bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relative reactivity of primary and secondary amine hydrogen atoms in the reaction between aniline and phenyl glycidyl ether: The effect of ethanol and other additives and the modifying effect of benzene as solvent
Authors: Johncock P. 
Published: April 2003

AbstractThe relative reactivity ratio (k2/k1) for the secondary and primary amine hydrogen atoms in the neat reaction between aniline and phenyl glycidyl ether was 0.30. This is significantly lower than a recently reaffirmed random value of 0.5 for this system. The ratio is sensitive to added ethanol and decreased with increasing concentration to a limiting value of about 0.20. With benzene as solvent, the effect of added ethanol was more complex, and a low concentration provided a value of 0.45 which decreased with increasing concentration. Other hydroxy additives behaved similarly, but boron trifluoride appears to have no effect on this ratio.
Polyimides from 4,4′‐(alkylene‐α,ω‐dioxy) bis(phenylsuccinic anhydride)s and bis(phenylglutaric anhydride)s
Authors: Teshirogi Takuma 
Published: April 2003

Abstract4,4′‐(Alkylene‐α,ω‐dioxy)bis(phenylsuccinic anhydride)s and bis(glutaric anhydride)s were obtained by the condensation of 4,4′‐diformyl‐α,ω‐diphenoxyalkanes with ethyl cyanoacetate followed by the addition of potassium cyanide or meldrum acid (2,2‐dimenthyl‐1,3‐dioxane‐4,6‐dione), hydrolysis with concentrated hydrochloric acid, and dehydration with acetic anhydride. Alkylene groups were ethylene, trimethylene, and tetramethylene. Polyimides were prepared from these anhydrides with 4,4′‐diaminodiphenyl ether, 4,4′‐diaminodiphenyl sulfide, and 4,4′‐diaminodiphenylmethane through thermal ring closure of polyamic acids obtained by solution polymerization in dimethylacetamide, and thermal stability of these polyimide film was examined by thermogravimetric analysis.
Synthesis of polyphenylene ether and thioether ketones
Authors: Durvasula V. R. , Stuber F. A. , Bhattacharjee D. 
Published: April 2003

AbstractThe known polymerization of 4,4′‐difluorobenzophenone (DFB) with the dianion of hydroquinone to poly(phenylene ether ether ketone) (PEEK) and polymerization of either DFB with the dianion of 4,4′‐dihydroxybenzophenone or self polycondensation of the anion of 4‐hydroxy‐4′‐fluoro‐benzophenone to poly(phenylene ether ketone) (PEK) were studied in N‐cyclohexyl‐2‐pyrrolidone (CHP), which is a high‐boiling aprotic polar solvent. The formation of high‐molecular weight PEEK and PEK in this solvent was very efficient. The reactivity in CHP can be ascribed to effective solvation of metal ions rendering the anion very reactive toward nucleophilic substitution. The polymerization was extended to 4,4′‐bis(4‐fluorobenzoyl)diphenyl ether and 1,4‐bis[4‐(4‐fluorobenzoyl)phenoxy]benzene to give a high molecular weight polymer with PEK and PEEK repeating units and PEEK respectively. The polymerization of DFB with purified anhydrous sodium sulfide in CHP gave rapidly a high molecular weight poly(phenylene ketone sulfide) (PKS). In contrast, diphenyl sulfone (DPS) was not very effective in obtaining such a high molecular weight PKS even with prolonged heating, which suggests the uniqueness of CHP in promoting a high degree of polymerization.
Photochromism of spirofluorenylindolizines
Authors: Deblauwe Veerle , Smets Georges 
Published: April 2003

AbstractThe decoloration kinetics of three spirofluorenylindolizines have been followed in solution and in polymer matrix. They are the 5′‐methyl‐spiro[9H‐fluorene‐9.1′(1′H)‐indolizine]‐2′‐3′‐bis‐methoxycarbonyl (I), its methacryloyl oxymethyl (II) derivative, and the copolymers of (II) with ethyl acrylate. In solution the reactions follow first‐order kinetics and show pronounced negative solvatochromism. In solid polymer film, the incorporation of the photochrome as side group of polyethylacrylate affects strongly the decoloration below Tg of the film. Above Tg the decoloration was interpreted on the basis of the WLF equation.
Microemulsion polymerization of styrene
Authors: Guo J. S. , El‐Aasser M. S. , Vanderhoff J. W. 
Published: April 2003

AbstractInitiation of polymerization in styrene oil‐in‐water microemulsions by water‐soluble potassium persulfate of oil‐soluble 2,2′‐azobis‐(2‐methyl butyronitrile) at 70°C gave stable latexes which were bluish and less translucent than the original microemulsions. The effects of initiator concentration, polymerization temperature, and monomer concentration on the kinetics, particle size distributions, and molecular weight distributions were investigated. The kinetics of polymerization were measured by dilatometry. In all cases, the polymerization rate shows only two intervals, which increased to a maximum and then decreased. There was no apparent constant rate period and no gel effect. A longer nucleation period was found for polymerizations initiated by potassium persulfate as compared to 2,2′‐azobis‐(2‐methyl butyronitrile). The small latex particle size (20–30 nm) and high polymer molecular weight (1–2 × 106) implies that each latex particle consists of two or three polystyrene molecules. The maximum polymerization rate and number of particles varied with the 0.47 and 0.40 powers of potassium persulfate concentration, and the 0.39 and 0.38 powers of 2,2′‐azobis‐(2‐methyl butyronitrile) concentration, respectively. This is consistent with the 0.4 power predicted by Smith–Ewart Case 2 kinetics. Microemulsion polymerizations of styrene–toluene mixtures at the same oil‐water phase ratio gave lower polymerization rates and lower molecular weights, but the same latex particle size as with styrene alone. A mechanism is proposed, which comprised initiation and polymerization in the microemulsion droplets, by comparing the kinetics of microemulsion polymerization with conventional emulsion and miniemulsion polymerization systems.
Radical‐initiated homopolymerization and copolymerization of ethyl α‐hydroxymethylacrylate
Authors: Ueda Mitsuru , Koyama Toshitaka , Mano Motokazu , Yazawa Masahiko 
Published: April 2003

AbstractEthyl α‐hydroxymethylacrylate (EHMA) was synthesized and homopolymerized in bulk and in solution. The poly(EHMA) is readily soluble in alcohol, acetone, tetrahydrofuran, and methylene chloride at room temperature. Intramolecular lactone formation occurred when poly(EHMA) was heated to 180–230°C. The kinetics of EHMA homopolymerization was investigated in ethyl acetate, using α,α′‐azobisisobutylonitrile as an initiator. The rate of polymerization Rp was expressed by Rp = k[AIBN]0.50[EHMA]1.4 and the overall activation energy was calculated as 71.9 kJ/mol. Kinetic constants for EHMA polymerization were obtained as follows: kp/k = 0.17L0.9mol−0.9s−0.5; 2fkd = 1.5 × 10−5 s−1. The relative reactivity ratios of EHMA(M2) copolymerization with styrene (r1 = 0.472, r2 = 0.564) in ethyl acetate were obtained. Applying the Q‐e scheme led to Q = 0.84 and e = 0.35 for EHMA.
Structure and morphology of the 60/40 poly(p‐oxybenzoate‐co‐ethylene terephthalate) copolymer
Authors: Quach L. , Hornbogen E. , Volksen W. , Economy J. 
Published: April 2003

AbstractThe copolyester composed of 60 mol% p‐hydroxybenzoic acid and 40 mol% ethylene terephthalate has been studied extensively by earlier workers. However, some confusion exists particularly with respect to the nature of the thermal transitions and the possible presence of additional phases. In the present study we have examined this copolyester and found that it is possible to separate the material into soluble and insoluble fractions with significantly different ratios of p‐hydroxybenzoic acid to ethylene terephthalate. In fact, the soluble PET‐rich fraction is blocky in nature, while the PHBA‐rich fraction is more random. The multiple thermal transitions can now be readily interpreted in terms of a heterogeneous composition which tends to segregate and phase separate.
Plasma polymerization of ethylene glycol monomethylether and water‐vapor permeability
Authors: Inagaki N. , Kubokawa Y. 
Published: April 2003

AbstractPlasma polymerization of ethylene glycol monomethylether (EGMME) was investigated by elemental analysis, infrared spectroscopy, and ESCA. The surface and permeation properties for the formed polymers were discussed. EGMME was plasma‐polymerized to yield films. The films contained a large amount of oxygen‐containing groups such as hydroxy, carbonyl, carboxylate ester, and ether groups. The formation of polymers having hydroxy groups was favorable in plasma polymerization at low W/FM values. Their surface energy was high (63.2–57 dyn/cm) and decreased with increasing the W/FM value. The plasma‐polymers from EGMME had slightly high water‐vapor permeability and low oxygen and nitrogen permeabilities. The plasma‐polymers, conclusively, are characterized to have high selectivity in water‐vapor permeation.
Studies on polymerization of vinyl acetate using ylide as an initiator and degradative transfer agent
Authors: Shukla A. K. , Saini S. , Kumar P. , Rai J. S. P. , Srivastava A. K. 
Published: April 2003

AbstractPolymerization of vinyl acetate initiated by β‐picolinium p‐chlorophenacylide was carried out at 30, 35, and 40°C, using conventional dilatometric technique. The initiator and the monomer exponent values were 0.80 ± 0.15 and unity, respectively. The polymerization was inhibited in the presence of hydroquinone, but was favored by nonpolar solvent and polymerization temperature. The energy of activation was 90.3 KJ mol−1. An average value of k/kt for the present system was found to be 0.37 × 10−2. The results are explained in terms of a radical mode of polymerization with degradative initiator transfer; the principal mode of termination, however, was bimolecular.
Study on the feasibility of TLC/FID to reveal chemical composition distributions of copolymers obtained by emulsion processes
Authors: Tacx J. C. J. F. , German A. L. 
Published: April 2003

AbstractThe CCD (chemical composition distribution) of poly(styrene‐co‐ethyl methacrylate) has been determined by thin layer chromatography/flame ionization detection (TLC/FID). It appeared that a mixture of five reference copolymers obtained by solution polymerization each having a narrow CCD, could be separated in five distinct peaks, provided a modified spotting procedure and a concentration gradient elution technique were applied. All copolymers prepared by solution polymerization could be successfully characterized. Copolymers obtained by emulsion techniques using nonionic or anionic surfactants containing oxyethylene groups, or in the absence of chain length modifier behaved anomalously and appeared to have spurious CCD's. Also the average composition calculated from these CCD's did not agree with the average composition determined by 1H‐NMR. This anomalous behaviour disappeared when using sodium lauryl sulfate as surfactant or when applying a chain length modifier (n‐dodecyl mercaptan) during the preparation of the polymer. Several possibilities have been proposed in order to explain these phenomena. The most probable explanation seems to be reaction of a growing polymer chain with surfactant molecules resulting in a quasi‐terpolymer. This polymer containing highly polar oxyethylene groups, remains strongly adsorbed on the silica surface during elution, thus disturbing the separation process.
Polymerizable tautomers. VI. Solvent effects on polymerization and copolymerization of ethyl 4‐methyl‐3‐oxo‐4‐pentenoate
Authors: Masuda Seizo , Tanaka Masami , Ota Tadatoshi 
Published: April 2003

AbstractThe radical polymerization of ethyl 4‐methyl‐3‐oxo‐4‐pentenoate (EMAA) was investigated at 60°C in benzene and acetonitrile. In both solvents, the kinetic results disagreed with the conventional model of radical polymerization. A remarkable solvent effect on monomer reactivity ratio was observed for the copolymerization of EMAA and styrene. Regression analysis of the monomer reactivity ratio with the solvatochromic parameters gives a good linear relationship, taking into account polarity and hydrogen‐bond donating acidity of the solvent as the major factors.
Polymerization of 2,6‐diarylphenols
Authors: Hay A. S. , Dana D. E. 
Published: April 2003

AbstractThe oxidative polymerization of 2,6‐diarylphenols that contain substituents (CH3, OCH3, and, ‐phenyl) in the para positions of the pendant phenyl groups is described. Copolymers of these phenols with 2,6‐diphenylphenol and blends of the polymers have also been studied.
Preparation and characterization of plasma‐polymerized N‐vinyl‐2‐pyrrolidone films
Authors: Marchant R. E. , Yu D. , Khoo C. 
Published: April 2003

AbstractThin films (< 1 μm) of plasma polymerized N‐vinyl‐2‐pyrrolidone (PPNVP) have been prepared, using an inductively coupled RF glow discharge in a flow‐through reactor system. PPNVP films were hydrophilic, smooth, and appeared morphologically homogeneous. The polymer deposition rate was found to increase linearly with NVP flow rate, and to decrease with the distance from the induction coil. ATR–FT–IR spectral studies suggested a highly branched polymer structure and included absorptions at 2150 and 1540 cm−1 which were unique to the plasma polymer and derived from lactam ring opening/breaking reactions. ESCA studies demonstrated that, under a given set of plasma reaction conditions, the surface composition was consistent throughout the reactor. However, polymer composition was influenced by larger changes in the plasma energy, since the nitrogen content was found to decrease with increasing W/FM. This corresponded to concomitant increases in the advancing water contact angles and to small but reproducible changes in the IR spectrum.
Poly(arylsulfone imide) as E‐beam resist: Synthesis and radiolysis
Authors: Chien James C. W. , Cheng Z. S. 
Published: April 2003

AbstractAromatic diamines containing SO2 and S moieties have been used to prepare soluble polyimides with ditrifluoromethyl methane bis(phthalic anhydride) (F‐series polyimides) and polyamic acid with pyromellitic dianhydride (P‐series). Gamma radiolysis gave G(S) values for scission between 1 to 2 with no crosslinking. Significant weight loss occurred with radiolysis is attributable to efficient SO2 bond scission for the F‐series polyimides, as well as imidization in the cases of P‐series polyamic acids.
Circular dichroism and exciton effect of syndiotactic methacrylic polymers with chiral diacyl hydrazide side chain. II. Poly(methacrylic acid–Nβ (L‐(+)‐lactoyl) hydrazide)
Authors: Thevissen J. , Mano E. B. , Klesper E. 
Published: April 2003

AbstractSyndiotactic poly(methacrylic acid hydrazide) has been condensed with L‐(+)‐lactic acid to form optically active side chains which are connected to the main chain by diacyl hydrazide moieties. A model compound was prepared in the same way from pivalic acid hydrazide. The CD spectra of polymer and model compound have been recorded in aqueous solution at different pH. In the acidic and neutral range, a strong Cotton effect is observed at 195 nm for the polymer which is not present for the model. This Cotton effect may be part of an exciton doublet, the second half of which may be located below 190 nm, the limit of the CD spectrometer employed. In the alkaline region, the diacyl hydrazide moiety is deprotonated and the polymer leads in contrast to the model to a well developed exciton effect centered around a crossover point of 241 nm. The influence of the addition of alcohols and salt on the CD spectra is studied, as well as the effect of temperature. For both the acidic to neutral range on one hand, and the alkaline region, on the other hand, ordered conformations are postulated. For the alkaline region a specific helical conformation is discussed.
Polyimides derived from 1,2‐bis(4‐aminophenoxy)propane
Authors: Tjugito Sukanto , Feld William A. 
Published: April 2003

AbstractThe diamine 1,2‐bis(4‐aminophenoxy)propane, containing the flexible 1,4‐dioxa‐2‐methylbutyl‐ene unit, was synthesized. Polyimidization was carried out with 5,5′‐[2,2,2‐trifluoro‐(trifluoromethyl)ethylidine]bis‐1,3‐isobenzofurandione in m‐cresol employing toluene as azeotroping agent to yield a polyimide that was soluble in a variety of solvents and had an inherent viscosity of 0.84 dL/g in N,N‐dimethylformamide. Poly(amic acid) formation with pyromellitic dianhydride, 4,4′‐carbonyldiphthalic anhydride, and 5,5′‐[ethanediylbis(oxy)]‐bis‐1,3‐isobenzofurandione was carried out in N,N‐dimethylformamide with imidization completed by heating at 160°C for 24 h under vacuum. All of the polyimides exhibited a 5% weight loss in air and in helium by 420°C.
Synthesis of poly(benzoxazinone)s by direct polycondensation of dicarboxylic acids with bis(anthranilic acid)s
Authors: Ueda Mitsuru , Komatsu Shinichi 
Published: April 2003

AbstractA convenient method for the synthesis of poly(benzoxazinone)s of high molecular weights has been developed. These polymers were prepared readily by direct polycondensation of aromatic dicarboxylic acids containing phenyl ether structures with bis(anthranilic acid)s using phosphorus pentoxide/methanesulfonic acid (PPMA) as a condensing agent and solvent. Polycondensations proceeded smoothly and were completed within several hours at 140°C to produce poly(benzoxazinone)s with inherent viscosities up to 2.6 dL/g. The synthesis of 2‐substituted benzoxazinones by the reaction of aromatic carboxylic acids or dicarboxylic acid with anthranilic acid in PPMA was studied in detail to demonstrate the feasibility of the reaction for polymer formation. The thermogravimetry of the aromatic poly(benzoxazinone)s showed 10% weight loss in air and nitrogen around at 440 and 460°C, respectively.
Influence of thermal initiation on the radical polymerization of unsaturated monomers
Authors: Guzman J. , Madruga E. L. , Riande E. 
Published: April 2003

AbstractThe effect of thermal initiation of the radical polymerization of unsaturated monomers has been analyzed by considering a kinetic scheme that includes thermal‐ and catalyst‐induced formation of free radicals, propagation, and termination reactions. Expressions relating the different rate constants with the instantaneous monomer concentration are derived and they indicate the great influence of thermal initiation on the kinetic results. Application to a real case suggests that evaluation of kd and kp/k from experimental results using the method of dead‐end polymerization may lead to erroneous values of these constants.
Poly(vinyl acetate) as a template for the radical polymerization of acrylonitrile
Authors: Tewari N. , Srivastava A. K. 
Published: April 2003

AbstractThe template polymerization of acrylonitrile (AN) along with atactic‐poly(vinyl acetate) of Mv (47,090), at 60°C for 120 min in dimethyl formamide (DMF) has been studied dilatometrically to study the effects of template, monomer, and initiator (benzoyl peroxide) concentration upon kinetics. Viscometric measurements showed that complexation between at‐PVAc and PAN was maximum when template/polymer ratio was 1:1 and time required for complete complexation was 15 min. The overall energy of activation was 57.76 and 77.01 kJ/mol in the presence and absence of, PVAc, respectively. The overall system follows mechanism I, i.e., the monomer molecules get adsorbed on the surface of the template macromolecules and then propagation proceeds.
Water‐soluble graft copolymers from macromonomer method
Authors: Tsukahara Yasuhisa , Ito Katsuji , Tsai Hsi‐Chuan , Yamashita Yuya 
Published: April 2003

AbstractWater‐soluble graft copolymers of well‐defined structure having hydrophobic polymethacrylate branches with different ester groups were prepared by the macromonomer method. Methacrylate macromonomers of controlled molecular weights having a methacryloyloxyl end group were synthesized by radical polymerization of the corresponding monomer in the presence of thioglycolic acid followed by the reaction of glycidyl methacrylate with the terminal carboxyl group. These macromonomers were copolymerized with methacrylic acid and methyl methacrylate to prepare tailor‐made graft copolymers composed of a hydrophlic backbone and different kinds of hydrophobic branches, which were characterized by elemental analysis, NMR, and GPC. The viscosities of the aqueous solutions of the sodium salts of these graft copolymers were measured. It was found that the viscosity of the dilute solution of the graft copolymer was remarkably high compared with the corresponding random copolymer irrespective of the ester group in branch segments. Solubilizing behavior of Orange‐OT in aqueous solutions of the graft copolymers and the random copolymer were also investigated to study the nature of the hydrophobic domain of the graft copolymers.
Synthesis of diols containing nucleic acid bases and their polyesters
Authors: Lu C. X. , Zhou Yan 
Published: April 2003

AbstractPreparation of four diols containing nucleic acid bases derived from 3‐(thymin‐1‐yl)propanoic acid (3‐TPA) and 3‐(uracil‐1‐yl)propanoic acid (3‐UPA), and the corresponding model polymers of polynucleotides with linear polyester backbone and nucleic acid base derivative as pendant side chains are described. N‐(1′,3′‐Dihydroxy‐2′‐methyl‐2′‐propyl)‐3‐(thymin‐1‐yl)propionamide (VIa, 3‐HMPTPA), N‐(1′3′‐dihydroxy‐2′‐methyl‐2′‐propyl)‐3‐(uracyl‐1‐yl)propionamide (VIb, 3‐HMPUPA) and their isomers, N(β,β‐dihydroxyethyl)‐3‐(thymin‐1‐yl)propionamide (VIIa, 3‐HETPA), and N‐(β,β‐dihydroxyethyl)‐3‐(uracil‐1‐yl)propionamide (VIIb, 3‐HEUPA) were synthesized through the selective N‐acylation of 2‐methyl‐2‐amino‐1,3‐propanediol and diethanolamine with 3‐TPA and 3‐UPA, respectively, by the active ester‐N‐hydroxyl‐1,4‐epoxy‐5‐cyclohexene‐2,3‐dicarboximide (HOEC) method. The resulting diols were polycondensed with active diamide of benzotriazole (HBT) such as 1,1′‐(isophthaloyl)bis‐benzotriazole (IPBBT), giving polyesters containing thymine and uracil derivatives as the side group, by the selective O‐acrylation of active amide‐benzotriazole method.
Copolymer of trifluoroethylmethacrylate–N‐p‐methoxyphenyl citraconimide as high TgE‐beam resist
Authors: Gong Ben‐Min , Chien James C. W. 
Published: April 2003

AbstractCopolymers of 2,2,2‐trifluoroethyl methacrylate (TFEMA) and N‐p‐methoxyphenyl citraconimide (MCM) have been synthesized. The Tg varies with composition reaching 150°C with 34% MCM. The copolymer has good radiation sensitivity according to both G values for chain scission and E‐beam measurements. Though they have lower contrast than PMMA, they have much higher resistance to plasma etching. The resistance increases markedly with MCM content to values comparable to that for polyimides. Therefore, TFEMA–MCM copolymers of high MCM content can be useful as high temperature plasma etchable positive E‐beam resists.