responsiveness,swelling relationship of poly(N -isopropylamide,chitosan) copolymers and their application to drug releaseJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 12 2004Chia-Fen Lee Abstract Poly [N -isopropylacrylamide (NIPAAm),chitosan] crosslinked copolymer particles were synthesized by soapless emulsion copolymerization of NIPAAm and chitosan. An anionic initiator [ammonium persulfate (APS)] and a cationic initiator [2,2,-azobis(2-methylpropionamidine)dihydrochloride (AIBA)] were used to initiate the reaction of copolymerization. The chitosan,NIPAAm copolymer synthesized by using APS as the initiator showed a homogeneous morphology and exhibited the characteristic of a lower critical solution temperature (LCST). The copolymer synthesized by using AIBA as an initiator showed a core,shell morphology, and the characteristic of LCST was insignificant. The LCST of the chitosan,NIPAAm copolymer depended on the morphology of the copolymer particles. In addition, the chitosan,NIPAAm copolymer particles were processed to form copolymer disks. Then, the effect of various variables such as the chitosan/NIPAAm weight ratio, the concentration of crosslinking agent, and the pH values on the swelling ratio of chitosan,NIPAAm copolymer disks were investigated. Furthermore, caffeine was used as the model drug to study the characteristics of drug loading of the chitosan,NIPAAm copolymer disks. Variables such as the chitosan/NIPAAm weight ratio and the concentration of the crosslinking agent significantly influenced the behavior of caffeine loading. Two factors (pore size and swelling ratio) affected the behavior of caffeine release from the chitosan,NIPAAm copolymer disks. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3029,3037, 2004 [source] Vibrational spectroscopic investigation of light-induced polymerization process of epoxy resin, polytetrahydrofuran and spirobislactonePOLYMER INTERNATIONAL, Issue 7 2007Yujie Zhang Abstract The light-induced polymerization process of bisphenol F diglycidyl ether (BFDGE), 5,5,-dicarboxylic-7,7,-dioxo-2,2,-spirodi(benzotetrahydrofuran) (DCSBL) and polytetrahydrofuran (pTHF-250) was studied. 4-[(2-Hydroxytetradecyl)oxy]phenyl-phenyliodoniumhexafluoroantimonate, camphorquinone and ethyl 4-dimethylaminobenzoate were used as a photoinitiator system. The polymerization process was induced by light and monitored using Fourier transform infrared spectroscopy. A novel combination-initiation polymerization process was proposed: first, cationic copolymerization of BFDGE and pTHF-250 was initiated by the photoinitiator system and heat was released by this polymerization; then, copolymerization of BFDGE and DCSBL was induced by that heat while pTHF-250 served as an anionic initiator. Copyright © 2007 Society of Chemical Industry [source] Preparation of isotactic-rich poly(dimethyl vinylphosphonate) and poly(vinylphosphonic acid) via the anionic polymerization of dimethyl vinylphosphonateJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 8 2010Takehiro Kawauchi Abstract A vinylphosphonate monomer, dimethyl vinylphosphonate (DMVP), has been polymerized by anionic initiators. Anionic polymerization of DMVP with tert -butyllithium (t -BuLi) in combination with a Lewis acid, tributylaluminum (n -Bu3Al), in toluene proceeded smoothly to give an isotactic-rich poly(dimethyl vinylphosphonate) (PDMVP) with relatively narrow molecular weight distribution. Although all the PDMVPs were soluble in water, the isotactic-rich PDMVP was insoluble in acetone and in chloroform which are good solvents for an atactic PDMVP prepared by radical polymerization. The isotactic-rich PDMVP showed higher thermal property than that of the atactic PDMVP. Moreover, we successfully prepared poly(vinylphosphonic acid) (PVPA) through the hydrolysis of the isotactic-rich PDMVP, which formed a highly transparent, self-standing film. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1677,1682, 2010 [source] Asymmetric anionic polymerization of 7-cyano-7-ethoxycarbonyl-1,4-benzoquinone methideJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2009Noboru Nakagaki An optically active polymer having configurational chirality in the main chain was synthesized from a prochiral monomer, 7-cyano-7-ethoxycarbonyl-1,4-benzoquinone methide (1), by asymmetric anionic polymerization using various chiral anionic initiators. The effects of the chiral ligand and solvent polarity on the specific rotations of the resulting polymers were investigated. The polymerization of 1 using iPrPhOLi/(,)-PhBox complex initiator in a mixture solution of dichloromethane/toluene ratio of 30/70 (in vol %) at ,78 °C afforded an optically active polymer with a large positive specific rotation ([,]435 = +90.4°). [source] Chiral polymers for resolution of enantiomersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 7 2009Yoshio Okamoto Abstract In 1979, the formation of one-handed helical poly(triphenylmethyl methacrylate) (PTrMA) was found through the helix-sense-selective polymerization of methacrylate using chiral anionic initiators, and the existence of a stable helical polymer without chiral side chains was proved. The chiral polymer exhibited unexpected high chiral recognition of various racemic compounds when used as the chiral packing material (CPM) for HPLC, which was commercialized in 1982 as the first chiral column based on an optically active polymer. This success encouraged us to develop further useful commercial chiral packing materials (CPMs) based on polysaccharides, cellulose, and amylose. By using these polysaccharide-based CPMs, particularly phenylcarbamate derivatives, nearly 90% of chiral compounds can be resolved not only analytically but also preparatively, and several chiral drugs have been produced using the CPMs. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1731,1739, 2009 [source] | ||||||||||