bluuebunny/crossref_metadata_2025_split huggingface dataset:
Grafting onto wool X. Graft copolymerization of vinyl acetate and methyl acrylate in presence of potassium persulphate — ferrous ammonium sulphate (KPS‐FAS) system as redox initiator
Authors: Misra B. N. , Dogra R. , Mehta I. K. , Singha A. S. 
Published: April 2003

AbstractGraft copolymerization of vinyl acetate (VAC) and methyl acrylate (MA) onto Himachali wool was studied at 40, 45, 50, and 60°C in aqueous medium by using (KPS‐FAS) system as redox initiator. The maximum grafting of both VAC and MA occurred at 60°C. The nature of vinyl monomer was found to influence grafting. The percentage of grafting was determined as functions of (a) concentration of monomer, (b) molar ratio of FAS/KPS, (c) reaction time and (d) temperature. Maximum grafting of both VAC and MA occurred at a molar ratio of FAS:KPS = 0.713 : 1. The rate of grafting (Rp) and the induction period (Ip) of VAC and MA were determined as a function of total initial monomer concentration. MA, an acceptor monomer was found to be several times more reactive than VAC, a donor monomer.
Grafting vinyl monomers onto wool fibers, IX. Graft copolymerization of methyl methacrylate onto wool using peroxydiphosphate‐cysteine redox system
Authors: Nayak Padma L. , Lenka Subasini , Mishra Munmaya K. 
Published: April 2003

AbstractThe graft copolymerization of methyl methacrylate onto wool was studied at 50°C using peroxydiphosphate‐cysteine redox system as initiator. The rate of grafting was determined by varying monomer, initiator, cysteine, acid and temperature. The grafting is considerably influenced by chemical modification prior to grafting. A suitable kinetic path has been pictured and a rate expression has been derived.
Functional monomers and polymers, 85. On the adsorption of bromine onto chitosan
Authors: Shigeno Yasuhiro , Kondo Koichi , Takemoto Kiichi 
Published: April 2003

AbstractThe adsorption of bromine onto powdery chitin, chitosan and cellulose was studied in an aqueous bromine‐potassium bromide solution at 30°C. Chitosan was found to show an excellent ability of adsorbing bromine as well as iodine. The chitosan film also exhibited high ability of adsorbing bromine both in methanol and in aqueous potassium bromide solutions.
Functional monomers and polymers, 74. Physico‐chemical study on the chitosan‐iodine complexes
Authors: Shigeno Yasuhiro , Kondo Koichi , Takemoto Kiichi 
Published: April 2003

AbstractThe adsorption of iodine on chitosan was studied by physico‐chemical methods. The scanning electron micrograph measurements of chitosan‐iodine adducts showed that iodine molecules were adsorbed uniformly on the chitosan film when the film was treated with aqueous iodine‐potassium iodide solution. The thermogravimetric analysis of the adducts revealed that the loss in weight began at about 190°C, and that iodine molecules were thus well‐complexed with chitosan. It was also found that the IR spectra of the chitosan films showed the amide I and amide II bands shifted to lower frequencies due to the iodine adsorption. The X‐ray diffractometry of these adducts was further carried out, and it was found that the iodine adsorbed chitosan showed no crystalline pattern, different from that of the original chitosan which showed crystallinity in some extent. The chitosan recovered after desorbing iodine by immersion in aqueous sodium thiosulfate solution was amorphous.
Preparation of copolymers from styrene and some unsaturated ketones and studies on their photodestruction in a condensed phase
Authors: Nenkov G. , Georgieva T. , Stoyanov A. , Kabaivanov V. 
Published: April 2003

AbstractA comparative photodestruction study was carried out on solid state copolymers of styrene with methyl vinyl ketone, methyl isopropenyl ketone, phenyl vinyl ketone, benzalacetone and benzalacetophenone. The photolysis of the examined copolymers was found to proceed rapidly higher destruction rates being observed with increasing the ketone concentration. The rate of light‐induced destruction for the first three copolymers was markedly greater than that of the styrene‐benzalacetone and styrene‐benzalacetophenone copolymers. The photodestruction proceeds probably by the Norrish II mechanism.
Heat transfer printing of polyester using alginate films
Authors: El‐Thalouth I. Abd , El‐Kashouti M. A. , Hebeish A. 
Published: April 2003

AbstractThe suitability of coloured alginate films in heat transfer printing of polyester fabric was examined. The colour strength of the prints depended on the dye concentration in the film, temperature and, to some extent, the time of transfer. The prints acquired excellent washing fastness and at least four prints having comparable colour strength could be achieved by using the same film.
Enzyme immobilization on polyglycidylmethacrylate graft‐copolymer of different polysaccharides
Authors: D'Angiuro L. , Cremonesi P. , Cantafi R. , Mazzola G. , Vecchio G. 
Published: April 2003

AbstractComparative results obtained in preparing and characterizing samples of enzymes immobilized by reaction with polyglycidylmethacrylate (PGMA) copolymers with different polysaccharide matrices are reported. Sepharose copolymers having between 25 and 50% synthetic polymer were used to find the best immobilization conditions of horseradish peroxidase (HRP) and glucose‐oxidase (GOD) (pH, time, temperature, enzyme cncentration). Activity, enzyme loading and coupling efficiency of immobilized HRP and GOD are greatly dependent on the type of matrix while the polymer content is less important. Coupling efficiencies between 0.8 and 1.5% have been obtained for HRP samples, whereas for GOD samples coupling efficiencies three times greater were obtained. HRP and GOD immobilized samples show Km′ values greater than those of corresponding free enzymes and this indicates diffusion limitation phenomena.Storage, thermal and operational stability were also studied. In general the storage stability could be considered satisfactory (50% residual activity after 360 days). Sepharose and starch HRP‐copolymers had an improved thermal stability compared with that of free enzyme. Residual activity found in continuous operation tests carried out on HRP‐immobilized samples turned out to be dependent on support. HRP‐PGMA‐Cellulose sample gave the best results (50% residual activity after 16 days). PGMA‐graft‐copolymers have also been used to immobilize other enzymes such as α‐amylase, α‐chymotrypsin and cellulase.
Reaktive Träuger mit Maleinimidgruppen zur Enzymimmobilisierung
Authors: Manecke Georg , Middeke Hermann‐Josef 
Published: April 2003

AbstractEs wurden hochpolymere Träger mit Maleinimidgruppen dargestellt und deren Bindungsverhalten für Cystein und thiolgruppenhaltige Enzyme in Abhängigkeit von verschiedenen Parametern wie Enzymkonzentration, Temperatur, pH‐Wert, Reaktionszeit und Harnstoffkonzentration untersucht. In Trypsin und α‐Chymotrypsin, die keine SH‐Gruppen aufweisen, wurden Thiolgruppen durch Thiolierung mit N‐Acetyl‐D,L‐homocysteinthiolacton eingeführt. Die am Polymeren gebundene Enzymmenge und die Aktivität der Immobilisate wurden bestimmt.
Biaxiales Recken und Orientierungszustand von Polymeren II. Experimentelle Untersuchungen an Polyethylenterephthalat‐Folien
Authors: Jungnickel Bernd‐ J. 
Published: April 2003

AbstractUnter Annahme eines pseudoaffinen Deformationsmechanismus wurden sehr allgemeine quantitative Zusammenhänge zwischen Orientierungszustand und Reckgeometrie hergeleitet. Diese Beziehungen werden zur Analyse des Bowing sowie der Abhängigkeit des Orientierungszustandes von der Recktemperatur bei technischen Polyethylenterephthalat‐Folien herangezogen. Rechtfertigend hierfür ist der Nachweis, daß bei aus dem amorphen Zustand gereckten Folien die pseudoaffin transformierten Strukturvektoren von der Kettenrichtung in den kristallinen Bereichen repräsentiert werden. Es zeigt sich, daß bereits geringe Störungen der Reckgeometrie zu einer deutlichen Verlagerung der mittleren Kettenrichtung führen. Die Unterschiede zwischen den berechneten und gemessenen Orientierungsgraden werden dem plastischen Anteil and der Verformung zugeschrieben.
Derivatives of lignin as synthetic tanning agents
Authors: Gemei Mervat S. , Makar Saad M. , Saleh M. Salah El‐Din 
Published: April 2003

AbstractAlkali lignin was successfully converted to chemical derivatives which could be used as synthetic tannins for leather production. The prepared lignin derivatives were: nitrolignin, aminolignin and chlorolignin. their affinity to chromed hide powder and polyamide powder as model substances for collagen was tested by column chromatography.Aminolignin showed a higher percentage adsorption on chromed hide powder than nitrolignin and chlorolignin, indicating strong irreversible bonding.Measurements of the shrinkage temperature (Ts) of the pelts tanned with those compounds showed that the tanning effect of aminolignin on delimed pelts was satisfactory, and almost similar to the tanning effect of vegetable tannins, followed by nitrolignin, whereas chlorolignin showed a slight increase in the Ts values of tanned pelts, i.e. weak tannage properties.
Synthesis and properties of some alkenyl‐ and alkinyl‐2‐cyanoacrylates
Authors: Kotzev Dimiter L. , Novakov Peter C. , Kabaivanov Vladimir S. 
Published: April 2003

AbstractSome alkenyl‐ and alkinyl‐2‐cyanoacrylate monomers, possessing adhesive properties were synthesized. The ease of esterification of cyanoacetic acid, the first step of the synthesis, with some alcohols was in the following order:
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After condensation of the cyanoacetates with formaldehyde to low molecular weight polymers and depolymerization in vacuum, allyl‐2‐cyanoacrylate, propargyl‐2‐cyanoacrylate, 1‐methyl‐2‐propinyl‐2‐cyanoacrylate and 1‐propyl‐2‐propinyl‐2‐cyanoacrylate were obtained, the last two for the first time. It was found that the strength of the adhesive bonds of these monomers depends primarily on the number of C atoms in the ester group of the molecule, i.e.
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The introduction of double and triple bonds increases the tensile strength properties. The unsaturated cyanoacrylates also have a better heat‐resistance of their bonds: CH2CHCH2 > CHCCH2 > CHCC(CH3)H > CHCC(C3H7)H > alkyl. This result is explained with the formation of cross‐links in the adhesive layer, confirmed by IR and thermogravimetric data.
Antioxidants and stabilizers, 81. Transformations of N,N′‐diphenyl‐ and N‐phenyl‐N′‐isopropyl‐1,4‐benzoquinonediimines on silicagel
Authors: Taimr L. , Pospíšil J. 
Published: April 2003

AbstractTransformations of N,N′‐disubstituted 1,4‐benzoquinonediimines have been investigated as a means for the elucidation of processes occurring in hydrocarbon polymers stabilized with amine antidegradants and of transformations accompanying the analyses of extracts of aged rubbers. N‐Phenyl‐N′‐isopropyl‐1,4‐benzoquinonediimine (1b) is quickly hydrolyzed on a silicagel surface, giving rise to N‐phenyl‐1,4‐benzoquinoneimine (3). The hydrolysis of N,N′‐diphenyl‐1,4‐benzoquinonediimine (1a) proceeds more slowly under the same conditions, but the released aniline quickly reacts with the initial (1a), giving rise to N,N′‐diphenyl‐1,4‐phenylenediamine(2a), 2‐(phenylamino)‐N,N′‐diphenyl‐1,4‐benzoquinonediimine (4) and azophenine (5). The Reaction is catalyzed by the weakly acid surface of silicagel. Compound (4) is readily disproportionated thermally to 1,2,4‐tris(phenylamino)‐benzene (8) and 2, 10‐dihydro‐10‐phenyl‐2‐(phenylimino)phenazine (9), even in the absence of a catalyst. A mechanism of the formation of compounds arising in the reaction has been suggested. Diimine (1a) possesses a higher oxidation potential than all the products derived from it, so that it is quickly reduced by these products to (2a). The gradual formation of (2a) may explain the retardation effects of (1a) in the autooxidation of hydrocarbon substrates.
Antioxidantien und Stabilisatoren, 82. Antioxidative Eigenschaften von Amiden der Phosphorsäure
Authors: Rüger C. , Schwetlick K. , Jiráčková L. , Pospíšil J. 
Published: April 2003

AbstractAromatische und aliphatische Amide der Brenzcatechylphosphorsäure wurden auf ihre Wirksamkeit als Antioxidantien überprüft. Es wurde der Einfluß dieser Verbindungen auf die AIBN‐initiierte Oxidation von Tetralin bei 60°C sowie auf die Oxidation von isotaktischem Polypropylen bei 180°C untersucht. Eine Aktivität der untersuchten Verbindungen als kettenabbrechende Antioxidantien tritt nur bei Phosphorsäureamiden, die sich von primären Aminen ableiten, auf. Gegenüber Derivaten der phosphorigen Säure ist die antioxidative Aktivität wesentlich erniedrigt. Es wird ein Wirkungsmechanismus von Esteramiden der Phosphor‐ bzw. phosphorigen Säure als radikalkettenabbrechende Antioxidantien diskutiert.
Mechanochemically initiated polymerizations. Characterization of poly(acrylonitrile) mechanochemically synthesized by vibratory grinding
Authors: Oprea Cleopatra Vasiliu , Popa M. 
Published: April 2003

AbstractMechanical energy which is released by vibratory grinding is able to initiate polymerization reactions of some vinylic monomers. On this way it was possible to obtain poly(acrylonitrile) without any initiator or classical catalyst. The paper presents the physico‐chemical properties of the products obtained by vibratory grinding of acrylonitrile. For the characterization of the obtained polymers, IR‐, ESR‐, and Mössbauer‐spectra were used, together with X‐ray diffraction. Based on the chemical composition and spectral analysis a reaction mechanism and the polymer structure were proposed.
The decomposition of hydrogen peroxide catalyzed with BF3 etherate; the use of this initiation system in the preparation of HO‐terminated telechelic polymers and copolymers of butadiene
Authors: Bouchal K. , Žůrková E. , Kálal J. 
Published: April 2003

AbstractKinetics of the catalyzed decomposition of hydrogen peroxide in the presence of BF3 etherate were investigated, and the basic kinetic parameters used in the discussion of the mechanism of this reaction were determined. The system hydrogen peroxide‐BF3 etherate was used in the initiation of the radical polymerization and copolymerization of butadiene. The parameter φ was determined using an analysis of the kinetics of copolymerization of butadiene with acrylonitrile and the Simha‐Branson equation; the dependence of φ on the composition of the copolymerization mixture was interpreted in terms of Arlman's equation. The cross‐termination reaction occuring in the copolymerization of butadiene with acrylonitrile was characterized by comparing theoretical and experimental functions.
Partial esterification of poly(vinyl alcohol) with acid chlorides
Authors: Arranz F. , Chaves M. Sánchez , Gil F. 
Published: April 2003

AbstractThis work deals with some features of the reaction of organic acid chlorides with poly(vinyl alcohol). The structure of the modified polymers was determined by means of IR, UV and NMR spectroscopy as well as by chemical analysis. Vinyl alcohol‐vinyl butyrate copolymers were obtained by reaction of poly(vinyl alcohol) with n‐butyryl chloride without any catalyst. The reaction appeared to satisfy a second order kinetics for conversions no higher than 50%. The activation energy found was of 9.9 kcal/mol. The use of pyridine as a catalyst involved a noticeable increase of the reaction rate, but this effect was found to be independent of the acid chloride used. When triethylamine was used as a catalyst, β‐keto ester groups were found to be grafted onto the polymer chain. The steric hindrance of these groups were thought to be sufficiently important for the conversion to reach a limit of about 30%. The observed swelling in water of vinyl alcohol‐vinyl butyrate copolymers made it reasonable to conclude that the hydrophilic character of the copolymers decreased progressively when the ester group content increased.
Reactive polymers, XXXIV. Complexes of Ag(I) and Ag(II) with ligands bound to solid support
Authors: Švec F. , Kálalová E. , Tlusťáková M. , Kálal J. 
Published: April 2003

AbstractThe sorption of Ag(I) ions on sorbents containing ethylenediamine (en) and iminodiacetate (ida) groups was investigated. The basic backbone consisted on macroporous glass coatd on its inner surface with poly(glycidylmethacrylate) (glass‐GMA), copolymer glycidylmethacrylate‐ethylenedimethacrylate (GMA‐EDMA), and GMA‐EDMA encapsulated in poly(‐2‐hydroxyethylmethacrylate). The rate of sorption of Cu(II) in sorbents modified with en decreased in the same order. For the sorption of Ag(II), a sorbent was synthesized by a reaction of GMA‐EDMA with 3‐aminopyridine, and the reaction with the ion was carried out in an oxidizing solution. The types of complexes formed in the sorption were determined spectroscopically in all cases.
Chemische Untersuchungen zum Abbau vernetzter Phenol‐Formaldehyd‐Harze
Authors: Braun D. , Steffan R. 
Published: April 2003

AbstractNeben der Pyrolyse und dem Abbau mit überhitztem Wasserdampf wird insbesondere die hydrogenolytische Spaltung ausgehärteter Phenol‐Formaldehyd‐Harze in Gegenwart von Wasserstoff‐Donatoren untersucht. Als H‐Donor wird hierbei 1,2,3,4‐Tetrahydronaphthalin (Tetralin) eingesetzt, das bei Temperaturen um 400°C unter Wasserstoff‐Transfer an die dispergierten Harzpartikel zu Naphthalin rearomatisiert. Bei maximalen Ausbeuten von insgesamt 98 Gew.‐% (bez. auf die eingesetzte Harzmenge) Phenol, Methylphenolen und oligomeren phenolischen bruchstücken wird eine Nutzung technischer Phenolharzabfälle unter Gewinnung verwertbarer Spaltprodukte diskutiert. Anhand von Abbau‐Kurven und rasterelektronenmikroskopischen Untersuchungen wird auf den Mechanismus der extraktiven hydrogenolytischen Phenolharzverflüssigung eingegangen.
Resacetophenone‐formaldehyde resins, II. Chelation ion‐exchange properties
Authors: Parmar J. S. , Patel M. R. , Patel M. M. 
Published: April 2003

AbstractThe resacetophenone‐formaldehyde (RAP‐F) resin showed to be a selective chelating ion‐exchange resin for certain metal ions. A batch equilibration method was used in the study of the selectivity of metal ion uptake. The method involved the measurement of distribution of a given metal ion between an aqueous solution and the resin. The study was carried out over a wide pH range and in media of various ionic strengths.
Urea‐formaldehyde resins 5. Drying of wet mixtures in the production of moulding compounds
Authors: Kumlin Kjell , Simonson Rune 
Published: April 2003

AbstractThe condensation of resin compounds during drying of wet mixtures consisting of resin and filler was examined by gel permeation chromatography of resins extracted from various intermediates being dried. The influence of pH (wet mixture), temperature, and drying time upon the molecular growth was studied.
Thermal degradation of methoxyanisole‐1,2‐dichloroethane resins
Authors: Patel J. , Patel R. , Patel V. S. , Patel K. C. , Patel R. D. 
Published: April 2003

AbstractThermal behaviour of m‐methoxyanisole‐1,2‐dichloroethane resins was studied at different heating rates. Kinetic parameters for the decomposition of the resins have been determined from TG and DTA studies using various methods of thermal analysis. The first stage of degradation had E1 ∼ 3, the second stage had E2 ∼ 28 and the overall degradation had E12 ∼ 36 kcal·mol−1, respectively.
Some fading characteristics of various monoazo dyes on polyester
Authors: Shakra S. , Hanna H. L. , Hebeish A. 
Published: April 2003

AbstractCharacteristic fading curves of some monoazo dyes on polyester films were examined. The slopes of these curves were dependent upon both the physical as well as the chemical properties of the dyes. Only for those dyes, which were capable of forming intramolecular hydrogen bonds negative slopes were shown, whereas for the other dyes the slopes were positive.
Graft copolymerization of vinyl monomers on modified cottons, XXI. Cu++/hydrazine hydrate redox system induced grafting of methyl methacrylate on periodate oxidized cellulose
Authors: Hebeish A. , El‐Rafie M. H. , El‐Kashouti M. A. , El‐Sisi F. 
Published: April 2003

AbstractPeriodate oxidized cellulose was grafted with methyl methacrylate using hydrazine hydrate in presence and absence of Cu++. The grafting reaction was favoured in presence of Cu++ and it was advantageous to treat first the cellulose material with copper sulphate solution rather than to incorporate it in the polymerization system. The graft yields depended upon the concentrations of copper sulphate and hydrazine hydrate, pH, temperature, and time of polymerization as well as degree of oxidation of cellulose. There were optimal concentrations of copper sulphate (6–8 mmol/l) and hydrazine hydrate (2 mmol/l). A polymerization medium of pH 6 and a temperature of 60°C constituted to optimal pH and temperature for grafting. Oxidized cellulose proved to be more amenable to grafting as compared with unoxidized cellulose and the magnitude of grafting relied on the degree of oxidation. A tentative mechanism was also suggested for grafting of cellulose substrates with a vinyl monomer using a Cu++‐hydrazine hydrate redox system.
Radiation grafting of poly(ethylene terephthalate) (PET) fibre, II. Hydrolysis of grafted poly(vinyl acetate) to poly(vinyl alcohol)
Authors: Faterpeker S. A. , Potnis S. P. 
Published: April 2003

AbstractPoly(ethylene terephthalate) fibres grafted with poly(vinyl acetate) by γ‐radiation were hydrolysed under alkaline and acidic conditions in order to obtain poly(ethylene terephthalate)‐graft‐poly(vinyl alcohol) fibres. In alkaline media poly(ethylene terephthalate) degraded without appreciable conversion of acetate to hydroxyl groups. During acid hydrolysis no change in tensile properties of the fibres was observed up to an extent of 50% conversion of acetate to hydroxyl groups. Further change in the tensile strength and the elongation at break was attributed partly to the grafted poly(vinyl acetate)/poly(vinyl alcohol) balance and partly to the loss due to degradation of the fibres.
Simultaneous determination of calibration and dispersion parameter in gel permeation chromatography by using a least square optimization method
Authors: Andreetta Héctor A. , Figini Ruben V. 
Published: April 2003

AbstractA method is described to obtain at the same time the parameters of the calibration and the dispersion function in GPC. It is possible to compare the logarithmic‐linear and non‐linear calibration function as well as symmetric and non‐symmetric dispersion functions with the experimental results in order to decide, which of them in a given case might be applied. It is not necessary to express the experimental elution curve by an analytical function. The experimental requirements to apply the method are not greater than those necessary to carry out a common calibration. The possibility of some other applications is also discussed.
New organic polymers, I. Synthesis and characterization of poly Schiff bases from benzidine‐3,3′‐dicarboxylic acid
Authors: Suthar B. P. , Patel S. R. 
Published: April 2003

AbstractThermally stable and semiconducting polymers are synthesized by condensing benzidine‐3,3′‐dicarboxylic acid (BDC), with dicarbonyl compounds like glyoxal, cyclohexane‐1,4‐dione, 4,4′‐diacetyl diphenyl ether and benzil under different experimental conditions. These poly Schiff bases are insoluble in common organic solvents. They are characterized by IR‐ and viscosity studies, thermal analysis, and the study of electrical properties at various temperatures. Variation of the electrical conductivity, σ, with temperature was found to confirm with the empirical relation: