bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal decomposition of poly(sec‐amyl methacrylate)
Authors: Kojima Takakazu , Kurotu Takuzo , Masuda Ken‐Ichi , Hosaka Yoshinobu
Published: April 2003

The thermal decomposition of poly(sec‐amyl methacrylate) is studied by simultaneous thermogravimetry–gas chromatography–mass spectrometry and by pyrolysis–gas chromatography. The TG curve has four distinct breaks and a plateau. Results of the identification of the evolved gas at the individual breaks by GC–MS techniques lead to the conclusion that these breaks correspond to the individual processes in the decomposition mechanism like that of poly(tert‐butyl methacrylate): the first break, the depolymerization initiated at the unsaturated chain ends; the second break, the depolymerization initiated at the saturated chain ends; the third break, the ester decomposition; the plateau, the inhibition of decomposition by the formation of poly(methacrylic anhydride); the fourth break, the decomposition of poly(methacrylic anhydride). The extent of ester decomposition is related to the substituent constants based on Hammett equation. The ester decomposition product is separated into three pentene isomers by pyrolysis–gas chromatography: trans‐2‐pentene, cis‐2‐pentene, and 1‐pentene. As raising decomposition temperature, the composition ratio of trans‐2‐pentene decreases and becomes constant above 620 K, and the composition ratios of cis‐2‐pentene and 1‐pentene increase and also become constant above 620 K. These results are accounted for by mobility of atoms included in the substituent at forming a ring transition state.
Curing of epoxy resins with metal(II)4,4′,4″,4‴‐tetraamino phthalocyanines‐modification with elastomers
Authors: Achar B. N. , Fohlen G. M. , Parker J. A.
Published: April 2003

The use of metal phthalocyanine tetraamines in curing epoxy resins to form high‐temperature‐resistant matrix polymers for composites has been reported earlier. The effect of adding carboxy‐terminated butadiene‐acrylonitrile (CTBN) elastomer is now described; preliminary measurements of tensile, flexural, and short‐beam shear strengths, dynamic moduli, resin content, and moisture absorption are presented, and the results of dynamic thermogravimetric analyses are given. In addition to their high char yield (86–87.5% at 800°C in a nitrogen atmosphere) and limiting oxygen index (48.3–50.3), the laminates showed good mechanical properties.
Quantitative determination of the surface composition of acrylate copolymer latex films by XPS (ESCA)
Authors: Pijpers A. P. , Donners W. A. B.
Published: April 2003

The interaction of copolymer latex particles with emulsifiers is governed to a great extent by the monomer composition of the particle surface. In this article it is demonstrated that for methylmethacrylate butylacrylate copolymer latexes this quantity, within certain limits, may be determined by XPS (ESCA) by a detailed analysis of the C(1s) line. It is shown that in this analysis secondary shifts in binding energy caused by the two carboxyl‐oxygen atoms have to be taken into account, a fact that has been neglected in the literature so far.
Grafting of polyesters onto carbon black. VI. Copolymerization of alkylene carbonate with cyclic acid anhydride initiated by alkali metal carboxylate groups on carbon black surface
Authors: Tsubokawa Norio , Ohyama Takeshi , Yamada Akihiro , Sone Yasuo
Published: April 2003

The ring‐opening copolymerization of alkylene carbonate with cyclic acid anhydride was found to be initiated by carbon black containing potassium carboxylate (COOK) groups to give an alternating polymer, i.e., polyester. The polyester was propagated from COOK groups and effectively grafted from carbon black surface: e.g., the grafting ratio of polyester from ethylene carbonate (EC) and phthalic anhydride (PAn) went up to over 100%. On the other hand, the initiating activity of alkali metal carboxylate groups increased, depending on the alkali metal countercation, in the following order: COOLi < COONa < COOK < COORb < COOCs. This order was in agreement with that of increasing electropositivity of the counteraction. The activation energy of the copolymerization of EC with PAn was determined to be 26.3 kcal/mol. The rate of the copolymerization was accelerated in an aprotic solvent such as N‐methyl‐2‐pyrrolidone. Furthermore, the effect of solvent and polymerization temperature on the grafting ratio of polyester was investigated.
Mechanochemically initiated polymerizations. VIII. Influence of chemical nature of monomers
Authors: Simionescu Cristofor I. , Oprea Cleopatra Vasiliu
Published: April 2003

The article presents some results which prove that vinylic, acrylic, dienic, and cyclic monomers, as well as substances which cannot be polymerized by conventional methods (acetonitrile) are activated under the influence of mechanical energy, by vibratory milling, and participate in polymerization and copolymerization reactions.
Conducting carbon‐nitrogen pyropolymers derived from cyanogen
Authors: Chen J. H. , Labes M. M.
Published: April 2003

Electropolymerization of cyanogen in acetonitrile containing an electrolyte yields a poly(cyanogen). Its structure involves an open‐structured dimer derived from the heterocyclic anion C7N7− mixed with a sequence of nitrile‐substituted, conjugated carbon–nitrogen bonds. Although this polymer is an insulating solid, pyrolysis in vacuo to 700°C leads to highly conducting carbon–nitrogen pyropolymers via crosslinking and nitrogen elimination. The 700° pyropolymer has a carbon–nitrogen ratio of 5:1, a room temperature conductivity of 1 Ω−1 cm−1, and an activation energy for conduction of ∼0.03 eV.
Bulk polymerization of diallyl benzene‐dicarboxylates I. Influence of temperature on allyl group reactivity
Authors: Kostański L Krzysztof , Króalikowski Wacław
Published: April 2003

The bulk polymerization of the three isomeric diallyl benzene‐dicarboxylates was carried out in the temperature range 80–285°C. The progress of the polymerization process was examined by determination of the conversion of allyl groups double bonds. The reactivity of these groups in the polymerization increases in the following order of isomers: ortho < para < meta at 80–230°C. At temperatures above 200°C the thermal polymerization with activation energies for ortho, meta and para isomers 32, 27, and 28 kcal/mol of allyl group, respectively, has been observed. With the increase of temperature from 80 to 230°C for each of the monomers the number of allyl groups consumed when forming one CC chain (degree of chain polymerization) decreases, but at the same time the kinetic chain length increases several times. The results have been explained by the growing role of chain transfer reactions with simultaneous increase of an ability to reinitiation by occured radicals. The mechanisms of thermal polymerization have been proposed.
Spectroscopic study on chemical structure of plasma‐polymerized hexamethyldisiloxane
Authors: Tajima Ichiro , Yamamoto Minoru
Published: April 2003

A plasma‐polymerized material was produced from hexamethyldisiloxane vapor by a glow discharge polymerization technique. Spectroscopic interpretation of the chemical structure of the polymerized hexamethyldisiloxane was studied by spectroscopic means such as IR, XPS, and NMR. The plasma polymer was barely soluble in the usual organic solvents, although it contained a small amount of the monomer and its oligomers. The IR spectrum indicated that the polymer consisted of SiCH3, SiO, SiCH2, and SiH groups. The surface of the polymer was found to retain structural units similar to the monomer from the XPS measurement. On the other hand, the 13C and 29Si high‐resolution, solid‐state NMR measurements revealed that the plasma polymer was highly crosslinked with a variety of conformations and a number of O atoms surrounding a Si atom. Results from the XPS and NMR spectra suggested that the bulk of the polymer was more oxidized than the surface layer; Si atom was preferentially oxidized. A hypothetical chemical structure was proposed for the polymerized hexamethyl‐disiloxane.
Poly(alkylene oxide) ionomers. XII. Hydrolysis of polymers and copolymers of methyl 10,11‐epoxyundecanoate
Authors: Bansleben Donald A. , Vogl Otto
Published: April 2003

Ester‐substituted oxyethylene polymers and copolymers of methyl 10,11‐epoxyundecanoate were prepared with an aluminumalkyl–water coordination initiator system modified with acetylacetone. Poly(ethylene oxide) ionomers, polyelectrolytes, and polycarboxylic acids were obtained by alkaline hydrolysis of the pendant carbomethoxy groups and by neutralizations with acetic acid. The high molecular weight substituted poly(ethylene oxide)s were characterized by spectral, thermal, and dilute solution measurements. The infrared spectra of carboxylate substituted poly(ethylene oxide)s, both homo‐ and copolymers, show the typical shifts in the carboxyl absorption when going from the ester to the carboxylate group to the free acid. Polymer transitions temperatures, as measured by DSC, changed accordingly. Wide‐angle x‐ray diffraction measurements strongly suggest the existence of ionic domains in the oxyethylene polymer matrix. Dilute solution properties of the ionomers show typical polyelectrolyte behavior, including a substantial change in viscosity when ionic solute is added.
The kinetics of the attachment of polymer chains to reactive latex particles and the resulting latex stabilization
Authors: Huang Yu‐Hui , Li Zhuo‐Mei , Wetz Herbert Mora
Published: April 2003

Poly(vinyl benzyl chloride) latex was reacted with ethanolamine and with amine terminated chain molecules containing up to 33 ethylene oxide residues. The kinetics of these reactions were essentially independent of the length of the chain carrying the amine group. An increasing length of the chains bound to the surface of the latex particles produced an increasing latex stabilization.
Heat‐resistant poly(metal phthalocyanine)imide copolymers using benzenetetracarboxylic dianhydride
Authors: Achar B. N. , Fohlen G. M. , Parker J. A.
Published: April 2003

Novel poly(metal phthalocyanine)imide copolymers of high thermal stability have been synthesized using metal(II) 4,4′,4″,4‴‐phthalocyanine tetraamine (metal = copper, cobalt, and nickel); diamines: p‐phenylene diamine; 4.4′‐methylene dianiline and 9,9‐bis(4‐aminophenyl)fluorene; and 1,2,4,5‐benzenetetracarboxylic dianhydride. Polymers with medium to high degree of polymerization can be prepared depending upon the metal phthalocyanine concentrations. Effects of temperature, order of addition, solvent type, and metal phthalocyanine concentrations were studied to ascertain the optimum conditions to obtain polymers having good thermal stability with a high degree of polymerization. These polymers had decomposition temperatures greater than 500°C both in air and in nitrogen atmospheres. Their anaerobic char yield at 800°C varied between 65–80%. These new copolymers have promising applications as heat resistant films, fibers, and varnishes.
Vinylsulfonylethyl derivatives of nucleic acid bases and their graft polymers on polyethyleneimine
Authors: Smith Walter T. , Brahme Nanda M.
Published: April 2003

Vinylsulfonylethyl (VSE) derivatives of the nucleic acid bases adenine, thymine, cytosine, and the nucleosides inosine and uridine have been prepared via a simple Michael reaction with divinyl sulfone. The VSE derivatives were grafted on a polyethyleneimine (PEI) backbone. PEI of different molecular weights (1400, 1800 and 50,000–100,000) were used and also two different molar ratios (1:1 and 1:2) of monomer to PEI were employed. From the 1H‐NMR and elemental analysis, it appeared that in almost all instances the grafting was quantitative. In one case, both 1‐VSE‐thymine and 9‐VSE‐adenine were grafted on the same PEI backbone. Interactions between some of these polymers were investigated by UV spectroscopy. The expected complementary base pairing was observed only in DMSO–ethylene glycol solvent system but not in DMSO. The adenine polymer showed a one‐to‐one interaction with the thymine polymer.
Cationic polyelectrolytes. V. On macromolecular chain conformational state during amination reactions of CMPS
Authors: Drǎgan Stela , Ioan Silvia , Petrariu I. , Dima M.
Published: April 2003

The macromolecular chain conformational state during the amination of chloromethylated polystyrene (CMPS) with two aliphatic amines, namely methyl(2‐hydroxyethyl)amine (MHEA) and N,N‐dimethyl(2‐hydroxypropyl)amine (DM2HPA), has been studied. Viscosimetric and light scattering measurements were performed during reactions in binary solvent mixtures. The observed kinetic deviations have been related with the conformational transformations of the macromolecular chain.
Semiconducting poly(dicyanoacetylenes)
Authors: Chien James C. W. , Carlini Carlo
Published: April 2003

Poly(dicyanoacetylene) (PDCA) has been synthesized and characterized. The pristine polymer has EPR g‐value, linewidth, unpaired spin concentration, spin—spin relaxation time (T2), and room temperature dc conductivity (σRT) very similar to those of pristine cis‐polyacetylene (PA), but shorter spin—lattice relaxation time (T1). Saturation doping with iodine has little effect on most EPR characteristics of the polymer except for a slight increase in T1. The doped PDCA has σRT value of only 5 X 10‐9 (Ω cm)‐1, indicating either low carrier concentration and/or carrier mobility. Partial cyclization of the nitrile groups by heating at 400°C of PDCA produces l‐PDCA with significant increases in unpaired spin concentration and σRT but marginal effects on other properties. Saturation doping of l‐PDCA with iodine increases σRT to 7 × 10‐3 (Ω cm)‐1 without appreciable changes in EPR characteristics. The dopants in both polymers can be removed by evacuation indicating only weak charge transfer interactions. The possible stereoelectronic contribution toward the property differences between the PDCA polymers and PA are discussed.
Preparation of amino group‐containing polymers by plasma polymerization
Authors: Inagaki N. , Oh‐Ishi K.
Published: April 2003

Plasma polymerizations of bis(dimethylamino)methylsilane (BDMAMVS), bis(dimethylamino) methylvinylsilane (BDMAMVS), and trimethylsilyldimethylamine (TMSDMA) were investigated by elemental analysis, IR spectroscopy, and ESCA. Polymer deposition was fairly faster in the BDMAMVS and TMSDMA systems than in the BDMAMS system, indicating that vinyl and methyl substituents contribute to polymer formation, whereas hydrogen substituents disturb the polymer formation. IR and ESCA spectra for these polymers showed that some dependence of the polymers formed in the chemical composition on the nature of the monomers. A part of methylamino groups in these monomers were oxidized to give amido and amine oxide groups. BDMAMVS and TMSDMA yielded polymers with few fragmentations of methylamino groups, whereas the polymers formed from BDMAMS had no methylamino groups.
The heterogeneity of the network structure of epoxy polymers studied by dynamic and DSC tests
Authors: Kontou E. , Spathis G. , Theocaris P. S.
Published: April 2003

The final network structure of epoxy polymers cured with a crosslinking agent is strongly connected with the type and amount of the curing agent and conditions. Concerning the morphology of this network, it has been reported that cured epoxies are two‐phase systems, containing roughly spherical floccules arranged in a matrix resembling the constituent phases. In this paper and by using an epoxy‐polymer cured with different amounts (i.e., different than the stoichiometric one) of a curing agent, strong indications of their network‐structure heterogeneity have been disclosed. For this study, two different experimental techniques, such as dynamic mechanical measurements and DSC tests have been utilised. It was found that cured epoxy‐polymers consist of two extreme regions, with low and high crosslink densities, whose volume fractions have been estimated by using a mechanical model applicable for two‐phase systems.
Oligomerization of phenylacetylene on fe‐catalysts
Authors: Voicechovsky Y. P. , Slivinsky E. V. , Fichte B. B. , Loktev S. M.
Published: April 2003

Using a low activity system as a catalyst gives additional opportunities for study of polymerization mechanism. We made an attempt using phenylacetylene as a monomer to synthesize, separate, and identify oligomers of this alkyne on melting iron catalyst—“naked” metal. Four components with the lowest molecular weight were identified as: (compound 1) isomers of 1,2‐diphenylcyclobutadiene, (compound 2) 1,3‐diphenylcyclobutadiene, (compound 3) 1,4‐diphenylbuten‐1‐yne‐3, and (compound 4) triphenyl substituted Dewar benzene. It was shown, that in the presence of iron catalysts the phenylacetylene oligomerization proceeds as a linear polymerization through a 2 + 2 cycloaddition.
Copoly(amide—ester)s from p‐aminobenzoic and hydroxybenzoic acids by the direct polycondensation with diphenyl chlorophosphate and LiCl
Authors: Higashi Fukuji , Ozawa Michihide , Hoshio Atsushi , Mochizuki Akihiko
Published: April 2003

The reaction promoted by diphenyl chlorophosphate (DPCP) and LiCl was found to be effectively used for the preparation of aromatic polyesters with high molecular weights directly from hydroxybenzoic acids when the condensing agent was added dropwise. The reaction was successfully to the direct polycondensation reaction of p‐aminobenzoic and hydroxybenzoic acids, giving high‐molecular‐weight copoly(amide—ester)s soluble in amide or phenolic solvents. Copolycondensations of isophthalic and terephthalic acids with bisphenols and aromatic diamines were also examined by adding the DPCP solution to a mixture of these monomers or by initial reaction of DPCP with the acids followed by dropwise addition of a mixture of bisphenols and the diamines. The latter stepwise reaction gave random copolymers soluble in amide and phenolic solvents. Thermal properties of these copolymers were studied.
Grafting onto polypropylene. I. Effect of solvents in gamma radiation‐induced graft copolymerization of poly(acrylonitrile)
Authors: Misra B. N. , Sood D. S. , Mehta I. K.
Published: April 2003

Graft copolymerization of acrylonitrile (AN) onto isotactic polypropylene (PP) fiber has been studied by using gamma rays from a 2100 Ci 60Co source as initiator by preirradiation technique. The preirradiated PP was treated with AN and the mixture was graft copolymerized by heating to 100°C for different time periods. The percentage of grafting is determined as a function of total dose, reaction time, and monomer concentration. The effect of different solvents such as H2O, CH3OH, and dioxane upon percentage of grafting has been studied. The maximum effect was observed in water and the minimum in CH3OH. PP—g—PAN was characterized by IR spectroscopic and thermogravimetric methods. A plausible mechanism of gamma radiation induced grafting of AN onto PP in the absence and in the presence of solvents has been proposed. An attempt has been made to compare the relative abilities of different solvents to influence grafting.
Synthesis and characterization of soluble aromatic polyamides derived from 2,5‐bis‐(4‐chloroformylphenyl)—3,4‐diphenylthiophene and aromatic diamines
Authors: Kakimoto Masa‐Aki , Negi Yuvraj Singh , Imai Yoshio
Published: April 2003

A new polymer‐forming monomer, 2,5‐bis(4‐carboxyphenyl)—3,4‐diphenylthiophene, was synthesized either by the Friedel—Crafts reaction of tetraphenylthiophene with oxalyl chloride directly, or by the Friedel—Crafts acetylation of tetraphenylthiophene, followed by oxidation. The low temperature solution polycondensation of 2,5‐bis(4‐chloroformylphenyl)—3,4‐diphenylthiophene with various aromatic diamines in N,N‐dimethylacetamide (DMAc) afforded tetraphenylthiophene‐containing aromatic polyamides with inherent viscosities of 0.5–1.0 dL/g. Copolyamides were obtained from a mixture of the diacid chloride and isophthaloyl or terephthaloyl chloride. Except for two polyamides, all the others were readily soluble in amidetype solvents including DMAc, and were cast into transparent and flexible films. These polymers had glass transition at around 300°C. Thermal stability of the polymers was evaluated by thermogravimetry which showed no weight loss below 390°C in both air and nitrogen atmospheres.
Syntheses of copolymers containing pendant cyclic iminoethers and crosslinking reactions of these copolymers with dithiols and dicarboxylic acids
Authors: Nishikubo Tadatomi , Tōkairin Atushi , Takahashi Makoto , Nosaka Waichi , Iizawa Takashi
Published: April 2003

Copolymers containing pendant cyclic iminoethers were prepared by radical copolymerizations of 2‐vinyl‐2‐oxazoline (VOZO), 5‐methyl‐2‐vinyl‐2‐oxazoline (MVOZO), 4,4‐dimethyl‐2‐vinyl‐2‐oxazoline (DMVOZO), 4,4‐dimethyl‐2‐vinyl‐5,6‐dihydro‐4H‐1,3‐oxazine (DMVOZI), and 4,4,6‐trimethyl‐2‐vinyl‐5,6‐dihydro‐4H‐1,3‐oxazine (TMVOZI) with styrene, methyl methacrylate (MMA), and ethyl acrylate (EA) using AIBN as an initiator. In addition, the monomer reactivity ratios of VOZO, MVOZO, DMVOZO, and DMVOZI with styrene and MMA were determined. The crosslinking reactions of these copolymers with polyfunctional thiols such as 6‐(N,N‐dibutyl)amino‐1,3,5‐triazine‐2,4‐dithiol (DBDT), 4,4′‐oxydi(benzenedithiol) (OBDT), and pentaerythritol tetrathioglycolate (PETT), and dicarboxylic acids such as succinic acid, adipic acid, and sebacic acid were carried out at several reaction temperatures. From these results, it was found that the order of reactivity of pendant cyclic iminoethers to the thiols was VOZO > DMVOZO ≥ DMVOZI > MVOZO > TMVOZI, and that of the cyclic iminoethers to the carboxylic acids was VOZO > MVOZO ≥ DMVOZI > TMVOZI ≥ DMVOZO. Furthermore, the order of reactivity of the thiols to the cyclic iminoethers was DBDT > OBDT > PETT, and that of the dicarboxylic acids to the cyclic iminoethers was succinic acid > adipic acid > sebacic acid.
Polymerization of perfluoro‐2‐alkynenitriles by π‐bis(benzene)chromium(O)
Authors: Huang Yaozeng , Li Jis En , Zhou Qilin , Zhou Jianqiang
Published: April 2003

Perfluoro‐2‐alkynenitriles can be polymerized into soluble polymers at low temperatures by π‐bis(benzene)chromium(O) in benzene/pyridine (10:1) solution. The degree of polymerization is 7.4 for perfluoro‐2‐butynenitrile, 6.5 for perfluoro‐2‐pentynenitrile, and 11 for perfluoro‐2‐hexynenitrile. These polymers were examined by UV and IR spectra. Their thermal stability and the electrical conductivity of nondoped polymers were also studied. The conductivities of polyperfluoro‐2‐butynenitrile(PPFBN) and polyperfluoro‐2‐pentynenitrile are found to be 4.8 × 10−8 and 6.6 × 10−8Ω−1 cm−1, respectively.
Cyclopolymerization of N,N′‐methylene bisacrylamide initiated by S2O82−–Fe2+ redox system
Authors: Gopalan A. , Paulrajan S. , Subbaratnam N. R. , Rao K. Venkata
Published: April 2003

Polymerization of the symmetrical nonconjugated diolefin, N,N′‐methylene bisacrylamide, was carried out using peroxodisulphate ion ‐Fe2+ as redox initiator. The rate of polymerization is found to depend on [M]3/2 and [S2O82−]1/2 and independent of [Fe2+] over a range. A polymerization mechanism involving cyclopolymerization in the propagation step is suggested. Evidence in favor of the cyclopolymerization mechanism is discussed. Evaluation of the rate parameters indicates that the deactivation of the primary radical SO4− by Fe2+ ion is a factor to be reckoned with.
Kinetics of the surfactant‐free emulsion polymerization of styrene:‐The post nucleation stage
Authors: Hearn J. , Wilkinson M. C. , Goodall A. R. , Chainey M.
Published: April 2003

The kinetics of the surfactant‐free emulsion polymerisation of styrene have been studied. Reactions were sampled at several stages throughout their course, and the samples characterized by electron microscopy, gravimetric weights analysis and gel permeation chromatography, After an initial period of particle nucleation and coagulation, the reaction proceeds at a constant number density. The theories developed for emulsion polymerisation in the presence of surfactant above its critical micelle concentration might be expected, in Interval II, to apply to the surfactant‐free system if due regard is taken of the lower number densities and larger particle sizes developed. The results are in best accord with theories invoking a surface phase polymerisation mechanism. None of these theories predict a bimodel molecular weight distribution as found here and which is ascribed to polymerisation in two loci. The activation energy was found to be the same as for surfactant containing emulsion polymerisations.
Preparation of polyamides via the phosphorylation reaction. X. A study of higashi reaction conditions
Authors: Krigbaum W. R. , Kotek R. , Mihara Y. , Preston J.
Published: April 2003

We report a study of the conditions of the phosphorylation reaction for the preparation of aromatic polyamides using the Higashi reaction medium. For poly(p‐phenylene terephthalamide) (PPD‐T), the optimum conditions are: reaction temperature, 115°C; monomer concentration, C = 0.083 mol/L; and ratio of triphenyl phosphite (TPP) to monomer, 2.0. These optimum conditions produce PPD‐T having ηinh = 6.2 dL/g. At temperatures of 120°C and above PPD‐T precipitates from the reaction mixture, leading to lower molecular weights. At lower temperatures the reaction mixture gels, and the gel time decreases with increasing reaction temperature. However, polycondensation continues in the gel state. Monomer concentrations C = 0.10 mol/L and above produce precipitation and yield polyamides of lower molecular weight. For the preparation of poly(p‐benzamide) (PBA), the optimum ratio of TPP to monomer is 0.6 for either p‐ aminobenzoic acid or N‐4‐(4′‐aminobenzamido)benzoic acid. In the former case the inherent viscosity of polymer prepared at 115°C showed little dependence upon the concentration of the monomer. The highest value, ηinh = 1.8 dL/g, was obtained with C = 0.40 mol/L and a TPP/monomer ratio of 0.6. However, for the same TPP/monomer ratio, the monomer containing a preformed amide linkage, N‐4‐(4′‐aminobenzamido)benzoic acid, gave PBA with ηinh = 4.6 dL/g when the monomer concentration is 0.33 mol/L. This is the highest value reported for PBA using the phosphorylation reaction. In A−A + B−B polycondensation, examples in which one of the monomers contained one or two preformed amide linkages produced polyamides having ηinh = 7.8 and 8.9 dL/g, respectively.
Syntheses of 2‐phenyl‐3‐vinyloxirane derivatives that undergo radical ring‐opening polymerization
Authors: Endo Takeshi , Kanda Naoki
Published: April 2003

2‐Phenyl‐3‐vinyloxirane derivatives that undergo radical ring‐opening polymerization were prepared from allyl bromide and corresponding aldehydes. The difunctional monomers containing vinyloxirane structure were also synthesized from dialdehydes such as isophthalaldehyde and terephthalaldehyde. The obtained monomers undertook the radical isomeric polymerization to obtain the corresponding polymers.
Microscopic appearance of fractured surfaces and mechanical properties of starch–extended poly(vinyl alcohol)
Authors: Nwufo Bethrand T. , Griffin Gerry J. L.
Published: April 2003

Mixtures of Mowiol [an industrial plasticized poly(vinyl alcohol)] and corn starch have been examined by scanning electron microscopy (SEM); their impact and crossbreaking strengths, as well as their flexural moduli, measured. The results show fracturing as well as pitting with increased corn starch in Mowiol. The starch granular sizes (determined randomly for a number of samples) fluctuated between 10 and 22 μm, without some definite trend in the distribution. However, a certain degree of uniformity of granular size distribution appears to be achieved with an increase in the starch content of Mowiol. Both the impact and crossbreaking strength decreased with increase in starch, while the flexural modulus increased as the starch content increased. The impact of these observations on the resultant Mowiol/starch composites has been discussed. That transformed poly(vinyl alcohol) is likely to be an invaluable engineering material is not in doubt.
Aqueous polymerization of acrylonitrile by ascorbic acid–peroxodisulfate redox system
Authors: Ariff Mohamed , Jainuddin Md. , Gopalan V. , Rao K. Venkata
Published: April 2003

The polymerization of acrylonitrile initiated by an ascorbic acid–peroxodisulfate redox system was studied in an aqueous solution at 35°C in the presence of air. Molecular oxygen was found to have no effect on the polymerization reaction. An increase in ionic strength slightly increased the rate. The overall rate of polymerization, Rp, showed a square dependence on [monomer] and a half‐order dependence on [peroxodisulfate]. A first‐order dependence on [ascorbic acid] at low concentrations (<3.0 × 10−3 mol L−1) followed by a decrease in Rp at higher concentrations of ascorbic acid (>3.0 × 10−3 mol L−1) was also noted. Rp remained unchanged up to 40°C and showed a decline thereafter. Addition of catalytic amounts of cupric ions decreased the rate whereas ferric ions were found to increase the rate. Added sulfuric acid in the range (6.0−50.0) × 10−5 mol L−1 decreased the Rp.
Homogeneous Ziegler–Natta catalysis. II. Ethylene polymerization by IVB transition metal complexes/methyl aluminoxane catalyst systems
Authors: Giannetti Enzo , Nicoletti Giuseppe Martino , Mazzocchi Romano
Published: April 2003

Homogeneous Ziegler‐Natta systems for the ethylene polymerization, deriving from R2R2′M complexes (R = cyclopentadienyl; R′ = alkyl, aryl; M = Ti, Zr, Hf) and oligomeric oxoalane compounds, were studied. Further results concerning the methyl aluminoxane synthesis and the related chemistry are reported. On the basis of spectroscopic data a delocalized electronic structure could be inferred for these compounds. Results from polymerization experiments showed that the highest productivities are obtained only by oxoalane cocatalysts having a high degree of oligomerization. The catalytic activity of the systems under investigation was strongly affected also by changing both the σ‐alkyl and the π‐cyclo‐pentadienyl ligands. Furthermore, it was found that in the presence of methyl aluminoxane, the homoleptic σ‐alkyl derivatives of IVB transition metals, such as Zr(CH2C6H5)4, are also able to polymerize ethylene with a fairly high productivity. Active species containing ZrOAl bonds have been postulated.
Ionomeric interpretation of thickening of polyesters by alkaline earth metal oxides
Authors: Rao K. Balakoteswara , Gandhi K. S.
Published: April 2003

Four resins of poly(propylene glycol adipate) were mixed with different amounts of MgO and their viscosities were measured after a month. The viscosities increased by several thousand but the increase was less for resins containing more water. The existing explanations of the thickening behavior, namely the polymerization and the coordinate complex formation theories, were found to be inadequate in accounting for the observations. Small‐angle x‐ray scattering (SAXS) and transmission electron microscopy (TEM) of the thickened resins revealed formation of aggregates of magnesium ions, much like those observed in other ionomers. It is postulated that domain formation is the cause of observed thickening. A correlation between the viscosity of thickened resins and the amount of metal oxide reacted, the water content, and other properties of resin was obtained.
Polyaromatic ether‐ketones and polyaromatic ether‐ketone sulfonamides from 4‐phenoxybenzoyl chloride and from 4,4′‐dichloroformyldiphenyl ether
Authors: Litter Marta I. , Marvel C. S.
Published: April 2003

Polyaromatic ether‐ketones possessing high thermal stabilities were prepared by Friedel—Crafts polymerizations from 4‐phenoxybenzoyl chloride and from 4,4′‐dichloroformyldiphenyl ether and diphenyl ether. Sulfonation and subsequent sulfamidation of these polymers afforded polyaromatic ether‐ketone sulfonamides with different degrees of substitution depending on the reaction conditions. Sulfonation reactions with chlorosulfonic acid did not cause much degradation on the polymers. The polysulfonamides were soluble in various organic solvents such as N,N‐dimethylformamide, dimethylsulfoxide, or chloroform, and could be cast into transparent films. These polymers may be used as desalination membranes.
Sulfone/ester polymers containing pendent ethynyl groups
Authors: Jensen B. J. , Hergenrother P. M.
Published: April 2003

Sulfone/ester polymers containing pendent ethynyl groups were prepared by multistep and direct routes. Hydroxy‐terminated sulfone oligomers(Mn = 2650 and 8890 g/mol) were reacted with diacid chlorides to yield high‐molecular‐weight polymers. In the multistep route, a pendent bromo group on the polymer was converted to an ethynyl group. In the direct route, the hydroxy‐terminated sulfone oligomers were reacted with a stoichiometric amount of 5‐(4‐ethynylphenoxy)isophthaloyl chloride to yield high polymers. The pendent ethynyl groups on the sulfone/ester polymers were reacted in the 200 to 300°C range to provide branching and crosslinking. The resultant polymers exhibited higher Tgs and better resistance to chloroform than comparable polymers void of ethynyl groups. Films of the cured polymers displayed good mechanical properties. The synthesis and characterization of the monomer, oligomers, and polymers are discussed.
Combinations of hydroxyl‐terminated polybutadiene and boron
Authors: Sandén, Roland
Published: April 2003

Mixing and curing experiments with suspensions of boron in hydroxyl‐terminated polybutadiene (HTPB) have been performed. In kneading experiments on a plastograph very high viscous masses with bad curing properties were obtained. The experiments indicated that HTPB is attached with its OH groups to acidic impurities on the surface of the boron powder. By adding a basic substance, such as octadecyl amine, mixing and curing were undertaken with much less difficulty.
The use of ylide (4‐picolinium 4‐chloro phenacyl methylide) as an initiator for the polymerization of methyl methacrylate
Authors: Tewari R. S. , Bajpai Anita , Srivastava A. K.
Published: April 2003

The thermal polymerization of methyl methacrylate [MMA] was carried out using ylide (4‐picolinium 4‐chloro phenacyl methylide) as an initiator. The rate of polymerization (Rp) increases with increasing monomer and initiator concentrations; The exponent value has been computed to be 1 ± 0.02 and 0.5, respectively. The reaction was carried out at four different temperatures and the overall activation energy has been computed to be 16.01 kcal/mol. The polymerization was inhibited in the presence of hydroquinone as a radical scavanger. Kinetic studies indicates that the overall polymerization takes place by a radical mechanism.
Multinuclear (13C, 15N) NMR study of polyethyleneimine‐based polymers
Authors: Axelson D. E. , Blake S. L.
Published: April 2003

Representative polyethyleneimine‐based polymers have been studied by 13C‐ and 15N‐nuclear magnetic resonance spectroscopy and an extensive set of chemical shift assignments has been proposed for the complex spectra obtained. The samples in question represent a complex mixture of both protonated and nonprotonated primary, secondary, and tertiary as well as quaternary monomeric units.
Polymerization of tert‐alkylacetylenes by Mo‐ and W‐based catalysts
Authors: Okano Yoshimichi , Masuda Toshio , Higashimura Toshinobu
Published: April 2003

Polymerization of three tert‐alkylacetylenes (3,3‐dimethyl‐1‐pentyne, 3,3‐dimethyl‐1‐nonyne, 1‐adamantylacetylene) by Mo‐ and W‐based catalysts provided new polymers in virtually quantitative yields. In contrast, Ziegler catalysts did not polymerize these monomers. Every polymer had a form of white solid, and had alternating double bonds along the main chain. Though some of poly(3,3‐dimethyl‐1‐pentyne)s contained a toluene‐insoluble fraction, the polymer was totally soluble when proper polymerization conditions were chosen. The molecular weights of soluble fractions were as high as 3 × 105. Poly(3,3‐dimethyl‐1‐nonyne) was also partly insoluble in toluene, and the quantity of soluble fraction was less than that of poly(3,3‐dimethyl‐1‐pentyne). The geometric structure of these two polymers could be controlled by the choice of suitable polymerization conditions. Poly(1‐adamantylacetylene) was insoluble in any organic solvents. Copolymerization of 1‐adamantylacetylene with suitable comonomers afforded soluble copolymers.
Thermal degradation of vinyl alcohol/vinyl acetate copolymers V. Study of the reaction products of statistical copolymers
Authors: Vasile Cornelia , Odochian Lucia , Paţachia Silvia Florica , Popoutanu Mercedes
Published: April 2003

By coupling the evolved gas detection method with various analysis methods, the thermal decomposition products of the statistical vinyl alcohol/vinyl acetate copolymers were analysed.

The data are presented comparatively with those obtained for the corresponding block copolymers of the same composition.

The differences in the nature and amounts of the reaction products are explained by the structural characteristics of the copolymers.
Thermal decomposition of cyclolinear and cyclic methylsiloxane polymers
Authors: Blazsó M. , Székely T. , Makarova N. M.
Published: April 2003

A series of branched‐chain methylsiloxane polymers built up of four‐membered siloxane cycles and linear segments of zero to four siloxy units, and another series consisting only of siloxane cycles of five to eight members were investigated. The samples were pyrolyzed at temperatures increased stepwise from 300 to 800°C. The pyrolysate was analyzed online by gas chromatography and mass spectrometry. In the pyrolysates, series of cyclic, bicyclic, and polycyclic methylsiloxane compounds were found. Quantitative analysis of the pyrolysates shows that their composition reflects the composition and structure of the pyrolyzed polymethylsiloxane. The amount of the cyclic dimethylsiloxanes is related to the length of the linear siloxane segments between the branching points. The amount of bicyclic and polycyclic dimethylsiloxane oligomers in the pyrolysates is related to the average frequency and vicinity of the branching points.
Kinetics and mechanism of emulsifier‐free emulsion polymerization: Styrene/surface active ionic comonomer system
Authors: Chen Show‐An , Chang Herng‐Show
Published: April 2003

The emulsifier‐free emulsion polymerizations of styrene in the presence of the surface active comonomer, undecylenic isethionate sodium salt (at concentration below its critical micelle concentration), and of the initiator, potassium persulfate, indicate that the number of polymer particles and the rate of polymerization at steady state is dependent on 1‐power of the comonomer concentration and 1/2‐power of the initiator concentration. This result suggests a homogeneous nucleation mechanism by which particles are formed from coiled‐up oligomeric radical chains originally dissolved in the aqueous phase. Size distribution of the particles is rather narrow and has a uniformity very close to one (ca. 1.02) after 30% conversion. Addition of salt such as sodium sulfate to increase the ionic strength in the aqueous phase results in a formation of micelles (which can grow to become polymer particles) in addition to the formation of polymer particles through the homogeneous nucleation mechanism. Variation of the ionic strength leads to a variation in the number of polymer particles due to a competition between these two nucleation mechanisms and gives a minimum of the number of polymer particles and a maximum of the average particle diameter.
Aromatic copolyamides: Effect of phenylene content on optical, spectral, and solubility properties
Authors: Rogers H. G. , Gaudiana R. A. , McGowan C.
Published: April 2003

A series of para‐linked phenylene, bis(trifluoromethyl)biphenylene and stilbene copolyamides was synthesized in order to examine the effect of comonomer ratio on absorption spectra, solubility and birefringence. The data clearly showed that decreasing the stilbene content significantly lowered the birefringence and hypsochromically shifted the absorption band. A decrease in the biphenylene content broadened and bathochromically shifted the absorption band and lowered the birefringence and the solubility.
Photostabilizing activity of N‐acylated hindered amine
Authors: Kurumada Tomoyuki , Ohsawa Hisayu , Fujita Takashi , Toda Toshimasa , Yoshioka Takao
Published: April 2003

The influence of the acyl groups of N‐acylated hindered amine on the photostabilization of polymers was discussed. The effects of the N‐acyl derivatives of 4‐benzoyloxy‐2,2,6,6‐tetramethylpiperidine (6) in the photostabilization of polypropylene were compared. Although the stabilizing effects of all the N‐acyl derivatives were lower than that of the N‐oxyl derivative (7), N‐acryloyl (4) and N‐benzoyl (5) derivatives showed higher effects than that of parent NH 6. To discuss the stabilizing mechanism of N‐acylated hindered amine, the reaction of N‐acylated hindered amine with model hydroperoxide (tert‐butyl hydroperoxide) was carried out at an elevated temperature (132°C). N‐Acylated hindered amine decomposed tert‐butyl hydroperoxide more rapidly than corresponding secondary hindered amine, and changed into the parent secondary amine.
Poly[amino‐p‐(hydroquinone or benzoquinone)]amides and poly(p‐benzoquinono)diimidazoles of phenylene dicarboxylic acids. IV
Authors: Kehayoglou A. H. , Sideridou‐Karayannidou I. , Karayannidis G. P.
Published: April 2003

Poly(amino‐p‐benzoquinone)amides were indirectly prepared by low‐temperature polycondensation of 2,3,5,6‐tetraamino‐p‐hydroquinone, with terephthaloyl, isophthaloyl, or phthaloyl dichloride and subsequent oxidation of the obtained poly(amino‐p‐hydroquinone)amides. Then the poly(amino‐p‐benzoquinone)amides were converted by cyclodehydration with heating to the corresponding poly(p‐benzoquinono)diimidazoles. The prepared redox thermally stable polymers were characterized by elemental analysis, UV, and IR spectral study, inherent viscosity solubility, and thermal analysis (DSC, TGA). The synthesis and properties of the corresponding model compounds are also reported.
Preparation of aromatic copolyesteramides by the direct polycondensation with a vilsmeier adduct derived from tosyl chloride and N,N‐dimethylformamide
Authors: Higashi Fukuji , Mihara Yuko , Takahashi Ikuo , Chen Wen‐Hsin , Chang Tech‐Chou
Published: April 2003

The reaction promoted by Vilsmeier adduct derived from tosyl chloride (TsCl) with N,N‐dimethylformamide (DMF) was successfully applied to the preparation of copolyesteramides of high molecular weights directly from aromatic dicarboxylic acids, diamines, and bisphenols. The polycondensation was significantly affected by the reaction of activated dicarboxylic acids with bisphenols and diamines. Addition of a mixture of bisphenols and diamines likely caused gelation of the reaction mixtures, resulting in insoluble polymers, especially with high mol % diamines. Stepweise addition of them, however, gave the homogeneous reaction mixtures and copolymers of better solubility. These phenomena were studied in terms of sequence length distribution of polyester units, which was estimated by thermal analyses of the random copolymers prepared under various conditions for the initial reaction with bisphenols.
Origin of the carbon 1s‐core level shifts in polyimide model compounds
Authors: Silverman B. D. , Sanda P. N. , Ho P. S. , Rossi A. R.
Published: April 2003

Carbon 1s (C1s) core‐level positions have been calculated for two model compounds which are similar in structure to the PMDA part of the PMDA‐ODA monomer of polyimide. It is found that either one or two N‐phenyl imide groups fused to a benzene ring will lower the C1s energy levels of the benzene ring. The difference in previous interpretation of the origin of the C1s (ESCA) spectra between the two model compounds examined is shown to be consistent with the difference in calculated magnitude of this shift between the two compounds.
A new route to semirigid poly(amide‐ester)s with ordered structure
Authors: Lu C. X. , Li Qiang , Pan Jingqi
Published: April 2003

Four novel semirigid poly(amide‐ester)s having the same ordered amide‐amide‐ester‐ester (‐AAEE‐) and the same or the different phenyl structure were synthesized from the various combination of active acylamide of benzotriazole (HBT) such as 1,1′‐(isophthaloyl)bisbenzotriazole (IPBBT) and 1,1′‐(terephthaloyl)bisbenzotriazole (PBBT) with diols such as N,N'‐bis(2‐hydroxyethyl)isophthamide (HEIPA) and N,N'‐bis(2‐hydroxyethyl)terephthamide (HEPTA) which prepared from the selective N‐acylation of IPBBT or PBBT with aminoethanol in excellent yield at room temperature. Before the preparation of diol monomers, a model reaction of selective N‐acylation was also completed from active monoacylamide of benzotriazole, 1‐benzoylbenzotriazole with aminoethanol. The ordered structure of poly(amideester)s were characterized by infrared (IR) and NMR spectra. On the bases of different reactivity between selective N‐acylation and O‐acylation of active acylamide of benzotriazole, poly(amide‐ester)s having the ordered AAEE and the same phenyl structure were also readily synthesized from the IPBBT or PBBT with aminoethanol under mild conditions by one‐bath process.
p‐carboxylation of linear high molecular‐mass polystyrene
Authors: Hird B. , Eisenberg A.
Published: April 2003

A simple method is reported for the post‐polymerization partial p‐carboxylation of linear polystyrene without degradation or crosslinking of the polymer. The method is based on Friedel–Crafts acetylation of the polystyrene under mild conditions, followed by oxidation of the acetyl groups by means of a phase‐transfer‐catalyzed haloform reaction. The method is well suited for the synthesis of high molecular mass, monodisperse ionomers with p‐carboxylate groups situated randomly along the polystyrene chain. © 1993 John Wiley & Sons, Inc.
Polyisophthalamides with phenylsulfonyl pendent groups
Authors: Lozano Angel E. , De La Campa Jose G. , Abajo Javier De , Preston Jack
Published: April 2003

A series of polyisophthalamides containing phenylsulfonyl groups was prepared from seven aromatic diamines and 5‐phenylsulfonylisophthalic acid by the phosphorylation condensation method, and from 5‐phenylsulfonylisophthaloyl chloride by the solution polycondensation method at low temperature. When compared to the analogous unmodified polyisophthalamides, the modified ones were found to be essentially amorphous, and they showed better solubility in organic solvents, and slightly higher glass transition temperatures. Thermogravimetric analysis showed that the polyisophthalamides containing pendent phenylsulfonyl groups have thermal stabilities similar to the unmodified ones. Mechanical strength of films and water sorption were also investigated. © 1993 John Wiley & Sons, Inc.
Emulsion polymerization of vinyl acetate using a polymerizable surfactant. III. Mathematical model
Authors: Urquiola M. B. , Sudol E. D. , Dimonie V. L. , El‐Aasser M. S.
Published: April 2003

A mathematical model was developed to aid in the further understanding of the growth of latex particles in the emulsion polymerization of vinyl acctate using a polymerizable surfactant, sodium dodecyl allyl sulfosuccinate (TREM LF‐40). The model incorporates the main features of the system observed experimentally: copolymerization in the aqueous phase, at the particle surface, and chain transfer to TREM LF‐40. The reactions at the particle/water interface and, more specifically, the chain transfer to TREM LF‐40 leading to a decrease in the average number of radicals per particle, was found to be the most significant mechanism for explaining the difference in kinetic results found for TREM LF‐40 and its nonpolymerizable counterpart. The copolymerization of vinyl acetate with TREM LF‐40 was also shown to slow the overall polymerization rate. However, the copolymerization alone was not sufficient to account for the decreased polymerization rates observed experimentally. A combination of copolymerization and chain transfer to TREM LF‐40 was found to provide a good fit of the experimental results. © 1993 John Wiley & Sons, Inc.