bluuebunny/crossref_metadata_2025 huggingface dataset:
New copolymethacrylates with azo‐chromophores in the side chain
Authors: Czapla Sylvia , Ruhmann Ralf , Rübner Joachim , Zschuppe Veit , Wolff Dietmar
Published: April 2003

The synthesis and characterization of new poly({6‐[4‐(4‐cyanophenylcarbamoyl)phenoxy]hexyl methacrylate}‐co‐{6‐[4‐(4‐ cyanophenylazo)phenoxy]hexyl methacrylate}) are reported. Their liquid‐crystalline properties are investigated using differential scanning calorimetry, polarizing microscopy and X‐ray diffraction techniques. The glass transition temperatures and the clearing points can be influenced by variation of the copolymer composition. The substances offer a relatively broad temperature range of mesomorphic properties suitable for photochemical studies.
Nucleation of the ß‐modification of isotactic polypropene on the surface of different crystalline phases of linear trans‐quinacridone pigments
Authors: Filho Delson dos Santos , Oliveira Clara Marize Firemand
Published: April 2003

Different crystalline phases of linear trans‐quinacridone (LTQ) pigments were prepared and added to isotactic polypropene (i‐PP). It was observed by X‐ray diffraction that the nucleation efficiency of the β‐modification of i‐PP strongly depends on the crystalline phases of LTQ. The α‐phase of LTQ does not induce the formation of the β‐modification of i‐PP but the δ‐modification of LTQ is a more effective β‐nucleator than the other crystalline phases of LTQ.
Crystallization kinetics of the ß‐modification of isotactic polypropene containing different crystalline phases of linear trans‐quinacridone pigments
Authors: Filho Delson dos Santos , Oliveira Clara Marize Firemand
Published: April 2003

The crystallization behavior of the ß‐modification of isotactic polypropene (i‐PP) induced by different crystalline phases of linear trans‐quinacridone (LTQ) is investigated. The crystallization of the ß‐modification depends on the crystalline phases of LTQ added to i‐PP and the cooling rates during crystallization from the melt. Non‐isothermal crystallization kinetics of i‐PP examined by differential scanning calorimetry indicated that the nucleating activity of the crystalline phases of LTQ is associated to the variation in fold surface free energy (δe) of formation of both the α‐and β‐modifications.
Electronic vs. Steric effects of substituents on the intramolecular excimer fluorescence from dilute solutions of halogen‐substituted polystyrenes
Authors: Chakraborty D. K. , Kurian J. , Trumbo D. , Harwood H. J. , Kennedy J. P. , Mattice Wayne L.
Published: April 2003

Steady state fluorescence measurements in dilute solution have been performed for eight halogenated polystyrenes and for poly(2,5‐dimethylstyrene). The monomers for halogenated polymers are o‐X‐styrene (X = F, Cl, Br), m‐fluorostyrene, p‐X‐styrene, and p‐chloro‐α‐methylstyrene. The position of the excimer band and the ratio of the intensities of the excimer and monomer fluorescence depend on the substitution. The results for poly(p‐chloro‐α‐methylstyrene) and poly(2,5‐dimethylstyrene) can be rationalized by a conformational analysis that examines the preferred geometries for face‐to‐face complexes by rings bonded to chain atoms i and i + 2. The results for the other polymers cannot be explained by a conformational analysis. They appear to arise from a combination of factors that alter the electronic properties of the chromophore.
Sorption and permeation properties of poly(p‐phenylene sulfide) crystallized in the presence of sorbed gas molecules
Authors: Schultze Joachim Dirk , Böhning Martin , Springer Jürgen
Published: April 2003

The sorption behaviour of CO2 and N2 in poly(p‐phenylene sulfide), PPS, crystallized in the presence of CO2 and N2O molecules was studied at 298 K in the pressure range of 1–30 bar. The CO2 transport properties of these samples were investigated at the same temperature in the pressure range of 1–20 bar. The temperature dependence of the CO2 transport parameters was examined between 293 and 343 K at a pressure of 5 bar, for the virgin material, thermal and CO2 crystallized specimen only. All measured properties are compared with those of PPS crystallized by annealing at vacuum conditions to a similar degree of crystallinity, and with the virgin, nearly amorphous material. For the samples crystallized in the presence of sorbed gases an increased CO2‐solubility was observed. A part of unrelaxed free volume is proposed to remain in the samples after crystallization in presence of sorbed gas molecules. These voids formed under sorbed gas conditions seem to be stable even after removal of the sorbed molecules. The measured diffusion coefficients for CO2 were lower in the samples crystallized in the presence of gas molecules, compared to the virgin sample. This is expected to be due to an increased diffusive resistance by passing the interfaces of the formed voids. Permeability, which is governed by both, diffusion and sorption, undergoes non‐uniform changes. An attempt is made to explain this behaviour based on the dual‐mode‐sorption and dual‐mobility model.
Positional effects of the methacrylate group on polymerization and microstructure of micelle‐forming quaternary ammonium salts studied by NMR spectroscopy
Authors: Dais Photis , Paleos Costas M. , Nika Georgia , Malliaris Angellos
Published: April 2003

The microstructure of polymers obtained by γ‐irradiation of monomer surfactant molecules above the critical micelle concentration (CMC) is investigated by means of 13C NMR spectroscopy. The polymer obtained from the monomer bearing the methacrylate group at the end of the hydrocarbon chain fits the Bernoullian propagation model with Pm = 0,18 indicating a highly syndiotactic polymer, whereas that obtained from the monomer having the polymerizable group at the polar head was found to be purely syndiotactic (Pm = 0).
Irreversible activation effects in ethylene polymerization
Authors: Pasquet Véronique , Spitz Roger
Published: April 2003

Activation and deactivation phenomena commonly observed in the case of slurry or gas phase ethylene polymerization kinetics are associated to molecular aspects of the formation and inhibition of active centers. As a preliminary study of the problem, we have to identify what step during the formation or action of the active centers is concerned by the well‐known activating agents: temperature, ethylene pressure and α‐olefins addition. They all lead to an irreversible increase in the polymerization rate, which can be attributed to the creation of new active centers. Hydrogen was also considered, since it is an activator for propene polymerization, but it deactivates ethylene polymerization. This deactivation is often partially reversible. Different explanations of this complex behaviour are presented.
Synthesis and characterization of poly[2,3,9,10,16,17,23,24‐octakis(dodecyloxycarbonyl)phthalocyaninatogermoxane]
Authors: Dulog Lothar , Gittinger Andreas , Roth Siegmar , Wagner Thomas
Published: April 2003

In this article we describe the preparation of poly[2,3,9,10,16,17,23,24‐octakis(dodecyloxycarbonyl)phthalocyaninatogermoxane] by thermal polycondensation of 2,3,9,10,16,17,23,24‐octakis(dodecyloxycarbonyl)phthalocyaninatogermanium dihydroxide, and its characterization. The average molar mass of the resulting polymer was determined. High molar masses are assessible, e.g., M̄w = 360000 g/mol, M̄n = 140000 g/mol, at moderate temperature for the polycondensation (200°C). The polymer shows a liquid‐crystalline phase in an extremely large temperature range. Furthermore, Langmuir‐Blodgett films (LB films) of the polymer and of the monomer were prepared and characterized. In LB films the phthalocyanine rings are preferentially oriented normal to the dipping direction.
Synthesis of polyamic acid di‐tert‐butyl esters by direct polycondensation of di‐tert‐butyl esters of tetracarboxylic acids with diamines using diphenyl (2,3‐dihydro‐2‐thioxo‐3‐benzoxazolyl)phosphonate
Authors: Ueda Mitsuru , Mori Hideharu
Published: April 2003

The direct polycondensation using the activating agent diphenyl (2,3‐dihydro‐2‐thioxo‐3‐benzoxazolyl)phosphonate (1) was successfully applied to the synthesis of polyamic acid tert‐butyl esters, which readily undergo AAL 1 type acid‐catalyzed deesterification. Polycondensations of di‐tert‐butyl esters of tetracarboxylic acids with diamines were conducted in N‐methyl‐2‐pyrrolidone in the presence of triethylamine at room temperature, producing poly(amide‐ester)s with inherent viscosities up to 1,1 dL · g−1. The effects of various factors, such as solvent, amount of solvent, and amount of the activating agent, were studied. The poly(amide‐ester)s are readily soluble in dipolar aprotic solvents and can be cast into uniform films from their solutions. Thermogravimetry of the polymers showed that the deesterification and imidization occur around 150–200°C, giving polyimides.
Poly(Phthalidylidenearylene)S. Transformation of poly(3,3‐phthalidylidene‐4,4′‐biphenylene) in acidic media
Authors: Zolotukhin Mikhail G. , Fattakhov Rinat K. , Kovardakov Viktor A. , Egorov Aleksander E. , Salazkin Sergei N. , Sultanova Venera S. , Muslukhov Rinat K. , Khalilov Leonard M.
Published: April 2003

The behaviour of poly(3,3‐phthalidylidene‐4,4′‐biphenylylene) (PPB) in acidic media was studied. In solvents with high acidity e.g. concentrated sulfuric acid, chlorosulfonic acid or PCl5, the phthalide groups of PPB were transformed into anthracen‐9‐one groups. Exposure time, solvent and temperature were found to affect the rearrangement of 3,3‐diphenylphthalide and PPB in the presence of PCl5. The resulted polymers are soluble in common organic solvents and contain either 10‐chloro‐10‐aryl‐anthracen‐9‐one, or after hydrolysis, 10‐hydroxy‐10‐arylanthracen‐9‐one units. Flexible and transparent polymer films were prepared by casting from the solution.
Kinetic and electron paramagnetic resonance studies on radical polymerization. Radical‐initiated polymerization of methyl N‐phenylitaconamate in N,N‐dimethylformamide
Authors: Sato Tsuneyuki , Okazaki Masanori , Seno Makiko , Tanaka Hitoshi
Published: April 2003

The polymerization of methyl N‐phenylitaconamate(methyl 2‐methylenesuccinanilate (1)) with dimethyl 2,2′‐azodiisobutyrate (2) was studied in N,N‐dimethylformamide (DMF) kinetically and by means of electron paramagnetic resonance (EPR) spectroscopy. The polymerization rate (Rp) at 55°C is given by the equation: Rp = k[2]0,58 · [1]1,6. The overall activation energy of the polymerization was calculated to be 54,2 kJ/mol. The number‐average molecular weight of poly(1) was in the range between 5000 and 17000. From an EPR study, the polymerization system was found to involve the EPR‐detectable propagating polymer radical of 1 at practical polymerization conditions. Using the concentration of polymer radicals, the rate constants of propagation (kp) and termination (kt) were determined for 55°C. The rate constant of propagation kp (between 8,4 and 12 L · mol−1 · s−1) tends to somehow increase with increasing monomer concentration. On the other hand, kt (between 1,9. 10−5 L · mol−1 · s−1) increases with decreasing monomer concentration, which results from a considerable dependence of kt on the polymer‐chain length. Such monomer‐concentration‐dependent kp and kt values are responsible for the high dependence of Rp on the monomer concentration. Thermogravimetric results showed that thermal degradation of poly(1) occurs rapidly at temperatures higher than 200°C and the residue at 500°C amounts to 26% of the initial polymer. For the copolymerization of 1 (M1) with styrene (M2) at 55°C in DMF the following copolymerization parameters were found: r1 = 0,52, r2 = 0,31, and Q, e values Q1 = 1,09 and e1 = +0,55.
Catalysis of the transesterification of poly[ethylene‐co‐(vinyl acetate)] by organometallic compounds in the melt
Authors: Hu Guo‐Hua , Sun Yi‐Jun , Lambla Morand
Published: April 2003

The transesterification reaction of poly[ethylene‐co‐(vinyl acetate)] (EVA) with 1‐octanol was studied in the molten state by the use of a batch mixer (Haake Rheocord) as the reactor. The conversion of the vinyl acetate group into the vinyl alcohol group was determined by Fourier transform infrared spectroscopy (FTIR). Several organometallic compounds were used as catalysts, of which tin‐based compounds, such as dibutyltin dilaurate and dibutyltin oxide, showed the highest activities. Experimental results suggested that the real catalyst is an intermediate product (dialkoxide) formed between an organotin compound and the reactive alcohol. This was confirmed by examining the interaction between a tin compound and an alcohol with the help of different techniques like infraed spectroscopy, high‐performance liquid chromatography and mass balance. Finally, a mechanism for the transesterification in the presence of an organotin compound as catalyst was proposed, suggesting that the overall reaction rate is proportional to the concentrations of the ester and the alcohol, and to the square root of the catalyst concentration. This was fully supported by kinetic studies.
One‐step synthesis of functional polymers by polycondensation: Polyesters with pendant hydroxyl side groups from potassium malate or tartrate and 1,4‐dibromobutane
Authors: Sepulchre Marie‐Odile , El Idrissi Hassan , Sepulchre Maurice , Spassky Nicolas
Published: April 2003

Polyesters with pendant hydroxyl side groups such as (R,S)‐ and (S)‐poly(tetramethylene malate)s and (R,R)‐poly(tetramethylene tartrate)s of moderately high molecular weights were prepared by polycondensation, at 105°C in 1‐methyl‐2‐pyrrolidone for 16 to 80 h, from potassium malate or tartrate and 1,4‐dibromobutane. It was shown by a detailed analysis of the 1H and 13C NMR spectra of the prepared polyesters that no branching occurs in the course of the reaction. The nature of the end‐groups was also clearly established by NMR spectroscopy. The presence of large cycles in the final products cannot be completely excluded.
Liquid‐crystalline polyacrylates containing biphenyl and chiral terminal groups in the side chain, 1. Influence of the spacer length on the liquid‐crystal behavior
Authors: Tabrizian Maryam , Bunel Claude , Vairon Jean‐Pierre , Friedrich Claude , Noël Claudine
Published: April 2003

Three acrylate monomers having mesogenic moieties based on 4‐(n)‐alkyloxy‐4′‐(2‐chloro‐propanoyloxy)biphenyl (n = 6, 8 or 10) have been synthesized. There is no evidence for liquid‐crystal properties in any of the three new monomers. The corresponding polymers have been prepared by free‐radical polymerization. Their liquid‐crystal behavior has been investigated by differential scanning calorimetry, polarized optical microscopy, and X‐ray diffraction. On cooling from the isotropic liquid, smectic A (SA), smectic B (SB) and crystalline phases (probably crystal‐like SE phases) have been evidenced. It should be noted that the chlorine atoms in the chiral groups do impose a local ordering of the mesogenic side groups.
Improved NMR characterization of high‐molecular‐weight polymers and polyelectrolytes through the use of preliminary ultrasonic degradation
Authors: Kulicke Werner‐Michael , Otto Matthias , Baar Andreas
Published: April 2003

High‐molecular‐weight polymers, especially ionic polymers, give rise to highly viscous solutions which are likely to entrap air bubbles, even at low concentrations. The 13C NMR spectra of these solutions exhibit poor signal‐to‐noise ratios and broad bands due to the shortened T2 relaxation times. Qualitative evaluation is thus made very difficult, and quantitative evaluation becomes impossible. In 1H spectroscopic analysis of xanthan, these problems occur at concentrations as low as 0,5 wt.‐%. A method of viscosity reduction is required that reduces the molecular weight but does not affect the tacticity or comonomer distribution nor lead to the formation of monomers. From the various methods that were examined, ultrasonic degradation was found to be the best means of fulfilling these requirements. This study includes both coiled synthetic polymers, such as polyacrylamide or poly(acrylamide‐co‐sodium acrylate), and semirigid biopolymers, such as xanthan or schizophyllan, with a view to finding a generally applicable method. It was shown that the recording time could easily be reduced by a factor of up to 20 and that the resolution was enhanced. No change in the functional groups was observed in any of the polymers, and in the case of xanthan no cleavage of side chains occurred. In schizophyllan the triple helix structure also remained intact after degradation. It is postulated that degradation is attributed to elongational flow conditions produced by cavitation in ultrasonic fields.
Photocrosslinkable polymers for membranes: polyamides from N‐cinnamoyl‐5‐aminoisophthalic acid and aromatic diamines
Authors: Ommer Harald J. , Ritter Helmut
Published: April 2003

N‐Cinnamoyl‐5‐aminoisophthalic acid was synthesized by acylation of 5‐aminoisophthalic acid with cinnamoyl chloride in N,N‐dimethylacetamide (DMAc) solution. The direct polycondensation of the new diacid with various aromatic diamines results in a new type of photoreactive aromatic polyamides with inherent viscosities of 0,4–1,7 dL/g. The preparation of homogeneous and asymmetric photocrosslinkable membranes from N‐methyl‐2‐pyrrolidone (NMP) solution was performed. The mechanical stability of a film was improved by UV irradiation while the permselectivities of ethanol/water and (tert‐butyl methyl ether)/methanol mixtures were not influenced by the photochemical crosslinking.
Preparation and characterization of fluorine‐containing aromatic condensation polymers, 3. Preparation and characterization of fluorine‐containing aromatic poly(ketone)s and copoly(ketone)s by direct polycondensation of 4,4′‐[1‐(trifluoromethyl)trifluoroethylidene]dibenzoic acid and/or 4,4′ ‐isopropylidenedibenzoic acid with diaryl compounds
Authors: Saegusa Yasuo , Kojima Akihiro , Nakamura Shigeo
Published: April 2003

Four types of fluorine‐containing aromatic poly(ketone)s, poly(ether/ketone), poly(ketone), poly(sulfide/ketone) and poly(sulfone/ketone), were synthesized from 4,4′‐[1‐(trifluoromethyl)‐trifluoroethylidene]dibenzoic acid and diaryl compounds, diphenyl ether, diphenyl ketone, diphenyl sulfide and diphenyl sulfone, by direct polycondensation using phosphorus pentoxide/methanesulfonic acid as both condensing agent and solvent. The expected chemical structures were confirmed by IR and 1H NMR spectroscopy and elemental analysis. Two series of fluorine‐containing copoly(ketone)s, copoly(ether/ketone) and copoly(sulfide/ketone), were also similarly prepared by using different proportions of the dicarboxylic acid and the corresponding analogous 4,4′‐isopropylidenedibenzoic acid but without fluorine, and the effect of the introduction of the fluorine atom on the properties of these polymers was discussed with relation to the fluorine contents. Most of the poly(ketone)s with and without fluorine were essentially amorphous and soluble in a wide range of organic solvents including chloroform and tetrahydrofuran, and afforded transparent films by solution casting. The contact angles of the films to water increased significantly and monotonously with increasing fluorine content in the copoly(ketone)s. Thermal properties such as glass transition temperature and thermal stability were also successfully improved by the introduction of a fluorine atom, and both of them increased markedly and monotonically with the increase of the fluorine content.
Alkoxy‐substituted liquid‐crystalline aromatic copolyesters, 2
Authors: Schleeh Thomas , Roetting Oliver , Bettge Dirk , Hinrichsen Georg , Koßmehl Gerhard
Published: April 2003

Number‐average molecular weights, Mn, up to 25 000, and inherent viscosities, ηinh, up to 2,88 dL/g, were found for the soluble members of an alkoxy‐substituted copolyester series (HTO5‐X series). A liquid‐crystalline (high‐temperature) phase was distinguished by IR and wide‐angle X‐ray scattering on molten and quenched samples in form of a nematic sanidic phase. In this phase no relationship exists between the orientation of the aromatic polyester backbone and that of the laterally attached alkoxy groups. Further, it was proven by IR that only the polyester backbone can be aligned by shear stress. If the applied shear stress is very strong, the orientation of the stiff backbone becomes sensitive to disturbances caused by mechanical forces.
Preparation and characterization of polyurethane‐type macroazo initiators for block copolymerization
Authors: Kinoshita Hiroshi , Tanaka Nobuo , Araki Takeo , Syoji Akio , Ooka Masataka
Published: April 2003

The use of dipropylene glycol in the polyaddition of 2,2′‐azobis(2‐cyanopropanol) (ACP) with hexamethylene diisocyanate results in soluble polyurethane‐type macroazo initiators (PUMAI) in high yields. By adjusting the amount of ACP used, the number‐average molecular weight of the polyurethane segments was adjusted in the range from 2000 to 6000 at an azo content in the PUMAI's of 0,18 to 0,5 mmol/g‐polymer (determined by UV). 13C NMR spectroscopy of the PUMAI's showed that no significant decomposition of azo groups occurred during polyaddition. At 80°C the PUMAI's initiated effectively the radical solution polymerization of vinyl monomers. As supposed from extraction results and the polymerization mechanism, block copolymers are formed. The whole process seems to be adequate for industrial applications.
Segmental mobility of model compounds for rubber reinforcement
Authors: Hommel Hubert , Touhami Ahmed , Legrand André Pierre , Balard Henri , Papirer Eugène
Published: April 2003

The motion of spin‐labeled poly(ethylene oxide) (PEO) grafted on a silica surface in contact with various dense media was studied by electron paramagnetic resonance spectroscopy. Grafted molecules of molecular weight 2000, with grafting ratios of 0,045, 0,057, 0,126 and 0,42 molecules/nm2 have conformations ranging from the single coil regime to the brush regime. A comparison is made between samples prepared by adding the melt of PEO to the grafted silica, and others prepared by adding model compounds of rubber, namely squalane and squalene

Squalane: system. name: 2,6,10,15,19,23‐hexamethyltetracosane.

Squalene: system. name: 2,6,10,15,19,23‐hexamethyl‐2,6,10,14,18,22‐tetracosahexaene.

. The local elementary mobilities of the loops and tails of PEO are shown to be affected by all these factors.
Behaviour of permeation and separation for aqueous organic acid solutions through poly(vinyl chloride) and poly[(vinyl chloride)‐co‐(vinyl acetate)] membranes
Authors: Okuno Hiroshi , Nishimoto Hiroaki , Miyata Takashi , Uragami Tadashi
Published: April 2003

The permeation and separation characteristics of poly(vinyl chloride) (PVC) and poly[(vinyl chloride)‐co‐(vinyl acetate)] (poly(VC‐co‐VAc)) membranes were investigated for aqueous organic acid solutions by pervaporation and evapomeation. The PVC membrane preferentially incorporates organic acids and predominantly permeates water from aqueous organic acid solutions. Water permselectivities of these aqueous solutions through the PVC membrane are significantly dependent on high diffusivity of water across the membrane. It was found that the permeation rate increases and the separation factor for the water permselectivity decreases with increasing vinyl acetate (VAc) content in the poly(VC‐co‐VAc) membrane. Preferential solubility of acetic acid into the poly(VC‐co‐VAc) membrane increases with the VAc content. This result was explained by a strong affinity between acetic acid and the VAc unit in the poly(VC‐co‐VAc) membrane.
Molecular‐weight distribution in the activated‐monomer polymerization of ethylene oxide. Mechanistic implications
Authors: Szymanski Ryszard , Manolova Nevena , Rashkov Ilia
Published: April 2003

The mechanism of the activated‐monomer polymerization of ethylene oxide catalyzed by protic acids was investigated by means of an analysis of the molecular‐weight distribution curves from the polymers obtained. The results suggest that polymer ether groups participate in the polymerization by forming hydrogen‐bonded complexes and tertiary oxonium cations in the reaction with the activated monomer, both being intermediates of the propagation reactions.
Stereospecific polymerization of methylthiirane in homogeneous phase, 3. Study of the enantioasymmetric process
Authors: Boucard Valérie , Dumas Philippe , Sigwalt Pierre , Guérin Philippe
Published: April 2003

Enantioasymmetry was studied for polymerizations of methylthiirane initiated by bis(isopropyl‐S‐cysteinato)cadmium and run in bulk. The ratio of rates of consumption of the two antipodes is independent of their concentrations. The enantioasymmetric constant kR, measuring the preferential choice of the R‐antipode, is depending on both the relative number of the two types of active sites and on their reactivities. An effect on enantioasymmetry of the molecular weight of the growing chains bearing the active sites, is occurring with two distinct stages: The first one is observed, with an enantioasymmetric constant kR = 1,5, from the appearance of stereospecificity up to molecular weights of 35000 (for the main chain) and the second one with kR = 1,07 for molecular weights higher than 35000. In the first stage, the cysteinato end group of the oligomer chain remains linked to cadmium (by cadmium‐nitrogen complexation) and the two active sites are diastereoisomers having different reactivities. In the second stage, the macrocyclic oligomer becomes too large and cadmium‐nitrogen interaction is suppressed. The active sites are now enantiomers having the same reactivity. In this case, enantioasymmetry depends only on the unbalance between the amounts of the two types of active sites. The maximum size the macrocyclic oligomer can reach depends on the initiator concentration.
Comb‐like methacrylamide polymers containing condensates of amino acids and azobenzene moieties in the side chains
Authors: Niemann Manfred , Ritter Helmut
Published: April 2003

The synthesis and free‐radical polymerization of 4‐(6‐methacryloylaminohexanoylamino)azobenzene (4), 4‐(11‐methacryloylaminoundecanoylamino)azobenzene (5), and 4‐[11‐(11‐methacryloylaminoundecanoylamino)undecanolyamino]azobenzene (6), are described. The monomers; the corresponding homopolymers 8–10, poly(4‐methacryloylaminoazobenzene) (7), and copolymers of 5 with stearyl acrylate, 11, and methyl methacrylate, 12, were characterized by DSC and TG analysis. Homopolymers with relatively long amino acid spacer groups were crystalline, the copolymer 12 was not crystalline. The UV‐induced E/Z photoisomerization and the thermal back‐isomerization were investigated for some of the monomers and polymers in solution and in solid films and correlated with the structures of the compounds. After photoisomerization the crystallinity of homopolymer 9 vanished because of disordering of the azobenzene side chains.
Synthesis of telechelics with furanyl end‐groups by radical polymerisation with azo‐initiators and network formation with unsaturated polyesters via Diels‐Alder additions
Authors: Edelmann Dirk , Ritter Helmut
Published: April 2003

New azo‐initiators with two and four furanyl groups were prepared: N,N′,N″,N″′‐Tetrafurfuryl 2,2′‐azo‐2,2′‐dimethyldiglutaramide (2), tetrakis[2‐(2‐furoyloxy)ethyl] 2,2′‐azo‐2,2′‐dimethyldiglutarate (4), bis[2‐(2‐furoyloxy)ethyl] 2,2′‐azodiisobutyrate (6), and N,N′‐difurfuryl‐2,2′‐azodiisobutyramide (9). The decay constants and the activation energies of the decomposition of the azo compounds were measured by thermogravimetric analysis. Radical polymerisations of styrene and some (meth)acrylates were performed under “dead‐end” conditions. The telechelic oligomers were characterized by GPC and NMR spectroscopy, proving a furanyl functionality of nearly two or four. The kinetics of Diels‐Alder reactions between the telechelics and the dienophils maleic anhydride and dimethyl maleate were measured under pseudo‐first order conditions. Addition of the telechelics to an unsaturated polyester prepared from maleic anhydride and diols led to a solid material with network structure.
LC‐polyimides, 10. Poly(ester‐imide)s derived from pyromellitic dianhydride and ω‐amino acids and various diphenols or α,ω‐diols
Authors: Kricheldorf Hans R. , Pakull Ralf , Schwarz Gert
Published: April 2003

Six dicarboxylic acids were prepared from pyromellitic dianhydride and ω‐amino acids, such as glycine, 4‐aminobutyric acid, 5‐aminopentanoic acid, 6‐aminohexanoic acid, 11‐aminoundecanoic acid and 12‐aminododecanoic acid. Polyesters were prepared from these dicarboxylic acids and 4,4′‐biphenyldiol, 2,6‐dihydroxynaphthalene, 2,7‐dihydroxynaphthalene, methyl‐, chloro‐and phenylhydroquinone. All polyesters were characterized by elemental analyses, viscosity and differential scanning calorimetry (DSC) measurements, and by optical microscopy. Several polyesters were also characterized by wide‐angle X‐ray scattering (WAXS) powder patterns, by penetration measurements and thermogravimetrical analyses. Those polyesters derived from highly symmetrical diphenols and diols are highly crystalline (>90%) and form a layer structure in the solid state. An amorphous phase was not detectable and the heat distortion temperature corresponds to the melting point. Poly(ester‐imide)s derived from less symmetric diphenols are semicrystalline and glass transition temperatures are detectable. However, true liquid‐crystalline phases were never found.
New polyurethane compositions containing high amounts of covalently bonded heparin
Authors: Marconi Walter , Barontini Paolo , Martinelli Andrea , Piozzi Antonella
Published: April 2003

Heparin was bonded covalently to hydrophilic polyurethanes. Polymers were characterized by spectroscopic techniques (IR and 1H, 13C NMR), molecular weight measurements and differential scanning calorimetry. The heparin content of the polymer films (up to more than 500 μg/cm2) was determined by a calorimetric system, and its biological activity was evaluated in vitro by APTT (activated partial thromboplastin time) measurements with a tenfold increase of the clotting time (about 300 s) with respect to the clotting time of human plasma (30 s). When heparin is bonded to a polymer provided with a hydrophilic polyfunctional spacer, the heparin content of the films is remarkably higher than previously described (about twice the reported values), and also the biological activity of the bonded heparin is favourably affected.
Poly(arylene)s containing structural units derived from the 1,2‐diketo building block
Authors: Chmil Knut , Scherf Ullrich
Published: April 2003

1,2‐Diketones may serve as starting materials for various carbo‐ or heterocyclic organic compounds. Two different synthetic routes towards poly(arylene)s containing structural units derived from the 1,2‐diketo building block are presented. The first route involves the generation of polymeric 1,2‐diketones via aryl‐aryl coupling, followed by polymer‐analogous derivatisation. The second synthetic sequence includes formation of the 1,2‐diketo derivatives on the stage of monomeric compounds and subsequent polycondensation of these monomers. In this manner, aromatic polymers possessing the quinoxaline, 1,2,4‐triazine and tetraphenylcyclopentadienone subunits are available. The polymeric 1,2,4‐triazines are particularly attractive because they offer the possibility of a thermal conversion into polymers containing the diphenylacetylene building block.
Application de la spectrométrie mécanique et diélectrique à i'analyse du comportement du poly(téréphtalate d'éthylène). Influence de la cristallinité
Authors: Gauthier Catherine , Chailan Jean‐François , Chauchard Jacques
Published: April 2003

In order to correlate crystallinity and dynamic mechanical properties, poly(ethylene terephthalate) (PETP) samples were prepared and subjected to viscoelastic measurements. The evolution of the glass‐rubber transition is analyzed for samples annealed at different temperatures. Multiplexing analysis allows to draw the Cole‐Cole plot and to develop a rheological model for the polymer behaviour. In the case of the amorphous PETP, the asymmetric Cole‐Cole plot may be represented by a “biparabolic” rheological model. On the other hand, for the semi‐crystalline polymer, the Cole‐Cole plot is symmetrical and the corresponding rheological model is the “liquid Cole” one. Dielectric spectroscopy experiments are in good agreement with the previous method. Particularly, the Cole‐Cole plot for semi‐crystalline samples is perfectly symmetric. The previous rheological models with, in addition, a static modulus are applicable to glass‐fibre reinforced PETP. These new models are called “limited biparabolic” and “Zener parabolic” model, respectively.
Synthesis of photocrosslinkable polysulfones containing 2,6‐distyrylpyridinium units and preparation of membranes for water‐ethanol separation
Authors: Koch Thomas , Ritter Helmut
Published: April 2003

Several unsaturated photoreactive polysulfones were synthesized by polycondensation of different amounts of 4,4′‐[pyridine‐2,6‐diylbis(vinylene)]diphenol (1) and 4,4′‐(isopropylidene)diphenol (2) with bis(4‐chlorophenyl) sulfone (3). Non‐uniform photoreactions were observed during UV‐irradiation, by kinetic measurements. (2+2)‐Cycloaddition of the styrylpyridinium vinyl groups as a main reaction leads to a network structure. The amorphos polycondensates were cast from CHCl3 solution to produced symmetric membranes, and the significant influence of the chemical structure and the UV‐irradiation on the permselectivity of the membranes towards water/ethanol was proved. A preferred permeation of water was observed in all cases.
Effects of matrix charges on the electrochromic behavior and degradation of polyaniline in its composite film with polyion complexes
Authors: Morita Mitsuyuki
Published: April 2003

Effects of charge balance were investigated of cationic and anionic groups, contained in a matrix polymer, on the electrochromic behavior and electrochemical degradation of polyaniline in its composite film with the matrix polymer, in contact with a non‐aqueous aprotic medium. Polyion complexes prepared with different weight ratios of poly(sodium 4‐styrenesulfonate) and poly(allylamine hydrochloride) were employed as the matrix polymer containing a controlled ratio of cationic and anionic charges. From in situ visible and ex situ FT‐IR spectroscopy of the polyaniline‐polyion complex composite films in different oxidized states, it is found that appropriate charge balances in the matrix polymer provide large electrochromic changes and high electrochemical stability of the polyaniline in the matrix. The redox process of polyaniline in aprotic media and the effect of the matrix charge balance on the process are also discussed.
Polymerizable tautomers, 9. Tautomerism and polymerization of vinyl acetoacetate
Authors: Masuda Seizo , Tanaka Masami , Asahi Yutaka
Published: April 2003

The keto/enol tautomeric constants of vinyl acetoacetate (1) were determined in various solvents. The tautomeric constants are significantly affected by the solvents, and the ketonic form is predominant in polar solvents. Regression analysis of the tautomeric constants with solvatochromic parameters gives a good linear correlation, taking into account, as major factors, polarity and hydrogen bond acceptor basicity of the solvent. The equilibria depend also on concentration and temperature. Copolymerization of 1 (M1) and styrene (M2) was carried out in benzene and acetonitrile. Monomer reactivity ratios were obtained as r1 = 0,08 and r2 = 9,36 in benzene, and r1 = 0,07 and r2 = 9,88 in acetonitrile. Q and e values of 1 were calculated to be 0,069 and −0,26 for copolymerization in benzene, and 0,062 and −0,19 for that in acetonitrile. Thus, the polymerization and copolymerization of 1 are not influenced by the solvents.
Formation of supermolecular structures of polysaccharide‐surfactant complexes in aqueous solutions. Influence of the polymer backbone
Authors: Aust Nicolai , Zugenmaier Peter
Published: April 2003

Novel water‐soluble derivatives of cellulose, amylose and dextran are synthesized and investigated with regard to their special interactions with the anionic surfactant sodium dodecylsulfate (SDS) by means of rheological flow‐ and oscillatory measurements as well as electrolytic conductivity in aqueous solution. The derivatives of amylose and dextran show a continuous adsorption of SDS with increasing surfactant concentration leading to an increase of the viscosity and of the viscous part of the shear modulus of the solution. Only low elastic parts are detectable. In contrast, the behaviour of cellulose derivatives differs extremely with increasing amount of SDS. The viscosity and the elastic part of the shear modulus of aqueous solutions reach a well pronounced maximum and then drop almost to the initial values. A similar behaviour is also observed by adding the cationic surfactant hexadecyltrimethylammonium bromide. It is concluded that the observed differences in properties of the cellulose derivatives on the one side and derivatives of amylose and dextran on the other are cause by the structure of the polymer main chain, because the side groups for all of these polymers are comparable.
Spontaneous polymerization of amphiphilic vinyl monomers, 3. Further studies on spontaneous polymerization of sodium alkyl 2‐hydroxy‐3‐methacryloyloxypropyl phosphates in micellar and reverse micellar systems
Authors: Yasuda Yutaka , Rindo Katsuhiko , Tsushima Rikio , Aoki Shuzo
Published: April 2003

Addition of sodium chloride and some surface active agents to the micellar or reverse‐micellar solution of sodium alkyl 2‐hydroxy‐3‐methacryloyloxypropyl phosphates (Cn‐AHMP) surprisingly changed the ability of spontaneous polymerization. Low‐reactive C8AHMP in water became spontaneously polymerizable upon addition of NaCl to achieve a conversion of ca. 100%, and the non‐reactive C16‐AHMP turned out to be highly reactive upon addition of an equimolar amount of sodium dodecyl glyceryl phosphate in water and in benzene. On the other hand, the high reactivity of C12‐AHMP decreased upon addition of the surfactants. These results indicate that the additives modify the monomer aggregation state, and that there is a state of aggregation that is most suitable to generate the initiating radical species. The NMR measurement of the proton spin relaxation time gave important information on the aggregation state. In the spontaneous copolymerization of C12‐ and C14‐AHMP in water, the total conversion decreased with increasing feed content of the C14 monomer, but the residual monomer ratios were equal to the initial ones. ESR spectra were detected directly in the spontaneous polymerization system of C12‐AHMP in both water and benzene. The polymerization of C16‐AHMP initiated with a pre‐polymerized solution of C12‐AHMP showed that some portion of the polymer radicals remained active for 2 − 3 h at room temperature, after the first‐stage polymerization of C12‐AHMP was complete.
High mileage catalysts for olefin polymerization, 34. Methanolysis of titanium, vanadium and chromium olefin polymerization catalysts
Authors: Nazaki Takashi , Chien James C. W.
Published: April 2003

14CH3O3H was used to quench ethylene polymerization by transition metal catalysts. 3H labeling occurred exclusively for Ti‐containing catalysts, whereas more than 95% of the chains were labeled with 14CH3 for the Cr‐containing catalysts. Both modes of labeling occurred with V‐containing catalysts. The observed phenomena indicate a change of “coordinate‐carbanionic” to “coordinate‐carbocationic” character for the alkyls of Ti, V and Cr in this order.
Complexation of sodium cations by polymeric esters of phosphoric acid
Authors: Szymanski Ryszard , Penczek Stanislaw
Published: April 2003

The complexation of sodium tetraphenylborate by poly(2‐methoxy‐2‐oxo‐1,3,2‐dioxaphospholane) and by poly(2‐methoxy‐2‐oxo‐1,3,2‐dioxaphosphorinane) in methanol solutions was studied using a previously derived relationship between solution composition and the width of a 23Na NMR signal. The results indicate that the equilibrium constants of complexation of sodium cations by both phosphoric‐ester polymers are of the same order of magnitude as the corresponding equilibrium constants of complexation of sodium cations by poly(oxyethylene).
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

New 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

The 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

The 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

Copolyesters 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

The 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

The 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.