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Ring Opening Polymerization (ring + opening_polymerization)
Selected AbstractsAB2 Functional Polyesters via Ring Opening Polymerization: Synthesis and CharacterizationMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 8 2009Ingrid W. Velthoen Abstract Aliphatic AB2 functional polyesters were conveniently prepared by the ring opening polymerization of , -caprolactone and L -lactide in the presence of the AB2 functional initiator 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) and Sn(Oct)2 as the catalyst. In L -lactide polymerization, both bis-MPA hydroxyl groups initiated the polymerization reaction, but for , -caprolactone polymerization this depended on the monomer to initiator to catalyst ratio. Initiation at two hydroxyl groups occurred at high monomer to initiator ([M]/[I]) ratio and at high Sn(Oct)2 to monomer ratio. The melting temperatures of the AB2 -functional PLLA and PCL polymers were comparable to linear polymers with a equal to the per arm in the polymer. [source] Ring opening polymerization of aliphatic cyclic carbonates in the presence of natural amino acidsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008Jiyan Liu Abstract Poly(dimethyl trimethylene carbonate) (PDTC) and poly(trimethylene carbonate) (PTMC) were synthesized by ring-opening polymerization (ROP) of dimethly trimethylene carbonate (DTC) and trimethylene carbonate (TMC) in the presence of five kinds of natural amino acids (L -alanine, L -valine, L -leucine, L -proline, and L -phenylalanine). PDTCs with number-average molecular weight (Mn) from 6700 to 18,900 g/mol and PTMCs with Mn from 7200 to 17,800 g/mol were obtained at a feed ratio of [monomer]/[L -phenylalanine] ranging from 50 to 200. The results of 1H nuclear magnetic resonance and titration proved amino acid connecting onto the polymer backbone. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Donor,Acceptor C60 -Containing Polyferrocenylsilanes: Synthesis, Characterization, and Applications in Photodiode Devices,ADVANCED FUNCTIONAL MATERIALS, Issue 3 2008Masato Nanjo Abstract A series of polyferrocenylsilane (PFS) random copolymers containing covalently bound pendant [C60]fullerene groups, the first well-characterized metallopolymers with pendant C60 units, have been prepared and characterized. The fullerene content of the prepared copolymers ranges from 7 to 24% relative to monomer unit. The desired copolymers were synthesized in three steps: metal-catalyzed ring opening polymerization of sila[1]ferrocenophanes was performed to synthesize random copolymers of poly(ferrocenylmethylphenylsilane -co- ferrocenylchloromethylsilane); the resulting random PFSs were then functionalized by reaction with 11-azido-1-undecanol to give PFSs with pendant azide groups; the desired donor,acceptor C60 -containing PFSs were then synthesized by the reaction of the azide group in the side chains with C60 in toluene at 110,°C. The resulting C60 -containing PFSs are air-stable and soluble in aromatic solvents, chloroform, or THF. The UV-vis spectra of these materials show broad absorption up to 800 nm. Thin films of these materials were examined as the active layer in rare examples of all solid-state sandwich-type diode devices based on ferrocene-fullerene dyads. The devices exhibit photoconducting and photovoltaic responses, with an open circuit potential of ca. 0.3 V under white light illumination. [source] Linear-dendritic copolymers as nanocatalystsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2009M. Adeli Abstract Functionalized poly(ethylene glycol) (PEG) containing four chloride end functional groups (PEG-Cl4) was synthesized through reaction between cyanuric chloride and PEG-(OH)2. Chloride end functional groups of PEG-Cl4 were able to initiate the ring opening polymerization of 2-ethyl-2-oxazoline and star copolymers containing a PEG core, and poly(2-ethyl-2-oxazoline) (POX) arms were obtained. Polymerization was quenched using diethanolamine, and star copolymers containing hydroxyl end functional groups (PEG-POX-OH) were obtained. ,-Caprolactone was then polymerized using the hydroxyl end functional groups of star copolymers and amphiphilic linear-dendritic copolymers containing PEG and POX, and poly(caprolactone) (PCL) blocks were synthesized. Linear-dendritic copolymers were able to load the organic and inorganic guest molecules. Application of host-guest systems such as nanocatalyst for Heck chemical reaction was also investigated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Biodegradable poly(vinyl alcohol)- graft - poly(,-caprolactone) comb-like polyester: Microwave synthesis and its characterizationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2007Zhaoju Yu Abstract Poly(vinyl alcohol)-initiated microwave-assisted ring opening polymerization of ,-caprolactone in bulk was investigated, and a series of poly(vinyl alcohol)- graft -poly(,-caprolactone) (PVA- g -PCL) copolymers were prepared, with the degree of polymerization (DP) of PCL side chains and the degree of substitution (DS) of PVA by PCL being in the range of 3,24 and 0.35,0.89, respectively. The resultant comb-like PVA- g -PCL copolymers were confirmed by means of FTIR, 1H NMR, and viscometry measurement. The introduction of hydrophilic backbone resulted in the decrease in both melting point and crystallization property of the PVA- g -PCL copolymers comparing with linear PCL. With higher microwave power, the DP of PCL side chains and DS of PVA backbone were higher, and the polymerization reaction proceeded more rapidly. Both the DP and monomer conversion increased with irradiation time, while the DS increased first and then remained constant. With initiator in low concentration, the DP and DS were higher, while the monomer was converted more slowly. Microwaves dramatically improved the polymerization reaction in comparison of conventional heating method. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104, 3973,3979, 2007 [source] Synthesis and degradation of biomedical materials based on linear and star shaped polyglycidolsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 13 2009Helmut Keul Abstract Linear and star shaped polyglycidols (synonym with polyglycerols) are prepared in a controlled ring opening polymerization of protected glycidols. Beside the molar mass and the polydispersity, the architecture of the polyglycidols is controlled by using mono- and multifunctional mono- and polydispers initiators. Copolymers of dissimilarly protected glycidols as well as copolymers with nonfunctional oxiranes were prepared by means of anionic polymerization while copolymers of protected glycidol with tetrahydrofuran were prepared by means of cationic polymerization. Polyethers with functional groups in the side chains (functional polyethers) with special emphasis on polyglycidols (containing hydroxymethyl groups in the side chains) were used to prepare multifunctional polymers and (hetero)grafted polymer brushes via chemical and enzyme catalyzed reaction. The potential of poly(glycidol- graft -,-caprolactone)- co -glycidol) prepared via enzyme catalyzed grafting of polyglycidols using ,-caprolactone as a monomer and Lipase B from Candida antarctica as a catalyst is presented. Finally, comparative degradation studies of densely and loosely grafted polyglycidols are presented and discussed. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3209,3231, 2009 [source] Poly(styrene- b -tetrahydrofuran)/clay nanocomposites by mechanistic transformationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 8 2009Zuleyha Yenice Abstract Synthesis of poly(styrene- block -tetrahydrofuran) (PSt- b -PTHF) block copolymer on the surfaces of intercalated and exfoliated silicate (clay) layers by mechanistic transformation was described. First, the polystyrene/montmorillonite (PSt/MMT) nanocomposite was synthesized by in situ atom transfer radical polymerization (ATRP) from initiator moieties immobilized within the silicate galleries of the clay particles. Transmission electron microscopy (TEM) analysis showed the existence of both intercalated and exfoliated structures in the nanocomposite. Then, the PSt- b -PTHF/MMT nanocomposite was prepared by mechanistic transformation from ATRP to cationic ring opening polymerization (CROP). The TGA thermogram of the PSt- b -PTHF/MMT nanocomposite has two decomposition stages corresponding to PTHF and PSt segments. All nanocomposites exhibit enhanced thermal stabilities compared with the virgin polymer segments. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2190,2197, 2009 [source] Dendrimer-like miktoarm star terpolymers: A3 -(B-C)3 via click reaction strategyJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 17 2008Ozcan Altintas Abstract Two samples of dendrimer-like miktoarm star terpolymers: (poly(tert -butyl acrylate))3 -(polystyrene-poly(,-caprolactone))3 (PtBA)3 -(PS-PCL)3, and (PS)3 -(PtBA-poly(ethylene glycol)3 were prepared using efficient Cu catalyzed Huisgen cycloaddition (click reaction). As a first step, azido-terminated 3-arm star polymers PtBA and PS as core (A) were synthesized by atom transfer radical polymerization (ATRP) of tBA and St, respectively, followed by the conversion of bromide end group to azide. Secondly, PS-PCL and PtBA-PEG block copolymers with alkyne group at the junction as peripheral arms (B-C) were obtained via multiple living polymerization mechanisms such as nitroxide mediated radical polymerization (NMP) of St, ring opening polymerization (ROP) of ,-CL, ATRP of tBA. Thus obtained core and peripheral arms were linked via click reaction to give target (A)3 -(B-C)3 dendrimer-like miktoarm star terpolymers. (PtBA)3 -(PS-PCL)3 and (PS)3 -(PEG-PtBA)3 have been characterized by GPC, DSC, AFM, and SAXS measurements. (PtBA)3 -(PS-PCL)3 did not show any self-organization with annealing due to the miscibility of the peripheral arm segments. In contrast, the micro-phase separation of the peripheral arm segments in (PS)3 -(PtBA-PEG)3 resulted in self-organized phase-separated morphology with a long period of , 13 nm. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5916,5928, 2008 [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] One-pot preparation of 3-miktoarm star terpolymers via click [3 + 2] reactionJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2007Ozcan Altintas Abstract The preparation of 3-miktoarm star terpolymers using nitroxide mediated radical polymerization (NMP), ring opening polymerization (ROP), and click reaction [3 + 2] are carried out by applying two types of one-pot technique. In the first one-pot technique, NMP of styrene (St), ROP of ,-caprolactone (,-CL), and [3 + 2] click reaction (between azide end-functionalized poly(ethylene glycol) (PEG-N3)/or azide end-functionalized poly(methyl methacrylate) (PMMA-N3) and alkyne) are carried out in the presence of 2-(hydroxymethyl)-2-methyl-3-oxo-3-(2-phenyl-2-(2,2,6,6-tetramethylpiperidin-1-yloxy)ethoxy) propyl pent-4-ynoate, 2, as an initiator for 48 h at 125 °C (one-pot/one-step). As a second technique, NMP of St and ROP of ,-CL were conducted using 2 as an initiator for 20 h at 125 °C, and subsequently PEG-N3 or azide end-functionalized poly(tert -butyl acrylate (PtBA-N3) was added to the polymerization mixture, followed by a click reaction [3 + 2] for 24 h at room temperature (one-pot/two-step). The 3-miktoarm star terpolymers, PEG-poly(,-caprolactone)(PCL)-PS, PtBA-PCL-PS and PMMA-PCL-PS, were recovered by a simple precipitation in methanol without further purification. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3588,3598, 2007 [source] Systematic MALDI-TOF CID Investigation on Different Substituted mPEG 2000MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 6 2010Katrin Knop Abstract Methoxy poly(ethylene glycol) 2000 (mPEG 2000) samples were substituted via esterification reactions to convert the hydroxyl end group of the mPEG into potential initiators for the cationic ring opening polymerization of 2-oxazolines. These substitution products were investigated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS); in addition, detailed MALDI-TOF/TOF-collision induced dissociation (CID) MS studies were performed to introduce this method as complementary structural characterization tool allowing the detailed analysis of the prepared macromolecules. The CID of the macroinitiators revealed 1,4-hydrogen and 1,4-ethylene eliminations forming very regular fragmentation patterns which showed, depending on the end groups, different fragmentation series. Furthermore, very pronounced McLafferty,+,1 rearrangements (1,5 hydrogen-transfer) of the introduced ester end groups were observed leaving the mPEG molecule as neutral acid. This incisive loss revealed the exact molar mass for each end group and, therefore, represents an important tool for end group determination of functionalized polymers. [source] Organic,Inorganic Interactions in Poly(trimethylene carbonate),Titania HybridsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 21 2009Elisa Cortecchia Abstract Polycarbonate,titania hybrids have been synthesized by a sol,gel reaction, starting from poly(trimethylene carbonate) (PTMC) and titanium isoproproxide in different ratios. PTMC with a given chain length was obtained by ring opening polymerization. FT-IR spectra reveal the presence of TiOC covalent bonds between organic and inorganic phases, and their number increases with increasing inorganic phase content. Solvent extractions show that hybrid soluble fraction contains low PTMC chains with isopropoxide ends, which suggests that TiOC bond formation is mainly promoted by transesterification reactions of isopropyl alcohol onto the polymer chain, catalyzed by Ti compounds. Hybrid thermal properties reflect the combined effect of the decrease of PTMC molecular weight and of bond formation between PTMC and the inorganic network. The nanometric dimension of the TiO2 domains, confirmed by atomic force microscopy, provides optically transparent hybrids. [source] AB2 Functional Polyesters via Ring Opening Polymerization: Synthesis and CharacterizationMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 8 2009Ingrid W. Velthoen Abstract Aliphatic AB2 functional polyesters were conveniently prepared by the ring opening polymerization of , -caprolactone and L -lactide in the presence of the AB2 functional initiator 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) and Sn(Oct)2 as the catalyst. In L -lactide polymerization, both bis-MPA hydroxyl groups initiated the polymerization reaction, but for , -caprolactone polymerization this depended on the monomer to initiator to catalyst ratio. Initiation at two hydroxyl groups occurred at high monomer to initiator ([M]/[I]) ratio and at high Sn(Oct)2 to monomer ratio. The melting temperatures of the AB2 -functional PLLA and PCL polymers were comparable to linear polymers with a equal to the per arm in the polymer. [source] Photochemically Cross-linked Poly(aryl ether ketone) RingsMACROMOLECULAR RAPID COMMUNICATIONS, Issue 23 2006Ian Teasdale Abstract Summary: Macrocyclic phenyl ether ketones were prepared via pseudo high dilution condensation. Irradiation of these rings with UV light in a solution containing isopropyl alcohol as hydrogen donor resulted in a photo-induced reduction of benzophenone to benzopinacol and the formation linked macrocycles. These rings can be heated to undergo ring-opening polymerization and produce a polymer network or they can be added to a polycondensation reaction to prepare poly(ether ether ketones) with variable degrees of cross-linking. Photochemical cross-linking of PEK rings and ring opening polymerization (n: 2,6). (a) h,, iPrOH, DCM; (b) CsF, 260,°C (polymer 3); (c) 4,4,,difluorobenzophenone, hydroquinone, diphenylsulphone, K2CO3, 260,°C (2% polymer 4; 6% polymer 5). [source] Iron(III) and Zinc(II) Calixarene Complexes: Synthesis, Structural Studies, and Use as Procatalysts for ,-Caprolactone PolymerizationCHEMISTRY - AN ASIAN JOURNAL, Issue 3 2010Abdessamad Arbaoui Dr. Abstract Treatment of the heterobimetallic iron(II) alkoxides [(THF)MFe(OtBu)3]2 with p - tert -butylcalix[4]areneH4 (L1H4) affords the oxo-bridged diiron(III) complexes {Fe[M(NCMe)x]2L1}2(,-O), M=Na, x=2 1,8(CH3CN), M=,K, x=3 2,3.5(CH3CN); similar use of p - tert -butylcalix[6]areneH6 (L2H6) afforded [{Fe2(,-O)Na2(OH2)(NCMe)2L2}2][{Fe2(,-O)Na(OH2)(NCMe)6L2}2]2,[Na(NCMe)5]22+3,9.46(CH3CN) and [{Fe2(,-O)L2(K(NCMe)2)2}2] 4,10.8(MeCN), respectively. In the case of 4, a minor product {(L22Fe8O8)[K(NCMe)1.5K(H2O)(NCMe)2.5]2} 5,6(CH3CN), which is comprised of chains of (L22Fe8O8) clusters bridged by K/MeCN fragments, is also isolated. Use of p - tert -butylcalix[8]areneH8 (L3H8) and two equivalents of [(THF)KFe(OtBu)3]2 affords [(K2(,-NCCH3)4(,-OH2))2(Fe2(,-O)L3H2)2(CH3CN)2] 6,9(CH3CN). In the case of p - tert -butyltetrahomodioxacalix[6]areneH6 (L4H6), reaction with [(THF)MFe(OtBu)3]2 (two equivalents) leads to isolation of the pseudoisomorphic complexes [M2(CH3CN)4L4Fe2(,-O)].4CH3CN M=Na 7,4(CH3CN), M=K 8,2(CH3CN); similar use of p - tert -butylhexahomotrioxacalix[3]areneH3 (L5H3) led to [Na2Fe2(,-OH)2(L5)2(CH3CN)4] 9,2(CH2Cl2). The complex [L4(ZnEt)4Zn2(CH3CN)4(,-OEt)2], 10,2(CH3CN), isolated from the reaction of L4H6 and ZnEt2 is also reported. Complexes 1,10 are structurally characterized (partially in the case of 4) and screened (not 5) as catalysts for the ring opening polymerization of ,-caprolactone. [source] | ||||||||||