bluuebunny/crossref_metadata_2025 huggingface dataset:
The picryl ether of polyethylene glycol: Preparation, characterization, and reaction with n‐propylamine
Authors: Dust Julian M. , Milton Harris J.
Published: April 2003

A new electrophilic polymer, the picryl ehter of methoxypolyethylene glycol (M‐PEG‐OPi), was prepared by reaction of the lithium alkoxide of methoxypolyethylene glycol with picryl chloride. The resultant M‐PEG‐OPi was characterized by 200 MHz 1H and 13C‐NMR, microanalysis, and hydrolytic behavior. The rate constant for hydrolysis in pH 8.0 buffer is consistent with that expected for SNAr hydrolysis of a polyethylene glycol picrate. Reaction of n‐propylamine with M‐PEG‐OPi in (CD3)2SO was followed by 1H‐NMR and UV‐visible spectroscopy. Evidence is presented for formation of a C‐1 Meisenheimer complex; no C‐3 adduct was observed in these experiments despite the steric bulk of the polymeric “group” on the picryl ring. Addition of a large excess of amine results in formation of a 2:1 dianionic complex, as shown by the UV‐visible spectrum. The possibility is discussed of using the reaction of M‐PEG‐OPi with protein amino groups as an analytical tool for measuring the number of available amino groups on protein chains.
Synthesis of novel primary amino‐terminated polymer and application for macromonomer
Authors: Ishizu Koji
Published: April 2003

The carboxyl‐terminated polystyrene (PS) was prepared by free radical polymerization of styrene initiated by functional azo‐initiator under a unimolecular termination mechanism. After replacement of the hydroxyl group of acids by chlorine, the end‐capping reaction of acyl halide‐terminated PS with a large excess of 1,6‐diaminohexane was carried out to obtain primary amino‐terminated PS. Subsequently, various PS macromonomers were derivated from primary amino‐terminated PS.
Syntheses and properties of polyureas from divalent metal salts of p‐aminobenzoic acid, diamine, and diisocyanate
Authors: Matsuda Hideaki , Takechi Shigetoshi
Published: April 2003

Metal‐containing polyureas having ionic links in the main chain were synthesized by the polyaddition reactions of 2,4‐toluylene diisocyanate with mixtures of divalent metal salts of p‐aminobenzoic acid and 4,4′‐diaminodiphenylmethane (4,4′‐methylenedianiline). Mg and Ca were used as the divalent metal. The polyureas obtained were slightly yellowish powders and those with low metal content were soluble in dimethylacetamide (DMAc) and dimethylsulfoxide (DMSO). The inherent viscosity (at 0.5 g/100 mL) of the polyureas decreased markedly with an increase in metal content. In addition, the reduced viscosities in DMAc and DMSO were very low at very low concentration but became higher as the concentration increased, especially in DMAc having a somewhat lower dielectric constant. This viscosity increase at high concentrations is attributed to ionic association. Introducing the metal into the polyurea lowered the thermal properties as indicated by decreased decomposition temperatures. The polyureas with low metal contents gave films by solvent‐casting although increasing the metal content made the films brittle. Further, dynamic mechanical properties were discussed.
Model filled polymers. I. Synthesis of crosslinked monodisperse polystyrene beads
Authors: Zou D. , Derlich V. , Gandhi K. , Park M. , Sun L. , Kriz D. , Lee Y. D. , Kim G. , Aklonis J. J. , Salovey R.
Published: April 2003

Monodisperse crosslinked polystyrene beads of varied size and crosslink density are prepared by emulsion copolymerization of styrene and divinylbenzene in the absence of emulsifier. Tumbling and internally stirred reactors were used for synthesis, with minimal agglomeration at at least 0.22 wt % potassium persulfate and up to 10% by weight of styrene in aqueous emulsion in the absence of oxygen. Particle sizes decreased from 800 to 200 nm on raising the polymerization temperature from 60 to 95°C. The glass transition temperature of the beads increased from 104.4 to 133°C by the inclusion of up to 10% by weight of divinylbenzene. The thermal stability of the beads was higher for peroxide than for persulfate initiation. The crosslink density estimated from the degree of swelling was about one third that expected from stoichiometry. The polystyrene beads are used as filler particles in polymer composites.
A new dual‐parameter for reactivities of vinyl monomers toward free‐radicals
Authors: Ito Osamu , Matsuda Minoru
Published: April 2003

A new dual‐parameter of vinyl monomers for the reactivities toward free‐radicals has been evaluated on the basis of kinetic data obtained by the flash photolysis method. As a model reaction system, the reversible addition reactions of the substituted phenylthiyl radicals to vinyl monomers are selected. The absolute rate constants and the relative equilibrium constants for these reactions have been determined. The Hammett reaction constants (ρ) for the addition reaction rates were evaluated by the variation of the substituents at the para‐position of the arylthiyl radicals. From the values, the polar parameters (P‐ values) have been evaluated. The P values of various vinyl monomers correlate with the e values of the Q‐e scheme proposed by Alfrey and Price. The resonance stabilization terms of the propagating radicals were evaluated from the equilibrium constants (K) which correlate with the Q values. The K‐P dual‐parameter can be used in order to predict the reactivities of vinyl monomers for the primary radicals (initiation step). The monomer reactivities from the copolymerization data are also correlated with the dual parameter. There are some advantages in the new dual‐parameter compared with the Q‐e scheme; the separation of the resonance term from the polar term is complete and the steric factor is not included in the polar term.
Use of rare earth coordination catalyst for ethylene oxide and propylene oxide copolymerization
Authors: Shen Zhiquan , Wu Jian , Wang Guoping
Published: April 2003

Neodymium tris(2‐ethylhexylphosphonate)‐triisobutylaluminum‐water system was investigated as a catalyst in ethylene oxide and propylene oxide copolymerization. Random copolymers of ethylene oxide and propylene oxide were obtained with high yield and high molecular weight in a short reaction time. The reactivity ratios of r1(EO) = 1.60 ± 0.04, r2(PO) = 0.45 ± 0.02 were determined. It was found that poly(propylene oxide) prepared with this catalyst system could initiate additional propylene oxide or ethylene oxide to form poly(propylene oxide) with higher molecular weight or propylene oxide‐ethylene oxide diblock copolymer. The microstructures of copolymers were studied by 13C‐NMR spectroscopy.
Synthesis and polymerization of a multimethacrylate
Authors: Jantas R.
Published: April 2003

By reacting poly(methacryloyl chloride) with 2‐hydroxyethyl methacrylate a multimethacrylate on a polymethacrylate template is obtained. Free‐radical polymerization of the multimethacrylate in dilute DMF solutions was investigated. The results obtained suggest that the polymerization process occurs along the template and results in partially ladder‐type polymers, containing unreacted double bonds. Based on the results of elemental analysis, IR, and 1H‐NMR spectra, structures of the multimethacrylate and the obtained polymer were proposed. The rate of disappearance of double bonds in the multimonomer during UV irradiation was examined. Thermogravimetric analysis of the multimethacrylate and related polymers was also performed.
Investigations of the chemical structure of sulfonated amino‐formaldehyde resins. I 13C‐NMR analysis of sulfonated urea‐formaldehyde resins
Authors: Pasch Harald , Dairanieh Issam S. , Al‐Tahou Baheeja
Published: April 2003

13C nuclear magnetic resonance has been successfully used for the determination of the chemical structure of sulfonated urea‐formaldehyde resins. Model compounds (such as dimethylol urea and trimethylene diurea) were prepared and their NMR spectra were analyzed. The model compounds were then sulfonated and the additional signals that appeared were assigned to carbon atoms whose hydroxy groups were replaced by sulfonate groups. Urea‐formaldehyde and sulfonated urea‐formaldehyde resins were prepared and their spectra were compared and the sulfonate groups signals were identified. Using a semiquantitative approach, the relative concentrations of the main structural units were calculated and the effect of the monomer composition on the structure of the final resin was investigated.
Investigations of the chemical structure of sulfonated amino‐formaldehyde resins. II. Size exclusion chromatography of sulfonated urea‐formaldehyde resins
Authors: Pasch Harald , Dairanieh Issam S. , Khan Zahida H.
Published: April 2003

The liquid chromatographic behavior of sulfonated urea‐formaldehyde resins in aqueous eluents was investigated and a suitable molecular weight calibration was established at a column system, consisting of μ‐PORASIL 60 Å and μ‐BONDAGEL (linear). It was demonstrated, that in deionized water electrostatic interactions between the stationary phase and the resin molecules occurred and the separation according to size exclusion mechanism was disturbed. Ion exclusion was successfully eliminated, using aqueous sodium sulfate solution as the mobile phase. The molecular weight of the sulfonated urea‐formaldehyde resins was shown to be influenced by the ratio of the resin components. Increasing the formaldehyde to urea ratio resulted in an increase in the resin's molecular weight, whereas increasing the sulfite to urea ratio led to a decrease in the molecular weights. An explanation of this observation was presented.
Dielectric investigation of the effect of ethylamine on viscose rayon
Authors: Mansour A. A. , Shinouda H. G. , Rizk H. A.
Published: April 2003

The effect of treating viscose rayon by aqueous ethylamine of 73.5% w/w for different treatment times on two dielectric relaxation processes (γ and β) observed initially in viscose was studied. Thus, measurements of dielectric constants, ϵ′, and dielectric loss, ϵ″, at frequencies of 0.1–10000 kc/s over a temperature range of 298–333 K, were carried out on four treated samples for 0.5, 1, 2, and 4 h of immersion in ethylamine. Some physical properties were also determined a priori, namely, dissolution and ash content percentages, as well as accessibility toward water and iodine molecules by measurements of heat of wetting and iodine absorption, respectively. In comparison with viscose rayon, the following results were obtained: (i) The γ‐relaxation process was gradually removed by the action of ethylamine, and completely disappeared in samples treated for 2 and 4 h. For this process, the loss, magnitude of polarization, shape parameter, and relaxation frequency decreased with the increase of the time of treatment. (ii) The β‐relaxation process appeared in all samples investigated over the entire working temperature range. The loss maximum and magnitude parameter decreased with lengthening the time of treatment, whereas the shape parameter and the relaxation frequency increased, all tending toward limiting values over practically the same immersion period of 2–4 h. The results obtained from dielectric measurements, as well as those from other physical measurements, suggested that the viscose fiber obtained after treatment of 0.5 h in ethylamine had acquired some compact structure in the residual low fractions, in which the γ‐process was supposed to originate, and that further lengthening of the period of immersion resulted, however, in the development of a less‐closely packed structure in the amorphous regions of the fiber, where the β‐process originated. Based on the above, it was finally concluded that the treatment of viscose rayon with ethylamine of the above concentration resulted in several fractions, which vary in the degree of lateral order of arrangement of the chain molecules; i.e., in the relative arrangement of the polar groups in adjacent chains which govern the interchain forces and in turn the dielectric absorption. At the same time, the explanation of the results obtained in this work supports a previous interpretation suggested for the γ‐ and β‐relaxation processes in viscose.
29Si‐NMR studies of dimethyl and vinylmethyl containing oligodiorganyl cyclosiloxanes and linear copolymers
Authors: Ramarao M. , Packirisamy S. , Ravindran P. V.
Published: April 2003

29Si‐NMR has been used to identify and analyze oligomeric mixtures of diorganyl cyclosiloxanes of the general formula FnDm−n (D = (CH3)2SiO, F = CH3(CH2CH)SiO, m = 3–5 and n = 0 −m). Chemical shift assignments were confirmed by comparing 29Si‐NMR and GC‐MS results for composition of the mixtures. The effect of vinyl group on the chemical shift of neighboring silicon atoms was estimated in terms of additivity parameters and good agreement was obtained between experimental and calculated chemical shift values. The distribution of dimethyl and vinylmethyl siloxy units in cyclosiloxanes is discussed. Pentad structures were observed in 29Si‐NMR spectra of poly(dimethyl‐co‐vinylmethyl)siloxanes and their intensities were found to be in confirmity with Bernoullian statistics.
Preparation of poly(amide‐imide)s by direct polycondensation with triphenyl phosphite. IV. Aliphatic‐aromatic poly(amide‐imide)s based on N,N′‐bis(ω‐carboxyalkyl)pyromellitimides
Authors: Hsiao Sheng‐huei , Yang Chin‐ping
Published: April 2003

Four diimide‐diacids 3a‐d were synthesized from pyromellitic dianhydride and amino acids of the formula HOOC  (CH2)m  NH2, with m = 1, 3, 5, 10. These diacids were condensed directly with various aromatic diamines using triphenyl phosphite in N‐methyl‐2‐pyrrolidone (NMP)–pyridine solution in the presence of calcium chloride. The resulting poly(amide‐imide)s have an aliphatic‐aromatic structure and the relation between the general properties and the amount of the aliphatic part in the repeat unit was studied. IR spectroscopy, elemental analysis, and inherent viscosity measurements were used for the characterization. Studies of solubility, DSC traces, thermal stability, and crystallinity were also made.
Infrared analysis of metal chloride‐doped poly(vinylchloride) films
Authors: Seibles L.
Published: April 2003

The influence of metal chloride dopants (CoCl2, CuCl2, and FeCl3) on the infrared spectrum of solution‐grown thin films of poly(vinylchloride) was investigated using Fourier transform infrared spectroscopy. Detailed analysis and interpretation of the spectral data revealed that solvated metal chloride complexes and residual solvent (N, N‐dimethylformamide) entrained in the polymer films induced specific spectral changes. Extensive vacuum drying of the metal chloride‐doped films reduced the level of entrained solvent but no evidence was found for metal‐induced perturbation of the polymer CCl bans through formation of metal chloride–polymer complexes. Thus the observed spectral changes and a previously reported 106‐fold increase in the electrical conductivity of the polymer films, on doping with metal chlorides, do not appear to result from a specific metal–polymer interaction.
Controlled “living” anionic polymerization of glycidyl methacrylate
Authors: Leemans L. , Fayt R. , Teyssié Ph. , Uytterhoeven H. , De Winter W.
Published: April 2003

The living anionic polymerization of glycidyl methacrylate (GMA) in THF at low temperature initiated with diphenyl hexyl lithium, 9‐anthracenyl methyl lithium, and α‐methylstyryl lithium leads to well characterized homo‐ and block copolymers, with predictable \documentclass{article}\pagestyle{empty}\begin{document}$\overline {M_n }$\end{document} and narrow molecular weight distributions and with all the oxirane groups intact. Broadening of the molecular weight distributions above a certain and very critical \documentclass{article}\pagestyle{empty}\begin{document}$\overline {M_n }$\end{document} supported the idea that the living polymerization at low temperature might proceed in micelle‐like structures. Diffusional restriction of the monomer access towards the living centers, due to lesser solvation and increasing compactness of the polymer coils is thought to give rise to broadening of the molecular weight distribution of PGMA homo‐and block copolymers.
Synthesis and characterization of polyamides and polyureas with acyclic and cyclic bipyridinediyl diamino structures in the polymer backbone
Authors: Mamo A. , Finocchiaro P. , Bottino F. , Pappalardo S.
Published: April 2003

A series of polyamides and polyureas containing cyclic (1b, 1c, and 1d) or acyclic (2b, 2c, and 2d) bipyridinediyl diamino units in the polymer backbone were prepared. By introducing aliphatic or aromatic comonomers, it was possible to influence the degree of rigidity of the resulting polymers. In the synthesis of the polymers 2c and 2d two new azamacrocycles 5 and 6, respectively, were also produced and they were isolated and characterized. 1H‐NMR and IR spectral data support the structure of the synthesized compounds. Thermal analysis data indicate that the polyureas posses lower PDT (polymer degradation temperature) values with respect to the corresponding polyamides.
Magnesium chloride supported high mileage catalysts for olefin polymerization. XX. Solid state NMR
Authors: Chien James C. W. , Dickinson L. Charles , Vizzini James
Published: April 2003

Magic‐angle spinning cross polarization solid state NMR spectra and relaxation data have been obtained for the MgCl2/ethyl benzoate (EB)/p‐cresol (PC)/AlEt3 (TEA)/TiCl4 catalyst (CW) system following each stage of preparation. The change of chemical shifts of certain carbons in EB and their extremely short TH1 suggest strong complexation of EB with MgCl2 and that the EB is in a rigid physical state. The broad linewidths indicate dispersity in binding sites giving a range of chemical shifts. PC also forms a rigid complex with MgCl2 and has the effect of rendering the bound EB less rigid. Reaction between PC and TEA produces EtnAl (OC6H4Me)3‐n species. The ethyl carbons cannot be observed by cross polarization or by a simple π/2 carbon polarization. Treatment with TiCl4 removes most but not all of the PC moieties by extraction and conversion of the aluminum compounds to AlCl3. The 13C‐NMR of EB in the catalyst have chemical shifts like in MgCl2/EB.
New polymer syntheses. XLII. Thermotropic polyesters of hydroquinone and various aryloxyterephthalic acids
Authors: Kricheldorf Hans R. , Engelhardt Jürgen
Published: April 2003

Aryloxyterephthalic acids were prepared from dimethyl nitroterephthalate and phenol, 4‐fluoro, 4‐chloro‐, 4‐bromo‐, 4‐phenyl‐, 4‐cyclohexyl‐, 4‐phenoxy‐ and 4‐cumyl phenol. Polycondensations with hydroquinone or its derivatives gave the best results, when the aryloxyterephthaloyl chlorides were condensed with hydroquinone in pyridine or with silylated hydroquinone in the molten state. The resulting polyesters were characterized by elemental analyses, inherent viscosities, DSC measurements, microscopy under polarized light, WAXS measurements, and thermogravimetric analyses. All polyesters derived from hydroquinone are semicrystalline with melting points (Tm) in the range of 300–370°C and glass transitions (Tg) in the range of 80–110°C. Most of them form a nematic phase above their Tm; only the homopolyesters of napthyloxy and (4‐cyclohexyl phenoxy) terephthalic acid are isotropic above Tm. Yet the amorphous copolyester of both terephthalic acids and hydroquinone is nematic above Tg, like all copolyesters prepared from two differently substituted terephthalic acids.
The block copolymers and polymer blends of nylon 6 with poly(4,4′‐diphenylsulfone terephthalamide). II. Morphologies and mechanical properties
Authors: Wang Huei‐Hsiung , Chen Wei‐Liang
Published: April 2003

The relationship between the morphological structure and the mechanical properties of the block copolymers and polymer blends of nylon 6 with poly (4,4′‐diphenylsulfone terephthalamide) (PSA) was investigated by use of the mechanical model and optical observations. From features on the morphology, it demonstrated that the dispersed‐phase structures were observed in both of the polymer blends and the triblock copolyamides. Nevertheless, the multi‐block copolyamides exhibited a more homogeneous structure. Based on the experimental results of the crystallization isotherms, it had shown that thenvalue, according to the Avrami's equation, was 2.1 and 2.3 for polymer blends containing 3 and 5 wt % PSA, respectively. The mechanical properties had remarkedly indicated that multiblock copolyamides had a more significant reinforcing effect than the others. Based on the mechanical analysis of polyblends, it was found that the results were quite consistent with those of the Takayanagi's two‐phase mechanical model, except at high PSA. The optimum PSA content in the nylon 6 was considered to be 10–15 wt %.
A new one‐component anhydride‐cured epoxy with an aliphatic disiloxane dianhydride and metal‐coordinated lewis bases
Authors: Eddy Victoria J. , Hallgren John E. , Colborn Robert E.
Published: April 2003

The use of 1,3‐di(5‐[2,2,1]‐bicyclohexyl‐2,3‐dicarboxylic anhydride)‐1,1,3,3‐tetramethyldisiloxane, 1, as a curing agent in the presence of typical epoxy resins with Lewis bases as catalysts produces thermosets with HDTs of 320°C. The solubility of 1 in the epoxy resin allows for the preparation of a one‐component formulation. A latent catalyst was developed which employs amine complexes of cobalt bis(2,4‐pentanedionate). These formulations exhibit long term storage at ambient conditions, yet cure rapidly at 180–200°C.
Amidation of esters using trimethylsilylamines
Authors: Derosa Thomas F. , Jennejahn Rosemary
Published: April 2003

Trimethylsilyl‐di‐n‐butylamine has been used to amidate methyl n‐propionate and polymethylmethacrylate (PMMA) in THF. Trimethylsilyl (N‐phenyl‐p‐phenyleneamine) amine was also prepared and used to amidate PMMMA and poly(ethylene‐co‐propylene)‐graft‐methylmethacrylate (OCP‐graft‐MMA) in THF and n‐hexane, respectively. Amidations were performed between 55 and 65°C. When trimethylsilyl‐di‐n‐butylamine was reacted with methyl propionate, less than 10% of the corresponding amide was generated because of a competitive aldol condensation. PMMA was smoothly amidated in excess of 60% using either trimethylsilyl(N‐phenyl‐p‐phenyleneamine)amine or trimethylsilyl‐di‐n‐butylamine without detectable competitive side reactions. OCP‐graft‐MMA was amidated in excess of 90% using a 5 M excess of trimethylsilyl(N‐phenyl‐p‐phenyleneamine)amine in n‐hexane.
Dispersion polymerization of styrene in polar solvents. IV. Solvency control of particle size from hydroxypropyl cellulose stabilized polymerizations
Authors: Paine Anthony J.
Published: April 2003

Changing solvent has a dramatic effect on the outcome of HPC stabilized dispersion polymerization of styrene in polar solvents. In methoxyethanol/ethanol mixtures, particle size varies from essentially infinity for unstabilized reactions (below 30% ethanol) to about 3 microns in ethanol. In a series of n‐alcohols, there was a maximum in particle size at intermediate chain length: particle size increased from 2 microns in methanol to 8.3 microns in pentanol, then decreased again to 1 micron in octadecanol. These results were rationalized in terms of the three‐component Hansen solubility parameters. The largest particles were obtained in solvents with Hanson polarity and hydrogen bonding terms closest to HPC. The generality of the three‐component solubility parameter approach was examined by reactions performed in eight mixed solvents with the same values of all three Hansen terms. Seven of the eight solvents gave particles of similar size and molecular weight. The two critical effects of solvent on both particle size and molecular weight appear to be: (a) the solubility properties of the grafted HPC‐PS formed, and (b) the partitioning of monomer and initiator between solution and particle phases subsequent to nucleation.
Synthesis of sulfone‐containing polyamides by direct polycondensation with triphenyl phosphite
Authors: Hsiao Sheng‐Huei , Yang Chin‐Ping
Published: April 2003

Several sulfone‐containing polyamides were prepared by the direct polycondensation reaction of 4,4′‐dicarboxydiphenyl sulfone (DCDPS) with various aromatic diamines by means of triphenyl phosphite in NMP‐pyridine solution containing 4 wt % LiCl. DCDPS was synthesized in two steps by the preparation of 4,4′‐dimethyldiphenyl sulfone (DMDPS) from toluene and chlorosulfonic acid and subsequent oxidation with an alkaline solution of potassium permanganate. The polyamides were obtained in 85–100% yield and had inherent viscosities in the range 0.42–1.65 dL/g. Their solubility, crystallinity, and thermal properties are also discussed.
Synthesis of polyethers containing viologen moiety and their application to electron‐transfer catalyst
Authors: Endo Takeshi , Kameyama Atsushi , Mambu Yoko , Kashi Yasuo , Okawara Makoto
Published: April 2003

Polyethers containing viologen moieties were prepared by the reaction of tosylated polyethers with bipyridine. Viologen moieties of these polymers having  ((CH2)2O)n  chains were reduced into the cation radicals by sodium dithionite in dichloromethane, methanol, and benzene. The reduction of vicinal dibromide, ethyl 2,3‐dibromo‐3‐phenylpropionate using these polymers as electron‐transfer catalyst (ETC) was performed in dichloromethane to obtain ethyl cinnamate in good yield.
A study of novel heat‐resistant polymers: Preparation of photosensitive fluorinated polybenzoxazole precursors and physical properties of polybenzoxazoles derived from the precursors
Authors: Yamaoka Tsuguo , Nakajima Nobuko , Koseki Ken'ichi , Maruyama Yutaka
Published: April 2003

A series of novel photosensitive polybenzoxazole precursors were prepared from polycondensation of 2,2‐bis(3,3′‐amino‐4,4′‐hydroxyphenyl)hexafluoropropane with photosensitive dicarboxylic acid chlorides such as p‐phenylenediacryloyl chloride and benzophenone‐4,4′‐dicarboxylic chloride. The precursors are soluble in common organic solvents owing to the presence of perfluoromethyl groups in the chain structure, and insolubilized in the solvents on irradiation with the light. Polybenzoxazole patterns with high resolution as well as high aspect ratio were reproduced by baking the precursor patterns at 300°C. The pattern shrinkage on the conversion to polybenzoxazole was slight. The polybenzoxazole films offered good heat‐resistance up to 400°C in addition to good electrical properties.
Controlled shrinkage polymers: Characterization of epoxy resins cured with spirobislactones
Authors: Sikes Allison M. , Brady Robert F.
Published: April 2003

The diglycidyl ether of bisphenol A (DGEBA) was cured with either an aliphatic or an aromatic spirobislactone using a tertiary amine catalyst. The products were characterized by FTIR, TGA, DSC, dilatometry, and single‐fiber adhesion measurements, and their performance was compared to that of DGEBA cured with acid anhydrides. Both aliphatic and aromatic bislactones are effective curing agents for DGEBA. FTIR and dilatometry confirm that both lactone rings open early in the curing reaction and initially offset shrinkage caused by polymerization. After the bislactone has been consumed, oxirane reactions proceed in a normal fashion. The final shrinkage of cured DGEBA polymers, with or without addition of bislactones, is 3.0–3.5%. Bislactone‐modified materials possess superior thermal properties, when compared to those of anhydride‐cured materials.
Kinetics and mechanism of emulsifier‐free emulsion polymerization. III. Styrene/nonionic comonomer (2‐hydroxyethyl methacrylate) system
Authors: Chen Show‐An , Chang Herng‐Show
Published: April 2003

The emulsifier‐free emulsion polymerizations of styrene in the presence of about 0.33–2.7% (relative to styrene) of the water soluble comonomer, 2‐hydroxyethyl methacrylate (HEMA), and of the initiator, potassium persulfate (KPS), were carried out. It was found that KPS plays a predominant role in the particle nucleation process, since the number density of polymer particles (Np) was dependent on the 0.97‐power of [KPS]. The nucleation ability of HEMA was weak, since Np was dependent only on the 0.17‐power of [HEMA]. The particle nucleation stage ceased quite early before 1% conversion, leading to nearly monodispersed polymer particles. The nucleation is suggested to be via the homogeneous nucleation mechanism. The particles grow via the core‐shell structure mechanism (shell region polymerization), since the particle size is rather large—from 1500 to 6000 Å. The amount of HEMA can affect the shell thickness and physical properties of the shell, such as the monomer swelling capacity and monomer diffusion rate.
Radical polymerization of N‐phenyl‐α‐methylene‐β‐lactam
Authors: Ueda Mitsuru , Mori Hideharu , Ito Hiroshi
Published: April 2003

N‐phenyl‐α‐methylene‐β‐lactam (PML), a cyclic analog of N,N‐disubstituted methacrylamides which do not undergo radical homopolymerization, was synthesized and polymerized with α,α′‐azobis (isobutyronitrile) (AIBN) in solution. Poly (PML) (PPML) is readily soluble in tetrahydrofuran, chloroform, pyridine, and polar aprotic solvents but insoluble in toluene, ethyl acetate, and methanol. PPML obtained by radical initiation is highly syndiotactic (rr = 92%), exhibits a glass transition at 180°C, and loses no weight upto 330°C in nitrogen. The kinetics of PML homo‐polymerization with AIBN was investigated in N‐methyl‐2‐pyrrolidone. The rate of polymerization (Rp) can be expressed by Rp = k[AIBN]0.55[PML]1.2 and the overall activation energy has been calculated to be 87.3 kJ/mol. Monomer reactivity ratios in copolymerization of PML (M2) with styrene (M1) are r1 = 0.67 and r2 = 0.41, from which Q and e values of PML are calculated as 0.60 and 0.33, respectively.
Magnesium chloride supported high mileage catalysts for olefin polymerization. XXI. Isospecific and regiospecific vanadium catalyst for propylene polymerization
Authors: Zhou Xinhua , Lin Shangan , Chien James C. W.
Published: April 2003

Several CW–V catalysts were prepared by supporting VCl4 on Mg Cl2 with ethyl benzoate and CH–V catalysts prepared by reacting MgCl2.ROH, phthalic anhydride, and VCl4. These vanadium catalysts, activated with TEA (triethyl aluminum)/MPT (methyl‐p‐toluate) produce mainly (88–96%) refluxing n‐heptane insoluble isotactic PP. The active site has
\documentclass{article}\pagestyle{empty}\begin{document}$ k_{p,i} = 1580 \left( M {\rm s} \right)^{ - 1}, k_{tr,i}^{\rm A} = 2 \times 10^{ - 3} {\rm s}^{ - 1} , k_{tr}^{\rm H} = 3.8 \times 10^{ - 2} \left( {\rm torr} \right)^{ - {1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} {\rm s}^{ - 1}$\end{document}
for the isospecific ones and
\documentclass{article}\pagestyle{empty}\begin{document}$ k_{p,a} = 58 \left( M {\rm s} \right)^{ - 1} ,k_{tr,a}^{\rm A} = 3 \times 10^{ - 3} {\rm s}^{ -1}$\end{document}
for the nonspecific sites. Catalyst of VCl3 supported on MgCl2 has comparable productivity as the VCl4/MgCl2 catalyst but catalyst of VCl2 supported on MgCl2 exhibit only one‐ninth of the productivity. Extensive comparison has been made between the CW–V and the CW–Ti systems which revealed striking similarities between their polymerization behaviors. MgCl2 exerts profound influence on the stereochemical control of the vanadium ion on its activity for monomer coordination and insertion.
Novel conjugated polymer containing anthracene backbone: Addition polymer of 9, 10‐diethynylanthracene with 9, 10‐anthracenedithiol and its properties
Authors: Kobayashi Eiichi , Jiang Jian , Ohta Hirotoshi , Furukawa Junji
Published: April 2003

9,10‐Diethynylanthracene was prepared by the alkaline hydrolysis of 9,10‐bis (trimethylsilylethynyl) anthracene. Another new monomer of 9, 10‐anthracenedithiol was prepared by the reduction of anthracene polydisulfide. A crystalline conjugated polymer of 9,10‐diethynylanthracene with 9,10‐anthracenedithiol was synthesized in a THF solution at 50°C by UV irradiation or by using radical initiators. The molecular weight (M̄n) of the insoluble polymer in THF is about 20000–30000 and the soluble is about 4000. From the sulfur content and IR spectrum of the insoluble polymer, it is realized that the obtained polymer has the alternating structure consisting of 9,10‐diethynylanthracene and 9,10‐anthracenedithiol units. X‐ray pattern indicated that the polymer has a layer structure. The conductivity of the undoped polymer was about 10−11S/cm, but enhanced up to 10−6 S/cm by doping with iodine. The enhancement of the conductivity seems to be the existence of the CT complex among the polymer backbone and iodine or iodine anion.
Preparation of sterically stabilized nanoparticles by desolvation from graft copolymers
Authors: Artursson Per , Brown Lyndon , Dix Jacqueline , Goddard Peter , Petrak Karel
Published: April 2003

A new method is described for the preparation of sterically stabilized nanoparticles of defined size and polydispersity which are stabilized in aqueous solution by the presence of covalently linked monomethoxy–poly (oxyethylene) (MeOPOE) chains. The nanoparticles (100–270 nm mean diameter) were prepared by a process of desolvation of a graft copolymer prepared from poly(2‐aminoethylmethacrylate) (PAEMA) and MeOPOE. Reproducible desolvation was achieved by the addition of sodium phosphate buffer to the copolymer in aqueous solution to give particles which were crosslinked in situ with the addition of glutaraldehyde. The size (mean diameter) and polydispersity (Q) of the particles were determined by Photon Correlation Spectroscopy (PCS). The temperature at which the desolvation reaction was performed was found to influence the particle size; at low temperatures (5–12°C), small particles were produced (99–121 nm, Q = 0.090–0.121), whereas at much higher temperatures (40–55°C), particles as large as 224–275 nm (Q = 0.138–0.127) were generated. Other parameters such as the graft copolymer concentration, the amount of glutaraldehyde added, the pH of the sodium phosphate buffer added, and the reaction time were found to be of relative insignificance in influencing the particle size. In addition to those involved in drug delivery, our method of nanoparticle preparation may be of interest to those engaged in the preparation of particulate materials and colloidal dispersions for other specific applications (e.g. stabilized photographic emulsions).
A new type of functional polymer: Preparation and crosslinking of poly(allenyl glycidyl ether)
Authors: Mizuya Jiro , Yokozawa Tsutomu , Endo Takeshi
Published: April 2003

The radical polymerization behavior of alkoxyallene containing the epoxy group, allenyl glycidyl ether (I), was investigated to obtain the more reactive polymer. The desired polymer was successfully synthesized only by the copolymerization of I with acrylonitrile (AN) at 80°C in DMF, although the homopolymer of I was converted to the crosslinked polymer during its purification. The same number of epoxy and two kinds of methylene groups were simultaneously introduced onto the polymer through propagating allyl radical. The obtained copolymer, therefore, was readily converted to the gelled polymer with methods such as heating and treating with Lewis acids or amines. Further, the copolymer containing two kinds of methylene groups was prepared similarly from methoxyallene (II) and AN, and was also converted to the crosslinked polymer with the cationic catalyst. These copolymers of I or II with AN will be expected to be new types of reactive polymers.
Inverse emulsions in a molten salt/hydroxy‐terminated polybutadiene system using block copolymers as emulsifiers
Authors: Litt M. H. , Lin C. S. , Krieger I. M.
Published: April 2003

Block copolymers of poly(N‐t‐butylbenzoyl ethylenimine) and poly(N‐propionyl ethylenimine) (Bx/Ey and Bx/Ey/Bx) or poly (N‐lauroyl ethylenimine) and poly (N‐propionyl ethylenimine) (Ux/Ey) were synthesized by cationic ring‐opening polymerization of 2‐substituted δ2‐oxazolines. Inverse emulsions (salt‐in‐oil) were made using these block copolymers as emulsifiers, hydroxy‐terminated polybutadiene (HTPB) as the nonpolar phase and methyl ammonium ethane sulfonate (MAES) as the polar phase. These inverse emulsions (S/O) were then cured using a triisocyanate to give a dispersion of molten salt (MAES) droplets in polyurethane. Pore sizes of these cured inverse emulsions were measured from scanning electron photomicrographs as a function of stirring time and concentrations of block copolymer and molten salt. The results indicate that pores with diameters in the range of 1.5 X 10−6 m can be obtained using triblock copolymer Bx/Ey/Bx, and that the surfactant molecules can be spread as a monolayer at the MAES‐HTPB interface.
The effect of direct interchange reactions on the MWD of condensation polymers
Authors: Lertola James G.
Published: April 2003

In this theoretical study, a relationship has been developed for the transient molecular‐weight distribution (MWD) of a condensation polymer undergoing a direct interchange reaction. Direct interchange is one of several reactions which can take place in condensation polymers in the melt. When compared to the more well‐known reactions of polycondensation, degradation, and interchange of an end‐group with a condensation linkage, direct interchange has a more complex statistical effect on the MWD and is less commonly observed. However, these types of reactions can be quite important in some polymeric systems, such as in the reaction of poly (butylene terephthalate) with polycarbonate. The MWD relationship was developed from the species balance: The rate of accumulation of chains of a given molecular weight is equal to their rate of generation minus their rate of consumption. For this reaction, development of the generation term is quite complex; it is approached here by describing five probability situations which are determined by each possible combination of reactant and product chains. Example distributions computed from these equations show that different transient paths are followed under direct and end‐group interchange, but that both reactions lead to the equilibrium most‐probable distribution.
Synthesis and properties of polyetheretherketone–polydimethylsiloxane block copolymers
Authors: Corfield G. C. , Wheatley G. W. , Parker D. G.
Published: April 2003

Polyetheretherketone‐polydimethylsiloxane (PEEK–PDMS) block copolymers were synthesized from the condensation of dimethylamino terminated PDMS and hydroxy terminated PEEK oligomers in 1‐chloronapthalene. Yields for block copolymers synthesised from low molecular weight PDMS oligomers were good but yields were significantly reduced when higher molecular weight PDMS oligomers were used. This was related to the limited solubility of higher molecular weight PDMS in the reaction solvent. Differential scanning calorimetry (DSC) studies indicated that phase separation of the block copolymers occurred at very short segment length (M̄n < 4000). A depression in the crystallinity of both the PEEK and PDMS phases in the block copolymer was observed. Thermogravimetric analysis (TGA) studies indicated that the PEEK–PDMS block copolymers displayed insufficient thermo‐oxidative stability to be melt‐processed successfully in PEEK based blends.
Silyl enol ethers as monomer. III. Radical polymerization and copolymerizations of 2‐trimethylsilyloxy‐1,3‐butadiene and desilylation of the resulting polymers
Authors: Nagai Katsutoshi , Asada Keisuke , Kuramoto Noriyuki
Published: April 2003

2‐Trimethylsilyloxy‐1,3‐butadiene (TMSBD), the silyl enol ether of methyl vinyl ketone, was homopolymerized with a radical initiator to afford polymers with a molecular weight of ca. 104. Radical copolymerizations of TMSBD with styrene (ST) and acrylonitrile (AN) in bulk or dioxane at 60°C gave the following monomer reactivity ratios: r1 = 0.64 and r2 = 1.20 for the ST (M1)–TMSBD (M2) system and r1 = 0.036 and r2 = 0.065 for the AN (M1)–TMSBD (M2) system. The Q and e values of TMSBD determined from the reactivity ratios for the former copolymerization system were 2.34 and −1.31, respectively. The resulting polymer and copolymers were readily desilylated with hydrochloric acid or tetrabutylammonium fluoride as catalyst to yield analogous polymers having carbonyl groups in the polymer chains.
Emulsion polymerization: Determination of the average number of free radicals per particle by use of the number average volume of the particles
Authors: Chen Show‐An , Wu Kuo‐Wei
Published: April 2003

For emulsion polymerization in the zero order region (Interval II) a relation between the average number of free radicals per particle, n̄(t), and the particle number average volume of a particle, v̄n(t), is derived as dv̄n(t)/dt = Kn̄(t), where K is volume growth rate of a particle containing one free radical and is constant. This relation is also extended to copolymerization systems with an appropriate modification of the definition of K. By use of the data of particle size distribution (PSD), n̄ can be calculated without knowing the total number of particles. In conjunction with this relation, the recently developed light‐scattering technique for measuring the PSD in addition to the conventional transmission electron microscope technique can provide a quick route for determination of n̄. Styrene and methyl methacrylate emulsion homopolymerizations are taken as calculation examples.
Halomethylated polysulfone: Reactive intermediates to neutral and ionic film‐forming polymers
Authors: Warshawsky A. , Kahana N. , Deshe A. , Gottlieb H. E. , Arad‐Yellin R.
Published: April 2003

Halomethylation of polysulfone (PS) with C8H17OCH2X (X = Cl, Br) in the presence of SnX4 (X = Cl, Br) led to PS–CH2X (X = Cl or Br or both) (Scheme 1). Under controlled conditions, PS–CH2X could be isolated and retains the good film forming properties of PS itself. Interhalogen exchange reactions occur in the presence of SnX4 (X = Cl, Br) under anhydrous conditions (Scheme 1), or a quaternary ammonium phase transfer catalyst R*R3N+X−, under aqueous conditions (Scheme 2). The exchange reactions with R*R3N+X−, are favored when R = C8C10, and with R = C4 only if n‐octanol is added; otherwise gelation occurs. Exchange in CHCl3 is attributed to dehydrohalogenation (and generation of dichlorocarbene) of the solvent in the presence of tetrabutyl ammonium hydroxide. Further chemical modifications of PS–CH2X by reaction with strong nucleophiles, led to hydroxymethyl polysulfone, acetoxymethyl polysulfone, and t‐butyl‐oxymethyl polysulfone (Scheme 3). Hydroxymethyl polysulfone sometimes gels under basic hydrolytic conditions and is best obtained by methanolysis of PS–CH2‐OAc. Both PSCH2OAc and PSCH2O‐t‐Bu are very stable, and provide a way to generate PSCH2Br on need by cleavage with HBr in acetic acid.

Direct oxidations with DMSO or tetrabutyl ammonium dichromate (Scheme 4) or indirect oxidations (Scheme 5) produce polysulfone with pendent CHO, CO2R and PO3R groups. Finally, polysulfones with linker arms including, carboxy alkyl, hexaglycol or sulfonamido crowns are described (Scheme 6). The reaction products were characterized by 1H‐ and 13C‐NMR. Double irradiation experiments, proved unequivocally, that the first substitution occurred on the B ring of the bisphenol A moiety (see Table I); the second substitution occurs on the A ring in position a. Thermogravimetric analysis generally shows for all modified polysulfones an extra transition at a lower temperature. The area of this band agrees generally with the values expected from calculated substitution degrees.
Metallocene–methyl aluminoxane catalysts for olefin polymerization. VIII. Infrared spectra of anisotactic polypropylene
Authors: Chien James C. W. , Rieger Bernhard , Herzog H. Martin
Published: April 2003

Polypropylenes obtained with the homogeneous racemic ethylene bis(indenyl) zirconium dichloride/methyl‐aluminoxane catalyst were fractionated by solvent extraction. The IR absorbance ratios, A998/A973 and A841/A973, were found to vary linearly with the homosteric sequence population, [m m m m] and [m m]. These results are compared with the results of a similar study by Burfield and Loi on commercial and laboratory polypropylenes of the conventional types.
Water‐Soluble imide‐amide copolymers. I. Preparation and characterization of poly [acrylamide‐co‐sodium N‐(4‐sulfophenyl) maleimide]
Authors: Hocking Martin B. , Syme David T. , Axelson David E. , Michaelian Kirk H.
Published: April 2003

Sodium N‐(4‐sulfophenyl) maleimide (SPMI) and its saturated succinimide counterpart were first prepared according to established methods. Hydrolysis experiments on these monomers monitored by 1H‐NMR showed that although SPMI monomer was about 15% hydrolyzed in D2O at 23°C in 24 h. Sodium N‐(4‐sulfophenyl) succinimide, which is similar in structure to the imide units in the copolymers, was only 1% hydrolyzed after 18 days at 23°C and 29% hydrolyzed after 18 days at 60°C. This indicated that the saturated imide rings in the copolymer might be sufficiently stable to hydrolysis for the copolymers to be useful. However, hydrolysis at high pH demonstrated that the imide rings would be rapidly saponified under alkaline conditions, destroying the structural rigidity that the intact rings might have provided in the copolymer chains. Sodium N‐(4‐sulfophenyl) maleimide (SPMI) was copolymerized with acrylamide in water at 30°C without cleavage of the imide ring. Water‐soluble poly [acrylamide‐co‐sodium‐N‐(4‐sulfophenyl) maleimide] (PAMSM) samples containing from 7.4 to 64 mol % imide were prepared. Photoacoustic FTIR and 13C‐NMR spectra were used to confirm the structure of the copolymers obtained. Elemental analysis was used to determine the imide content of the copolymers, and from this composition data reactivity ratios were calculated for the two component monomers.
Water‐Soluble imide‐amide copolymers. III. Preparation and characterization of poly (acrylamide‐co‐N,N‐diallylaniline) and poly (acrylamide‐co‐sodium N,N‐diallylsulfanilate)
Authors: Hocking Martin B. , Syme David T. , Axelson David E. , Michaelian Kirk H.
Published: April 2003

N,N‐diallylaniline monomer was prepared in good yields, for use in preparation of homopolymer and for copolymerization with acrylamide. Functionalized N,N‐diallylaniline monomer, as sodium N,N‐diallylsulfanilate, was also prepared in good yields for copolymerization with acrylamide. Both monomers were fully characterized by elemental analysis, IR, and NMR. Poly (N,N‐diallylaniline) was obtained by polymerization of a strongly acidic aqueous solution of N,N‐diallylaniline initiated with hydrogen peroxide. Spectroscopic data from this homopolymer was used to facilitate spectral assignments of the new copolymers. Copolymers of acrylamide with N,N‐diallylamine were prepared at monomer feed ratios of 10, 20, and 30 mol % amine and gave 3.5, 7.4, and 8.9 mol % incorporation, respectively. Similar diallyl monomer incorporation rates were obtained for the copolymerization of sodium N,N‐diallylsulfanilate with acrylamide. With 10, 30, and 50 mol % of the sodium salt relative to acrylamide, 3.9, 8.4, and 19.2 mol % incorporation of the diallyl monomer was obtained.
Phase transfer Pd(0) catalyzed polymerization reactions. III. Polymerization by cross‐coupling of alkyl–boron compounds and aromatic halides catalyzed by PdCl2 (dppf) and bases
Authors: Cramer Edwin , Percec Virgil
Published: April 2003

This paper describes a novel polymerization reaction which consists of a sequence of hydroboration of a diolefin with 9‐borabicyclo[3.3.1]nonane (9‐BBN) followed by the intermolecular cross‐coupling of the resulting 1,1′‐bis(B‐alkanediyl‐9‐borabicyclo[3.3.1]nonanes with dihaloarenes. The reaction is performed in the presence of dichloro[1,1′‐bis(diphenylphosphino)ferrocene] palladium (II) [PdCl2 (dppf)], a base, and a phase transfer catalyst. Both steps are performed in the same reaction flask. Alternatively, this polymerization reaction can be applied to bifunctional monomers containing an olefin and a haloarene group, for example, p‐bromostyrene.