bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of etching mechanism of polyimide films on silicon chips
Authors: Xue G. 
Published: April 2003

AbstractThe etching mechanism of polyimide films on silicon chips has been studied. As the film contacts with alkaline solution, the imide bonds hydrolyze quickly, resulting in the formation of polyions. The polyion coils are expanded by electrostatic repulsion. Within the etching time, most part of the polyimide dissolves into solution. The remaining gel contains 10% of original imide bonds and has a molecular weight of 12,000. The gel is not a classical one, but a physical gel which contains relatively small polymer molecules jointed by secondary forces.
Retardation of V5+‐thiourea initiated polymerization of acrylonitrile by phenol
Authors: Mohanty A. K. , Misra M. , Singh B. C. 
Published: April 2003

AbstractStudies have been made on the kinetics and mechanism of the retardation of V5+‐thiourea initiated polymerization of acrylonitrile by phenol in the temperature range 40 – 50°C. The effects of retarder (phenol), metal ion, monomer, sulphuric acid, some inorganic salts, and organic solvents have also been studied. The most remarkable observation in the present investigation is the positive intercept obtained from the plot of [M]/Rp vs. 1/[M]. A reaction mechanism has been suggested and a suitable rate expression has been proposed and explained in the light of experimental findings.
Chemistry and application of organic isocyanates, VIII. Conversion of 5‐isocyanato‐1‐(isocyanatomethyl)‐1,3,3‐trimethylcyclohexane into biuret and urea derivatives by means of hexamethylenediamine
Authors: Balewski Andrzej , Lesiak Tadeusz 
Published: April 2003

AbstractAttempts on the conversion of 5‐isocyanato‐1‐(isocyanatomethyl)‐1,3,3‐trimethylcyclohexane (IPDI) into biuret and urea derivatives by treatment with hexamethylene diamine (HDA) at 140°C, 155°C, and 170°C at different molar ratios have been described. By means of gel permeation chromatographic analyses, the approximate contents of the mainly formed prepolymers were estimated. On the basis of the results of physico‐chemical measurements, the influence of temperature and molar ratios of the reagents on the properties of the resulting products have been interpreted. It has been shown, that 12 prepolymers of molecular weights up to 1226 having a biuret or a urea structure are formed.
Thermogravimetrische untersuchung der dehydrohalogenierungspolymerisation von 4‐methylphenyl‐phenyldichlormethan. Untersuchungen über poly(arylenvinylene), 31
Authors: Opfermann Johannes , Scherf Ullrich , Raabe Dietrich , Nowotny Jürgen , Hörhold Hans‐Heinrich 
Published: April 2003

AbstractDie Bildung von Poly(1,4‐phenylen‐1‐phenylvinylen) aus 4‐Methylphenyl‐phenyl‐dichlormethan wurde thermogravimetrisch im quasi‐geschlossenen System untersucht.Für den beobachteten zweistufigen HCl‐Eliminierungsprozeß wurden durch Modellierung die Reaktionsordnungen ni, die Aktivierungsenergien Ei und die Geschwindigkeitskonstanten Zi zu n1 = 1,4; E1 = 105 kJ/mol und Z1 = 108,9 s−1 für die erste Stufe bzw. zu n2 = 1,3; E2 = 103 kJ/mol und Z2 = 106,7 s−1 für die zweite Stufe ermittelt. In der ersten Stufe wurden 77% des Gesamtgehaltes an HCl eliminiert. Der Mechanismus der Dehydrohalogenierungspolymerisation wird diskutiert.
Selective carbon monoxide adsorbent composed of polystyrene resin having amino groups and copper(I) chloride
Authors: Hirai Hidefumi , Wada Keiichiro , Kurima Kazunori , Komiyama Makoto 
Published: April 2003

AbstractA carbon monoxide adsorbent composed of 10 g of a polystyrene resin having amino groups and 70 mmol of copper(I) chloride was prepared by refluxing the resin and copper(I) chloride in acetonitrile, followed by evaporation of the liquid phase at 5 mmHg, 80°C. The adsorbent rapidly adsorbs 15.9 mmol of carbon monoxide under 1 atm at 20°C. 11.4 mmol of adsorbed carbon monoxide are desorbed when the adsorbent is subjected to a reduced pressure (5 mmHg) at 80°C for 10 min. In the second and the later adsorptions, the amount of adsorbed carbon monoxide is virtually constant at 11.4 mmol. The amount of carbon dioxide adsorbed by the adsorbent under 1 atm at 20°C is 2.8 mmol, and the value for methane is 0.0 mmol. The prepared adsorbent is applicable to selective separation of carbon monoxide from gas mixtures containing both carbon dioxide and methane.
Mechanical properties of carboxyl terminated polybutadiene cured with epoxides
Authors: Schwartz Anders 
Published: April 2003

AbstractCarboxyl terminated polybutadiene (CTPB) has been cured with two trifunctional epoxides, ERL‐0510 and EPON 812, by means of ferric acetyl acetonate (FeAA) and chromium chelates of isopropyl salicylic acid (CrDIPS) as catalysts. In CTPB cured with ERL‐0510 there have been incorporated a carbon black, Sterling MT, and a plasticizer, dioctyl adipate (DOA). Tensile tests have been made at different temperatures and strain rates. The results of maximum stress, strain at break, and modulus have been treated according to the WLF‐equation to give temperature and rate reduced master curves. Addition of carbon black decreases strain at break and increases maximum stress and modulus. Addition of plasticizer increases strain at break and decreases maximum stress and modulus. CrDIPS gives the mixtures shorter curing time than FeAA. Polymers cured with the two epoxides have approximately the same strength properties.
Synthesis of linear p‐dimethylaminobenzoylated polystyrene
Authors: Mateo José L. , Manzarbeitia José A. , Sastre Roberto 
Published: April 2003

AbstractLinear p‐dimethylaminobenzoylated polystyrenes have been synthesized. Two routes, one of them by polystyrene lithiation and the other one by polystyrene‐amide formation, have been followed. With the first route, poly‐p‐iodostyrene → poly‐p‐lithio‐styrene and reaction of lithiated polystyrene with methyl‐4‐N,N‐dimethyl‐aminobenzoate, a crosslinked polymer was always obtained which contained hydroxylic groups and in some cases, in the presence of an excess of methyl‐4‐N,N‐dimethylaminobenzoate and low temperatures, dimethylaminobenzoyl groups. The second route, polystyrene‐amide formation and subsequent reaction of this linear functionalized polystyrene with POCl3 and dimethyl‐aniline, yielded a linear p‐dimethylaminobenzoylated polystyrene. Starting with cumene and following the same procedure described for the polystyrene, the model compounds N‐phenyl‐p‐isopropylbenzamide and 4‐isopropyl‐4′‐N,N‐dimethylaminobenzophenone were also obtained. Both model compounds and functionalized polystyrenes were characterized by IR, UV, 1H‐NMR and mass spectroscopy as well as molecular weight determinations. From polystyrene‐amide, polystyrene‐ester and polystyrene‐acid were also obtained.
Polystyrolaustauscher mit 5‐(4‐dimethylaminobenzyliden)‐rhodanin als ankergruppe für die abtrennung von silber, gold und quecksilber
Authors: Hofmann B. , Lieser K. H. 
Published: April 2003

AbstractDie Verteilungskoeffizienten von Ag+, Au3+ und Hg2+ an dem Polystyrolaustauscher mit 5‐(4‐Dimethylaminobenzyliden)‐rhodanin als Ankergruppe werden als Funktion des pH‐Werts in 0,1 M NaNO3 als Grundlösung und unter Zusatz von NaCl, NH4NO3, Na2S2O3 oder NaCN bestimmt. Ag+‐Ionen werden mit verhältnismäßig hohen Verteilungskoeffizienten gebunden, sofern die Konzentrationen an NaCl, NH4NO3 und NaCN niedrig sind. Na2S2O3 stört auch in niedrigen Konzentrationen. Au3+‐ und Hg2+ ‐Ionen werden auch in Gegenwart von 0,5 M NaCl mit verhältnismäßig hohen Verteilungskoeffizienten gebunden.
Zur berechnung von molmassenverteilungen bei binären radikalischen copolymerisationen
Authors: Weickert Günter , Wagner Eberhard 
Published: April 2003

AbstractDas vorgeschlagene Verfahren zur Berechnung der Molmassenverteilung binärer Copolymerisate auf Grundlage des „chemisch kontrollierten Modells”︁ ist allen bisher in der Literatur publizierten Verfahren bezüglich Rechengenauigkeit und/oder geringem Speicherplatzbedarf und/oder Rechengeschwindigkeit überlegen. Es ist auf Mikrocomputern programmierbar und ermöglicht durch den geringen Rechenaufwand die Prozeßsteuerung nach der Molmassenverteilung.
New accelerators for vulcanization of rubber, 4. Synthesis and characterization of polythiocarbamyl sulfenamides
Authors: Khamrai Asim K. , Adhikari Basudam , Maiti Mrinal M. , Maiti Sukumar 
Published: April 2003

AbstractPolythiocarbamyl sulfenamides were synthesized by the reaction of different aliphatic and aromatic diamines with carbon disulfide and using iodine as oxidant. The polymerization proceeds by radical mechanism. All the polymers are soluble in polar solvents like N‐methylpyrrolidone (NMP), dimethylformamide (DMF), m‐cresol etc. The structure of the polymers was confirmed by elemental analysis (nitrogen and sulfur), IR, and 1H‐NMR spectral analysis. The effects of aliphatic and aromatic moieties in the diamines were reflected in their reactivities.
Chemistry and application of organic isocyanates, IX. Conversion of tolylene‐2,4‐diisocyanate into urethane derivatives by means of heptane‐1,4,7‐triol
Authors: Ciemniak Grażyna , Lesiak Tadeusz , Balewski Andrzej 
Published: April 2003

AbstractInvestigations on the conversion of tolylene‐2,4‐diisocyanate (2,4‐TDI or TDI) with heptane‐1,4,7‐triol 1,4,7‐HPT or HPT) at 55–85°C and various molar ratios of starting materials are described. By means of mass spectroscopic analysis and gel permeation chromatography, molecular weights of six oligomers and their percent contents in the products have been estimated. Moreover, a scheme of the formation of all prepared isocyanate prepolymers has been proposed. It has been shown, that apart from oligomers having the structures resulting from the reaction of 1,4,7‐HPT with the isocyanate group in the position “4”, reaction products contained oligomers, which confirmed the reactivity of isocyanate group in the position “2”, too.
Reaction of poly(vinyl alcohol) with diketene
Authors: Arranz F. , Sánchez‐Chaves M. , Jarrín C. M. 
Published: April 2003

AbstractA study has been made on the modification of poly (vinyl alcohol) with diketene using tertiary amines as catalysts. The structure of the resulting polymers was determined by means of IR, 1H‐ and 13C‐NMR spectroscopy as well as by chemical analysis. Vinyl alcohol‐vinyl acetoacetate (VAL‐VAA) copolymers were obtained. It has been found a linear dependence of reaction rate on polymer, diketene and pyridine concentrations, respectively. The activation energy was found to be 35.5 kJ/mol (8.5 kcal/mol). 13C‐NMR spectroscopy was used for the determination of the sequence distribution in VAL‐VAA copolymers. The obtained results show that VAA units have a little alternating tendency in the copolymer chain. Polymeric chelates between VAL‐VAA copolymers and cupric ions have been prepared. It is noteworthy that not all the β‐keto ester groups in the VAL‐VAA copolymers participate in binding cupric ions.
Chlorocarboxylation of polyethylene. II. Reaction mechanism of the process
Authors: Joshi Shashikant G. , Natu Arvind A. 
Published: April 2003

AbstractChlorocarboxylated polyethylene (CCPE) is produced by simultaneous reaction of chlorine and maleic anhydride (MA) with polyethylene (PE). Hydrogen atoms on the PE chain are substituted either by chlorine atoms or by maleic anhydride moieties. The reaction mechanism involves creation of an active site, i.e. a radical on the PE chain. There is competition between chlorine and MA molecules for the reaction with this macroradical. Chlorine reacts to give chlorinated polyethylene (CPE) type segments, while MA reacts as a single unit (as chloro derivative) without forming any graft copolymer. There is a marked reduction in the rate of chlorination of PE due to the presence of MA. This is probably due to the competitive nature of the process and the radical scavenging action of MA.
Untersuchungen zur strahlenchemischen Polymerisation und Vernetzung verschiedener mehrfunktioneller Acrylate
Authors: Fürst Walter , Heusinger Helmut 
Published: April 2003

AbstractDie Vernetzung verschiedener mehrfunktioneller Acrylate wird beschrieben und nach der Vernetzungstheorie von Charlesby untersucht. IR‐spektroskopische und gelchromatographische Untersuchungen führen zu Aussagen über den Netzwerkaufbau der mehrfunktionellen Acrylate. Die vernetzten Acrylate werden chemisch abgebaut. Die entstandenen Polysäuren werden zu Polyestern umgewandelt. Durch GPC‐, MS‐ und IR‐Untersuchungen werden die abgebauten Polyester charakterisiert und die Abhängigkeit der Polymerisation und Vernetzung von der Dosis und Dosisleistung untersucht.
Styrene — divinylbenzene copolymers, IV. Porosity changes during chloromethylation
Authors: Okay Oǧuz 
Published: April 2003

AbstractThe change in the porosity of styrene‐divinylbenzene (S‐DVB) copolymers during the chloromethylation reaction was investigated using apparent densities and equilibrium swelling in toluene. Maximum porosity of S‐DVB copolymers does not change appreciably with the chloromethylation reaction. Only a slight decrease in the maximum porosity was observed in rigid networks, probably due to the partial destruction of the pore structure. However, with the substitution by chloromethyl groups, the degree of swelling decreases, which results in an increase in the stability of the porous structure in chloromethylated copolymers.
Unvernetzte epoxid‐amin‐additionspolymere, 15. 15N‐NMR‐spektroskopie von DGEBA‐anilin‐additionspolymeren
Authors: Hörhold Hans‐Heinrich , Klee Joachim , Schütz Heidrun , Radeglia Reiner 
Published: April 2003

Abstract15N‐NMR Spektren von Bisphenol‐A‐diglycidylether (DGEBA)‐15N‐Anilin‐Additionspolymeren und deren Acetylderivate zeigen nur das Signal für die tertiäre Phenylamino‐dialkyl‐Gruppe, so daß der lineare Verlauf der Additionspolymerisation bestätigt wird. Aus Signalaufspaltungen bei 15N‐ und einigen N‐benachbarten 13C‐Signalen ist ersichtlich, daß diastereomere Aminodiol‐Einheiten in annähernd gleicher Konzentration gebildet werden. Bei telechelen Präpolymeren mit Anilinüberschuß werden hohe Konzentrationen an sekundären Phenylamino‐Endgruppen gefunden.
Zu den ursachen des unterschiedlichen zähigkeitsverhaltens von polycarbonat, polyestercarbonat und einem polyester auf basis bisphenol A
Authors: Biskup Ulrich , Rathmann Dietrich , Tacke Peter 
Published: April 2003

AbstractPolycarbonat (PC), Polyestercarbonat (PEC) und ein aromatischer Polyester auf Basis von Bisphenol A (APE) wurden hinsichtlich ihrer Schlagzähigkeit und Kerbschlagzähigkeit im Temperaturbereich von −50 bis 100°C verglichen. Während alle drei Polymere ein ähnlich duktiles Schlagbiegeverhalten zeigen, treten im Kerbschlagbiegeversuch charakteristische Unterschiede auf. Die Ursachen dieser Unterschiede wurden u. a. anhand des Relaxationsverhaltens, der Wärmetönung der Enthalpierelaxation nach Temperung und des beim Bruch auftretenden shear‐yieldings diskutiert.
Synthetic resins, IV. Preparation and characterization of resins prepared from hydroxyacetophenone
Authors: Patra Santosini , Lenka Subasini , Nayak Padma L. 
Published: April 2003

AbstractNew resins have been synthesized from o‐hydroxyacetophenone by reaction with substituted aromatic compounds and formaldehyde in the presence of various acids and bases as catalyst following two different techniques. The polymer samples are characterized by IR spectra. The solution, thermal, and chemical properties of the resins are investigated. The solubility parameters of the resins calculated according to the investigations of Small agree well with the experimental values. The resins are found to be fairly thermostable and the energy of activation is evaluated from TG curve by applying (i) Freeman‐Anderson method and (ii) Broido method.
Reactive polymers, 56. Interaction of reactive sites of macroporous copolymers glycidyl methacrylate‐ethylene dimethacrylate
Authors: Švec František 
Published: April 2003

AbstractAn analysis of the results obtained in a series of studies dealing particularly with the reactions and synthesis of macroporous copolymers of glycidyl methacrylate‐ethylene dimethacrylate showed that relatively freely mobile poly(glycidyl methacrylate) chains are bound on the surface of globules which form the basic unit of a bead structure. These chains, in turn, make possible the formation of products with requirements on the steric order of substituents, on the one hand, but impede an effective application of the macroporous polymer as a protecting group, on the other. Their presence is explained on the basis of kinetics and copolymerization mechanism of the monomers.
Investigation into the interactions of metals and metal ions in polymer matrices
Authors: Payne R. , Fritz G. , Naarmann H. 
Published: April 2003

AbstractThe dispersion of transition metal sols (gold, ferric hydrous oxide, chromium hydroxide) in a water soluble polymer (PVA 4–88) was investigated and from the films produced, a comparison made of their mechanical and electrical properties. Extending to non aqueous solvents (dimethylformamide, tetrahydrofuran) interactions of polyvalent metal ions (Fe(III), Al(III), Ti(IV), Zr(IV), Pd(0), Ag(0), Au sols) with a specific metal complexing polymer (poly(acrylamideoxime)) and a block copolymer containing styrene and butadiene (Buna BL 6533) were investigated.
Electronic processes in poly(p‐phenylene) and related compounds, II. Structure and electrical properties of polymers related to poly(p‐phenylene sulfide)
Authors: Czerwiński Wojciech 
Published: April 2003

AbstractPoly(p‐phenylene sulfide) was prepared by polymerization of benzene with elemental sulfur in the presence of aluminium chloride as catalyst. The synthesis product was exactly purified from catalyst and oligomers. IR spectra of the resulting material and the application of other analytical methods indicated a structure like PPS. The polymer is thermally resistant up to 773 K and has a small degree of crystallinity. Conductivity of the pristine polymer is higher than that of the original poly(p‐phenylene sulfide). After doping with iodine the conductivity rises more than 6 orders in magnitude to a level of 10−4 Sm−1 and the spin concentration is from five to ten times larger than in the virgin polymer. The activation energy of the conductivity decreases from 0.11 eV for the original polymer to 0.03 eV for the doped one. I — V characteristics are ohmic for both the virgin and the doped materials. The barrier height of metal (Au) and polymer semiconductor junction for the doped sample is smaller than for the undoped substance.
Chlorocarboxylation of polyethylene, III. Kinetics of the process
Authors: Joshi Shashikant G. , Kulkarni Bhaskar D. 
Published: April 2003

AbstractThe paper presents the kinetic model and derives the values of the kinetic parameters for the simultaneous reaction of chlorine and maleic anhydride with polyethylene in tetrachloroethyane solution. The sites of attack in the investigated reaction being the hydrogen atoms in the polyethylene chain, the concept of occupied and vacant sites available for the reaction has been used to derive the kinetic model.The temperature dependence of the ratio of rate constants (kCl/kMA) for the attack of chlorine and maleic anhydride is obtained by applying Arrhenius law. The analysis of the results reveals that the activation energy difference (ECl — EMA) is of the order of − 19 kcal/mol and the pre‐exponential factor ratio (ACl/AMA) is of the order of 735. The generalized form of the equations is also presented in order to extend this method of kinetic analysis to many other similar systems.
Polyphenylquinoxaline‐amide‐imides
Authors: Korshak V. V. , Krongauz E. S. , Belomoina N. M. , Brumă M. , Diaconu I. , Simionescu C. I. 
Published: April 2003

AbstractNew thermostable heterocyclic polymers containing phenylsubstituted quinoxaline and both amide and imide units have been synthesized by low temperature solution polycondensation of diaminophenylquinoxalines with diacid chlorides of certain aromatic acids containing preformed imide rings. The thermal stability as well as electrical properties of these polyphenylquinoxaline‐amide‐imides are discussed.
Effect of copolymers modifying PVC on its physical and mechanical properties and its UV‐radiation resistance, VII. The influence of structure of pvc chains on tensile strength of irradiated films
Authors: Kamińska A. , Kaczmarek H. 
Published: April 2003

AbstractPVC films and films containing the modifying copolymers, irradiated by increasing dose of UV‐radiation of λ = 253.7 nm were investigated. It was previously stated1–3 that 1–10% content of modifying copolymers in PVC films distinctly change the resistance of PVC to UV‐radiation and this is the cause that photochemical processes have a different course. Thus it makes it easy to observe the effect of branching, crosslinking, dehydrochlorination, and oxidation processes on mechanical properties of the samples.It was stated, that an introductory crosslinking of PVC has a positive influence on its tensile strength (σ) but only when the density of crosslinking is ≤ 1, i.e., when all the polymer is still soluble. Whereas with the increase of density of crosslinking above 1, i.e., when insoluble gel is formed in the samples, this process distinctly makes σ values of PVC worse.The oxidation products of the occurring concentration range in the investigated samples do not have prevailing influence on the tensile strength of PVC.
Interaction of multi‐chain copoly(α‐amino acid)s with 2‐(4′‐hydroxyphenylazo) benzoic acid (HABA)
Authors: Kuramoto Noriyuki , Aoyama Tomoyuki , Yamaguchi Mieko , Nagai Katsutoshi , Hayama Shigeru 
Published: April 2003

AbstractA number of multi‐chain Nε‐copoly(L‐lysine · HBr γ‐methyl‐L‐glutamate) copoly‐(L‐lysine γ‐methyl‐L‐glutamate)s with various intervals of the grafting sites in the core molecules were prepared in N,N‐dimethylformamide (DMF) containing dimethyl sulfoxide (DMSO) by the reaction of the N‐carboxy anhydride (NCA) of Nε‐carbobenzoxy(Cbz)‐L‐lysine and the NCA of γ‐methyl‐L‐glutamate with random copoly‐(L‐lysine · HBr γ‐methyl‐L‐glutamate)s of different composition with various anhydride‐initiator ratios. The interactions between anionic azo dye (HABA) and multichain copoly(α‐amino acid)s were investigated by means of difference UV‐VIS spectroscopic measurements. From the obtained binding constants and thermodynamic parameters, it was concluded that the hydrophobic moieties of γ‐methyl‐L‐glutamate units in the multi‐chain copoly(α‐amino acid)s have an important role on the HABA and multi‐chain copoly(α‐amino acid)s interaction.
Molecular weight‐intrinsic viscosity relationship of trans‐16‐hydroxy‐9‐enoate hexadecenoic acid polyesters
Authors: Gupta P. C. , Bhattacharya P. R. , Misra G. S. 
Published: April 2003

AbstractThe uncatalysed kinetics of self‐esterification of trans‐16‐hydroxy‐9‐enoate hexadecenoic acid has been found to follow third order. A relationship between intrinsic viscosity and molecular weight of its polyesters [η] = 14.2 · 10−5 M0.95 (25°C, chloroform) has been put forward. The polymolecularity studies of the polyester have shown usual characteristics of integral and differential curves.
Poly(vinyl chloride) blends. I. Aspects of processability
Authors: Rusu Mihai , Petraru Filip , Grămescu Livia 
Published: April 2003

AbstractThe paper deals with the influence of chlorinated polyethylene (CPE) as an impact modifier on the processability of unplasticized PVC blends, with and without clay as filling material, using the Brabender plastograph.It was found that, for both types of blends, increase of the CPE content causes increase of the torque, fusion performance and fusion factors (Brabender and Böttner‐Rosenthal), and reduction of fusion time, fusion coefficient and, between limits, of the thermal stability of the blends. This behaviour may be explained by the reduction of the lubrication action brought about by this impact modifier.By addition of CPE to the filled blends, a compensation of disadvantages caused by the introduction of the filling material into the compound is achieved.