bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of polymeric photosensitizers, 3. Synthesis of multifunctional polymeric photosensitizers containing pendant 4‐nitrophenoxy moieties and various kinds of quaternary phosphonium or ammonium salts and their application to the photo‐isomerization of potassium cinnamate
Authors: Nishikubo Tadatomi , Abe Koichi , Uchida Jiro 
Published: April 2003

AbstractSome multifunctional polymeric photosensitizers containing both pendant photosensitizing groups and substrate‐attracting groups were synthesized by partial substitution reaction of poly(chloromethylstyrene) with potassium 4‐nitrophenoxide under the conditions of phase transfer catalysis, followed by addition reactions of the resulting polymer with various kinds of tert‐phosphines or amines. The reactivity of tert‐phosphine was found to decrease with increasing lenght of the alkyl chain in the tert‐phosphine. However, the addition reaction of the polymer with tert‐phosphines and ‐amines proceeded quantitatively at 80°C for 48 h in DMF, respectively. The photo‐isomerization of potassium cinnamate (PCIN) was carried out using the multifunctional polymeric photosensitizers in methanolic aqueous solution. The polymeric photosensitizer (polymer 3) containing the small and hydrophilic substrate‐attacting benzyltri‐ethylphosphonium chloride moiety showed a higher efficiency than the polymers (polymers 5 and 7) containing bulky and hydrophobic substrate‐attracting moieties like benzyltributyl‐ or benzyltrioctylphosphonium chloride. Polymer 3 has the highest efficiency at a content of 10 mol‐% of pendant 4‐nitrophenoxy (NP) moieties, and polymers 5 and 7 have their highest efficiency at a content of 15 mol‐% of pendant NP moieties. Polymeric photosensitizers containing pendant quaternary phosphonium salts as the substrate‐attracting group have a higher efficiency than the polymers containing pendant quaternary ammonium salts. Further more, the rate of photo‐isomerization of PCIN was found to be strongly affected by the concentration of the polymeric photosensitizers in solution, and also by the polarity of the reaction medium.
Liquid membranes with organic polyphosphates as ionic carriers
Authors: Narȩbska Anna , Wódzki Romuald , Wyszyńska Alicja 
Published: April 2003

AbstractPoly(hexylene phosphate) (1) and poly[poly(ethylene glycol)phosphate] (2) were examined as ionic carriers for concentration/separation processes, applying the liquid membrane technique. Experiments were performed with nickel and cobalt ions pertracted both from a single solution and bicomponent mixtures. 2, dissolved in 1,2‐dichloroethane, was found to be an effective carrier of nickel ions. The system seems to offer efficient separation of Ni(II)/Co(II) ions.
Synthesis of amphiphilic star‐shaped and graft copolymers based on polystyrene and poly(ethylene oxide)
Authors: Berlinova Iliyana V. , Panayotov Ivan M. 
Published: April 2003

AbstractAmphiphilic block macromonomers possessing a central unsaturation were synthesized by condensation of polystyrene half‐ester of maleic acid {α‐[2‐(3‐carboxyacryloyloxy)ethyl]‐ω‐sec‐butylpoly[1‐phenylethylene]} with poly(ethylene glycol) monoether or polystyrene‐block‐poly(ethylene oxide). In the radical monomer cis‐trans‐isomerization homopolymerization of the diblock macromonomers, four‐to eight‐armed amphiphilic star‐shaped copolymers were obtained. Radical copolymerization of the diblock macromonomers with styrene led to graft copolymers with low degree of grafting. The triblock macromonomers proved to be unable to polymerize.
Synthesis and characterization of processable conducting polyazomethines
Authors: Lee Kwang‐Sup , Won Jong Chan , Jung Jin Chul 
Published: April 2003

AbstractA series of the wholly aromatic polyazomethines (PAM) having flexible side chains was synthesized by solution and melt polycondensation of 2,5‐dialkoxyterephthalaldehydes and aromatic diamines. The solution polycondensation was carried out at 80°C for 24 h in 1,3‐dimethyl‐3,4,5,6‐tetrahydro‐2(1H)‐pyrimidinone (DMPU)/N‐methyl‐2‐pyrrolidone (NMP) mixtures. The melt polycondensation was conducted in N2 atmosphere at 200°C for 2,8 h. All of the polymers were soluble in CCl4, CHCl3, THF, benzene, toluene, etc. The inherent viscosity (ηinh), measured at 30°C in CHCl3, was 0,13–0,32 dL/g, and 5% weight loss in TG curves appeared at 365–390°C in N2 atmosphere. The electrical conductivities of I2‐treated dialkoxy‐substituted PAM were low, 10−4 < σ < 10−6 S/cm, compared with unsubstituted I2‐treated PAM.
Perfluoroalkylated monomers and polymers
Authors: Freund Lothar , Jung Holger , Nießner Norbert , Schmidt Hans‐Werner , Heitz Walter 
Published: April 2003

AbstractTrifluoromethyl‐, pentafluoroethyl‐ and other perfluoroalkylbenzenes (2a–d, 4 and 3) were prepared by the reaction of the corresponding aromatic halides with perfluorocarboxylic acids in the presence of copper(I) iodide. These products were modified by oxidation or (and) substitution reactions and subsequently polymerized to give perfluoroalkyl‐substituted polyamides, polyesters and poly(thio‐1,4‐phenylene)s showing good solubility.
Polymers and oligomers with substituted 2,5‐thienylene units. Preparation and electrical conductivity properties
Authors: Yamamoto Takakazu , Kashiwazaki Akio , Kato Kazunori 
Published: April 2003

AbstractNi‐catalyzed dehalogenation polycondensation of 3‐formyl‐, 3‐hydroxyiminomethyl‐ and 3‐cyano‐2,5‐dibromothiophene with zinc affords oligo(3‐formyl‐2,5‐thienylene) (2a), oligo‐(3‐hydroxyiminomethyl‐2,5‐thienylene) (2b), and oligo(3‐cyano‐2,5‐thienylene) (2c). Electrochemical polymerization of 3‐methoxythiophene and 3,4‐dimethoxythiophene give blueblack films of oligo(3‐methoxy‐2,5‐thienylene) (2d) and poly(3,4‐dimethoxy‐2,5‐thienylene) (2e). Iodine adducts of 2a–2c show electrical conductivity values between 1,8 · 10−11 and 8,8 · 10−8 S · cm−1. Doped 2d shows electrical conductivity of 2 · 10−1 S · cm−1, whereas doped 2e exhibits an electrical conductivity between 1,5 and 30 S · cm−1. Doping of undoped 2d and 2e causes profound changes in their IR and NMR spectra, colour, and electrical conductivity properties.
Etude par 1H NMR des groupements chlorométhyles du poly(chlorure de vinyle), 2. Etude par écho de spin et comparaison avec des modèles moléculaires
Authors: Llauro‐Darricades Marie‐France , Pétiaud Roger 
Published: April 2003

AbstractIn order to assign all CH2Cl resonances observed by 1H NMR in poly(vinyl chloride), (PVC), a preliminary study of the diastereoisomers of molecular models for the groups CH2ClCHCl [II] and is used, in conjunction with spin echo experiments. The complex region [3,5–4,0 ppm] which corresponds to saturated CH2Cl chloromethyl protons is completely assigned. A separate evaluation of CHClCH2Cl [II], CH2CH2Cl [III] and is proposed and tested on raw PVC samples. The main interest of this 1H NMR determination is the fact that raw PVC can be used and that it gives the ratio [II]/[III] which is not accessible by 13C NMR on reduced samples.
An example of polymer reactivity affected by the presence of another polymer
Authors: Casinos Ismael , Fernández María Jesús 
Published: April 2003

AbstractThe acid hydrolysis of the cellulose portion of cellulose‐g‐poly(vinyl acetate‐co‐methyl acrylate) was carried out. The effect of the synthetic polymer in the reaction medium on the reactivity of cellulose in its acid depolymerization was studied. It could be shown that this effect is the same whether the synthetic polymer is covalently linked to cellulose or not and it was found that the hydrolysis time needed to degrade the cellulosic part of the graft copolymer is strongly dependent on the composition of the reaction mixture. This work showed that only a restricted range of graft copolymer compositions can be hydrolyzed in the shortest reaction time here established (14h). In order to hydrolyze graft copolymer samples with different compositions to those of the cited range, in the same hydrolysis time of 14h, two methods are suggested: (a) elimination of an adequate portion of cellulose from the graft copolymer and (b) addition of an appropriate amount of synthetic polymer to the graft copolymer sample. The second method is not useful from the point of view of polymer characterization. A molecular description of the reaction medium on the basis of the system components is attempted.
Synthesis, characterization and polymerization of new epoxy compounds containing azomethine linkages
Authors: Mikroyannidis John A. 
Published: April 2003

AbstractNew epoxy compounds bearing azomethine linkages were synthesized and characterized. A series of epoxy derivatives of bis(azomethine)s (2a – d) was synthesized by reacting an aromatic diamine with 4‐hydroxybenzaldehyde in a 1:2 mole ratio to afford the corresponding bis(azomethine)s (1a – d), and subsequent reaction with excess 1‐chloro‐2,3‐epoxypropane in presence of a quarternary ammonium bromide as catalyst. In addition, epoxy compounds 4a, b and 5b were synthesized by reacting 1,4‐benzenedicarbaldehyde with 4‐aminophenol, 4‐aminobenzoic acid or 5‐aminoisophthalic acid in a 1:2 mole ratio and then with 1‐chloro‐2,3‐epoxypropane. The epoxy compounds were characterized by elemental analyses as well as by IR and 1H NMR spectroscopy. All epoxy compounds were thermally polymerized in the presence of 4,4′‐sulfonyl dianiline (6). The polymerization was investigated by DTA. The thermal stabilities of the resulting polymers were evaluated by dynamic TG and isothermal gravimetric analysis (IGA). The polymers derived from diepoxy compounds are stable in nitrogen up to 293–340°C and afford an anaerobic char yield of 43–62% at 800°C.
A formylstyrene‐styrene‐divinylbenzene resin. Synthesis, condensation reactions, and low‐molecular‐weight model compounds
Authors: Strasdeit Henry , Friedemann Marion , Pohl Siegfried , Driessen Willem L. , Reedijk Jan 
Published: April 2003

AbstractA formylated resin (1a) containing 4‐formylphenyl groups was obtained from poly[styrene‐co‐divinylbenzene (2%)] by reaction with Cl2CHOCH3/SnCl4 and subsequent hydrolysis of the intermediate. 1a reacted with N‐methyltrimethylenediamine with the formation of azomethine groups. From the nitrogen content of the product the degree of functionalization of 1a was calculated to be 50%. Condensation reactions between 1a and N‐ethylethylenediamine, cystamine, methanol, 1,2‐ethanedithiol, 2,3‐dimercapto‐1‐propanol (BAL), and 2‐aminobenzene‐thiol were also studied. A new chloromethylated resin was prepared from 1a and BAL in the presence of conc. hydrochloric acid (OH/Cl exchange). The formylation of 2,4‐diphenylpentane yielded the low‐molecular‐weight model compounds 4‐(1‐methyl‐3‐phenylbutyl)benzaldehyde (2a) and 2‐(1‐methyl‐3‐phenylbutyl)benzaldehyde (2b) in an 87:13 mole ratio, suggesting that ca. 90% of the aldehyde groups in 1a are in para‐position.
Polymers from multifunctional isocyanates, 4. Synthesis of alkylene(or arylene)bis(ω‐isocyanatocarboxamide)s and polyaddition to sequential poly(diamidodiurethane)s and poly(diamidodiurea)s
Authors: Mormann Werner , Hohn Elke 
Published: April 2003

AbstractAlkylene‐ and arylenebis(ω‐isocyanatodicarboxamide)s were obtained in high yields by regioselective reaction of isocyanatoacyl chlorides with silyl protected diamines (1,2‐ethanediamine, 1,6‐hexanediamine, piperazine, p‐ and m‐phenylenediamine). 3‐Isocyanatopropanamides undergo cyclization through intramolecular attack of the amide nitrogen by the isocyanate group to form six‐membered acylureas (5,6‐dihydro‐(1 H, 3 H)‐2,4‐pyrimidinediones), which do not react further with amines or alcohols. Poly(diamidodiurethane)s and poly(diamidodiurea)s were made from bis(isocyanatobutanamide)s and bis(isocyanatohexanamide)s by polyaddition with 1,4‐butanediol or diamines. The polymers have a regular sequence of two amido and two urethane (urea) groups; they are crystalline materials. Starting from a given diisocyanatodicarboxamide the urea melts about 40 to 60°C higher than the urethane. The poly(urethane)s from piperazine‐based diisocyanatodicarboxamides have rather low melting points due to the missing possibility of the amide group to act as hydrogen bond donor. Thermogravimetric results show higher thermostability for the poly(diamidodiurea)s than for the corresponding poly(diamidodiurethane)s and increasing thermostability with increasing length of the isocyanatoalkanamide applied.
Preparation and characterization of a series of poly[oxy‐1‐(ω‐bromoalkyl)ethylene]s
Authors: Wicks Douglas A. , Tirrell David A. 
Published: April 2003

Abstract2‐Bromoethyloxirane (2b), 3‐bromopropyloxirane (2c), and 4‐bromobutyloxirane (2d), were prepared by epoxidation of the corresponding bromoalkenes. Treatment of the oxiranes with a triethylaluminium/acetylacetone/water mixture afforded the polyethers 3b–d in good yield as tacky, white elastomers. Substitution of bromide by benzoate ion established essentially equal reactivities for the three polymers; each was substantially more reactive than any of the halogenated polyether elastomers available heretofore.
Racemic resolution of mandelic acid on polymers with chiral cavities, 4. A kinetic study
Authors: Sarhan Ali 
Published: April 2003

AbstractL‐Mandelic acid‐1,2‐O‐(4‐vinylphenyl)boronate (2) was copolymerized with divinylbenzene to yield a highly crosslinked macroporous polymer. 59% of incorporated L‐mandelic acid (used as template) could be split‐off on hydrolysis. The resulting polymer, with phenylboronic acid groups in the chiral cavities of type P1, was equilibrated in a batch process with D,L‐mandelic acid in acetonitrile. The change of covering percentage, and that of the efficiency for racemic resolution, with time were followed by acidimetric titration and measurement of the optical rotation. A reasonable mechanism for the polymer‐substrate interaction could de deduced. The selectivity terms for each of the forward and reverse reaction could be separately evaluated. Diffusional limitations significantly affect the observed efficiency of racemic resolution. Thermodynamically controlled separation, attainable by a suggested exchange reaction, required much more time than the considerably less effective kinetically controlled separation.
Copolymerizations of styrene with magnesium, calcium, strontium and barium acrylates in dimethyl sulfoxide
Authors: Gronowski Adam , Wojtczak Zbigniew 
Published: April 2003

AbstractRadical copolymerizations of styrene with acrylates of magnesium, calcium, strontium and barium were carried out in dimethyl sulfoxide. The monomer reactivity ratios were determined by the Yezrielev‐Brokhina‐Roskin and the Kelen‐Tüdős methods. In all cases the monomer reactivity ratio for styrene exceeded one and those for the salts were less than one. The Q‐values of the Alfrey‐Price scheme for the metal acrylates were within the range 0,1 − 0,2. For the values of the polarity parameter e the following sequence was found: eMgA2 < eCaA2 < eSrA2 < eBaA2 and the tendency for alternation in copolymerizations increased in the same order. The results indicate that the course of copolymerizations under study is predominantly affected by polarization of the vinyl groups in the salts.
Polymeric chiral crown ethers, 4. Substituent effects of methyl and phenyl groups in the 3,3′‐positions on chiral recognition of poly(crown ether)s synthesized by cyclopolymerization of divinyl ethers derived from 1,1′‐bi‐2‐naphthol
Authors: Kakuchi Toyoji , Hasegawa Toshiyuki , Sasaki Hiroshi , Ohmori Hiroshi , Yamaguchi Kazumi , Yokota Kazuaki 
Published: April 2003

AbstractChiral poly(crown ether)s were synthesized by cationic cyclopolymerization of (S)‐2,2′‐bis(2‐vinyloxyethoxy)‐3,3′‐dimethyl‐1,1′‐binaphthyl [(S)‐1b] and (R)‐2,2′‐bis[2‐(2‐vinyloxyethoxy)‐ethoxy]‐3,3′‐dimethyl (or 3,3′‐diphenyl)‐1,1′‐binaphthyl [(R)‐3b or (R)‐3c]. The substituents in the 3,3′‐positions of binaphthyl moiety disturb the intramolecular cyclization in the polymerization of monomer (S)‐1b, but have no influence on the cyclopolymerization tendency of monomers (R)‐3b and (R)‐3c. The polymers from (R)‐3b and (R)‐3c [(R)‐4b and (R)‐4c] have a higher ability of chiral recognition towards a‐amino acids, such as phenylglycine, phenylalanine, valine, and methionine, than the polymer from (R)‐3a [(R)‐4a], which has no substituent in 3,3′‐positions. The methyl and the phenyl substituents in the 3,3′‐positions undoubtedly act as additional barrier causing an increase in the ability of chiral recognition, though the effect is less than expected from the result of model crown ethers.
Preparation of poly(amide‐imide)s by means of triphenyl phosphite, 1. Aliphatic‐aromatic poly(amide‐imide)s based on trimellitimide
Authors: Yang Chin‐Ping , Hsiao Sheng‐Huei 
Published: April 2003

AbstractAliphatic‐aromatic poly(amide‐imide)s with high molecular weight (ηinh up to 2,91 dl/g in DMAc/5% LiCl) were synthesized by direct polycondensation reaction of imide‐containing dicarboxylic acids and aromatic diamines using triphenyl phosphite in N‐methyl‐2‐pyrrolidone (NMP)/pyridine solution in the presence of metal salts. The factors affecting the reaction of N‐(trimellitoyl)glycine and 4,4′‐oxydianiline were investigated. The molecular weight of the polymer varied with the amount of metal salts, showing a maximum at a concentration of about 1 wt.‐% CaCl2 or about 2 wt.‐% LiCl in the reaction mixture. A monomer concentration of about 0,2 mol/l gave the most favorable result. Among the solvents tested, NMP was most effective. Similarly, polycondensations of several combinations of three imide‐diacids with various aromatic diamines were carried out. Solubility, thermal properties, and tensile properties of the polymers are discussed.
Terpolymerization of sulfur dioxide with maleic anhydride and vinyl monomers
Authors: Florjańczyk Zbigniew , Raducha Dorota , Zygadło Ewa 
Published: April 2003

AbstractThe free radical polymerization in ternary systems comprising sulfur dioxide, maleic anhydride and vinyl monomers, such as ethylene, propene, 2‐methylpropene, 1‐hexene, 1,3‐butadiene, styrene, α‐methylstyrene, vinyl chloride and methyl acrylate, was studied. In systems with α‐methylstyrene only a copolymer of this monomer with maleic anhydride was obtained. In systems with methyl acrylate a terpolymer containing mainly methyl acrylate monomeric units was produced, whereas in all the other systems terpolymers containing ca. 50 mol‐% of vinyl monomeric units were formed. In terpolymerizations carried out at low temperatures, SO2 is a more reactive monomer than maleic anhydride. With increasing temperature the content of SO2 monomeric units decreases in the products obtained. This is connected with an enhancement of the depropagation rate of this monomer. On the basis of the results obtained some aspects of the propagation and depropagation mechanisms in the systems studied are discussed.
Group transfer polymerization of methyl acrylate in acetonitrile
Authors: Schubert Walter , Bandermann Friedhelm 
Published: April 2003

AbstractResults of group transfer polymerization (GTP) of methyl acrylate (MA) in acetonitrile with 1‐methoxy‐1‐propenyloxytrimethylsilane (MTP) as initiator and tris(dimethylamino)sulfonium difluorotrimethylsilicate, tris(piperidino)sulfonium difluorotrimethylsilicate, tris(dimethylamino)sulfonium bifluoride, tris(piperidine)sulfonium bifluoride, tetrabutylammonium fluoride trihydrate and tetraethylammonium cyanide as catalysts are presented. Difluorotrimethylsilicate‐and bifluoride‐derived catalysts are more active in GTP of MA than fluoride‐ and cyanide‐derived ones, and lead to higher but in no case complete conversion. Polymers with number‐average molecular weights up to 10000 and dispersion indices as low as Mw/Mn = 1,3 can be prepared. Molecular weight control is poor and not possible without calibration of reaction conditions, since all catalysts activate side reactions of MA (to low‐molecular‐weight compounds and oligomers), of MTP, and (as is assumed) also of growing chains with the solvent acetonitrile under termination. Furthermore, catalysts containing fluoride and cyanide anions initiate an anionic polymerization of MA, accompanying GTP to an appreciable extent.
Structural characterization of vinylidene fluoride/vinyl fluoride copolymers
Authors: Guerra Gaetano , Di Dino Gabriele , Centore Roberto , Petraccone Vittorio , Obrzut Jan , Karasz Frank E. , MacKnight William J. 
Published: April 2003

AbstractThe crystalline structure and the melting behavior of vinylidene fluoride/vinyl fluoride (VF) copolymers are reexamined. For copolymers containing even a small mole fraction of VF units (≈︁ 12%) a structure similar to the β‐form of poly(vinylidene fluoride) and to the crystalline structure of poly(vinyl fluoride) is stabilized. Combined wide‐angle X‐ray scattering, differential scanning calorimetry and dielectric measurements show that in contrast to other vinylidene fluoride copolymers, no crystal‐crystal transition below the melting region is present.
Active transport of linear polyions in oppositely charged swollen polyelectrolyte networks
Authors: Kabanov Victor A. , Zezin Alexander B. , Rogacheva Valentina B. , Prevish Victoria A. 
Published: April 2003

AbstractThe interaction between oppositely charged linear and crosslinked polyelectrolytes and the molecular mechanism of the transport of linear polyelectrolytes into oppositely charged gels were studied. The mechanism represents a “relay‐race” transfer of polyion segments from one fragment of the polyelectrolyte network to the other via interpolyelectrolyte exchange reaction. Thus, the whole layer of the formed interpolyelectrolyte complex serves as an active zone. The driving force for the transport is produced by interpolyelectrolyte addition reaction on the solution/gel interface.
In‐situ photopolymerization of oriented liquid‐crystalline acrylates, 3. Oriented polymer networks from a mesogenic diacrylate
Authors: Broer Dirk J. , Boven Jan , Mol Grietje N. , Challa Ger 
Published: April 2003

AbstractSynthesis, mesomorphism, orientation and photo‐initiated chain crosslinking of the liquid‐crystalline diacrylate 1,4‐phenylene bis{4‐[6‐(acryloyloxy)hexyloxy]benzoate} (1) are studied. Monomer 1 exhibits a broad nematic phase between 108 and 155°C and a monotropic smectic phase below 88°C. The monomer is uniaxially oriented in its nematic phase at a substrate which has been coated with polyimide and unidirectionally rubbed with tissue. At the transition temperature to the smectic phase the order parameter is measured to be 0,7. During polymerization, the ordering of the mesogens is frozen‐in, yielding a uniaxially crosslinked network. The clear films of oriented poly(1) exhibit a birefringence Δn between 0,12 and 0,15, depending on the polymerization temperature. In the highest oriented state of 1 a small reduction of the degree of order is observed during the crosslinking reaction, whereas at higher temperatures and lower ordering of 1, the uniaxially orientation increases upon reaction. A special feature of the oriented networks is that the ordering is maintained while heating at high temperatures. The polymerization of the acrylate groups in the mesomorphic phases proceeds fast and to high conversion. Below 90°C the polymerization behaviour is similar to that of conventional isotropic diacrylates. Above 90°C the polymerization reaction of the liquid‐crystalline diacrylate proceeds faster than that of an isotropic diacrylate.
Spacer effect on the asymmetric addition of butyllithium to aldehydes with chiral polymers containing (+)‐bornane moieties as catalysts
Authors: Liu Jui‐Hsiang , Wang Jenn‐Hwa , Kuo Jue‐Cheng 
Published: April 2003

AbstractThree types of chiral polymer containing dimethylaminobornane moieties were synthesized. The asymmetric addition of butyllithium to various aldehydes in the presence of chiral polymers as catalysts were carried out at different reaction temperatures. The highest enantiomeric excess (54,7%) was achieved with the chiral homopolymer with a spacer inserted between the polymer chain and the dimethylaminobornane moiety. The chiral polymers can be easily separated from the reaction mixture and re‐used.