bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymerization of para‐xylylene derivatives (parylene polymerization). I. Deposition kinetics for parylene N and parylene C
Authors: Kramer P. , Sharma A. K. , Hennecke E. E. , Yasuda H. 
Published: April 2003

AbstractKinetic aspects of parylene N [unsubstituted poly(para‐xylylene)] and Parylene C [monochlorosubstituted poly(para‐xylylene)] were studied. The conversion of starting material (dimer of either p‐xylylene or chloro‐para‐xylylene) to polymer is quantitative (ca. 100%). Consequently, the total polymer formed in a closed system is directly proportional to the amount of dimer charged. However, the percentage of the total amount of polymer formed which deposits on substrate surfaces, placed in the deposition chamber, as well as the polymer film growth rate are dependent on operational factors such as the temperature of the substrate, sublimation of dimer temperature, flow pattern of the reactive species, etc. Parylene C, being a heavier and more polar molecule, has the tendency to deposit easily in the deposition chamber compared to the deposition of Parylene N. Parylene C also has a higher ceiling temperature for deposition than Parylene N. This situation has been investigated from the viewpoint of excess thermal energy which hinders polymer formation (deposition) due to the exceedingly high entropy change necessary for polymer deposition to occur. The addition of a cool (i.e., room temperature) inert gas was shown to increase the deposition of Parylene N on substrate surfaces placed in the deposition chamber. The deposition increase and acceleration of deposition (film growth) rate were found to be related to the size and molecular weight of the inert gas pressure maintained in the system. The accelerating effect is explained by the increase in third‐body collisions to dissipate the excess thermal energy of the reactive species.
Acid–base complexes of polymers
Authors: Fowkes F. M. , Tischler D. O. , Wolfe J. A. , Lannigan L. A. , Ademu‐John C. M. , Halliwell M. J. 
Published: April 2003

AbstractThe physical interactions of polymers with neighboring molecules are determined by only two kinds of interactions: London dispersion forces and Lewis acid–base interactions. These two kinds of attractive energies (together with certain steric restrictions) determine solubility, solvent retention, plasticizer action, wettability, adsorption, adhesion, reinforcement, crystallinity, and mechanical properties. The London dispersion force interaction energies of polymers have been quantified by the dispersion force contribution to cohesive energy density (δ2d) and the dispersion force contribution to surface energy (δd). The Lewis acid–base interactions, often referred to as “polar” interactions, can be best quantified by Drago's CA and EA constants for acid sites and CB and EB constants for basic sites. In this article infrared spectral shifts are featured as a method of determining enthalpies of acid–base interaction, and the C and E constants for polymers, plasticizers, and solvents. Examples are given where acid–base complexation of polymers with solvents dominate solubility and swelling phenomena. Enthalpies of acid–base complexation in polymer blends are determined from spectral shifts.
Partial miscibility in multicomponent polymer system
Authors: Jung Hae Young , Jhon Mu Shik 
Published: April 2003

AbstractIt has been shown, using the significant structure theory of liquids, that a lower critical solution temperature behavior as well as a upper critical solution temperature behavior can be expected for polymer–polymer systems and that a phase diagram of closed‐loop‐type in a polymer–polymer–solvent system can be possible. In this article the sublimation energy of a mixture was expressed as a quadratic form of segment surface fractions on pure components rather than that of mole fractions, and the effect of the segment surface fractions on critical compositions was explained. The calculated partial miscibilities were in good agreement with the experiment.
Characterization of copolymers of vinyl acetate with ethyl α‐cyanocinnamate
Authors: Kharas Gregory , Kohn David H. 
Published: April 2003

AbstractAlternating and random copolymers of ethyl α‐cyanocinnamate and vinyl acetate were studied. Infrared, 1H, and 13C spectra of the copolymers are discussed by comparison with a model compounds, poly(vinyl acetate), and various copolymers. The decomposition temperature and Tg of copolymers of various composition, studied by TMA and DSC, increase both with increasing content of ethyl α‐cyanocinnamate.
Copolymerization of vinyl acetate with benzylidenemalononitrile
Authors: Kharas Gregory , Kohn David H. 
Published: April 2003

AbstractVinyl acetate was copolymerized with benzylidenemalononitrile in bulk by radical initiation at 80°C up to low conversions. Alternating copolymers were formed over a wide range of monomer feed ratios. The copolymerization parameters were determined by the conventional scheme. The copolymers were characterized by IR, proton, and 13C spectroscopy and their basic properties, solubility, viscosity, and thermal behavior were determined.
Cationic polymerization of β‐pinene
Authors: Martinez Francisco 
Published: April 2003

Abstractβ‐Pinene was polymerized with cationic initiators in reactions that were carried out to study the solvent, temperature, initiator, and monomer‐to‐solvent ratio. Polymers obtained under different conditions were characterized by intrinsic viscosity, softening point, and gel permeation chromatography.
Matrix polycondensation through hydrogen bonding interaction
Authors: Ogata Naoya , Sanui Kohei , Iwaki Fusako , Nomiyama Atsuko 
Published: April 2003

AbstractPolycondensation of diesters having hydroxyl or pyridine groups was carried out with hexamethylenediamine (HMD) in the presence of (vinyl alcohol/vinyl acetate) copolymers as a matrix polymer. Apparent rates of the polycondensation of dimethyl tartrate (DMT) with HMD increased with increasing contents of PVA units in the copolymers and a strong entanglement between growing polyamide chains and PVA copolymers took place through the adsorption of HMD and DMT on the matrix copolymers. 2,6‐Dimethyl pyridine dicarboxylate (2,6‐DMP) reacted with HMD in the presence of the PVA copolymers or polysaccharide, while the rate enhancement effect of the matrix polymers was not significantly observed, as in the case of DMT. The effect of the matrix polymers on the polycondensation was discussed in terms of hydrogen bonding interactions.
Synthesis of some graft polymers of uracil
Authors: Brahme Nanda M. , Smith Walter T. 
Published: April 2003

AbstractPoly‐6‐(acryloyloxymethyl)uracil was prepared by radical‐catalyzed polymerization of monomeric 6‐(acryloyloxymethyl)uracil. The reaction of 6‐chloromethyluracil with the potassium salt of polyacrylic acids of molecular weights 5000 and 90,000 gave polymers with both carboxylate groups and 50–70% pendant uraciles. Some inferences concerning the arrangement of uracil groups are drawn from the nuclear magnetic resonance (NMR) spectra of the latter polymers. No interaction between poly(A) and the synthetic polymers could be observed.
Hydrophilic polymer‐immobilized lipoamides‐iron(II) system as a new reducing catalyst for the reduction of O‐benzylhydroxylamine by sodium borohydride
Authors: Kijima Masashi , Nambu Yoko , Endo Takeshi , Okawara Makoto 
Published: April 2003

AbstractBased on a redox function of 1,2‐dithiolane ⇌ 1,3‐dithiol, lipoamide immobilized on hydrophilic polymers such as polyacrylamide, polyethyleneimine, and chitosan was found to work as polymeric reducing catalysts for the reduction of O‐benzylhydroxylamine to benzyl alcohol and ammonia with sodium borohydride in the presence of ferrous ion. These polymers were easily separable and maintained high reactivities even after repeated uses.
Phase‐transfer reactions catalyzed by polymer‐supported crown ethers
Authors: Tomoi Masao , Yanai Noriyuki , Shiiki Satoshi , Kakiuchi Hiroshi 
Published: April 2003

AbstractPolymer‐supported crown ethers were prepared from chloromethylated or ω‐bromoalkylated polystyrene resins and hydroxymethylbenzo‐18‐crown‐6 and 15‐ or 18‐membered monoazacrown ethers. Effects of the cavity size of crown ethers, the degree of crosslinking, the degree of ring substitution, particle size, spacer chains, and solvents on the activity of the polymer‐supported crown ethers in the reaction of 1‐chloro‐ or 1‐bromo‐octane with aqueous NaI or KI were investigated and mechanisms of the reaction were discussed in terms of mass transfer, intraparticle diffusion, and intrinsic reactivity.
Synthesis and characterization of polymers and copolymers of vinylruthenocene
Authors: Willis T. Chad , Sheats John E. 
Published: April 2003

AbstractHomopolymers of vinylruthenocene and its copolymers with methyl acrylate, styrene, and n‐vinylpyrrolidinone have been prepared by free‐radical polymerization. No evidence for the electron transfer termination mechanism postulated for polymerization of vinylferrocene was observed. Yields of soluble polymers were 40–90% with Mw (4–25) × 103 and Mw/Mn = 3.0–13.2. TGA analysis showed little weight loss up to 300°C but rapid decomposition above 300°C. Polyvinylruthenocene is a highly brittle material with Tg above 250°C. Torsional braid analysis of the copolymer samples showed Tg in the range 90–130°C which in some samples increased upon cooling and reheating. Several samples showed weak thermal transitions occurring prior to or following Tg. The rise in Tg upon cooling and reheating is indicative of possible decomposition, crosslinking, or realignment of the polymer chains.
Ring formation on heating poly(methyl vinyl ether‐alt‐ammonium maleamate)
Authors: Field Nathan D. , Li Chi 
Published: April 2003

AbstractPoly(methyl vinyl ether‐alt‐ammonium maleamate), when heated at up to 100°C while removing volatiles, is converted to polymer whose infrared, elemental analysis and Tg are consistent with a structure predominantly that of poly(methyl vinyl ether‐alt‐maleic anhydride). Maleimide comonomer units are a substantially lesser component. Evidence is presented that a part of the reaction sequence may involve hydrolysis of imide or amide.
Chemistry of alkenyl azlactones. I. Radiation‐sensitive materials derived from azlactone‐containing copolymers
Authors: Heilmann Steven M. , Rasmussen Jerald K. , Palensky Frederick J. , Smith Howell K. 
Published: April 2003

Abstract2‐Vinyl‐4,4‐disubstituted azlactones were shown to be effective comonomers in free radical addition polymerizations for purposes of subsequently preparing radiation‐sensitive materials by attaching an unsaturated nucleophile. The azlactone‐functional copolymers could be reacted with amine‐, thiol‐, and hydroxy‐functional nucleophiles over the course of a few hours in solution at room temperature to effect covalent attachment of the nucleophile. The electron beam‐ and UV‐sensitive materials were shown to be useful as photoresist and embossable video disk recording media.
Direct mass spectrometry of polymers. XI. Primary thermal fragmentation processes in aromatic–aliphatic polyesters
Authors: Foti Salvatore , Giuffrida Mario , Maravigna Pietro , Montaudo Giorgio 
Published: April 2003

AbstractThe thermal decomposition of two series of isomeric aromatic–aliphatic polyesters was studied by direct pyrolysis‐mass spectrometry. The results indicate that intramolecular exchange reactions predominate in the primary thermal fragmentation processes to cause the formation of cyclic oligomers. Several secondary thermal processes may occur after the primary step: hydrolytic cleavage of the ester bond, decarboxylation, and β‐hydrogen transfer.
Structural characterization of polybenzyls by high field 13C‐NMR spectroscopy
Authors: Ul Hasan Misbah , Tsonis Christos P. 
Published: April 2003

Abstract13C‐NMR Spectroscopy has been used for the structural characterization of polybenzyls synthesized from the polymerization of benzyl chloride catalyzed by arene chromium tricarbonyls. The 13C‐chemical shifts for various mono‐, di‐, tri‐, and tetrasubstituted phenyl groups in a polybenzyl have been calculated by the use of additivity parameters and compared with their observed shifts. Although from a theroetical point of view, polysubstitution on a phenyl ring gives rise to a number of isomers, the results indicate the preferential formation of only a few of them due to steric and electronic considerations. Based on quantitative 13C‐NMR data, several important structural parameters including the percentage of mono‐, di‐, tri‐, and tetrasubstituted phenyl rings in the polybenzyl can be calculated. The extent of branching in a number of polybenzyls prepared under different experimental conditions was determined. The results indicate an increase in branching with the increase in reaction temperature.
The photopolymerization of isoprene with the use of hydrogen peroxide as photoinitiator
Authors: Tang D. K. , Ho S. Y. 
Published: April 2003

AbstractThe photochemical polymerization reactions of isoprene with the use of H2O2 as the photoinitiator have been studied in benzene, acetone, and tetrahydrofuran solutions. Hydrogen peroxide is photodecomposed to form hydroxyl radicals which may initiate the polymerization of isoprene with hydroxyl terminated polyisoprene as the product. Average molecular weight, microstructure, and the functionality of the hydroxyl terminated polyisoprene are determined. A suitable reaction mechanism and the polymerization rate equations are proposed. The overall activations energy is evaluated to be about 3.8 kcal/mol.
Polymeric arylsulfonylmethyl isocyanide, a novel polymer reagent
Authors: Kamogawa Hiroyoshi , Maeda Kazunori 
Published: April 2003

Abstractp‐Vinylphenylsulfonylmethyl isocyanide (1M) was synthesized starting with sodium p‐styrenesulfinate via p‐vinylphenylsulfonylmethylformamide (4M). Free‐radical polymerization of 1M provided cross‐linked insoluble polymers (1), whereas 4M provided soluble polymers, which could be converted to soluble polymer 1. Conversions of carbonyl compounds to nitriles and Schiff bases to 1,5‐disubstituted imidazoles with both soluble and cross‐linked polymers 1 as reagents proceeded almost as efficiently as with their low molecular weight analog. Reusability of polymer 1 was fairly good.
Emulsion polymerization of styrene. III. Effect of Ti(III) and Cl(1) on the polymerization of styrene initiated by potassium persulfate
Authors: Bataille P. , Gonzalez A. 
Published: April 2003

AbstractThe emulsion polymerization of styrene initiated by potassium persulfate catalyzed by Ti+3 ions was studied. Two sources of Ti+3 ions were used: the titanium trichloride and titanium sulfate. It was found that the titanium ions used in conjunction with potassium persulfate decrease both the reaction rate and the average molecular weight. An even greater drop of reaction rate was noted when chlorine anions (TiCl3) were present. The presence of these ions had a stabilizing effect on the polydispersity.
Structure and properties of poly(ethylene terephthalate) crystallized by converging flow and high pressure
Authors: Ledbetter Marshall , Cuculo John , Tucker Paul 
Published: April 2003

AbstractThe structure and properties of a poly(ethylene terephthalate) extrudate, prepared by converging flow and high pressure, were examined. Relatively high levels of crystallinity and orientation were produced by the combination of an orienting flow and high‐pressure quench. The fine structure was examined in detail by x‐ray diffraction, negative staining–transmission electron microscopy, and amine etching–gel permeation chromatography. The morphology was directly relatable to this unique preparative technique. Modulus was determined by a compressive Rheovibron technique. Low shrinkage and the compressive modulus were related to the structure in the development of a structural model.
Mass spectroscopy of epoxylated novolac resin cured with phthalocyanine tetraamines
Authors: Achar B. N. , Fohlen G. M. , Hsu M. S. , Parker J. A. 
Published: April 2003

AbstractMass spectroscopy was done at different temperatures on epoxylated novolac resin DEN 438 (Dow Chemical Co.) alone, and after curing with various metal(II) phthalocyanine tetraamines (MPTA). Possible modes of fragmentation are given to explain the experimental results. Gas‐chromatographic/mass‐spectroscopic (GC–MS) analyses of MPTA derivatives indicated the presence of only trace quantities of benzene, aniline, cyanobenzene, and orthodicyanobenzene. The GC–MS studies of the cured DEN 438 epoxy resins indicated that the mechanisms of thermal degradation are qualitatively similar, and some common features were observed in their fragmentation in an electron beam and by thermal degradation. This study is a further assessment of the utility of these phthalocyanine derivatives for curing epoxy resins to produce heat‐resistant polymer systems.
Effect of structure on properties of polypyromellitimide films
Authors: Varma I. K. , Tripathi Anita , Goel T. C. , Murthy K. R. , Tripathi A. K. 
Published: April 2003

AbstractPolypyromellitimides were prepared by the reaction of di(4‐aminophenyl) ether (E)/di (4‐aminophenyl) methane (M), and pyromellitic dianhydride in dimethylformamide, followed by thermal cyclization in a nitrogen atmosphere. Copolyimides were obtained by taking different molar ratios of diamines in the initial monomer feed. Differential scanning calorimetric, thermogravimetric analysis, and thermally stimulated current studies were carried out on these samples. It was concluded that the dielectric relaxation in these copolymers is due to trapping of the charge carriers. The dielectric relaxation parameters and activation energies were also calculated.
Polymerization of alkyl allyl oxalates in the evolution of carbon dioxide at elevated temperatures
Authors: Yamawaki Masataka , Matsumoto Akira , Oiwa Masayoshi 
Published: April 2003

AbstractRadical polymerization of several alkyl allyl oxalates, including methyl allyl oxalate (MAO), ethyl allyl oxalate, propyl allyl oxalate, butyl allyl oxalate, and octyl allyl oxalate, was conducted in the evolution of carbon dioxide at elevated temperatures, and was compared with the anomalous polymerization behavior of diallyl oxalate (DAO) discussed in our earlier articleA. Matsumoto, I. Tamura, M. Yamawaki, and M. Oiwa, J. Polym. Sci. Polym. Chem. Ed., 17, 1419 (1979).
. The kinetic equations for the polymerization of alkyl allyl oxalate were derived following the kinetic treatment of the DAO polymerization by further consideration of the absence of cyclization of the growing polymer radical and the effective reinitiation by alkyl radical, and were then satisfactorily applied to the polymerization of MAO, as a representative alkyl allyl oxalate. The evolution of carbon dioxide in the polymerization of alkyl allyl oxalates was enhanced with the increase of bulkiness of the alkyl substituent, as a result of steric suppression of the propagation of the growing polymer radical.
Mechanisms of antioxidant action: Transformations of 4‐hydroxy‐2,2,6,6‐tetramethylpiperidinoxyl (HTMPO) in polypropylene during processing
Authors: Bagheri Rouhalla , Chakraborty Khirud B. , Scott Gerald 
Published: April 2003

AbstractWhen 4‐hydroxy‐2,2,6,6‐tetramethyl piperidinoxyl (HTMPO) is processed in polypropylene in a closed mixer, almost 50% is converted to other products during the first few minutes whilst the applied torque in the mixer is high. There is associated formation of unsaturation and this fact, in conjunction with the almost complete regeneration of nitroxyl within five minutes, suggests that the corresponding hydroxylamine (HTMPOH), which can be qualitatively identified, is the major transformation product. A study of the UV stability of PP films fabricated from polymer processed for varying times shows that UV stability is related to the quantity of the redox couple (HTMPO + HTMPOH) remaining in the polymer. This is considerably reduced by severe processing. The redox capable has almost no thermal antioxidant (oven aging) activity.
Syntheses of poly[N‐(1‐pyrenyl)acetyl ethylenimine] [pyrene‐substituted linear poly(ethylenimine)] and poly[methyl 2‐(1‐pyrenyl)acetamidopropenoate] [pyrene‐substituted poly(dehydroalanine methyl ester)]
Authors: Arora Kartar S. , Overberger C. G. 
Published: April 2003

AbstractThe syntheses of two new pyrene‐containing monomers—2‐(1‐pyrenyl)methyl‐2‐oxazoline (6) and methyl 2‐(1‐pyrenyl)acetamidopropenoate (12)—and their polymerization are described. Cationic isomerization polymerization of 6 with ethylene glycol ditosylate initiator gave poly[N‐(1‐pyrenyl)acetyl ethylenimine] (7) and free‐radical polymerization of 12 with AIBN initiator gave poly[methyl 2‐(1‐pyrenyl)acetamidopropenoate] (15). The monomer model compounds of the two polymers, namely, N,N‐diethyl(1‐pyrenyl)acetamide (9) and methyl 2‐methyl‐2‐(1‐pyrenyl)acetamidopropanoate (14), were also synthesized. The polymers were characterized by elemental analysis, IR spectroscopy, and a comparison of their 1H‐NMR spectra with those of the respective monomer model compounds.
W/O microemulsions of styrene monomer and dimer
Authors: Friberg Stig E. , Liang Paul 
Published: April 2003

AbstractThe reason for the lower water solubility in W/O microemulsions of the styrene dimer, trans, trans‐1,4‐diphenyl‐1,3‐butadiene, in comparison with the monomer was investigated by determining the phase equilibria in the microemulsion system with pentanol as the cosurfactant and sodium dodecyl sulfate as the surfactant. The main factor for the low tolerance for water in the system was the incompatibility of the dimer with the cosurfactant and surfactant.
Fire‐ and heat‐resistant adhesive resins based on maleimido and citraconimido substituted 1‐[(dialkoxyphosphinyl)methyl]‐2,4‐ and ‐2,6‐diaminobenzenes
Authors: Mikroyannidis John A. 
Published: April 2003

AbstractA novel class of fire‐ and heat‐resistant bisimide resins was prepared by thermal polymerization of maleimido or citraconimido derivatives of 1‐[(dialkoxyphosphinyl)methyl]‐2,4‐ and ‐2,6‐diaminobenzenes (1). The neat bisimide resin prepared by curing 1‐[di(2‐chloroethoxyphosphinyl)methyl]‐2,4‐ and ‐2,6‐bismaleimidobenzene exhibited a limiting oxygen index 75% higher and smoke evolution about 30 times lower compared with the parent polymer obtained by curing m‐phenylenebismaleimide. The char yield of cured bisimide resins at 700°C was 58–70% in a nitrogen atmosphere and 35–60% in air. An increase in formula weight between the imide groups slightly reduced the char yield. The polymer precursors were synthesized by reacting the phosphorus‐containing diamines (1) (1 mol) with maleic anhydride/citraconic anhydride (2 mol) or by reacting the monomaleimido derivative of (1) with benzophenone tetracarboxylic dianhydride/methylenebis(4‐phenylisocyanate) in a 2:1 mole ratio. The monomers were characterized by elemental analysis, Fourier‐transform–infrared (FT‐IR), proton nuclear magnetic resonance (1H‐NMR) spectroscopy, and gas chromatography–mass spectroscopy (GC‐MS). Direct cleavage of the PC bond and inversion of the synthesis reaction may occur during their pyrolysis. The thermal polymerization of the monomers was investigated by differential scanning calorimetry (DSC). Biscitraconimides are thermally polymerized at a relatively lower temperature than the corresponding bismaleimides.