bluuebunny/crossref_metadata_2025 huggingface dataset:
Macroporous membranes, IV. Synthesis and properties of poly[(2,3‐epoxypropyl methacrylate)‐co‐(N‐vinyl‐2‐pyrrolidone)‐co‐(ethylene dimethacrylate)] membranes
Authors: Hradil J. , Azanova A. A. , Ilavský M. , Švec F.
Published: April 2003

Macroporous membranes based on terpolymers of 2,3‐epoxypropylmethacrylate, N‐vinyl‐2‐pyrrolidone, and ethylenedimethacrylate were prepared by radical suspension copolymerization and subsequently modified with ammonia. The membranes were characterized by their porosity, specific surface area, pore size, water permeability and mechanical properties. The low content of N‐vinyl‐2‐pyrrolidone improves the mechanical properties of the membranes. The mechanism of formation of the macroporous structure and heterogeneities is discussed.
Removal of escherichia coli from water by systems based on insoluble poly(glycidyl methacrylate)‐G‐tetraethylenepentamine and ‐G‐polyethylenimine
Authors: Tashiro Tatsuo
Published: April 2003

A study was made of the removal of Escherichia coli (E. coli) from water by systems based on insoluble poly(glycidyl methacrylate)‐g‐tetraethylenepentamine and ‐g‐polyethylenimine, i.e., the reaction products of insoluble poly(glycidyl methacrylate) (PGMA) beads with tetraethylenepentamine (TEP) or polyethylenimine having molecular weights of about 600 (PEI600). The polymers (PGMA‐TEP and PGMA‐PEI600) were brought into contact with E. coli in sterilized physiological saline. These polymers made the viable cell numbers decrease in this medium. It was confirmed by observation of polymer surfaces with a scanning electron microscope that this decrease was caused by adsorption of the bacterial cells onto these polymers. The decrease coefficients of viable cell numbers (D) for E. coli by these polymers were 53 ml g−1 h−1 for PGMA‐TEP and 62 ml g−1h−1 for PGMA‐PEI600, being compared with D by other polymers studied previously.
Thermal dehydrochlorination of PVC in the presence of rubber seed oil
Authors: Okieimen Felix E. , Ebhoaye Justus E.
Published: April 2003

Dehydrochlorination rates of PVC in nitrogen atmosphere were determined in the presence of rubber seed oil (RSO), epoxidized rubber seed oil (ERSO), barium soap of rubber seed oil fatty acids and barium soap of epoxidized fatty acid of rubber seed oil. The initial rates of dehydrochlorination and the time required for the degradation to attain 1% conversion showed that the rubber seed oil derivatives exert a stabilizing effect on the degradation of PVC. The order of the stabilizing effect was found to be metal soaps of ERSO < metal soaps of RSO < ERSO < RSO.
Wirkung von Diisocyanat als reaktiver Koppler in TPU/PA6‐Blends
Authors: Franke C. , Pötschke P. , Rätzsch M. , Pompe G. , Sahre K. , Voigt D. , Janke A.
Published: April 2003

Zur Verbesserung der Werkstoffeigenschaften von thermoplastischen Polyurethanen (TPU), wie etwa der Wärmeformbeständigkeit, ist es sinnvoll, ein Blending mit Thermoplasten vorzunehmen. Eine gute Phasenverträglichkeit und Phasenhaftung bei thermodynamisch unverträglichen Blendkomponenten kann durch geeignete reaktive Koppler erreicht werden. Bei den Blends aus TPU and PA6 wird Diisocyanat während der Extrusion in der Schmelze eingebracht. Durch die ablaufenden chemischen Reaktionen werden bei extrudierten und verspritzten Blends und bei aus der Lösung erzeugten Systemen aus Polyesterpolyurethan und PA6 verträglichkeitsverbessernde Wirkungen erreicht. Diese wurden als Folge von mit 4,4′‐Diphenylmethandiisocyanat (MDI) initiierten Reaktionen in der Grenzschicht erkannt, wobei die möglichen Reaktionen mit der PA6‐Phase anhand eines Modellsystems aus der Lösung diskutiert werden. Bei Blends aus Polyetherpolyurethan und PA6 wurde keine Verträglichkeitsvermittlung durch MDI nachgewiesen. Die chemische Charakterisierung der Blends erfolgte durch GPC und FTIR, während die morphologischen Eigenschaften mittels DSC, DMA und Elektronenmikroskopie dokumentiert wurden.
Studies on simultaneous curing of nadimides and allyl nadic‐imides and thermal behaviour of cured resins
Authors: Mathur A. , Varma I. K.
Published: April 2003

The effect of composition and chemical structure of addition polyimides on thermal characteristics was investigated using commercially available allyl nadic‐imide resins and phosphorus‐containing nadimide resins. Thermogravimetric analysis, in N2 atmosphere, of resins cured at 300°C for 1 h revealed improvement of thermal stability.
Dextran functionalized by cyclic carbonate groups as supports of bioactive compounds
Authors: Ramírez J. C. , Sánchez‐Chaves M. , Arránz F.
Published: April 2003

This work deals with some features of the reaction of dextran with ethyl chloroformate using triethylamine as catalyst. The presence of cyclic and acyclic carbonate groups in the resulting modified dextrans was demonstrated by IR, 1H and 13C NMR spectroscopy. Preliminary experiments have shown that the reaction of cyclic carbonate groups with several model amines is greatly dependent on the basic character of the amine. Model amino type drugs (Phenethylamine and tyramine) were quantitatively bound to activated dextran with cyclic carbonate groups. The heterogeneous hydrolysis of dextran‐phenethylamine or dextran‐tyramine adducts showed that no hydrolysis takes place under the applied conditions.
Photochromism of polyurethane cationomers with pendent azo groups
Authors: Buruianǎ E. C. , Buruianǎ T. , Airinei A. , Robilǎ G.
Published: April 2003

A new polyurethane cationomer with pendent azo groups bounds to quaternary nitrogen atoms has been synthesized by polyaddition reaction between poly(tetramethylene oxide) (PTMO), 4,4′‐bibenzyldiisocyanate and N‐methyldiethanolamine, followed by quaternization of tertiary nitrogen with 4‐(3‐chloropropionyloxy)azobenzene.

E–Z photoisomerization of azo chromophores by UV irradiation with a high pressure mercury lamp and Z–E thermal relaxation were studied both in solution and film. An azo urethane model and a synthetic mixture of polyurethane cationomer with azobenzene were used for comparison.
Triazene polymers designed for excimer laser ablation
Authors: Lippert Th. , Wokaun A. , Stebani J. , Nuyken O. , Ihlemann J.
Published: April 2003

The excimer laser‐induced ablation of triazene polymers at a wavelength of 308 nm has been investigated as a function of laser fluence deposited on the surface in one or several pulses. PMMA, which as a homopolymer can not be ablated at 308 nm, has been sensitized for ablation at this wavelength by synthesizing a copolymer in which 0.3 mol‐% of the side chains contain the triazene functional groups. The high ablated depths per pulse achieved in this manner are similar to the ones observed upon physical doping of PMMA with monomeric triazene compounds. In an alternative approach, the triazene functional group is introduced once (polymer TP 1) or twice (TP 2) into each repeating unit of the polymer backbone by a polycondensation reaction. Irradiation of TP 1 gives rise to ill‐defined ablation profiles with sloping wall. In contrast, clean circular ablation profiles are obtained with polymer TP 2, which are characterized by circular contours, steep edges, and flat bottoms of the ablated craters. The origins of these differences are investigated. A comparative study of excimer laser ablation of TP 2 at 248 and 308 nm shows that the latter wavelength is more effective; the plateau value of the ablated depth per pulse corresponds to ≈ 1 μm at 248 nm and ≈ 3 μm at 308 nm. This dependence is attributed to the photolysis behaviour of the triazene compounds: nitrogen released upon photolytic bond cleavage acts as a driving gas which promotes the ablation. As a consequence, no ‘incubation pulses’ are required for triazene polymer ablation in the investigated fluence range.
Nichtadditivität von Brechungsindexinkrementen bei Copolymeren mit N‐Phenylmaleimid
Authors: Francuskiewicz Frieder , Glöckner Gottfried , Kratochvíl Pavel
Published: April 2003

Brechungsindexinkremente der Copolymeren von N‐Phenylmaleimid mit Styrol, Methylmethacrylat und Acrylnitril sowie der entsprechenden Homopolymeren wurden in verschiedenen Lösungsmitteln bei 536 nm und 25°C gemessen. Die Brechungsindexinkremente der Copolymeren mit Styrol und Methylmethacrylat zeigten in allen verwendeten Lösungsmitteln positive Abweichungen von der für die meisten Copolymeren üblichen Additivität. Dies wurde durch unabhängige Mesungen der partiellen spezifischen Volumina bestätigt. Mögliche Ursachen der Nichtadditivität werden erörtert.
PET/PHB‐LC polyesters with improved mechanical properties — terminal group coupling with diisocyanate, I
Authors: Leistner Dirk , Stephan Michael , Häßler Liane , Vogel Roland , Rätzsch Manfred
Published: April 2003

In order to increase the molecular weights of poly(ethylene terephthalate‐co‐oxyben‐zoate)s (PET/PHB) these polymers were modified with methylene‐diphenyldiisocyanate (MDI) in the melt to couple the carboxy terminal groups, forming a copolyester amide. Starting from M̄n 12 500, various M̄n values, partly up to 60 400, were obtained in dependence on the MDI quantity. The copolyester amides were characterized by IR spectroscopy, DSC, M̄n and rheological measurements. The MDI modification of PET/PHB causes also an increase in melt viscosity and a decrease in crystallinity in the solid state. Injection molded samples showed a considerable increase in tensile strength, elastic modulus and above all impact strength.
Precipitation polymerization of acrylic acid: Kinetics, viscosity and heat transfer
Authors: Poersch‐Panke Hans‐Günter , Avela Arno , Reichert Karl‐Heinz
Published: April 2003

The free‐radical precipitation polymerization of acrylic acid in toluene was studied in an isothermal reaction calorimeter. The polymerization shows an autocatalytic behaviour of the rate of polymerization typical for precipitation polymerizations. The rate of polymerization with respect to conversion can be modeled by taking the volume fraction of the precipitated polymer into consideration.

The viscosity of the reaction mixture increases with increasing volume fraction of precipitated polymer. The viscosity runs through a maximum at high conversion. The final viscosity decrease is probably due to shear stress caused aggregation phenomena of the polymer particles. A model is discussed which can describe the increase and decrease of viscosity of the system.

By means of reaction calorimetry it is possible to determine the reaction‐sided heat transfer coefficient during polymerization. The comparison of the experimentally determined temperature course of the reaction mixture and the temperature course calculated with a coupled model of the polymerization and the calorimeter shows that the heat‐transfer characteristic changes instantaneously during a small conversion interval at the very beginning of the polymerization.
Pervaporation and membrane distillation through membranes made of poly(2,6‐dimethyl‐1,4‐phenylene oxide)
Authors: Schauer J. , Schwarz H. H. , Eisold C.
Published: April 2003

The ability of poly(2,6‐dimethyl‐1,4‐phenylene oxide) membranes to separate water‐ethanol mixtures by pervaporation was examined. Asymmetric membranes were prepared from solutions containing chloroform as a solvent and 1‐butanol as a nonsolvent by the phase‐inversion process. Homogeneous, dense membranes were prepared from chloroform solutions by evaporation. Nonporous membranes (membranes precipitated from solutions with a low amount of the nonsolvent or prepared by evaporation) were preferentially permeable to water. Microporous membranes (precipitated from solutions with a high amount of the nonsolvent) were preferentially permeable to ethanol, provided the membrane is not wetted by the feed solution.
Kompensationsspannung als zusätzliches Beurteilungskriterium für PAN‐Precursorfasern
Authors: Mikołajczyk Teresa , Kamecka Katarzyna , Krucińska Izabella , Mikołajczyk Włodzimierz
Published: April 2003

Fasern aus Poly(acrylnitril‐co‐methylacrylat‐co‐itaconsäure) wurden unter unterschiedlichen Bedingungen verstreckt. Die verstreckten Fasern wurden bezüglich des allgemeinen Orientierungsgrads und des Orientierungsgrads und Anteils der parakristallinen Gebiete charakterisiert; mechanische Kennwerte der Fasern wurden gemessen. Aus der Korrelation der erhaltenen Werte mit der sogenannten Kompensationsspannung der Fasern wird geschlossen, daß letztere ein Maß für die Eigenspannungen in den Fasern darstellt und eine Optimierung der Herstellung und Weiterverarbeitung der Fasern ermöglicht.
Removal of escherichia coli from water by systems based on polystyrene‐g‐ and poly(glycidyl methacrylate)‐g‐amines
Authors: Tashiro Tatsuo
Published: April 2003

Reaction products of soluble chloromethylated polystyrene with diethylamine, poly(styrene‐co‐chloromethylstyrene) with diethanolamine, and poly(styrene‐co‐glycidyl methacrylate) with diethanolamine were prepared and supported on activated alumina granules. A study was made of removal of Escherichia coli cells from water by these supported alumina granules. When these granules (0.100 g) were stirred in a viable cell suspension (107–8 cells/ml, 20 ml), the viable cell number decreased by the adsorption of the cells to the granules. The adsorption attained approximately to the equilibrium (saturated adsorption) after about 2 h from the start of the adsorption. The decrease coefficient (D, which corresponds to the adsorption rate constant) was determined from the decrease in the viable cell number in the adsorption for about 2 h from the start.
Supported titanium catalyst for propylene polymerization. Convenient synthesis of unsolvated anhydrous magnesium chloride from MgCl2 · 6 H2O
Authors: Gupta Virendra Kumar , Satish Sheo , Bhardwaj Ishwar Singh
Published: April 2003

Reaction of chlorosilanes (Me3SiCl, R2SiCl2, SiCl4; RMe, Ph) with MgCl2 · 6 H2O were investigated for the efficiency of removal of water. The nature of chlorosilane is found to govern the rate of dehydration. The treatment of hydrated magnesium chloride with dichlorodiphenylsilane gives unsolvated anhydrous magnesium chloride in high yields. Anhydrous MgCl2 is used as support for the preparation of titanium catalyst. The catalyst in conjunction with Et3Al and Ph2Si(OMe)2 as cocatalyst system shows high activity for propylene polymerization.
Syntheses and reactions of photopolymers, II. Interfacial polycondensation, microencapsulation, photodegradation, release measurements
Authors: Nuyken Oskar , Dauth Jochen , Stebani Jürgen
Published: April 2003

Photosensitive microcapsules, which are thermally quite stable, are formed via interfacial polycondensation in which one of the shell‐forming reactants contains an azo function.

An azo monomer, containing α,ω‐carboxylic diacid dichloride was reacted with a trifunctional aliphatic amine on the oil‐water interface resulting in a shell‐forming crosslinked polyamide. The size of the resulting photosensitive microcapsules was determined. It could be shown that these microcapsules can be opened by means of UV‐light.
The dependence of enzyme leakage on crosslink density in poly(N‐vinyl‐2‐pyrrolidone) hydrogels with immobilized urease
Authors: Güven Olgun , Şen Murat
Published: April 2003

Urease enzyme was immobilized in hydrogels prepared from vinyl pyrrolidone/water/crosslinking agent ternary mixtures by γ‐irradiation of the solutions at room temperature. Two types of crosslinking agents used, namely ethylene glycol dimethacrylate and trimethylol propane triacrylate, yielded hydrogels with different swelling and crosslink density properties. The activity of immobilized urease was measured at the optimum conditions of temperature and pH over a period of time. It has been determined that for hydrogels with average molecular weights between crosslinks, Mc, above 2000, urease leakage is a serious problem. When Mc is around and below this value, immobilized systems showed a long time activity.
Die reaktive Verarbeitung von Polyethylen und Ethylen‐Vinylacetat‐Copolymerem. Verfolgung des Reaktionsverlaufs und Nachweis der Eigenschaftsänderungen
Authors: Vogel Jürgen , Heinze Carina
Published: April 2003

Der Reaktionsverlauf der peroxidischen Vernetzung (1 Gew.‐% Dicumylperoxid (DCP)) von Polyethylen niederer Dichte (LDPE) mit Ethylen‐Vinylacetat‐Copolymerem (EVA) im Kleinstkneter wurde anhand der Anderung des temperaturkorrigierten Drehmomentes verfolgt. über die Variation der Temperatur und Drehzahl wurde der Einfluß der Verarbeitungsbedingungen auf die Vernetzungskinetik untersucht. Sowohl Temperatur‐ als auch Drehzahlerhöhung bewirkten eine Beschleunigung der radikalischen Reaktion. Die Vernetzung der einzelnen Komponenten und des LDPE/EVA Compounds führte zu einer signifikanten Abnahme des Kristallinitătsgrades, was sich makroskopisch in einem Abfall des E‐Moduls im dynamischen Biegeschwingversuch bemerkbar machte. Für den Reaktionsverlauf und die sich ausbildende Morphologie sowie für die mechanischen Eigenschaften des Compounds ist die Schmelzemorphologie vor dem radikalischen Angriff von entscheidender Bedeutung.
Untersuchungen zur thioladdition an polybutadiene
Authors: Klemm Elisabeth , Gorski Ute
Published: April 2003

Die radikalische Addition von Octylmercaptan (RSH) an Polybutadiene unterschiedlicher zahlenmittlerer Molmasse und Konfiguration der Doppelbindungen erfolgt stereoselektiv an die 1,2‐vinyl‐ und 1,4‐cis‐konfigurierte Doppelbindung, während die 1,4‐trans‐konfigurierte Doppelbindung unverandert bleibt. Die Reaktivitätsabstufung 1,2‐ > cis‐ > trans‐Doppelbindung wird in Modellversuchen an den isorneren Pentenen gleichfalls bestatigt. Die Addition ist durch einen Olefin/RSH‐Charge‐Transfer‐Komplex als Pre‐Initiierungsschritt begünstigt.
Sulfobetaine polyurethane ionomers, 2. Dielectric relaxation in polyether‐based polymer and related compounds with Co2+
Authors: Diaconu I. , Buruiană T. , Buruiană E. C. , Coman P.
Published: April 2003

Dielectric relaxation processes in sulfobetaine polyurethane ionomers based on polyether, were studied comparatively to nonionic polyurethane and related compounds with Co2+ (complexed and H2S‐treated forms) by using thermally stimulated depolarization currents (TSDC).

Four relaxation processes denoted as γ, βs, β′ and βh in polyurethane ionomers over the 110–370 K range were observed. Molecular origin of these processes was suggested. The effects of the hard segments content, complexation and H2S treatment on the relaxation processes were explained in terms of the structural modifications of the hard and soft microphases.
Metal ion complexation of poly(acrylamide)‐supported amines crosslinked with N,N′‐methylene‐bis‐acrylamide
Authors: Mathew Beena , Rajasekharan Pillai V. N.
Published: April 2003

The complexation of amino functions supported on poly(acrylamides) with 2–20 mol‐% of N‐(acrylamidomethyl)acrylamide (NNMBA) crosslinks towards Co(II), Ni(II), Cu(II), Zn(II), and Hg(II) ions was investigated. The metal ion uptake was found to be dependent on the extent of the NNMBA crosslinking. The observed trend in complexation is Hg(II) ≫ Cu(II) > Zn(II) > Ni(II) > Co(II). The kinetics of complexation was found to be of first order. The derived metal complexes were characterised by IR and EPR. The complexed resins can be recycled several times without capacity loss. The metal‐desorbed resins showed specificity to the metal ion which was initially present. The extent of swelling of the complexed resins is lower than that of the uncomplexed resins and it varies with the extent of crosslinking.
Conduction mechanism of polycarbonate doped with different transition metals
Authors: Amin M. , Mounir M. , El‐Shekeil Ali , Darwish K. A. , Abu Elez M.
Published: April 2003

The electrical conduction of polycarbonate (PC) doped with different transition metals was studied in the temperature range of 293–493 K. The conductivity of PC doped with FeCl3 is 7 orders higher in comparison with the other samples. The effective potential barrier (Φ) for pure PC was calculated (0.2 eV). Also, the dielectric constant at different temperatures was studied.
Volume change by solvent and temperature of poly(vinyl alcohol) crosslinked by electron irradiation
Authors: Yoshii Fumio , Sudradjat Adjat , Darwis Darmawan , Razzak Mirzan T. , Makuuchi Keizo
Published: April 2003

Responsive poly(vinyl alcohol) PVA hydrogels obtained by electron irradiation after heating of a water‐swollen film show higher elasticity and tougher properties even after boiling in water, although some swelling did occur. The volume of the hydrogel after boiling was very sensitive to solvent (acetone) and temperature. The crosslinked hydrogels show higher tensile strength after rapid contraction by immersion in acetone. The crosslinked PVA was boiled and cooled to induce contraction and swelling cycles. The swelling ratio of hydrogel decreased remarkably at temperatures higher than 40°C.
Change of mechanical properties of crosslinked polyethylene during its thermo‐oxidative aging
Authors: Langlois V. , Audouin L. , Courtois P. , Verdu J.
Published: April 2003

The thermal aging of extruded samples of electron beam‐crosslinked linear polyethylene has been studied in the 110–170°C temperature range. Short and long term changes of mechanical (tensile) properties were observed, and the corresponding mechanisms are discussed on the basis of complementary sol‐gel and gravimetric measurements on whole samples, and density, FTIR and tensile testing on microtome sections.

Two mechanisms are involved in short term changes: a post‐crosslinking and a change of the crystalline morphology (for samples exposed above the melting point). The latter effect is especially important in the case under study where the polymer was crosslinked in the solid state and leads to a noticeable decrease (∼5 MPa) of the yield stress.

The long term changes take place after the end of the induction period of oxidation. They can be interpreted in terms of ductile‐brittle transition induced by structural changes occurring on the macromolecular level (chain scission) as well as macroscopically (core‐shell structure resulting of the diffusion control of oxidation kinetics). It appears that noticeable changes of ultimate elongation occur just before the end of the induction period as detected by IR or DSC method.
Poly(3‐octylthiophene) as semiconductor for schottky barrier: Effects of doping and storage time
Authors: Chen Show‐An , Fang Yih
Published: April 2003

Schottky diodes of aluminium/poly(3‐octylthiophene)(P30T)/indium‐tin oxide with large active area are prepared by using the proposed new casting technique. Their rectifying behavior and junction characteristics are dependent on whether the P30T is doped and on the storage time, but independent of the thickness of the P30T layer. The present technique can also be applied in a fabrication of electronic devices with other soluble conjugated polymers.
Thermal properties of copoly(1,4‐arylene‐1,2,4‐oxadiazole)s having n‐alkyloxymethyl side branches
Authors: Park Sang‐Bong , Jung Jin Chul
Published: April 2003

Two series of copoly(1,4‐arylene‐1,2,4‐oxadiazole)s (co‐PAOs) having n‐butyloxymethyl and n‐octyloxymethyl side branch were prepared by solution cyclodehydration of the corresponding precursor copoly(1,4‐arylene terephthaloyl amide oxime)s (co‐PAAs) obtained by solution polycondensation of mixtures of 2,5‐bis(n‐alkyloxymethyl)‐1,4‐benzenediamide oximes (DIS‐TADO) and terephthaldiamide oxime (TADO) with terephthaloyl chloride. Thermal properties of the copolymers were investigated and discussed in connection with the length and the content of side branches. All the copolymers are crystalline.
Polyurethane ureas with various urea structures. Solution behaviour and morphology
Authors: Joel Detlef , Pohl Gerhard , Hiller Wolf‐Gerald
Published: April 2003

Both the effect of the diamine chain extender on solution properties and the effect of added LiCl destroying the urea hydrogen bonds of the PUU's (polyurethane ureas) in DMF have been investigated. PUU solutions with an even number of CH2 units in the chain extender have higher viscosities than the corresponding solutions with an odd number of CH2 units. While the viscosity of solutions with odd‐numbered methylene groups is independent of time, the even‐numbered ones show a drastic increase in dependence on time and gelation may even occur. Due to diminished associates, time‐independent solution systems of low viscosity have also been obtained by adding a small amount of LiCl to solutions with even‐numbered methylene groups.

In films cast from the solutions the effect of LiCl has been proved in the solid state.
Syntheses of cellulose exchangers carrying chelating anchor groups for selective separation of uranyl ions
Authors: Fischer H.‐J. , Lieser K. H.
Published: April 2003

Syntheses of cellulose exchangers carrying tailor‐made chelating anchor groups are described. One type of anchor groups offers three coplanar carboxy groups for the complexation of UO2+2, a second type coplanar amidoxime‐hydroxamic acid groups and a third type amidrazone‐hydrazide groups. The distance of the groups is varied by use of different terminal dibromo‐n‐alkanes. The anchor groups of type 1 are obtained from malonic acid diethyl ester and dibromalkanes, type 2 and 3 from cyanacetic acid ethylester and dibromoalkanes. The products containing malonic acid diethylester and alkane groups or cyanoacetic acid ethylester and alkane groups, respectively, in the mole ratio 3 : 2 are coupled with hydrazinedesoxycellulose. The carboxy groups are set free by hydrolysis of the ethyl esters in case of type 1, whereas the anchor groups of types 2 and 3 are obtained by reaction with hydroxylamine and with hydrazine, respectively.

The procedures of the syntheses are presented in detail. The products are characterized by the degree of substitution and the content of the individual groups. The anchor groups are inverstigated by means of their 1H‐NMR spectra. The exchange properties are discussed.
Effect of impregnation on the degree of polymerization of cellulose during bleaching of sodapulped sugar cane bagasse
Authors: Marx‐Figini Marianne , Maximino Mirta
Published: April 2003

Samples of sugar cane bagasse pulps, digested at different times without and with previous impregnation, have been bleached and the bleached materials submitted to a detailed study of their degree of polymerization (DP) and the corresponding distributions. The respective results turn out that like in the case of the effect of impregnation on the digestion process, impregnation affects also the bleaching reaction of the digested samples, causing a further remarkable decrease of the degree of polymerization of the cellulose molecules and a deviation of its distribution from the character of a most probable one. The impregnated bleached materials show in addition to the decrease of their DP a certain, albeit slight, diminution in their tensile strength.
Porous ion exchange membranes as potential antifoulants
Authors: Bryjak Marek , Trochimczuk Witold
Published: April 2003

The effect of surface hydrophilization on antifouling properties of ultrafiltration membranes was investigated. The enhanced film model as well as experimental data showed the vital role of surface charge on amount of deposited bovine serum albumin. Two types of materials were studied: high flux polysulfone (capillary, asymmetrical) and low flux polyethylene (flat, symmetrical) membranes. The antifouling effect, revealed mostly by polyethylene membranes, pointed on solute convection as an important factor. When membrane and solute borne this same sign of charge the antifouling effect was governed by the net charge of membrane.
Chemical surface treatment of poly(tetrafluoroethylene) powder
Authors: Huang Chi‐Yuan , Chiang Wen‐Yen
Published: April 2003

Poly(tetrafluoroethylene) powder has been treated with sodium‐naphthalene complex in tetrahydrofuran (THF) to improve its surface properties. The cryocondition (−40°C) was taken to keep the active species alive so that the PTFE powder surface could be etched homogeneously and a large area of PTFE could be etched. The Na‐treated PTFE powder was examined by IR, ESCA (electron spectroscopy for chemical analysis), X‐ray diffractometry, thermal analysis and SEM (scanning electron microscopy). IR spectra showed that the surface structure of Na‐treated PTFE powder possessed a lot of CFCF− double bond structures. ESCA surface analyses also revealed the formation of CFCF− double bonds. During the process of sodiumnaphthalene complex etching, most of NaF salt formed was adsorbed on the surface of treated PTFE (CPTFE, NaF adsorbed) and a small amount of NaF salt was found doped into treated PTFE. As a result, part of the surface of treated PTFE was found doped into treated PTFE. As a result, part of the surface of treated PTFE was similar to a free alkali‐fluoride‐doped polyfluoroacetylene. It was shown by SEM that the etched PTFE had a web‐like surface.
A novel Si‐containing copolymer for a resist highly etching‐resistant to oxygen plasma
Authors: Chiang Wen‐Yen , Lu Jin‐Yuh
Published: April 2003

A new copolymer, poly(maleimide‐alt‐trimethylvinylsilane) (PMVS), with a high silicon content was synthesized by free‐radical copolymerization, in order to obtain a positive photoresist containing diazonaphthoquinone sulfonate as a dissolution inhibitor. PMVS shows a high etching selectivity of 1 : 16 compared to a commercially available, hard‐baked photoresist (HPR‐204). In addition, the rigid cyclic maleimide group is responsible for high temperature stability.
Characteristics of permeation and separation of aqueous alcoholic solutions with chitosan derivative membranes
Authors: Uragami Tadashi , Kinoshita Hiroyuki , Okuno Hiroshi
Published: April 2003

Permeation and separation characteristics for the feed vapours from aqueous alcoholic solutions through chitosan derivative membranes such as chitosan acetate (GA‐ChitoA), chitosan (GA‐Chito), and carboxymethyl chitosan acetate (GA‐CM‐ChitoA) membrane crosslinked with glutaraldehyde were investigated by evapomeation. The GA‐Chito and GA‐CM‐ChitoA membranes prepared from casting solutions containing an optimum amount of glutaraldehyde showed a high permeation rate and high water permselectivity for an azeotropic composition in an aqueous ethanol solution. The permselectivity for water through the GA‐CM‐ChitoA membrane in evapomeation was in the order of aqueous solutions of methanol < ethanol < 1‐propanol. The effect of the chemical and physical structure of these hydrophilic membranes on the permeation and separation characteristics is discussed.
Coemulsion and electrodeposition properties of mixtures of a poly(oxypropylene)‐modified cationic epoxy resin and nonionic crosslinker system
Authors: Chen Yahn‐Haur , Yang Chin‐Ping
Published: April 2003

The emulsification and electrodeposition properties of mixtures of a poly(oxypropylene) (POP)‐modified cationic epoxy resin (III) and nonionic pentaerythritol/toluene diisocyanate/2‐ethylhexanol (PETOL‐TDI‐2EH, V) were investigated and the compositions of their electrodeposited films were obtained by Fourier Transform Infrared (FTIR) quantitative analysis to study the effects of soft segments (oxypropylene groups) contained in resins III on the coemulsion and electrophoretic behavior.

The results indicate that the deposition yield and throwing power of an emulsion of individual III are deeply affected by its average molecular weight (AMW). Resin III with higher AMW has higher deposition yield but lower throwing power. Moreover, the deposition yield of V/III coemulsion also increases with increasing the AMW of III. On the other hand, the throwing power of V/III coemulsion is not related to the AMW of III but affected by the amount of soft segments in III. Increasing “Soft segment” Content in III increases the throwing power of coemulsion. Furthermore, at the conditions providing stable coemulsion, the composition of electrodeposited film is almost equal to the resin composition of coemulsion.
Chemical modification of poly(epichlorohydrin) with unsaturated potassium carboxylates
Authors: Reina J. A. , Cádiz V. , Mantecón A. , Serra A.
Published: April 2003

Poly(epichlorohydrin) was modified by nucleophilic substitution with some aliphatic potassium carboxylates containing terminal double bonds (10‐undecenoate, 4‐pentenoate and 3‐butenoate). In order to monitor the degree of substitution achieved, different reaction conditions were tested. The polyethers obtained were characterized by spectroscopic techniques, elemental analysis, thermal methods, viscosity determinations and osmometric measurements. A slight crosslinking and the reported main chain cleavage were both detected. Finally, it must be pointed out that, during the substitution reaction with the vinylacetate, isomerization to crotonic ester took place.
Viscosity characteristics of some para‐nonylphenol formaldehyde novolac epoxy resins
Authors: Caşcaval Constantin N. , Mustaţǎ Fǎnicǎ , Roşu Dan
Published: April 2003

Para‐nonylphenol formaldehyde novolac epoxy resins with molecular weights between 640 and 3150 were studied regarding the viscosity behaviour. The estimation of both the intrinsic viscosity and the molecular weight of the epoxidized resins resulted in a straight relationship between these experimental parameters: [η] = k1 + k2M̄n, where k1 = 137 dl/g and k2 = 99.2·10−3 dl/g.

Study of the flow behaviour of the molten epoxide resins allowed the measurement of the apparent shear viscosity, the shear stress, the shift factor, the melt flow index, the consistency index, and the flow activation energy. The flow data, which were analysed both as a function of temperature and of the shear rate, led to the conclusion that para‐nonylphenol formaldehyde novolac epoxy resins show a non‐Newtonian rheological behaviour of pseudoplastic type.
Antioxidants and stabilizers, 118. Influence of the carbon black chezacarb EC on thermooxidation of cyclohexene doped with hydroperoxide decomposers and metal deactivators
Authors: Rotschová Jitka , Pospíšil Jan
Published: April 2003

A model system consisting of cyclohexene and various amounts of carbon black was oxidized with O2 at 60°C in the presence of hydroperoxide decomposers, bifunctional antioxidants and metal deactivators. No metal deactivating contribution to the antioxidant effect was observed with phosphites. Efficient chain‐breaking activity was achieved with 4,4′‐thiobis(2‐tert‐butyl‐5‐methylphenol). However, metal deactivators were able both to prolong the induction period and retard the oxidation rate after the induction period. An efficient long‐term stabilization with Chezacarb EC cannot be achieved without chelate‐forming stabilizers.
Photo‐ and thermoinitiated curing of epoxy resins by sulfonium salts
Authors: Stapp Bernhard , Schön Lothar , Bayer Heiner , Hoffmann Michael
Published: April 2003

A number of benzylthiolanium salts have been synthesized, analysed and evaluated by differential scanning calorimetry and viscosity measurements with respect to their potential use as thermal curing agents for epoxy resins. Over a wide range of Hammett constants a correlation exists between initial reactivity, shelf life and the electronic substituent effects of the benzyl group. A combination with arylsulfonium salts leads in singular cases to dual cure systems with attractive properties of thermal and UV induced curing. The sensitization of benzylthiolanium salts also leads to dual cure systems. This opens up new possibilities for UV curable epoxy resins in electronic applications requiring additional curing in shaded areas.
Grafting of different vinyl monomers onto sodium salt of partially carboxymethylated amylose
Authors: Patel Bipin K. , Patel Chandrakant P. , Trivedi Harikrishna C.
Published: April 2003

In order to study the reactivity of different vinyl monomers, the grafting of different vinyl monomers such as acrylonitrile (AN), methylacrylate (MA), ethylacrylate (EA), methyl methacrylate (MMA), butylacrylate (BA) and vinyl acetate (VAc) onto the sodium salt of partially carboxymethylated amylose (DS = 0.313) has been carried out using ceric ammonium nitrate as an initiator. The following reactivity order of monomers has been found: AN > MA > EA > MMA > BA > VAc.
Preparation and characterization of carboxylic cation exchange resins from the reaction of poly(vinyl alcohol) with melamine‐formaldehyde and some hydroxy acids
Authors: Ibrahim N. A. , Abo‐Shosha M. H.
Published: April 2003

The synthesis of cation exchange resins via the reaction of poly(vinyl alcohol) as a carrier, citric acid as a catalyst and reactive additive to produce resin structures with grafted carboxy groups, along with a melamine‐formaldehyde precondensate, responsible for crosslinking‐reinforcing and insolubilizing the resin structure as well as for fixing and binding the acidic functional groups onto the resin structure, has been investigated using varied molar ratios of reactants and varied time as well as temperature. Reaction conditions were selected to prepare a cation exchange resin based on citric acid. Two other cation exchange resins based on tartaric acid and glycolic acid, were also prepared under the same selected reaction conditions. These three resins were characterized by potentiometric titration, water solubility and swellability, as well as durability to use.
Surface modification of a polypropylene film by low‐pressure discharge and the adhesion of a vacuum‐deposited layer of aluminium
Authors: Garby L. , Chabert B. , Sage D. , Soulier J. P. , Bosmans R.
Published: April 2003

Low‐pressure discharge treatments were applied to the surface of polypropylene. ESCA analyses, wettability measurements and adhesion tests were carried out to characterize surface modifications as a function of treatment time and nature of gas (air or argon). Advancing and receding contact angles were measured with an automatic dynamical tensiometer. The liquids used were water (very polar liquid) and methylene iodide (apolar liquid). The results show an increase in wettability by the surface treatment. This is due to the creation of high‐energy polar sites. ESCA analysis also shows that the modified surface layer is soluble in methanol and is made up of low‐molecular‐weight material.

Adhesion of polypropylene/aluminium is also increased by the low pressure discharge treatment from the few first seconds of the treatment. This adhesion increase is a function of the polar component of the polymer surface energy.
Poly‐ε‐caprolactone/poly(Methylmethacrylate) reactive blends: Correlation between synthesis, morphology and physical properties
Authors: di Liello V. , Malinconico M. , Martuscelli E. , Ragosta G. , Rizzo A. , Volpe M. G.
Published: April 2003

Blends of poly‐ε‐caprolactone (PCL) and poly(methylmethacrylate) (PMMA) were prepared by a reactive method and characterized by thermal, morphological, dynamic mechanical and mechanical analyses. For comparison, “mechanical” blends, obtained by melt‐mixing of preformed polymers, have been prepared and characterized. The two series of blends are different in phase structure and in mechanical tensile properties, probably due to the formation of grafted species during reactive blending.
Effectiveness of UV‐stabilizers based on oligomeric benzophenone on the stabilization of poly(methyl methacrylate)
Authors: Menon Susha V. , Parmar Jayant S.
Published: April 2003

New oligomeric UV‐stabilizers of the type of 2‐hydroxy‐4‐alkoxy benzophenone‐formaldehyde prepared earlier were incorporated into poly(methyl methacrylate). Accelerated photooxidation as well as oven ageing tests were performed. The stabilizer effectiveness was estimated by IR and UV spectral study, mechanical testing, viscosity measurement, and weight loss measurement. Compared to monomeric stabilizers, the oligomeric compounds show better performance.
Photomodifizierung von Ultrafiltrationsmembranen, 1. Photochemiche Modifizierungen von Polyacrylnitril‐Ultrafiltrationsmembranen mit Arylaziden
Authors: Ulbricht Mathias , Hicke Hans‐Georg
Published: April 2003

Durch Photoreaktionen aromatischer Azide sollte die ternwirksame Oberfläche von Ultrafiltrationsmembranen aus Polyarcrylnitril chemisch modifiziert werden, um deren Ultrafiltrations‐Eigenschaften gezielt zu verändern. Neun mit unterschiedlich hydrophilen bzw. hydrophoben Gruppen substituierte Azide wurden eingesetzt. Durch Träanken mit 0,05 molaren Lösungen der Arylazide in Methanol naöhmen die Membranen insgesamt 1,25–1,95 · 10−4 mol/g auf. Davon wurden ca. 1 ·10−4 mol/g an der Oberfläche der Porenmembran (79 m2/g, mit Hilfe der p‐Nitrophenol‐Adsorptions‐isotherme ermittelt) adsorbiert. Die HPLC‐Analyse der Extrakte von Membranproben gestattete für 4‐Azidobenzoesäuremethylester als Modellverbindung die Ermittlung von Umsatz und Produktverteilung bei der UV‐Photolyse. Die Umsatzgeschwindigkeit nimmt mit der Belichtungsdauer ab, nach 32 min waren 59% Azid photolysiert. Als lösliche Photolyseprodukte wurden 4‐Nitroso‐, 4‐Nitro bzw. 4‐Aminodenzoesäuremethylester in 3%, 13% bzw. 5% Ausbeute gefunden, die Azo‐ bzw. Azoxy‐Verbindungen traten nur in Spuren auf. Mit Hilfe von UV‐Reflexions‐ und FT‐IR‐ATR‐Spektroskopie an PAN‐Membranen konnte eine Funktionalisierung der Membranoberfläche durch sekundäre Amin‐Strukturen als Ergebnis der Photomodifizierung nachgewiesen werden. Die entwickelte Photomodifizierungsvariante sollte durch Einsatz von Arylaziden mit Prinzipiell analoger Photogreaktivität, aber unterschiedlichen funktionellen Gruppen die Herstellung spezifisch oberflächenmodifizierter PAN‐UF‐Membranen gestatten.
Photocrosslinking of oriented ultra‐high molecular weight polyethylene
Authors: Zamotaev Pavel V. , Chodak Ivan
Published: April 2003

The crosslinking of drawn tapes and fibers from ultra‐high molecular weight polyethylene (UHMW‐PE) initiated by UV‐irradiation has been investigated. Both xanthone and sulphuryl chloride (SO2Cl2) appeared to be rather effective photoinitiators and high gel content was obtained after UV‐exposition in air. The effect of crosslinking on the properties of UHMW‐PE tapes and fibers was examined by tensile tests, dynamic mechanical spectroscopy, and differential scanning calorimetry. High temperature resistance was shown to increase; photocrosslinked fibers retain the storage modulus being about 100 MPa at 200°C whereas uncrosslinked samples break at 135–137°C. No reducation of mechanical properties was found at ambient temperature and hydrophilization of the surface was observed.
Reactive blending of bioaffine polyesters through free‐radical processes
Authors: Cavallaro Pasquale , Immirzi Barbara , Malinconico Mario , Martuscelli Ezio , Volpe Maria Grazia
Published: April 2003

Blends of poly‐ε‐caprolactone (PCL) and poly(β‐hydroxybutyrate‐co‐β‐hydroxy‐valerate) (PHBV) containing 4 mol‐% of hydroxyvalerate were prepared by mixing the two polymers in the presence of either dicumylperoxide (DCPO) at 160°C or dibenzoylperoxide (DBPO) at 100°C. Similarly, blends were obtained by mixing the two polymers without any peroxide added. The blends were prepared in to complementary compositions, namely 70 wt.‐% PCL/30 wt.‐% PH BV and 30 wt.‐% PCL/70 wt.‐% PHBV, respectively. Also pure polymers were reacted with DCPO at 160°C in the same way as the blends.

Thermal (DSC), mechanical (tensile tests) and SEM analyses were performed on the blends and on the pure polymers.

Significant differences were found in the chemical‐physical characteristics of blends with and with out peroxides as well as in blends prepared at low and high temperatures.
Poly(benzimidazole‐imide‐amide)s containing hexafluoroisopropylidene units
Authors: Hamciuc Elena , Bruma Maria , Mercer Frank W. , Simionescu Cristofor I.
Published: April 2003

New poly(benzimidazole‐imide‐amide)s containing hexafluoroisopropylidene units in the backbone have been synthesized by polycondensation of diaminobenzimidazoles with novel diacid dichlorides which incorporated both imide and hexafluoroisopropylidene groups. These polymers have high thermal stability and low dielectric constant and are soluble in polar aprotic solvents giving transparent, flexible films by casting their solutions. Such properties make them attractive for applications as dielectric coatings in microelectronics.
Polychelates of poly[N‐(4‐carboxy‐3‐hydroxyphenyl)maleimide]
Authors: Patel Dinesh K. , Patel Chetan G. , Parmar Jayant S.
Published: April 2003

The reactions of the bidentate polymeric chelating ligand poly[N‐(4‐carboxy‐3‐hydroxyphenyl)maleimide] with Co(II), Ni(II), Cu(II), Zn(II) and UO2(II) metal ions were investigated. Analytical, magnetic, spectral and thermal studies were used to characterize these polychelates. All these polychelates are stable, intensely coloured solids and insoluble in common organic solvents.
Grafting of polyesters by free‐radical chain transfer
Authors: Braun D. , Hempler P.
Published: April 2003

Graft copolymerizations of polyesters with styrene by free‐radical chain transfer reactions were investigated. A model polyester of trans‐l,4‐cyclohexanediol and sebacoy1 dichloride was used as backbone chain. The graft products were characterized. Furthermore, liquid crystalline polyesters with 1,4 : 3,6‐dianhydrosorbitol and 1,4‐anhydroerythritol as diol components were synthesized and used in graft copolymerizations with styrene. Polymer blends of tetramethylbisphenol A polycarbonate and the LC‐polyester with and without polystyrene grafts were prepared by common precipitation of polymer solutions and their behaviour was examined by torsion pendulum, dynamic‐mechanical thermoanalysis and scanning electron microscopy. The grafted polyester turned out to be an efficient phase compatibilizer.
Structural, physical and mechanical properties of carbon fibre‐reinforced composites of diglycidyl ether of bisphenol‐A and bisphenol‐C
Authors: Soni Hitesh K. , Patel Ranjan G. , Patel Vithal S.
Published: April 2003

Carbon fibre‐reinforced composites of conventional diglycidyl ether of bisphenol‐A (DGEBA) and liquid diglycidyl ether of bisphenol‐C (DGEBC) were prepared, using 4,4′‐diaminodiphenylmethane (DDM) or 4,4′‐diaminodiphenylsulfone (DDS) curing agent and evaluated for their physical properties (density, void content) and mechanical properties (flexural strength and interlaminar shear strength). Thick films of the neat resin were also prepared and their flexural strength has been studied. It is observed that DGEBC‐curing agent system shows improved properties compared to DGEBA‐curing agent system.
Preparation and characterization of new synthetic noncross‐linked anion exchange membranes
Authors: Lin Mei‐Chih , Takai Nobuharu
Published: April 2003

New synthetic noncross‐linked anion exchange membranes have been prepared by casting a solution of quaternized chloromethylstyrene‐methyl methacrylate copolymers containing 64.0, 42.9, 19.7, 12.9 and 11.0 mol‐% chloromethylstyrene. The ion exchange capacity, water content and physicochemical properties (membrane potential and transport number) of these membranes were studied. The results showed that the copolymers can be fabricated in membrane form after treatment with tertiary amine, of which the membranes produced from the 12.9 and 11.0 mol‐% copolymer exhibited excellent dimensional stability and mechanical strength towards dilute alkali solution, dilute acid solution and salt solution, and were soluble in a variety of organic solvents, such as acetone, methyl ethyl ketone and methanol. Their anion transport numbers determined from the membrane potential measurements in 0.01 N and 0.3 N KCI solution were 0.96 and 0.97, respectively.