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Resultant Polymers (resultant + polymer)
Selected AbstractsSynthesis of hollow crosslinked miktoarm polymer using miniemulsion as templatesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2009De'an Xiong Abstract Hollow crosslinked polymers (HCPs) were synthesized using arm first method via atom transfer radical polymerization. The polymerization process was performed in miniemulsion system, in which the macroinitiator, PEG-Br, was in the water phase, whereas the vinyl-monomer, 4-vinylpyridine (4VP), and the crosslinker, DVB, were in the butanone phase. TEM images and light scattering characterization showed that the resultant polymer contained a hollow space, and the volume of the hollow space could be adjusted by changing the ratio of water to butanone. Also, hollow crosslinked Miktoarm polymers (HCMPs) were synthesized through this method when two different macroinitiators, PEG-Br and PNIPAM-Br, were used to coinitiate the polymerization of the vinyl-monomer, 4VP and DVB. The 1H NMR spectra showed that the hollow polymers contained both PEG arms and PNIPAM arms. The hollow morphologies of the resultant Miktoarm polymers were the same as the HCPs. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1651,1660, 2009 [source] Synthesis and characterization of radio-opaque thermosensitive poly[N -isopropylacrylamide-2,2,-(ethylenedioxy)bis(ethylamine)-2,3,5-triiodobenzamide]POLYMER INTERNATIONAL, Issue 8 2009Christine M Leon Abstract BACKGROUND:In situ gelling polymers, like poly(N -isopropylacrylamide) (poly(NIPAAm)), have many potential medical applications due to their biocompatibility and thermosensitivity. RESULTS: Radio-opaque thermosensitive poly(NIPAAm) grafted with 10.7 wt% 2,2,-(ethylenedioxy)bis(ethylamine)-2,3,5-triiodobenzamide was successfully synthesized and characterized. The conjugated polymer showed good visibility with X-ray fluoroscopy. The polymer had a lower critical solution temperature of 30 °C after conjugation with triiodobenzamide as determined by cloud point determination and a transition peak temperature of 33.3 ± 0.57 °C as determined by differential scanning calorimetry. CONCLUSION: The polymer synthesized was highly visible under X-rays, based upon the percentage incorporation of triiodobenzamide. After conjugation of the NIPAAm to the triiodobenzamide through a bis(ethylamine) linkage, the resultant polymer retained lower critical solution temperature characteristics in a temperature region that makes it physiologically useful. Copyright © 2009 Society of Chemical Industry [source] Cyclic alkoxyamine-initiator tethered by azide/alkyne-"click"-chemistry enabling ring-expansion vinyl polymerization providing macrocyclic polymersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2010Atsushi Narumi Abstract A cyclic initiator for the nitroxide-mediated controlled radical polymerization (NMP) is a powerful tool for the preparation of macrocyclic polymers via a ring-expansion vinyl polymerization mechanism. For this purpose, we prepared a Hawker-type NMP-initiator that includes an azide and a terminal alkyne as an acyclic precursor, which is subsequently tethered via an intramolecular azide/alkyne-"click"-reaction, producing the final cyclic NMP-initiator. The polymerization reactions of styrene with cyclic initiator were demonstrated and the resultant polymers were characterized by the gel permeation chromatography (GPC) and the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). These results prove that the ring-expansion polymerization of styrene occurred together with the radical ring-crossover reactions originating from the exchange of the inherent nitroxides generating macrocyclic polystyrenes with higher expanded rings. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3402,3416, 2010 [source] Ethylene polymerization and ethylene/hexene copolymerization with vanadium(III) catalysts bearing heteroatom-containing salicylaldiminato ligandsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 14 2009Ji-Qian Wu Abstract A series of novel vanadium(III) complexes bearing heteroatom-containing group-substituted salicylaldiminato ligands [RNCH(ArO)]VCl2(THF)2 (Ar = C6H4, R = C3H2NS, 2a; C7H4NS, 2c; C7H5N2, 2d; Ar = C6H2tBu2 (2,4), R = C3H2NS, 2b) have been synthesized and characterized. Structure of complex 2c was further confirmed by X-ray crystallographic analysis. The complexes were investigated as the catalysts for ethylene polymerization in the presence of Et2AlCl. Complexes 2a,d exhibited high catalytic activities (up to 22.8 kg polyethylene/mmolV h bar), and affording polymer with unimodal molecular weight distributions at 25,70 °C in the first 5-min polymerization, whereas produced bimodal molecular weight distribution polymers at 70 °C when polymerization time prolonged to 30 min. The catalyst structure plays an important role in controlling the molecular weight and molecular weight distribution of the resultant polymers produced in 30 min polymerization. In addition, ethylene/hexene copolymerizations with catalysts 2a,d were also explored in the presence of Et2AlCl, which leads to the high molecular weight and unimodal distributions copolymers with high comonomer incorporation. Catalytic activity, comonomer incorporation, and polymer molecular weight can be controlled over a wide range by the variation of catalyst structure and the reaction parameters, such as comonomer feed concentration, polymerization time, and polymerization reaction temperature. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3573,3582, 2009 [source] Homopolymerization of cyclic esters initiated by lanthanide isopropoxides supported by 2,2,-ethylene-bis(4,6-di- tert -butylphenolate) ligandsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2006Xiaoping Xu Abstract Lanthanide isopropoxides supported by carbon-bridged bisphenolate ligands of 2,2,-ethylene-bis(4,6-di- tert -butylphenoxo) {[(EDBP)Ln(,-OPri)(THF)2]2, where Ln is Nd (1), Sm (2), or Yb (3) and THF is tetrahydrofuran} were synthesized by protic exchange reactions in high yields with Cp3Ln compounds as raw materials, and complex 1 was structurally characterized. Complexes 1,3 were shown to be efficient initiators for the ring-opening polymerization of ,-caprolactone (,-CL) and 2,2-dimethyltrimethylene carbonate (DTC). Complexes 1,3 could initiate the controlled polymerization of ,-CL, and the polymerization rate was first-order with respect to the monomer. The influence of the reaction conditions on the monomer conversion, molecular weight, and molecular weight distribution of the resultant polymers was investigated. End-group analyses of the oligomers of ,-CL and DTC showed that the polymerization underwent a coordination,insertion mechanism. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4409,4419, 2006 [source] Synthesis of homopolymers and multiblock copolymers by the living ring-opening metathesis polymerization of norbornenes containing acetyl-protected carbohydrates with well-defined ruthenium and molybdenum initiatorsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 17 2004Yoshitaka Miyamoto Abstract The ring-opening metathesis polymerization (ROMP) of norbornenes containing acetyl-protected glucose [2,3,4,6-tetra- O -acetyl-glucos-1- O -yl 5-norbornene-2-carboxylate (1)] and maltose [2,3,6,2,,3,,4,,6,-hepta- O -acetyl-maltos-1- O -yl 5-norbornene-2-carboxylate (2)] was explored in the presence of Mo(N -2,6- iPr2C6H3)(CHCMe2Ph)(OtBu)2 (A), Ru(CHPh)(Cl)2(PCy3)2 (B; Cy = cyclohexyl), and Ru(CHPh)(Cl)2(IMesH2)(PCy3) (C; IMesH2 = 1,3-dimesityl-4,5-dihydromidazol-2-ylidene). The polymerizations promoted by B and A proceeded in a living fashion with exclusive initiation efficiency, and the resultant polymers possessed number-average molecular weights that were very close to those calculated on the basis of the monomer/initiator molar ratios and narrow molecular weight distributions (weight-average molecular weight/number-average molecular weight < 1.18) in all cases. The observed catalytic activity of B was strongly dependent on both the initial monomer concentration and the solvent employed, whereas the polymerization initiated with A was completed efficiently even at low initial monomer concentrations. The polymerization with C also took place efficiently, and even the polymerization with 1000 equiv of 1 was completed within 2 h. First-order relationships between the propagation rates and the monomer concentrations were observed for all the polymerization runs, and the estimated rate constants at 25 °C increased in the following order: A > C > B. On the basis of these results, we concluded that ROMP with A was more suitable than ROMP with B or C for the efficient and precise preparation of polymers containing carbohydrates. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4248,4265, 2004 [source] Facile synthesis and characterization of hyperbranched poly(aryl ether ketone)s obtained via an A2 + BB,2 approachPOLYMER INTERNATIONAL, Issue 10 2010Xiujie Li Abstract A fast and highly efficient approach for the synthesis of hyperbranched poly(aryl ether ketone)s (HPAEKs) via the polycondensation of A2 and BB,2 monomers is described. Commercially available hydroquinone (HQ, A2 monomer) and easily synthesized 2,4,,6-trifluorobenzophenone (TF, BB,2 monomer) were thermally polycondensed to prepared fluoro- or phenolic-terminated HPAEKs with K2CO3 and Na2CO3 as catalysts. During the reaction, the fluorine at the 4,-position of TF reacts rapidly with the phenolic group of HQ, forming predominantly dimers and some other species. The dimer can be considered as a new AB,2 monomer. Further reactions among molecules AB,2 and AB,2 with some other species result in the formation of HPAEKs. Fourier transform infrared and 1H NMR spectra revealed the structures of the resultant polymers. The degree of branching (DB) of the fluoro-terminated hyperbranched polymers was determined to be in the range 50,57% from 1H NMR spectra, whereas the DB of the phenolic-terminated hyperbranched polymers was determined to be 100%. These hyperbranched polymers exhibit excellent solubility in general organic solvents and possess moderate molecular weights with broad distributions determined using gel permeation chromatography. Moreover, the structure and performance of the HPAEKs can be conveniently regulated by adjusting the type and feed ratio of the two monomers. 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