bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and properties of polymers based on acetyl derivatives of cobalticinium
Authors: Teplyakov Mikhail M. , Dvorikova Raisa A. , Rukhlyada Nataliya N. , Leonova Elena V. , Petrovskii Pavel V. 
Published: April 2003

AbstractNew polycondensation network polymers containing cobalticinium fragments have been synthesized using two different methods: (i) polycondensation of di‐ and monofunctional monomers [1,1′‐diacetylcobalticinium hexafluorophosphate (1a) or a mixture of 1a and 1‐acetyl‐1′‐ ethylcobalticinium hexafluorophosphate (1b)] with acetophenone, in the melt at 140–200°C in the presence of triethyl orthoformate (TEOF) and p‐toluenesulfonic acid (p‐TSA); (ii) introduction of cobalticinium fragments in the polymer chain through the interaction of acetyl derivatives of cobalticinium with acetyl‐terminated oligophenylenes at 200°C in the presence of p‐TSA. The resulting polymers reveal the properties of strongly, middle and weakly basic anionites and retain ion‐exchange properties after heating at 125°C.
Polymerization of lactones, 17. Synthesis of ethylene glycol‐L‐lactide block copolymers
Authors: Jedliński Zbigniew , Kurcok Piotr , Walach Wojciech , Janeczek Henryk , Radecka Izabella 
Published: April 2003

AbstractThe anionic polymerization of L‐lactide in the presence of the sodium poly(ethylene glycol)ate in tetrahydrofuran at 25°C yields “tailored” ABA triblock copolymers having the expected compositions and molecular weights. During the polymerization, a slight racemization of L‐lactide was observed. The water absorption experiments indicate that the introduction of the poly(ethylene glycol) block into the L‐lactide polymer chain markedly increases its hydrophilicity. It was revealed that the morphology and mechanical properties of block copolymers depend strongly on their composition and thermal treatment.
Reactive comb‐like polymers. Kinetic studies of the Diels‐Alder reaction of furan‐containing comb‐like polymers with dimethyl butynedioate by means of 1H NMR spectroscopy
Authors: Ritter Helmut , Sperber Rolf , Weisshuhn Carl Michael 
Published: April 2003

AbstractThe syntheses of some novel furan‐containing monomers, N[ω‐(furfurylcarbamoyl)alkyl]‐methacrylamide (2) and N‐furfurylmethacrylamide (3), and their corresponding polymers are described. Time‐conversion measurements of their Diels‐Alder reactions with dimethyl butynedioate by means of 1H NMR spectroscopy showed a deviation from pseudo‐first‐order kinetics. The influence of spacer length on the reaction velocity is explained by steric hindrance and neighboring group effects. No deviations from pseudo‐first‐order kinetics were observed during the Diels‐Alder reaction of the low‐molecular‐weight model compounds N [ω‐(furfuryl‐carbamoyl)alkyl]isobutyramide (8) and N‐furfurylisobutylamide (9) under the same reaction conditions.
Synthesis and characterization of copolyesters based on poly(tetramethylene terephthalate) and p‐hydroxybenzoic acid
Authors: Fakirov Stoyko , Goranov Konstantin , Zachmann Hans Gerhard , Chen Di 
Published: April 2003

AbstractCopolyesters of poly(tetramethylene terephthalate) (PTMT) and p‐hydroxybenzoic acid (PHB) are obtained by means of transesterification in the molten state using different ratios of the starting reagents. After treatment with trifluoroacetic acid, the total reaction product could be divided into a soluble part and an insoluble one, differing in the tetramethylene terephthalate/oxybenzoate (TMT/OB) units ratio. It was proved by 1H NMR that the fraction of OB units in the soluble part of the copolyester varies from 3 to 12 mol‐% for PHB feed contents of 10–80 mol‐%. There is no systematic influence of the PHB feed content on the copolyester composition. The maximum OB content was achieved at 20 mol‐% PHB in the starting mixture. The results from 13C NMR, DSC, WAXS and crystallization kinetics measurements suggest the presence of blocks of TMT units in the macrochains. The observed thermal properties and crystalline structure are explained in terms of the inhomogeneity of both chemical composition and units sequence in the total reaction products. This leads to the coexistence of at least two phases differing mainly in their content of OB units.
Study on structure‐property relationship of polyimide blends, 2. Structure and miscibility of polyimide PBPI‐E/PTI‐E blends
Authors: Zhang Ping , Sun Zhenhua , Li Guang , Zhuang Yugang , Ding Mengxiam , Feng Zhiliu 
Published: April 2003

AbstractThe structure and miscibility of polyimide PBPI‐E/PTI‐E blends were studied by wide‐ and small‐angle X‐ray scattering and dynamic mechanical analysis, where PBPI‐E is a biphenyldianhydride‐based polyimide, and PTI‐E is a polyimide from 4,4′‐thiodiphthalic anhydride and 4,4′‐oxydianiline. The results obtained show that there exists a paracrystalline structure in the blends with high content of PBPI‐E, but this does not affect the miscibility of the blends. The blends are miscible over the entire composition range, since only one Tg was observed for each blend. Meanwhile, the segregation of PTI‐E during crystallization of PBPI‐E in the blends is interlamellar.
A mechanistic study of the radical copolymerisation of p‐methoxystyrene with citraconic anhydride via 13C NMR spectroscopy
Authors: Brown Paul G. , Fujimori Kiyohisa 
Published: April 2003

AbstractThe composition and monomer unit sequence distribution of copolymers of p‐methoxystyrene (p‐MST) with citraconic anhydride (CA) prepared in methyl ethyl ketone (MEK) at 50,0 ± 0,1°C were determined over a range of comonomer feed mole fractions using 13C NMR spectroscopy. The monomer units in these copolymers were found to display an increasingly strong tendency to alternate as the mole fraction of CA in the feed increases. The existence of a 1:1 charge‐transfer complex formed between p‐MST and CA in the feed was confirmed via UV spectroscopy and the equilibrium constant for complex formation was determined. The terminal, penultimate and complex‐participation models were tested for applicability to the mechanism of copolymerisation for this comonomer system. On the basis of copolymer composition data, the penultimate and complex‐participation models were found to provide each an adequate description of the mechanism of copolymerisation in the comonomer system via non‐linear least squares methods. The inadequacies of the terminal and penultimate models in describing the copolymers were exposed more explicitly through an analysis of their comonomer unit sequence distributions using reactivity ratio related test functions.
Star‐shaped polymers by living cationic polymerization, 6. Amphiphilic star‐shaped block copolymers of vinyl ethers with carboxyl groups: synthesis and host‐guest interaction
Authors: Kanaoka Shokyoku , Sawamoto Mitsuo , Higashimura Toshinobu 
Published: April 2003

AbstractAmphiphilic star‐shaped polymers (5 and 6) of vinyl ethers (VEs), the arms of which consist of apoly(carboxylic acid)/poly(alkyl VE) AB block copolymer, were prepared on the basis of living cationic polymerization. Thus, a sequential living polymerization of a VE with a pendant malonate group [CH2  CHOCH2CH2CH(COOCH2CH3)2] and and isobutyl VE with HI/ZnI2 at −15°C in toluene led to a living block copolymer (3a), which was subsequently allowed to react with a small amount of a bifunctional vinyl ether [1; CH2  CHOCH2CH2OC6H4C(CH3)2‐C6H4OCH2CH2OCH  CH2] to give a star‐shaped block copolymer (4a). Alkaline hydrolysis of the ester functions of 4a, followed by neutralization, gave the amphiphilic star copolymer (5a, diacid form; \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm \{ H\rlap{--} [CH}_2 {\rm CH(OCH}_2 {\rm CH}_2 {\rm X)\rlap{---} ]}_m {\rm \rlap{--} [CH}_2 {\rm CH(O}i{\rm Bu)\rlap{--} ]}_n \} _f - {\rm (core)}, $\end{document} X = CH(COOH)2) with hydrophilic poly(carboxylic acid) segments in the outer region, and subsequent decarboxylation led to the monoacid form 6a (X = CH2COOH). Amphiphilic star copolymers (5b and 6b; \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm \{ H\rlap{--} [CH}_2 {\rm CH(O}i{\rm Bu)\rlap{---} ]}_m {\rm \rlap{--} [CH}_2 {\rm CH(OCH}_2 {\rm CH}_2 {\rm X)\rlap{--} ]}_{n'} \} _f - {\rm (core)}, $\end{document} 5b: X = CH(COOH)2, 6b: X = CH2COOH) with an opposite segment sequence(inner polyacid chains) were also prepared. The star copolymer 5b (m′ = 30, n′ = 10) was insoluble in methanol, in which the polymer 5a (m = 10, n = 30) with the opposite segment sequence was soluble, and both 5a and 5b as well as both 6a and 6b differed in solubility from the corresponding linear polymer. The amphiphilic polymers 5 and 6 were also found to interact selectively with guests with polar functional groups such as benzoic acid and benzylamine.
Reaction between carbon monoxide and a Ti‐polyethylene bond with a MgCl2‐supported TiCl4 catalyst system
Authors: Shiono Takeshi , Ohgizawa Masaaki , Soga Kazuo 
Published: April 2003

AbstractThe reaction between carbon monoxide and the Ti‐polyethylene bond was investigated by using a stopped‐flow polymerization method which can provide quasi‐living polymers with very low molecular weights. Ethylene polymerization was conducted with a typical MgCl2‐supported TiCl4 catalyst combined with triisobutylaluminium (Al(i‐C4H9)3) or Al(CH3)3. The quasi‐living polymers were introduced into either the heptane solution saturated with carbon monoxide or the heptane solution containing 13C‐enriched carbon monoxide at −78°C. The mixture was gradually heated up to room temperature. During this procedure, a small portion of the reaction mixture was taken out at −78°C, 0°C and at room temperature. The polymers produced were analyzed by means of Fourier‐transform infrared spectroscopy, gel‐permeation chromatography, proton nuclear magnetic resonance (1H NMR) and 13C NMR spectroscopy. The analytical data show that carbon monoxide is predominantly incorporated into the polymers as a ketonic carbonyl.
Investigations on the ring‐opening polymerization of cyclic ketenacetals
Authors: Klemm Elisabeth , Schulze Thomas 
Published: April 2003

AbstractThe synthesis of five‐membered cyclic ketenacetals was investigated. It was shown that 2‐methylene‐1,3‐dioxolanes have various properties of polymerization in dependence on the substituents in 4‐ and 5‐position. While 4‐methylene‐3,5‐dioxatricyclo[5.2.1.02,6]decane (1) polymerizes without ring opening to high‐molecular‐weight polyacetals, which are insoluble in common solvents, 4‐methylene‐8,9:10,11‐dibenzo‐3,5‐dioxatricyclo[5.2.2.02,6]undeca‐8,10‐diene (2) yields oligomers (number‐average molecular weight M̄n (vapour pressure osmometry) = 900–1500) with ring‐opened and non‐ring‐opend units.
New polymer syntheses, 72. Telechelic and star‐shaped poly(ether‐sulfone)s by polycondensation of 4‐fluoro‐4′‐trimethylsiloxy(diphenyl sulfone)
Authors: Kricheldorf Hans R. , Adebahr Thorsten 
Published: April 2003

AbstractThe homopolycondensation of 4‐fluoro‐4′‐trimethylsiloxy(diphenyl sulfone) (2) in bulk and its cocondensation with 4‐fluoro‐4′‐trimethylsiloxybenzophenone (1) yielded high‐molecular‐weight, amorphous (co)poly(ether‐sulfone)s. The cocondensation with 4,4′‐difluoro(diphenyl sulfone) (4) afforded telechelic oligomers or polymers with two fluorobenzophenone end‐groups. Cocondensation with 4,4′‐bis(2,4‐difluorobenzoyl)[diphenyl ether] (5) gave star‐shaped polymers with four branches. Cocondensation with 1,3,5‐tris(trimethylsiloxy)benzene (6) yielded star‐shaped poly(ether‐sulfone)s with three longer than calculated star arms. Cocondensations with 2,2′,4,4′‐tetrakis(trimethylsiloxy)benzophenone (7) did not result in the formation of star‐shaped polymers, but yielded telechelic linear poly(ether‐sulfone)s with two trimethylsiloxy end‐groups. It was found that rapid cyclization of the benzophenone derivative (yielding a bis(trimethylsiloxy)xanthone) precedes the polycondensation.
NMR imaging of polymer materials
Authors: Bl¨︁umich Bernhard , Blümler Peter 
Published: April 2003

AbstractThe principles of NMR imaging applicable to materials are reviewed, and examples of current developments given. Among the different types of materials, polymers are particularly suitable for NMR imaging, because they are rich in protons, the most sensitive NMR nucleus. While the spatial resolution in solid materials is restricted to dimensions larger than 50 μm, the interest in NMR as an imaging technique derives from the abundance of parameters, which can be converted to image contrast for localization and identification of material morphology, chemistry and physics. Particular progress has been achieved in imaging of polymer melts and liquids, where diffusion and non‐Newtonian flow are investigated as well as of elastomers, where composition, deterioration by thermal and mechanical aging, and stress distribution can be characterized.
Analysis of hydrodynamic data on polymethacrylates with mesogenic pendant groups
Authors: Netopilík Miloš , Bohdanecký Miloslav , Wehrstedt Carla , Ruhmann Ralf , Schulz Günter 
Published: April 2003

AbstractDilute solutions of poly{6‐[4‐(4‐methoxyphenoxycarbonyl)phenoxy]hexyl methacrylate} (1 a, structure‐based IUPAC name poly(1‐{6‐[4‐(4‐methoxyphenoxycarbonyl)phenoxy]hexyloxycarbonyl}‐1‐methylethylene)) were investigated by means of size‐exclusion chromatography (SEC), osmometry, light scattering, and viscometry. It was found that the universal calibration of SEC is not valid with this polymer and that dilute solution properties (intrinsic viscosity, second virial coefficient) are at variance with predictions from the two‐parameter theory of polymer solutions. The latter discordance is explained on the basis of the theory of hydrodynamic properties of wormlike chains which takes into account the effective diameter of the chain. The characteristic ratio (C ∞ = 15,1) and the Kuhn segment length (λ−1 = 28 · 10−8 cm) were estimated. The polymer‐solvent interaction parameter was shown to decrease in the series of solvents: 1,1,2,2‐tetrachloroethane, chloroform, tetrahydrofuran, N,N‐dimethylformamide. The interaction of the solvents with the side groups was shown to be the determining factor.
A novel imaging system by dye‐sensitized photooxidation of oxazole groups attached to a polymer backbone
Authors: Ito Hiromitsu , Ikeda Tomiki , Ichimura Kunihiro 
Published: April 2003

AbstractCopolymers of 2‐(3‐methacryloyloxypropyl)‐4,5‐diphenyloxazole (3) with various monomers were prepared. It was observed that the oxazole rings attached to the copolymer backbone are converted efficiently to the corresponding triacylamino residues by photooxidation using meso‐tetraphenylporphin as a photosensitizer in solution and in a thin film of the polymer. This photoinduced transformation in a copolymer 5c having N‐isopropylacrylamide as a comonomer was found to be applicable to a positive working photoresist by development with an aqueous solution of amines to dissolve the exposed areas of the film. A new system for positive image formation by visible light is presented.
Poly(p‐phenylene)s with polar side groups, 1. Pd‐catalyzed synthesis, characterization and modification of poly(p‐phenylene)s bearing butoxymethyl side chains
Authors: Rau Iris Ursula , Rehahn Matthias 
Published: April 2003

AbstractThis is a description of the Pd‐catalyzed synthesis of two poly(p‐phenylene) (PPP) derivatives which have butoxymethyl side groups on each, or every alternate, phenylene moiety. For the latter, details are given of the quantitative transformation of the ether functionalities into bromomethyl pendant groups. Subsequent reaction of these bromo functionalities with sodium 4‐cyanophenolate or sodium acetate produced structurally homogeneous PPP's which had 4‐cyanophenoxymethyl and acetoxymethyl side groups, respectively. The PPP derivatives described here are soluble in common organic solvents and were characterized in detail by NMR spectroscopy, membrane osmometry and size exclusion chromatography (SEC). The degrees of polycondensation of the butoxymethyl‐substituted polymers were found to be in the order of 30–65. No evidence for chain degradation during the following conversions was found on the basis of the NMR and SEC measurements.
Microstructure analysis of three segmented copolymers containing polydimethylsiloxane by solid‐state high‐resolution NMR
Authors: Feng Hanqiao , Shi Linqi , Feng Zhiliu , Shen Lianfang 
Published: April 2003

AbstractThe microstructure of two bicomponent and one tricomponent segmented copolymers, based on polydimethylsiloxane, poly(p‐hydroxystyrene) or/and polysulfone, were investigated using an extended Goldman‐Shen pulse sequence, proton spin‐spin relaxation measurements, and 13C and 29Si NMR spectra. The results indicate that there exist four phases with different sizes, components and morphological structure in the segmented copolymers studied in this work, i.e., a rigid‐chain phase of very slow motion, a rigid‐chain‐rich phase of slow motion, a flexible‐chain‐rich phase of fast motion and a flexible‐chain phase of faster motion. The sizes of different domains, calculated from the spin diffusion rates, are about 50–100 Å for the flexible‐chain‐rich phase of fast motion and 200–300 Å for the flexible‐chain phase of faster motion. The relative quantities of polydimethylsiloxane in the flexible‐chain phase of fast motion are slightly different in different kinds of segmented copolymers.
Effect of the external donors on the polymerization of 4‐methyl‐1‐pentene with high activity MgCl2/TiCl4 catalytic system
Authors: Frolov Ilia , Kleiner Vladimir , Krentsel Boris , Mardanov Robert , Munshi Kalyan , Bukatov Gennady , Zakharov Vladimir , Sergeev Sergey 
Published: April 2003

AbstractIn order to find out correlations between the structure of an external donor and the obtained polymer, the effects of different external donors on the activity and stereospecificity of the MgCl2/TiCl4 catalytic system in the bulk polymerization of 4‐methyl‐1‐pentene (4MP) were carefully studied. Different silane compounds of the structure RnSi(OR')4‐n (where: n = 1–3, R = alkyl/phenyl, R = alkyl) and Al(i‐Bu)3 (TIBA) were used as external donors and cocatalyst, respectively. The effect of the donor/TIBA mole ratio on the activity and stereospecificity of the catalytic system was studied. Some major effects were observed for the three different external donors, namely, Me3Si(OMe), Me2Si(OMe)2, and Me3Si(OBu)3, in the 4MP polymerization process. It was observed that the effect of the external silane donor on the polymerization strongly depends upon the size of the alkoxy and hydrocarbon (alkyl/phenyl) groups which are attached to the silicon atom. A selective deactivation of the non‐stereospecific centers, as well as a transformation of the non‐stereospecific into isospecific centers, is assumed to occur. On the basis of the obtained results and literature data available for the propene polymerization, the concept of structural conformity between the ligand‐surrounded active center and the monomer molecule was carried forward.
Synthesis of hydroxy‐terminated poly(vinyl ethers) by hydrogen chloride‐based living cationic polymerization
Authors: Hashimoto Tamotsu , Iwao Shigeki , Kodaira Toshiyuki 
Published: April 2003

AbstractA new initiating system consisting of CH3CHCIOCH2CH2OCOCH3 (2, the hydrogen chloride adduct of 2‐vinyloxyethyl acetate) and ZnCl2 was applied for the synthesis of hydroxyterminated telechelic poly(vinyl ether). The 2/ZnCl2 was applied for the synthesis of hydroxy terminated telechelic poly(vinyl ether). The 2/ZnCl2 system induced living cationic polymerization of isobutyl vinyl ether in CH2Cl2 at −40°C to give a living polymer with a “head” (α‐end) acetoxy group originating from the initiator. Addition of an excess amount of water to the reaction mixture immediately terminated the living end to incorporate the “tail” (α‐end) aldehyde group. The obtained polymer exhibited narrow molecular weight distribution and end‐functionalities close to unity for both terminal functions. The treatment of the terminal groups with LiAlH4 led to a telechelic polymer with hydroxy end groups. Acetylation and subsequent structural analysis of the hydroxy polymer showed the existence of two hydroxy groups per polymer chain. Monofunctional poly(isobutyl vinyl ethers) with one hydroxy or aldehyde terminal were also obtained by similar hydrogen chloride‐based living cationic polymerization.
Polymerization by [3 + 2]‐cycloaddition, 5. Telechelics with isocyanate end‐groups
Authors: Maier Gerhard , Losert Klaus , Nuyken Oskar 
Published: April 2003

AbstractThe “criss‐cross” cycloaddition reaction between derivatives of benzaldehyde azine and several diisocyanates is used for the synthesis of polymers with an uncommon structure element: the 1,3,5,7‐tetrazabicyclo[3.3.0]octane‐2,6‐dione. The nature of the diisocyanate determines the reactivity in this cycloaddition polycondensation and the solubility of the new polymers. A degree of polymerization up to Pn = 72 could be achieved. Due to the nature of the polycondensation reaction, the polymers have two isocyanate end‐groups, independent of the stoichiometry of the monomer mixture at the beginning of the reaction. Thus, a prepolymer was synthesized and the chain extension by reaction of its isocyanate end‐groups with diamines was studied in some detail.
Copolymers of L‐ and D,L‐lactide with 6‐caprolactone: synthesis and characterization
Authors: Perego Gabriele , Vercellio Tiziano , Balbontin Giulio 
Published: April 2003

AbstractL‐ and D,L‐lactide copolymers with 6‐caprolactone were synthesized and characterized in a wide range of compositions. The polymerizations were carried out in batch at 130°C, with Sn(II) octoate as a catalyst, a monomers/initiator mole ratio of 5000/1 and a reaction time of 48 h. The copolymers having from 5 to 40 wt.‐% of 6‐caprolactone are characterized by higher values of non‐reacted monomers and deviations of the polymer composition from the feed ratio. In the same interval of compositions, L‐lactide copolymers showed progressive hardening with time at room temperature, attributable to the tendency to crystallization of homopolymeric sequences. This behaviour was more deeply studied in the case of poly(L‐lactide‐co‐6‐caprolactone) with 30 wt.‐% of 6‐caprolactone. 1H NMR at 300 MHz appeared to be a suitable method for the determination of the monomer sequence.
Structure and electronic properties of polythiophene and poly(3‐alkylthiophene) films electropolymerized on indium tin oxide (ITO) glass at elevated potentials
Authors: Mårdalen Jostein , Samuelsen Emil J. , Gautun Odd R. , Carlsen Per H. J. 
Published: April 2003

AbstractHomogeneous and flexible films of polythiophene are known to be difficult to obtain electrochemically on indium tin oxide (ITO) glass electrodes using normal 1,6–1,7 V applied voltage. The situation is greatly improved by using higher voltage. 0,1–10 μm thick films of polythiophene (PT) and various poly(3‐alkylthiophene)s (P3AT's) (alkyl = methyl (P3MT), hexyl (P3HT) and octyl (P3OT)) were electropolymerized on ITO‐covered glass anodes under an applied voltage of 8 V vs. an Ag/AgCl reference electrode. In this paper we report upon the properties of these films compared to their chemically and at low‐voltage electrochemically polymerized equivalents. Generally, the films have all the properties known for PT and P3AT's. Characteristics such as thermo‐ and solvatochromism, conductivity and electronic band structure as studied by ultraviolet photoemission spectroscopy and optical absorption were comparable to the properties shown by the reference samples. However, the structure of high‐voltage films differs considerably from those reported for chemically polymerized samples. The high‐voltage films contain a higher amorphous fraction, and the polymer is more cross‐linked and branched.