bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of some acrylic monomer/sulfur dioxide copolymers
Authors: Tsonis Christos P. , Ali Sk. Asrof , Wazeer Mohammed I. M. , Abdennabi Abdul M. 
Published: April 2003

AbstractThe copolymerization of acrylic monomers (M) [acrolein (AL), methyl acrylate (MA), acrylamide (AM) and acrylonitrile (AN)] with liquid sulfur dioxide (S) at low temperature and high dilution in the presence of tert‐butyl hydroperoxide gives high SO2 incorporation into the resulting copolymers. Analysis of the composition of these polysulfones, by elemental analyses and 13C NMR, shows that they consist mostly of the MMM, SMM, MMS and MSM triad monomer sequences. Thermal (TG) analyses of selected samples demonstrate that their thermal stability, up to 30% weight loss, increases for different acrylic comonomers as follows: AL < AM < MA < AN. Preliminary flammability tests revealed that flame retardancy increases with increasing SO2 content in the copolymer.
Controlled synthesis of α,β‐difunctional poly(hexafluoropropylene oxide)
Authors: Ding Ji‐Feng , Proudmore Martin , Mobbs Richard H. , Khan A. Rashid , Price Colin , Booth Colin 
Published: April 2003

AbstractAn improved method is described for the preparation of difunctional poly(hexafluoropropylene oxide) of moderate molecular weight (Mn ≈ 6000) in good yield (>80 wt.‐%). With the dependence of chain transfer constant on initiator concentration known, at least under controlled conditions, good molecular‐weight control can be achieved.
Synthesis and 1H NMR study of aromatic poly(amide‐thioether)s
Authors: Nykolyszak Tania , Fradet Alain , Maréchal Ernest 
Published: April 2003

AbstractThe synthesis of aromatic poly(amide‐thioether)s by reaction between 4,4′‐thiodianiline, 4,4′‐thiodibenzoic acid and 4‐(4‐aminophenylthio)benzoic acid is studied. Depending on the initial monomer ratio, polymers with head‐to‐head, head‐to‐tail or statistical distribution of amido groups along the polymer chains were obtained. Corresponding triads effects were observed in the 1H NMR spectra and assigned. The synthesis of the same aromatic poly(amidethioether)s by reaction between dichlorobenzanilides and Na2S is also studied. Only the Cl substituents in para position to a carbonyl groups are reactive and a head‐to‐head poly(amidethioether) was obtained by reaction of N,N′‐thiobis(1,4‐phenylene)‐di‐4‐chlorobenzamide (2f) with Na2S.
Sequencing analysis and study of substituent effects in aromatic poly(amide‐thioether)s by 13C NMR spectroscopy
Authors: Nykolyszak Tania , Fradet Alain , Maréchal Ernest 
Published: April 2003

AbstractPoly(amide‐thioether)s with different microstructures are studied by 13C NMR spectroscopy. Alternating copolymers with head‐to‐head or tail‐to‐head arrangement of amido groups in the chain give quite different NMR spectra which are assigned. The spectra of statistical copolymers exhibit resonances which are not present in the spectra of alternating copolymers due to the existence of new triads. The study of chemical shift differences between the alternating copolymers and copolymers with 4‐iminobenzoyl, terephthaloyl or 1,4‐diiminophenylene units show that these sequencing effects are transmitted through S links but not through CONH links. This was explained by the participation of the sulfur atom in the mesomeric system of the two neighbouring 1,4‐phenylene groups.
Radical polymerization and copolymerization of bis{3‐[tris(trimethylsiloxy)silyl]propyl} fumarate
Authors: Otsu Takayuki , Yoshioka Masahiro 
Published: April 2003

AbstractRadical polymerization and copolymerization of bis{3‐[tris(trimethylsiloxy)silyl]propyl} fumarate (BSPF (1)) were investigated. The reactivity of BSPF in homopolymerization was found to be very low, and only low‐molecular‐weight poly(BSPF) was obtained in low yields. On the other hand, copolymerizations of BSPF with diisopropyl fumarate (DiPF) and di‐tert‐butyl fumarate (DtBF) proceed with moderate rates to give high‐molecular‐weight copolymers. The monomer reactivity ratios were determined to be as follows; r1 = 0,07, r2 = 0,87 for BSPF (M1) and DiPF (M2); r1 = 0,21, r2 = 0,67 for BSPF (M1) and DtBF (M2). The resulting copolymers are soluble in many common organic solvents. Tough and brittle films were obtained by solution casting of the copolymers of BSPF and DtBF. The copolymers exhibit excellent oxygen permeability.
Swellable polymeric networks with star‐like branching points from styrene, acrylonitrile and multifunctional cyclosiloxanes
Authors: Koβmehl Gerhard , Fluthwedel Andrea , Schäfer Horst 
Published: April 2003

AbstractCyclosiloxanes with four and six vinyl groups, 2,4,6,8‐tetramethyl‐2,4,6,8‐tetravinylcyclotetra‐siloxane (2a) and 2,2,4,4,6,6‐hexavinylcyclotrisiloxane (2b), were copolymerized with styrene and acrylonitrile, both in bulk and under special preparation conditions, to yield macroporous polymers. The reproducible sorption properties of the obtained materials in several organic solvents (with swelling degrees up to 1828% for toluene and 98% for phenol) were compared with networks from styrene and acrylonitrile cross‐linked with p‐divinylbenzene (DVB) (with swelling degrees up to 637% for toluene and 80% for phenol). Macroporous polymer networks cross‐linked with DVB exhibit considerably smaller pore diameters than those cross‐linked with 2a or 2b.
Size control of poly(methyl methacrylate) particles by dispersion polymerization in polar media
Authors: Kobayashi Shiro , Uyama Hiroshi , Matsumoto Yasuhiro , Yamamoto Ikuo 
Published: April 2003

AbstractDispersion polymerization of methyl methacrylate (MMA) in aqueous methanol solution was carried out using poly[(propionylimno)ethylene] (PPIE) as a steric stabilizer. The dispersion polymerization in the aqueous methanol solution (methanol: water = 70:30 wt.‐%) gave monodisperse particles in the micrometer range. The diameter of the particles decreased as the molecular weight and the concentration of PPIE increased. Effects of other polymerization parameters, such as monomer and initiator concentrations, solvent composition, and addition of methyl 2‐methylpropionate, on the size and size distribution of the particles were examined.
Multiblock poly(ether‐ester‐amide)s based on polyamide‐6 and poly(ethylene glycol), 1. Effect of polyether segment length on the properties of poly(ether‐ester‐amide)s with various polyamide/polyether ratios
Authors: Fakirov Stoyko , Goranov Konstantin , Bosvelieva Eliana , Du Chesne Alexander 
Published: April 2003

AbstractA series of multiblock poly(ether‐ester‐amide)s (PEEA) based on polyamide‐6 (PA6) and poly(ethylene glycol) (PEG) is synthesized in a two‐step process. The first step represents the hydrolytic polymerization of ε‐caprolactam (CL) in the presence of adipic acid (AA) to carboxyl‐terminated PA6 oligomers of different chain lengths and the second is their polycondensation with PEG of molecular weights 420 (PEG 400) and 1150 (PEG 1000) in the presence of catalyst and thermostabilizer. The formation of the new ester bond between PA6 and PEG is proved by infrared spectroscopy. The content of the hard (PA6) and the soft (PEG) segments in the copolymer is determined by 1H NMR and elemental analysis. The shift in glass transition temperature Tg above that of pure PEG and the depression of the melting temperature Tm assigned to PA6 are characteristic for phase‐separated block copolymers. The degree of crystallinity of the PA6 component does not seem to be affected by the actual weight composition but depends on the different segment lengths. For the copolymers containing PEG‐1000 it is close to that of the respective homopolymer PA6. The tensile parameters of the copolymers studied are similar to those of available PEEA products.
New comb‐like polymers with prospective nonlinear optical properties
Authors: Combellas Catherine , Petit Michel A. , Thiébault André , Froyer Gérard , Bosc Dominique 
Published: April 2003

AbstractNew methacrylic copolymers with prospective second‐order nonlinear optical effects are synthesized by radical copolymerization of methyl methacrylate with conjugated zwitterionic methacrylate monomers (2,6‐di‐tert‐butyl‐4‐[1‐(ω‐methacryloyloxyalkyl)‐4‐pyridino]phenolates,1a and 1b). These monomers are obtained via a multi‐step reaction. First, 4‐(3,5‐di‐tert‐butyl‐4‐hydroxyphenyl)pyridine (2) is electrosynthesized by an SRN1 reaction in liquid ammonia. Then, this pyridine derivative is N‐alkylated by an ω‐bromoalkyl methacrylate (5a or 5b) which, in its turn, is obtained by esterification of an ω‐bromoalcohol and methacryloyl chloride.
Transition kinetics of smectic liquid‐crystalline polyesters
Authors: Tsai Ruey‐Shi , Tsai Hong‐Bing , Hu Andrew Teh , Lee Yu‐Der 
Published: April 2003

AbstractTwo smectic main‐chain liquid‐crystalline polyesters containing biphenyl as mesogen and spacers with 8 and 18 methylene carbon atoms were prepared, and their transition kinetics were investigated by means of differential scanning calorimetry (DSC). The isothermal liquid‐crystallization was analyzed using the Avrami equation. The Avrami exponent n was found to be 2 to 4 indicating that the liquid‐crystallization of these two smectic polyesters would be a process of two‐to three‐dimensional growth rather than of one‐dimensional growth as for nematic liquid‐crystalline polymers. The nonisothermal liquid‐crystallization and crystallization were also analyzed by means of DSC. The crystallization from the smectic phase was found to be a very fast process and the supercooling of crystallization was small. Thus, the smectic phase might nucleate crystallization. The transition kinetics of these two smectic polyesters are considerably different from those of nematic liquid‐crystalline polymers due to the different orders of the liquid‐crystalline phases.
New perfluoroalkyl telomeric non‐ionic surfactants: synthesis, physicochemical and biological properties
Authors: Pavia André A. , Pucci Bernard , Riess Jean G. , Zarif Leila 
Published: April 2003

AbstractBoth the experimental conditions and the kinetic parameters governing the telomerization of hydroxy‐functional acryloyl derivatives in the presence of perfluoroalkanethiols were determined with the purpose of synthesizing new amphiphilic telomers with high surface activity for the preparation of stable perfluoro emulsions capable of carrying oxygen in vivo. Several perfluoro‐alkylated non‐ionic telomeric surfactants (FmTACn) were obtained in one step with an average yield of 80%, by free‐radical telomerization of tris(hydroxymethyl)acrylamidomethane in the presence of various perfluoroalkanethiols as chain‐transfer reagents. Surface activity, critical micelle concentration and emulsifying capability established the superiority of the FmTACn surfactants over Pluronic® F68, the major surfactant used presently in the FDA‐approved injectable fluorocarbon emulsion: Fluosol®.
Influence of intermolecular interactions on phase behaviour and miscibility of para‐linked aromatic polyesters with polycarbonate and mechanical properties of the blends
Authors: Land Horst‐Tore , Heitz Walter , Karbach Alexander , Pielartzik Harald 
Published: April 2003

AbstractThe synthesis of aromatic liquid‐crystalline polyesters soluble in common organic solvents is described. The polyesters carry methyl, tert‐butyl, phenyl and 4‐biphenyl substituents. The polyesters with biphenyl substituents have an isotropization temperature below 300°C. Blends of these polyesters with polycarbonate show one glass transition temperature in differential scanning calorimetry whereas transmission electron microscopy indicates a homogeneous dispersion of the polyester in the polycarbonate, but not on a molecular level. The moduli of the components of the blends are additive.
Bis(dialkylamino)‐substituted isopropenyltriazines: effect of the length of the alkyl chains on the polymerization as well as on the properties of the resulting comb‐like polymers
Authors: Kunisada Hideo , Yuki Yasuo , Kondo Shuji , Goto Ken‐ichi 
Published: April 2003

AbstractNew isopropenyltriazines, e.g., 2‐diethylamino‐4‐dimethylamino‐6‐isopropenyl‐1,3,5‐triazine (2a) and 2‐dimethylamino‐4‐dioctadecylamino‐6‐isopropenyl‐1,3,5‐triazine (2b) were prepared by the alkylation reaction of 2‐amino‐4‐dimethylamino‐6‐isopropyl‐1,3,5‐triazine (1) with corresponding alkyl halides in the presence of sodium hydride. In the free‐radical homopolymerization of these monomers, the polymerization yield of 2b was lower than that of 2a due to a lower ceiling temperature. Copolymerizations of these monomers with styrene and methyl methacrylate were carried out, and monomer reactivity ratios (r1 and r2) were determined. The monomer reactivity decreases by the introduction of two octadecyl groups into the monomer. Exothermic crystallization and endothermic melting peaks based on the octadecyl side chains were observed in differential scanning calorimetry of the resulting comb‐like polymers. The thermal stability of the polymers is not affected by the long alkyl groups.
Synthesis and characterization of homo‐ and co‐oligomers of tetracyclo[4.4.0.12,5.17,10]dodecene‐3 by cationic polymerization
Authors: Sagane Toshihiro , Mizuno Akira , Takata Toshimasa 
Published: April 2003

AbstractCationic homopolymerization of tetracyclo[4.4.0.12,5.17,10]dodecene‐3 (TCD) and its copolymerization with styrene (St) were carried out with the catalyst system Al(C2H5)Cl2/tert‐butyl chloride, and the effects of temperature and TCD/St feed ratio, on polymer solubility, molecular weight and glass transition temperature (Tg) were investigated. A soluble oligomer with a molecular weight of 1000 was prepared by homopolymerization of TCD at +10°C or by copolymerization with St (>4 mol‐% in the feed) at −50°C. 13C NMR analysis of the TCD homo‐ and TCD/St copolymers revealed both 3,4‐ and 3,11‐additions for the repeating units from TCD. A polymerization mechanism including initiation, propagation, termination (deprotonation), and further crosslinking reactions is proposed. Moreover, it was demonstrated that a TCD/St copolymer with a controlled Tg in the range of 100 to 260°C can be prepared by selecting the TCD/St composition.
Preparation and co‐catalytic properties of amphiphilic diblock copolymers consisting of polystyrene and ionene
Authors: Schipper Eugène T. W. M. , van Hest Jan C. M. , Piet Pieter , German Anton L. 
Published: April 2003

AbstractWell defined amphiphilic diblock copolymers, consisting of an oligomeric quaternary ammonium block, a so‐called ionene, and a polystyrene block, were synthesized. The route started with the preparation of monofunctionalized polystyrene by anionic polymerization, using 3‐(dimethyl‐amino)propyllithium as initiator. The polystyrene was obtained with relatively narrow molecular weight distributions (M̄w/M̄n = 1,2–1,4). This polystyrene was coupled stepwise with a number of different monodisperse oligomer units of 2,4‐ionene, having reactive end‐groups, resulting in a monodisperse 2,4‐ionene block. End‐group titration, size exclusion chromatography, thin‐layer chromatography and infrared spectroscopy were utilized to characterize the polymers. Additionally the block copolymer in combination with tetrasodium phthalocyaninatocobalt(II)tetrasulfonate (CoPc(NaSO3)4) was tested as co‐catalyst in the phase‐transfer‐catalyzed autoxidation of 1‐dodecanethiol. Very high catalytic activities (775 mol O2/(mol Co · s)) were achieved, 40 times higher as compared with the polymer‐free system, due to a combination of the formation of the most active species and hydrophobic interaction with the hydrophobic thiol. This hydrophobic interaction resulted in an enhancement of the autoxidation rate by a factor 2,5, compared with the analogous hydrophilic homopolymer 2,4‐ionene.
Sulfur‐containing optically active polymers, 1. Synthesis and chiroptical properties of poly(γ‐ketosulfide)s derived from (−) (2R, 3R)‐1,4‐dimercapto‐2,3‐butanediol
Authors: Angiolini Luigi , Carlini Carlo , Salatelli Elisabetta 
Published: April 2003

AbstractThe synthesis of optically active poly(γ‐ketosulfide)s from bis‐Mannich bases or α,β,α′,β′‐unsaturated ketones and (−) (2R, 3R)‐1, 4‐dimercapto‐2,3‐butanediol, is described. The corresponding low‐molecular‐weight analogs were also synthesized. The products were fully characterized and their stereochemical features investigated by NMR. The relations between chiroptical and conformational properties in solution were also studied by circular dichroism measurements. Although an appreciable local asymmetric induction on the chromophores belonging to the starting achiral co‐reagent is observed, the macromolecules do not display any occurrence of ordered secondary structures due to a low stereoregularity degree orginated by the presence of randomly distributed constitutional repeating units having different diastereomeric configurations.
Intrinsic viscosity versus molar mass relationship of poly(3‐hexylthiophene) in toluene
Authors: Bi Xiping , Ying Qicong , Qian Renyuan 
Published: April 2003

AbstractThe Mark‐Houwink‐Sakurada equation for poly(3‐hexylthiophene) (PHTh) in toluene has been determined from seven fractions of a chemically polymerized sample: [η] = 1,312 . 10−2 M0,77. The polymer chain turned out to be rather flexible, and a persistence length of 25 Å was obtained from a Bohdanecky treatment of the Yamakawa‐Fujii theory for a worm‐like cylinder. In order to reconcile the conjugation length of six monomeric units (23,4 Å along the backbone) and the statistical Kuhn length of 50 Å, a block copolymer model of rigid coplanar segments of six monomeric units and flexible segments, involving many successive rotating inter‐ring bonds, has been proposed for the PHTh chain in solution.
Metathesis polymerization behavior of 2‐cyanobicyclo[2.2.1]hept‐5‐ene
Authors: Asrar J. , Curran Sean A. 
Published: April 2003

AbstractThis paper describes the ring‐opening methathesis polymerization of homopolymers and copolymers of exo‐ and endo‐2‐cyanobicyclo[2.2.1]hept‐5‐ene (norbornenenitrile) in solution. Polymerization kinetics were followed via 1H NMR spectroscopy in real time while the final polymer microstructure was determined via 13C NMR. While pure endo monomer does not polymerize readily, it copolymerizes with exo monomer, rapidly and to high conversions. The structure of the copolymer appears to be quite similar to that of exo homopolymer. We conclude that exo monomer adds directly to either exo or endo, while endo‐endo addition is sterically hindered.
Synthesis of functional unsaturated polyesters using rare earth coordination catalysts, 3. Mechanistic aspects of maleic anhydride‐epichlorohydrin copolymerization with Nd[(RO)2 PO2]3/Al[CH2CH(CH3)2]3 as a catalyst
Authors: Chen Xianhai , Zhang Yifeng , Shen Zhiquan 
Published: April 2003

AbstractRing‐opening alternating copolymerization of maleic anhydride and epichlorohydrin was carried out at 70°C with rare earth coordination catalysts composed of Nd[(RO)2 PO2]3 (R = CH3(CH2)3CH(C2H5)CH2)and trialkylaluminium. Anlaysis of end‐groups showed that the copolymer chain contains one OH and one CHCHCOCH2CH(CH3)2 end‐group. IR, UV‐Vis, 1H NMR and GPC results imply that a catalyst‐maleic anhyride complex is formed in the initiation step that the ring‐opening copolymerization proceeds via coordinate insertion mechanism accompanied with chain‐transfer.
Sucrose‐based polymers, 1. Linear polymers with sucrose side‐chains
Authors: Jhurry Dhanjay , Deffieux Alain , Fontanille Michel , Betremieux Isabelle , Mentech Julio , Descotes Gérard 
Published: April 2003

AbstractPolymers and copolymers based on the monomethacryloyl ester and the vinylbenzyl ether of sucrose, bearing either blocked or free hydroxyl groups, were synthesized in the presence of free‐radical catalysts, and their structures and dimensions were characterized. A range of copolymers of styrene and O‐methacryloylsucrose was prepared. Reactivity ratios of the comonomers were calculated by the extended Kelen‐Tüdős method. The influence of the hydroxyl groups of the sucrose moiety on the thermomechanical properties was assessed by comparing the glass transition temperatures of both blocked and unblocked copolymers. Their solubility characteristics were also determined, and it was shown that the hydrophilic‐hydrophobic properties can be controlled by the amount of sucrose methacrylate in the copolymer.
Preparation of the precursors of new tannin‐like polymers with potential biological effects
Authors: Yuan Hui Liang , Fei Bi Hua , Párkányi Cyril , Caple Gerald , Eastman Michael P. , Loy Douglas A. 
Published: April 2003

AbstractNew acrylate based polymers, with the potential to be converted to polyphenolic polymers — poly[2‐(4‐benzyloxyphenyl)ethyl acrylate] (4) and poly[3‐(4‐benzyloxy‐3‐methoxyphenyl)propyl acrylate] (9) — were prepared from the corresponding monomers 3 and 8 by free‐radical polymeri‐ zation, initiated by 2,2′‐azoisobutyronitrile (AIBN). The acrylate monomers, 2‐(4‐benzyloxy‐ pheny1)ethyl acrylate (3) and 3‐(4‐benzyloxy‐3‐methoxyphenyl)propy1 acrylate (8), were synthes‐ ized from acryloyl chloride and the corresponding alcohols — 2‐(4‐benzyloxyphenyl)ethanol(2) and 3‐(4‐benzyloxy‐3‐methoxyphenyl)‐ 1 ‐propano1 (7), respectively. The monomer 7 was prepared from 3‐(4‐benzyloxy‐3‐methoxyphenyl)‐1‐propene (6) by hydroboration/oxidation and 6 was obtained from eugenol(4‐allyl‐2‐methoxyphenol) as the starting material. The compounds were characterized by1H NMR,13C NMR, FTIR, and elemental analyses. The molecular weight of the synthesized polymers was determined by gel‐permeation chromatography (GPC).
Synthesis of frequency doubling polymeric materials, 1. Second‐order nonlinear optical properties of poled chromophore‐functionalized polymethacrylates
Authors: Rondou Philippe , Beylen Marcel Van , Samyn Celest , S'Heeren Gert , Persoons Andre 
Published: April 2003

AbstractThe synthesis and second harmonic coeficients d33, d 31 and the susceptibilities χ(2) are reported of three series of (co)polymethacrylates that possess 4‐(2,2‐dicyanovinyl)‐ or 4‐(2‐cyano‐2‐methoxycarbonyl)vinyl‐N,N‐dialkylaniline (P1 and P2), 4‐(2,2‐dicyanovinyl)‐ or 4‐(2‐cyano‐2‐methoxycarbonyl)vinyl‐(‐piperidino)benzene (P5 and P6) and 4‐(2,2‐dicyano)‐ or 4‐(2‐cyano‐2‐methoxycarbonyl)vinyl‐1‐alkoxybenzene (P3 and P4) dyesSystem. names of the monomers see Exptl. part.
. The second‐order nonlinear optical properties of corona‐poled aligned polymer films were evaluated by second harmonic generation measurements. The χ values for the P1 and P2 polymers vary from 58 to 318, respectively 32 to 106 · 10−9 esu, for P3 and P4 from 7,6 to 19, respectively 4,4 to 7,4 · 10 −9 esu and for P5 and P6 from 219 to 42,8 respectively 28,1 to 8,1 · 10−9 esu, depending on the dye chromophore concentration incorporated in the polymer structure.
The formation of oligomers in the inhibited thermal copolymerisation of styrene and acrylonitrile
Authors: Schellenberg Jürgen , Wigand Günter 
Published: April 2003

AbstractThe formation of oligomers up to molecular weights as high as about 800 was investigated in the iodine‐ and 4‐nitrosophenol‐inhibited thermally initiated copolymerisation of styrene and acrylonitrile by using column exclusion chromatography. In contrast to other possible approaches, such as the estimation of the rate of inhibition by analysing the inhibition period or trapping the initiating radicals through spin traps, this method offers the advantage of detecting the molecular species appearing during the inhibition reaction by directly estimating their molecular weights even in the higher ranges. A structural assignment of the discovered species is suggested and supported by the results of copolymerisation statistics. With iodine and 4‐nitrosophenol as inhibitors, the oligomers of the thermal reaction of copolymerisation initiation, the reaction products of inhibitors with initiating radicals, as well as components of a higher molecular weight were detected and classified, and the mechanisms of their formation are discussed.