bluuebunny/crossref_metadata_2025 huggingface dataset:
Propenyl ethers. II. Study of the photoinitiated cationic polymerization of propenyl ether monomers
Authors: Crivello J. V. , Jo K. D.
Published: April 2003

The results of studies of the photoinitiated cationic polymerization of mono‐, di‐, and multifunctional propenyl ethers are reported in this article. Real‐time infrared spectroscopy and differential scanning photocalorimetry were used to determine the reactivity of the monomers with respect to each other and in relation to other types of cationically polymerizable monomers. Propenyl ethers were observed to be highly reactive monomers in photoinitiated cationic polymerization undergoing very high conversions to polymer at very short irradiation times. Attempts were also made to correlate the structures of these monomers with their reactivity as well as to examine the effects of various experimental parameters on their photopolymerization. © 1993 John Wiley & Sons, Inc.
Synthesis of poly(styrene‐graft‐ethylene oxide) by ethoxylation of amide group containing styrene copolymers
Authors: Jannasch Patric , Wesslén Bengt
Published: April 2003

Graft copolymers containing poly(ethylene oxide) side chains on a polystyrene backbone have been synthesized. Styrene copolymers synthesized by free radical mechanism and containing between 5 and 15 mol % acrylamide or methacrylamide were used as backbones. The amide groups in the copolymers were ionized by using potassium tert‐butoxide or potassium naphthalene, and grafting was achieved by utilizing the amide anions as initiator sites for the polymerization of ethylene oxide in 2‐ethoxyethyl ether at 65°C. The graft copolymers were characterized with respect to molecular weight and composition using elemental analysis, NMR, gel permeation chromatography, IR, and viscosity measurements. The size of the side chains were between 600 and 2000 g/mol. GPC results from a hydrolyzed graft copolymer sample suggest a narrow size distribution for the poly(ethylene oxide) grafts. Solution properties of the graft copolymers were investigated in different toluene/methanol mixtures. The intrinsic viscosities of the graft copolymers were found to depend primarily on the poly(ethylene oxide) content rather than the graft density or the poly(ethylene oxide) chain length. © 1993 John Wiley & Sons, Inc.
Rigid rod polymers with flexible side chains. X. Thermotropic mesophases from aromatic stiff‐chain polyamides bearing n‐alkoxy side chains
Authors: Steuer M. , Hörth M. , Ballauff M.
Published: April 2003

The synthesis of stiff‐chain poly(1,4‐phenylene terephthalamide)s substituted by two as well as by four flexible side chains per repeating unit is described. The solubility of the materials bearing only two side chains is still very low. Appending of four side chains leads to polyamides which dissolve in common organic solvents. All polyamides reported herein form layered structures in the solid state as well as in the mesophase. Polyamides with two side chains have a very weak tendency for crystallization and do not exhibit a transition to the isotropic state even for the longest side chains. Polyamides with four side chains show three reversible thermal transitions: a disordering transition of the side chains, a transition to a layered, smectic‐like mesophase, and finally the transition to an isotropic melt. It is shown that the phase behavior of these materials is mainly governed by the strong segregation of main‐ and side‐chains which can be compared best to the microphase separation in block copolymers. © 1993 John Wiley & Sons, Inc.
Redistribution of cyclosiloxanes to favor formation of decamethylcyclopentasiloxane
Authors: Lambert Joseph B. , Kania Lidia , Schulz William J.
Published: April 2003

Efforts to optimize the formation of the cyclic D5 oligomer (D = Me2SiO) of polydimethylsiloxane have led to the development of a new class of redistribution catalyst, the silyl perchlorates. Where as previous Lewis and Bronsted acid catalysts have transformed D3 almost exclusively into D3n oligomers, use of phenyldimethylsilyl perchlorate as the catalyst gives predominantly D4, D5, and other non‐D3n oligomers. This redistribution reaction is particularly useful for obtaining large amounts of the difficulty available D5. Similar studies of D4 with variation of solvent and catalyst led to little redistribution. © 1993 John Wiley & Sons, Inc.
Ultrathin self‐assembled polymeric films on solid surfaces. I. Synthesis and characterization of acrylate copolymers containing alkyl disulfide side chains
Authors: Sun Fang , Grainger David W.
Published: April 2003

Copolymers of 2‐hydroxyethyl acrylate and 2‐methoxyethyl acrylate with variable compositions were synthesized, fractionated, and characterized by 1H‐NMR, IR, GPC, and viscometry. These copolymers were further modified via polymer analog esterification of copolymer hydroxy groups by a series of disulfide‐containing carboxylic acids including lipoic acid and (n‐pentyldithio) alkyl carboxylic acids (n‐C5H11SS(CH2)mCOOH, m = 10, 15, 22) in the presence of 1,3‐dicyclohexylcarbodiimide (DCC). Esterification reactions were quantitative for copolymers possessing hydroxy monomer contents ≤ 40% when excess acid and DCC were present for sufficiently long reaction times (2–4 days) at room temperature. Copolymer DSC analysis demonstrates a systematic variation of Tg with copolymer composition in good agreement with ideal mixing theory. These disulfide‐bearing copolymers spontaneously yield two‐dimensional ultrathin polymer films with side chain‐dependent layer thicknesses of 20–45 Å by solution adsorption onto freshly deposited gold surfaces. Such ultrathin polymer films are expected to have diverse applications as bound polymeric surface modification reagents. © 1993 John Wiley & Sons, Inc.
The use of platinum and rhodium catalysts for the preparation and cationic ring‐opening polymerization of silicon‐containing epoxides
Authors: Chung P. H. , Crivello J. V. , Fan M.
Published: April 2003

Regioselective platinum and rhodium catalysts were employed for the preparation of novel silicon‐containing polyethers. First, silicon‐containing monomers bearing cycloaliphatic epoxy groups were prepared by a rhodium‐catalyzed regioselective hydrosilation. Then these monomers were polymerized using a platinum‐catalyzed, cationic, ring‐opening polymerization to give the linear polyethers. The obtained polyethers were compared with polymers prepared by photoinitiated cationic ring‐opening polymerization using onium salt photoinitiators and found to be identical. © 1993 John Wiley & Sons, Inc.
Heat‐resistant resins obtained from polymer precursors bearing β,β′‐dicyanovinyl terminal groups
Authors: Mikroyannidis John A.
Published: April 2003

Certain polymer precursors of the general formula:
magnified image
where A is an aromatic structure bearing ester, amide, azomethine, or imide linkages were synthesized. Particularly, 4‐hydroxybenzaldehyde was condensed with malonitrile to afford 4‐hydroxy‐β,β′‐dicyanostyrene which reacted with a half molar amount of terephthaloyl dichloride in the presence of an acid acceptor. In addition, 3‐nitrobenzaldehyde was condensed with malonitrile to yield 3‐nitro‐β,β′‐dicyanostyrene that was catalytically hydrogenated to the corresponding amine. The latter reacted with a half molar amount of terephthaloyl dichloride, terephthaldehyde, pyromellitic dianhydride, or benzophenone tetracarboxylic dianhydride. The polymer precursors were characterized by elemental analyses as well as IR and 1H‐NMR spectroscopy. Their curing behavior was investigated by DTA. Crosslinked polymers were obtained by curing the monomers at 300°C for 24 h. They were stable up to 407–437°C in N2 and afforded an anaerobic char yield of 65–50% at 800°C. The thermal stability of resins was correlated with their chemical structures. © 1993 John Wiley & Sons, Inc.
Controlled modification of poly(hydroxybutyrate) surfaces by a perfluorohexane plasma: ESCA and contact angle studies
Authors: Flösch Dietmar , Clarotti Giorgio , Geckeler Kurt E. , Göpel Wolfgang
Published: April 2003

Poly(hydroxybutyrate) films and inorganic glass slides were treated by cold plasma. The composition of the gas mixture of perfluorohexane and hydrogen was varied to obtain controlled surface coatings of different hydrophobicities. The analysis by weight variation, scanning electron microscopy (SEM), electron spectroscopy for chemical analysis (ESCA), and contact angle measurements were used to evaluate the influence of the flow rate, composition, and the plasma power on the surface structure after the plasma deposition. High‐resolution ESCA spectra were used to determine quantitatively the amount of different fluorine‐containing species present in the plasma‐deposited layers. Molecular structures and surface energies of deposited layers on polymer substrates were compared with those on inorganic substrates. In both cases a strong correlation was found between the surface free energy and the fluorine/carbon ratio as well as the oxygen/carbon ratio. Furthermore, samples with high carbon/fluorine ratios showed a high content of CF2 and CF3 groups. © 1993 John Wiley & Sons, Inc.
Peroxidase‐catalyzed synthesis of lignin–phenol copolymers
Authors: Blinkovsky Alexander M. , Dordick Jonathan S.
Published: April 2003

Horseradish peroxidase catalyzes the copolymerization of phenols with kraft lignin in aqueous‐organic solvent mixtures. Nearly all of the lignin and over one‐third of the phenol (either p‐cresol or p‐phenylphenol) is incorporated into the copolymer which is highly insoluble in dimethylformamide (DMF), presumably because of crosslinking of lignin molecules via polyphenol bridges. The copolymer consists of 80% lignin, by weight. In the absence of a phenol, lignin is polymerized into a noncrosslinked, DMF‐soluble material. Thermal analysis shows that the copolymerization of phenols with lignin results in a material with markedly lower glass transition temperatures and higher (and more uniform) curing exotherms. The materials appear to act as thermosets and may have application as replacements of conventional phenolic resins. © 1993 John Wiley & Sons, Inc.
Investigation of a resorcinol–formaldehyde resin by 13C‐NMR spectroscopy and intrinsic viscosity measurement
Authors: Kim Moon G. , Amos Larry W. , Barnes Edwin E.
Published: April 2003

Various molecular weight fractions and oligomers isolated from a novolac type resorcinol–formaldehyde (RF) wood adhesive resin were studied by 13C‐NMR, gel permeation chromatography (GPC), and intrinsic viscosity measurements. The 13C‐NMR results indicate that methylene groups occur mostly between C4–C′4 and C2–C′4 carbons and in minor amounts between C2–C′2 carbons of resorcinol rings. By suppressing the nuclear Overhauser effect (nOe) and using a long delay time for 13C‐NMR measurements, reasonable methylene/aromatic carbon ratios were obtained from the aromatic C1 carbon patterns that have resulted from different numbers of methylene groups bonded on the aromatic ring. This analysis results indicate that the RF resin has an appreciable amount of branch structures and compare favorably with the gel permeation chromatography and intrinsic viscosity measurement results. © 1993 John Wiley & Sons, Inc.
Kinetics of thermoset cure and polymerization in the glass transition region
Authors: Stutz H. , Mertes J. , Neubecker K.
Published: April 2003

A theoretical approach to thermoset cure kinetics based on Arrhenius kinetics and mobility was developed by considering the activation of the reacting group and chain mobility as elementary steps for reaction. This extended kinetic equation was successfully applied to the curing of an epoxy by an amine, the trimerization of a cyanate, and to the polymerization of methyl methacrylate. Full agreement between theory and experimental data was obtained in all cases. The activation energies for chain mobility were exceptionally low (0.3–1 kJ/mol for bisphenol‐A‐based epoxy and cyanate) which indicates that the structural units must undergo only small‐angle rotational oscillations to allow a reaction. A theoretical time–temperature–transformation (TTT) diagram is also presented. © 1993 John Wiley & Sons, Inc.
Chain transfer reaction in the polymerization of substituted acetylenes. II. Chain transfer reaction to trimethylvinylsilane in the polymerization of disubstituted acetylenes by MoCl5–n‐Bu4Sn
Authors: Kouzai Hiroaki , Masuda Toshio , Higashimura Toshinobu
Published: April 2003

The effect of various olefins as chain transfer agents was studied in the polymerization of 1‐chloro‐1‐octyne, 1‐chloro‐2‐phenylacetylene, 2‐octyne, etc., catalyzed by MoCl5–n‐Bu4Sn (1 : 1). Si‐containing olefins, especially trimethylvinylsilane, greatly lowered the polymer molecular weight in the polymerization of the Cl‐containing acetylenes, e.g., the Mn of poly(1‐chloro‐1‐octyne) was 4.2 × 105 without an olefin, whereas it decreased to 3.4 × 104, i.e., below 1/10 in the presence of trimethylvinylsilane (1/2 equiv to monomer). In contrast, the molecular weight of poly(2‐octyne) did not decrease that much, even with trimethylvinylsilane. The Cl‐containing polyacetylenes obtained in the presence of trimethylvinylsilane as chain transfer agent possessed the trimethylsilyl group. Thus, the present study enables control of the molecular weight of substituted polyacetylenes by chain transfer, and further verifies the metal carbene mechanism for the polymerization of substituted acetylenes. © 1993 John Wiley & Sons, Inc.
Radical polymerization of 4‐methylene‐4H‐1,3‐benzodioxin‐2‐ones: Cyclic α‐substituted styrenes
Authors: Ueda Mitsuru , Toyota Hidetsugu , Sone Atsushi , Ito Hiroshi
Published: April 2003

4‐Methylene‐4H‐1,3‐benzodioxin‐2‐one (MBDOON), an α‐substituted cyclic styrene derivative, was synthesized and polymerized readily with 2,2′‐azobis(isobutyronitrile) (AIBN) as an initiator in solution. The kinetics of the MBDOON homopolymerization with AIBN was investigated in N‐methyl‐2‐pyrrolidone (NMP). The rate of polymerization, Rp, can be expressed by Rp − k[AIBN]0.52[MBDOON]1.1 and the overall activation energy has been calcualted to be 75.7 kJ/mol. Monomer reactivity ratios in copolymerization of MBDOON (M2) with styrene (M1) are r1 = 0.31 and r2 = 3.20, from which Q and e values of MBDOON can be calculated as 3.0 and −0.7, respectively. Ring‐substituted MBDOON monomers such as 6‐chloro, 6‐methyl, and 7‐methoxy derivatives were synthesized and polymerized with AIBN. The 6‐substituted MBDOON's readily underwent radical polymerization while the 7‐methoxy‐MBDOON was slower to polymerize. Poly(MBDOON) is predominantly heterotactic. (rr = 35, mr = 46, and mm = 19%). The polymer releases carbon dioxide at about 200°C and is converted with some depolymerization to poly[(o‐hydroxyphenyl)acetylene]. The thermolysis temperature is very much affected by the ring substituent. The onset of carbon dioxide liberation was observed at 140°C in the case of the 7‐methoxyl derivative while the 6‐substituents had a smaller effect on the decarboxylation temperature. © 1993 John Wiley & Sons, Inc.
Preparation of amphiphilic polyisobutylenes‐b‐polyethylenamines by mannich reaction. II. Study of mannich reaction on model systems
Authors: Jamois Didier , Tessier Martine , Maréchal Ernest
Published: April 2003

The study of the reactions which take place when α‐methyl‐ω‐phenolpolyisobutylene is polycondensed with triethylenetetramine (TETA) and para‐formaldehyde (Mannich condensation) is carried out on model systems including monofunctional [2,4‐di‐tert‐butylphenol (A), dibutylamine (B), and dodecylamine (B′)] and difunctional reactants [4‐tert‐butylphenol (A′) and 1,6‐hexamethylenediamine (B″)]. With the exception of the A + B system which gives only Mannich condensation, all the systems including at least one difunctional reactant are characterized by side reactions which accompany the Mannich condensation. However, when one of the compounds is monofunctional (A + B;′ A′ + B′) only nonpolymeric molecules are formed; their structures were determined by 1H‐ and 13C‐NMR spectroscopy. On the other hand, when both reactants are bifunctional (A′ + B; A′ + TETA) polymers are formed whose monomer units were identified by comparison of their spectra with those of the nonpolymeric molecules. © 1993 John Wiley & Sons, Inc.
Preparation of amphiphilic polyisobutylenes‐b‐polyethylenamines by mannich reaction. III. Synthesis of polyisobutylenes‐b‐polyethylenamines
Authors: Jamois Didier , Tessier Martine , Maréchal Ernest
Published: April 2003

Copolymers associating α‐phenololigoisobutylene and triethylenetetramine blocks in the same chain are prepared by reacting aqueous formaldehyde with α‐phenololigoisobutylene and triethylenetetramine. When para‐formaldehyde is used instead of monomeric formaldehyde, the reaction does not take place, contrary to what is observed when low molecular weight models are used instead of oligomers. The ability of these copolymers to disperse sludges in motor oil was evaluated by the “spot‐test” method. When oil does not contain water, the efficiency of the copolymers is comparable to that of commercial compounds. When oil contains water (1% w) the efficiency of the dispersive agent is drastically reduced. We show that this is due to the presence of phenol group. © 1993 John Wiley & Sons, Inc.
Degradable polymer blends. I. Screening of miscible polymers
Authors: Domb Abraham J.
Published: April 2003

Blends of biodegradable polymers having properties distinct from the individual polymer components, and that are suitable for use as carriers of pharmaceutically active agents, were prepared from two or more polyanhydrides, polyesters, and mixtures of polyanhydrides and low molecular weight polyesters. The blends have different properties than the original polymers, providing a mean for altering the characteristics of the polymeric matrix without altering the chemical structure of the component polymers. Aliphatic, aromatic, and copolymers of polyanhydrides were miscible in each other and formed less crystalline compositions with a single melting point which was lower than the melting point of the starting polymers. The polyesters: poly(lactide‐glycolide), poly(caprolactone), and poly(hydroxybutyric acid) presented some miscibility in each other. However, the polyanhydrides were immiscible with the polyesters resulting in a complete phase separation both in solution or in melt mixing. Only low molecular weight polyesters (in the range of 2000) of lactide and glycolide, mandelic acid, propylenefumarate, and caprolactone presented some miscibility with polyanhydrides. Similarly, poly(orthoester) and hydroxybutyric acid polymers formed a uniform mixture with the anhydride polymers which had the two melting points of the original polymers. Drug release from polymer blends composed of poly(hydroxybutyric acid) or low molecular weight poly(lactic acid) with poly(sebacic anhydride) (PSA) showed a constant release of drug for periods from 2 weeks to several months as a function of the PSA content in the blend. Increasing the content of PSA, a fast degrading polymer, increases the release rate from the blend. © 1993 John Wiley & Sons, Inc.
Morphology of block copolyurethanes. IV. Effect of synthetic procedure on chain structure
Authors: Wang Tzong‐Liu David , Lyman Donald J.
Published: April 2003

Analysis of products formed in the end‐capping step during the synthesis of two block copolyurethanes being studied as biomedical materials has shown the presence of dimeric soft segments and free diisocyanate. In this standard two‐step synthesis, the presence of these compounds lead to block copolyether‐urethane‐ureas containing sizeable amounts of dimeric hard and soft segments. These standard copolymers are compared in terms of IR spectra, stress‐strain properties, and dynamic mechanical properties to their pure analogs which contain no dimeric segments. © 1993 John Wiley & Sons, Inc.
Fluorine substitutent effects on poly(2,6‐diphenylphenylene ether)
Authors: Yang Hu , Hay Allan S.
Published: April 2003

A series of fluoro‐substituted poly(2,6‐diphenylphenylene ether)s (P3O) with systematically varied structures were prepared. The properties of the polymers change significantly with the variations in the polymer structures. By increasing the number of fluorine substituents on P3O polymer, the melting points and the tendency to crystallize for these polymers decrease significantly. Random copolymers from fluoro‐substituted 2,6‐diphenylphenols and 2,6‐diphenylphenol were also prepared. The influence of copolymer structure on the transition temperatures and crystallinity of the resulting copolymers is described. © 1993 John Wiley & Sons, Inc.
Equilibrium constants and the prediction of miscibility windows for polymer blends containing poly(tetrafluoroethylene‐alt‐vinyl alcohol)
Authors: Coleman Michael M. , Yang Xiaoming , Zhang Hongxi , Painter Paul C. , Scherer Kirby V.
Published: April 2003

Theoretical calculations of miscibility windows for binary polymer blends in which one component is an essentially alternating copolymer of tetrafluoroethylene and vinyl alcohol (FVOH) are reported. FVOH has an inherently low solubility parameter [≈ 6.2 (cal. cm−3)0.5] that is outside the range commonly encountered in miscible polymer blends and thus represents a stringent test of the predictive capabilities of an association model we have used in previous work. The application of this model requires that we determine dimensionless equilibrium constants describing the self‐association of a model compound 3,4‐pentafluorobutan‐2‐ol (PFB) at 25°C from infrared spectroscopic data. Analogous equilibrium constants for FVOH were scaled from those of PFB by taking into account differences in the molar volume of the model and the specific repeat of the copolymer (see M. M. Coleman, J. F. Graf, and P. C. Painter: Specific Interactions and the Miscibility of Polymer Blends, Technomic, Lancaster, PA, 1991). Equilibrium constants describing the inter‐association of FVOH with ester type carbonyl groups were obtained from spectroscopic studies of miscible blends with poly(ethyl methacrylate). These equilibrium constant values were then used to calculate theoretical miscibility windows for the complete range of blends of FVOH with polymethacrylates, ethylene‐co‐methyl acrylate, styrene‐co‐methyl acrylate, and ethylene‐co‐vinyl acetate copolymers. Experimental results performed in our laboratories confirm the general validity of the predicted miscibility windows. © 1993 John Wiley & Sons, Inc.
Postcondensation and oxidation processes in molten polyamide 6
Authors: Marechal Ph. , Legras R. , Dekoninck J. M.
Published: April 2003

Polyamide samples were heated under vacuum or mixed in a Brabender plastograph. UV absorbance, chain end concentration, and molecular weight were studied. Postcondensation was observed for polyamide heated under vacuum. For polyamide samples mixed in the plastograph, atmosphere, shear rate, and temperature changed. Melt viscosity and intrinsic viscosity are in good correlation in a log‐log plot. Oxidation effect on molecular weight and amine chain end concentration could be well related to UV absorbance. The oxygen diffusion into the molten polyamide is a critical parameter. The oxygen concentration in the polyamide mixed under air is ca. 20 times higher than when mixed under nitrogen. The introduction of preoxidized material in the molten polyamide or mixing in the presence of oxygen have similar effects. Postcondensation and oxidation strongly influence the melt behavior of polyamides. © 1993 John Wiley & Sons, Inc.
Soluble copolyimides with high modulus and low moisture absorption
Authors: Shiang William R. , Woo Edmund P.
Published: April 2003

A series of transparent copolyimides were prepared from PMDA‐ODPA‐TFDB via chemical imidization of the corresponding poly(amic acid)s. Copolyimides containing less than 70% PMDA were completely soluble in DMAc and other amide solvents and gave ductile films with unexpectedly high tensile moduli (up to 8.9 GPa). Water absorption, after boiling in water for 72 h, were less than 1 % for the copolymer with 67% PMDA and less than 0.5% for copolymers with less PMDA. Thermooxidative stability was comparable to a commercial polyimide film up to 325°C. A copolyimide containing 34% PMDA had the best overall properties based on the above tests. Additional evaluations revealed a coefficient of linear expansion of about 6 X 10−6/°C, an essentially frequency independent dielectric constant of 2.8, a dissipation factor of about 0.004–0.01 over the range of 1–1000 kHz, and complete retention of tensile properties after exposure to a humid environment for 16 weeks. A model compound study suggests the probable presence of short blocks in these copolymers. © 1993 John Wiley & Sons, Inc.
Kinetics and mechanisms of emulsion polymerization initiated by oil‐soluble initiators. IV. Kinetic modeling of unseeded emulsion polymerization of styrene initiated by 2,2′‐azobisisobutyronitrile
Authors: Nomura M. , Ikoma J. , Fujita K.
Published: April 2003

To explain the kinetic features of particle formation and growth in unseeded emulsion polymerization initiated by oil‐soluble initiators, a mathematical kinetic model is proposed, based on the assumption that when initiator radicals or monomer radicals in the water phase enter monomer‐solubilized emulsifier micelles, initiate polymerization, and propagate to a chain length which is long enough not to desorb from the micelles, the micelles are regarded to be transformed into polymer particles. It is demonstrated by comparing the experimental results obtained in the emulsion polymerization of styrene initiated by the oil‐soluble initiator, 2,2'‐azobisisobutyronitrile, with sodium lauryl sulfate as emulsifier that the proposed kinetic model satisfactorily explains the kinetic features such as the effects of initial emulsifier, initiator, and monomer concentrations on both the number of polymer particles produced and the monomer conversion versus time histories. © 1993 John Wiley & Sons, Inc.
Synthesis and polymerization of 2‐alkylanilines
Authors: Bodalia R. , Stern R. , Batich C. , Duran R.
Published: April 2003

2‐Alkylanilines with alkyl groups in the range of 4–15 carbon atoms were synthesized via a known method as well as via a more general path which should allow the introduction of a larger variety of substituted alkyl groups into the ortho position of aniline, e.g., alkenyl or OH, NH2, COOH, and phenyl functionality. Polymerization was found to be achievable according to a method previously described for unsubstituted aniline, i.e., chemically with Cu(ClO4)2 · 6H2O in acetonitrile. Intrinsic viscosities of the obtained poly(2‐alkylaniline)s lay between 0.10 and 0.26 dL/g (97% H2SO4 at 30°C). The dc conductivity of the HCl salts decreased with increasing length of the alkyl side chains from 1 S/cm (polyaniline) over 3 X 10−4 S/cm [poly(2‐butylaniline)] to 1 X 10−6 S/cm poly(tridecylaniline). Further characterization of the polymers were performed by means of UV/VIS/NIR‐and‐IR spectroscopy, in dilute solutions or as KBr pellets, respectively, and by solubility tests. © 1993 John Wiley & Sons, Inc.
Influence of the seed polymer on the chromatographic properties of size monodisperse polymeric separation media prepared by a multi‐step swelling and polymerization method
Authors: Hosoya Ken , Fréchet Jean M. J.
Published: April 2003

Monodisperse polymer particle‐based separation media were prepared by a multi‐step swelling and polymerization method with two pairs of monomers and two porogenic solvents. Their chromatographic properties were compared to those of beads prepared by a corresponding suspension polymerization method without the use of seed polymer to ascertain the influence of the seed polymer on their porous structures. A large change in porous structure was observed when the swollen particle consisting of monomers and porogenic solvents contained at least one good solvent for the polystyrene seed polymer, allowing it to remain in the polymerizing medium. In contrast, when the polystyrene seed particle was excluded from the swollen oil droplets, due to its poor solubility in the monomers and the porogenic solvents, there was no difference in the chromatographic properties such as pore volume, pore size, pore size distribution, or retention selectivity between the multi‐step swelling and polymerization method and the suspension polymerization method. Since the only difference between the multi‐step swelling and polymerization method and the suspension method is the use of the seed polymer, it appears that a very small amount (< 1% v/v) of seed polymers in the enlarged swollen droplets plays an important role as a porogen and affects the porous structure as well as the chromatographic properties of the monodisperse polymer particle‐based separation media. © 1993 John Wiley & Sons, Inc.
Syntheses and properties of aromatic polyamides and polyimides derived from 9,9‐bis[4‐(p‐aminophenoxy)phenyl]fluorene
Authors: Yang Chin‐Ping , Lin Jiun‐Hung
Published: April 2003

9,9‐Bis[4‐(p‐aminophenoxy)phenyl]fluorene (II) was used as a monomer with various aromatic dicarboxylic acids and tetracarboxylic dianhydrides to synthesize polyamides and polyimides, respectively. The diamineIIwas derived by a nucleophilic substitution of 9,9‐bis(4‐hydroxyphenyl)fluorene withp‐chloronitrobenzene in the presence of K2CO3and then hydro‐reduced. PolyamidesIVa‐ghaving inherent viscosities of 0.73–1.39 dL/g were prepared by the direct polycondensation of the diamineIIwith various aromatic diacids using triphenyl phosphite and pyridine as condensing agents. All the aromatic polyamides were amorphous and readily soluble in various polar solvents such asN,N‐dimethylacetamide,N,N‐dimethylformamide, dimethylsulfoxide, andN‐methyl‐2‐pyrrolidone. Transparent and flexible films of these polymers could be cast from the DMAc solutions. These aromatic polyamides had glass transition temperatures in the range of 283–309°C and 10% weight loss occurred up to 460°C. The polyimides were synthesized from diamineIIand various aromatic dianhydrides via the two‐stage procedure that included ring‐opening poly‐addition in DMAc to give poly(amic acid)s, followed by thermal or chemical conversion to polyimides. The poly(amic acid)s had inherent viscosities of 0.62–1.78 dL/g, depending on the dianhydrides. Most of the aromatic polyimides obtained by chemical cyclization were found to be soluble in NMP. These polyimides showed almost no weight loss up to 500°C in air or nitrogen atmosphere. © 1993 John Wiley & Sons, Inc.
Interpenetrating polymer networks based on poly(chloroprene) and poly(carbonate‐urethane)
Authors: Xue Yongpeng , Frisch H. L.
Published: April 2003

Simultaneous interpenetrating polymer networks (SIN's) of poly(chloroprene) (CR) and poly(carbonate‐urethane) (PCU) were prepared and characterized. The effect of composition on the phase morphology of full IPN's of CR/PCU has been studied by DSC and SEM. A single phase morphology of IPN's has achieved when the content of CR component is below 50 wt %. The microphase separation of the component networks in the IPN's occurred in samples whose weight percentage of the CR component was 50% and higher. © 1993 John Wiley & Sons, Inc.
Poly(aryl ether amide)s
Authors: Lucas M. , Brock P. , Hedrick J. L.
Published: April 2003

A general method for the preparation of poly(aryl ether amide)s has been developed where the generation of an aryl ether linkage is the polymer‐forming reaction. The amide linkage was found to be sufficiently electron‐withdrawing to activate halo‐substituents towards nucleophilic aromatic substitution analogous to conventional activating groups (i.e., sulfone, ketone, etc.). Model reactions demonstrated that the amide‐activated displacement occurred with high selectivity in near quantitative yield and was judged suitable as a polymer‐forming reaction. Appropriately fluoro‐substituted amides were prepared and subjected to displacement polymerization with bisphenoxides in a N‐methyl‐2‐pyrrolidone (NMP)/N‐cyclohexyl‐2‐pyrrolidone (CHP) solvent mixture. High molecular weight polymers with glass transition temperatures in the 200–225°C range were obtained. © 1993 John Wiley & Sons, Inc.
Synthesis of substituted poly(1‐vinylpyrene)s and investigation of their fluorescent properties
Authors: Katritzky Alan R. , Zhu Dong‐Wei , Schanze Kirk S.
Published: April 2003

A series of functionalized linear poly(1‐vinylpyrene) (PVP) polymers bearing substituents such as NO2, CHO, NH2, Br, and CHC(CN)2, were prepared by chemical modification of PVP in solution. The degree of substitution in PVPCHC(CN)2 was varied from 40% to nearly 100% by control of the reaction conditions. The other polymers were partially functionalized. The UV‐visible and fluorescence spectroscopy of the polymers were studied in solution. The influence of solvent polarity, excitation energy, and degree of substitution on the fluorescence of the polymers were examined. © 1993 John Wiley & Sons, In
The synthesis, characterization, and weathering behavior of polycarbonates derived from bis(P‐hydroxyphenyl) dimethylsilane (BPSI)
Authors: Factor A. , Engen P. T.
Published: April 2003

Polycarbonates and copolycarbonates based on BPSi and BPA were easily made using the standard interfacial technique. Molecular weight and NMR data indicate that up to 4 mol % of the BPSi decomposes during polymerization via a base‐catalyzed rearrangement of BPSi to arylsiloxanes. Oxygen index studies show an increased flame resistance with increasing BPSi monomer content. DSC measurements show a decrease in glass transition with BPSi monomer concentration while TGA shows an increase in char residue with BPSi monomer content. In addition, TGA indicates no change in either thermal or thermooxidative stability with the relative BPSi/BPA concentrations. Outdoor weathering of BPSi PC and BPA PC films indicates that BPSi PC is ca. 5 times more weathering resistant than BPA PC. This latter result can be attributed to a combination of BPSi PC's lower UV absorptivity, higher water repellency, and lower likelihood for side chain photooxidation. © 1993 John Wiley & Sons, Inc.
Synthesis and characterization of novel epoxy monomers and liquid crystal thermosets
Authors: Mallon Joseph J. , Adams Paul M.
Published: April 2003

Four new epoxy monomers have been synthesized and characterized as part of a program to prepare novel liquid crystal thermoset (LCT) materials. Three of the new epoxy monomers contained a biphenyl mesogen and were not liquid crystalline (LC). The remaining epoxy monomer, which contained a 1,4‐dibenzoyloxybenzene mesogen, was synthesized in an overall yield of 30% and displayed a broad (83°C) nematic liquid crystalline phase. The new liquid crystalline epoxy monomer was cured at 120°C and postcured at 175°C with a stoichiometric amount of 1,4‐phenylenediamine. The thermal transitions of the resulting LCT were studied by differential scanning calorimetry (DSC), polarized light optical microscopy (POM), thermomechanical analysis (TMA), and wide angle x‐ray diffraction (WAXD) as a function of cure time and temperature. A process characterization diagram was constructed which shows that LCTs based on this new LC monomer can be processed in the liquid crystalline phase over a broad range of times and temperatures. Qualitative agreement with previous epoxy LCT results was found, as LCT's with smectic phases and without clearing temperatures were observed at long cure times (high crosslink densities), whereas nematic phases with clearing temperatures predominated in networks at short cure times (low crosslink densities). © 1993 John Wiley & Sons, Inc.
Crosslinked polystyrene with improved mechanical properties
Authors: Sundell Mats J. , Pajunen Esko O. , Hormi Osmo O. E. , Nåsman Jan H.
Published: April 2003

The synthesis of some divinyl monomers—bis(vinylphenyl)ethane (2), bis(vinylbenzyloxy)hexane (3a), and bis(vinylbenzyloxy)dodecane (3b) is reported. Copolymers of the new monomers and styrene were evaluated as an alternative to divinylbenzene‐crosslinked polymers for use as matrices and absorbents. The mechanical properties and the amount of residual double bonds in the copolymers were compared. It was found that the new copolymers, unlike the divinylbenzene‐crosslinked polymers, retained their mechanical strength even at high crosslinking degrees. Stress at break values of 79, 68, and 18 N/mm2 were found for the polymers crosslinked with 20 mol % of 3a, 2, and divinylbenzene; 5, 25 and 45% of the divinyl units in these polymers were left as pendant double bonds. Porous styrene–2 copolymers were synthesized and shown to have lower surface areas than the corresponding divinylbenzene‐crosslinked polymers. The pore size distribution showed that this was due to the absence of the smallest pores which are found in the divinylbenzene‐crosslinked polymers in between heavily crosslinked nodules. © 1993 John Wiley & Sons, Inc.
Synthesis and polymerization of oligo(oxyethylene) macromonomer bearing sodium sulfonate
Authors: Zhang Sheng‐Shui , Liu Qing‐Guo , Yang Lei‐Ling
Published: April 2003

Oligo(oxyethylene) macromonomers bearing sodium sulfonate group have been synthesized through four reactions: (1) ring‐opening polymerization of oxirane, (2) etherification of monomethoxyl oligo(oxyethylene) and epichlorohydrin, (3) sulfonation of cycloxyl compound, and (4) end‐capping of sodium oligo(oxyethylene) sulfonate by methacrylic group. A desired length of oligo(oxyethylene) in the macromonomers can easily be achieved by controlling the ratio of reactants in the ring‐opening step. The structures of the products of each reaction were identified by IR, 1H‐NMR, and GPC. Polymers of the monomers were also characterized by GPC and DSC. © 1993 John Wiley & Sons, Inc.
Influence of HCL on polypyrrole films prepared chemically from ferric chloride
Authors: Ayad Mohamad M.
Published: April 2003

Smooth, adherent films of the electrically conducting polypyrrole formed on surfaces in contact with unstirred aqueous solutions containing the pyrrole monomer and the oxidant, FeCl3. Contradictory reports in the literature concerning the influence of HCl on the growth rate and electrical conductivity of polypyrrole grown in this manner prompted this study of the growth rate and conductivity of films. With no intentional addition of HCl, the growth rate of the films, measured using a quartz crystal microbalance, was fit to a simple second‐order model in which the rate was limited by the bulk depletion of reactants. The conductivity of the films was found to be about 1 S cm−1. Both the growth rate and the electrical conductivity initially increased with the deliberate addition of HCl to the solution. The conductivity was found to peak at a value about 20 S cm−1 at an initial HCl concentration of 0.3 M. At initial HCl concentration of 2M or more, films could not be grown. © 1994 John Wiley & Sons, Inc.
Gel permeation chromatographic analysis of polyurethane prepolymer synthesis kinetics II. The effects of stoichiometry and type of diisocyanate
Authors: Thompson Corley M. , Taylor Sue G. , McGee William W.
Published: April 2003

The kinetics of formation of polyurethane prepolymers is studied by an analytical technique which involves reactive quenching of the isocyanate, separation of the oligomeric species by GPC, and measurement by UV absorbance of the quenched moieties. The precision of the kinetic parameters and the ratios of the oligomers are determined. The effect of changes in reactant stoichiometry on the ratio of oligomers is measured and compared to the value predicted by an equation from Flory. Toluene diisocyanate is shown to give fewer high oligomers than predicted, while methylene diphenylene diisocyanate gives nearly the predicted values. Tetramethylxylene diisocyanate gives more high oligomers than predicted, an unexpected but possibly important result. Catalyst is shown to increase the reaction rate of the last by more than 200 times. © 1994 John Wiley & Sons, Inc.
Silolene‐Bridged zirconocenium polymerization catalysts
Authors: Tsai Woei‐Min , Chien James C. W.
Published: April 2003

A new silolene‐bridged compound, racemic (1,4‐butanediyl) silylene‐bis (1‐η5‐in‐denyl) dichlorozirconium (1) was synthesized by reacting ZrCl4 with C4H8Si (IndLi)2 in THF. 1 was reacted with trialkylaluminum and then with triphenylcarbenium tetrakis (penta‐fluorophenyl) borate (2) to produce in situ the zirconocenium ion (1+). This “constraint geometry” catalyst is exceedingly stereoselective for propylene polymerization at low temperature (Tp = −55°C), producing refluxing n‐heptane insoluble isotactic poly(propylene) (i‐PP) with a yield of 99.4%, Tm = 164.3°C, δHf = 20.22 cal/g and M̄w = 350 000. It has catalytic activities of 107−108 g PP/(mol Zr · [C3H6] · h) in propylene polymerization at the Tp ranging from −55°C to 70°C, and 108 polymer/(mol Zr · [monomer] · h) in ethylene polymerization. The stereospecificity of 1+ decreases gradually as Tp approaches 20°C. At higher temperatures the catalytic species rapidly loses stereochemical control. Under all experimental conditions 1+ is more stereospecific than the analogous cation derived from rac‐dimethylsilylenebis (1‐η5‐indenyl)dichlorozirconium (4). The variations of polymerization activities in ethylene and in propylene for Tp from −55°C to +70°C indicates a Michaelis Mention kinetics. The zirconocenium‐propylene π‐complex has a larger insertion rate constant but lower thermal stability than the corresponding ethylene π‐complex. This catalyst copolymerizes ethylene and propylene with reactivity ratios of comparable magnitude rE ˜ 4rp. Furthermore, rE.rp ˜ 0.5 indicating random copolymer formation. Both 1 and 4 activated with methylaluminoxane (MAO) exhibit much slower polymerization rates, and, under certain conditions, a lower stereo‐selectivity than the corresponding 1+ or 4+ system. © 1994 John Wiley & Sons, Inc.
Phosphorus containing polymers. III. Polyimidophosphonates
Authors: Banerjee Susanta , Palit Sunanda K. , Maiti Sukumar
Published: April 2003

Synthesis of dihydroxybisimide monomers and their subsequent polycondensation with dichlorophenylphosphine oxide by use of a phase‐transfer catalyst are reported. The monomers were characterized by melting point, elemental analysis, and IR spectroscopy. The polyimidophosphonates were characterized by viscosity measurement, molecular weight determination, elemental analysis, IR, ESCA, 1H‐NMR, 31P‐NMR, and X‐ray diffraction. Thermal stability and glass transition temperature (Tg) of the polymers were evaluated by TGA, DTA, and TMA. These polymers are self‐extinguishing and readily soluble in highly polar solvents like DMF, DMSO, DMAC, NMP, HMPA, etc. © 1994 John Wiley & Sons, Inc.
Synthesis of copolymers of 1,3‐dioxan‐2‐one and oxepan‐2‐one using coordination catalysts
Authors: Albertsson Ann‐Christine , Eklund Maria
Published: April 2003

A new type of copolymer is synthesized in a bulk polymerization from 1,3‐dioxan‐2‐one and oxepan‐2‐one (ϵ‐caprolactone) using either Sn‐oct, ZnAc2, Bu2SnO, or Bu3SnCl as the catalyst. SEC analysis shows that it is possible to achieve high molecular weights and narrow molecular weight distributions. 13C‐NMR analysis confirms the existence of copolymers. Conversion studies have been made and reactivity ratios, r1 and r2, have been determined to distinguish between the reactivities of 1,3‐dioxan‐2‐one and oxepan‐2‐one. The Finemann‐Ross method and the Kelen‐Tüdös method were used to calculate the ratios and the agreement was good between the methods. The composition of the copolymer agrees with the feed composition at high conversions. Thermal analysis of copolymers by DSC shows crystalline melting resulting from a somewhat blocky copolymer. The glass transition temperatures of the copolymers are in agreement with the Fox equation. The corresponding blends of the two homopolymers show a constant melting point and glass transition temperature. A nonionic insertion mechanism and a Lewis acid alcoholysis mechanism are discussed. © 1994 John Wiley & Sons, Inc.
Synthesis and radical polymerization of spiro orthocarbonates bearing exomethylene groups
Authors: Sanda Fumio , Takata Toshikazu , Endo Takeshi
Published: April 2003

Synthesis and radical polymerization of spiro orthocarbonates (SOCs) bearing exomethylene groups at the α to the ether oxygen (1a–1e) were studied. SOCs 1a–1e were prepared by the successive reactions of dichlorodiphenoxymethane with two different diols followed by dehydrochlorination. Radical polymerization of the SOCs was carried out in the presence of an appropriate initiator (3 mol % versus monomer) at 130 and 180°C. The obtained polymer insoluble in n‐hexane contained both vinyl polymerization unit 13 and double ring‐opening polymerization unit 14 (ketone‐carbonates). The degree of ring‐opening followed the order: 1a <1b < 1d, 1e. n‐Hexane‐insoluble polymer was not obtained in the polymerization of 1c. Both steric hindrance of methyl group and ring size affected the degree of ring‐opening. The introduction of methyl group into SOC increased the degree of ring‐opening (1a <1b), whereas the degree of ring‐opening of either 1d, consisting of six‐ and seven‐membered rings, and 1e, consisting of two seven‐membered rings, was higher than those of 1a and 1b, consisting of five and seven‐membered rings. From the molecular orbital calculation (PM3, UHF method), it was concluded that if the first single ring‐opening occurs, then the successive second ring‐opening takes place more smoothly. The first ring‐opening requires more energy than the vinyl polymerization does. © 1994 John Wiley & Sons, Inc.
New polymer syntheses. LXXV. 2,5‐biaryloxyterephthalic acids and rigid‐rod polyaramides derived from them
Authors: Kricheldorf Hans R. , Bürger Rolf
Published: April 2003

Several 2,5‐bisaryloxyterephthalic acids were prepared by a new method, namely arylation of diethyl‐2,5‐bistrimethylsiloxyterephthalate. Rigid‐rod polyaramides were prepared by polycondensation of silylated diamines with a terephthaloylchloride with two diphenylsulfone side chains. Another polyamide was prepared from 2,5‐bis(4′‐cyanophenoxy) terephthalic acid and 1,4‐diaminobenzene. None of these polyaramides is meltable and their solubilities differ largely. A copolymer of 1,4‐diaminobenzene and 3,3′‐dimethoxybenzidine is soluble in various organic solvents including polar vinyl monomers. © 1994 John Wiley & Sons, Inc.
Quantification of end groups in polystyrenes by pyrolysis–gas chromatography
Authors: Ito Yoshiro , Ohtani Hajime , Ueda Shouji , Nakashima Yasuki , Tsuge Shin
Published: April 2003

The determination of end groups in polystyrenes (PSts) polymerized anionically with n‐butyllithium as the initiator was carried out by pyrolysis‐gas chromatography (Py‐GC). The relative proportions of the end groups decrease with increasing molecular weight (MW). Consequently, the peaks which reflect the structure of the end groups can be distinguished by comparing pyrograms of samples with different MW. By comparing the intensities of these peaks relative to total intensities of all the peaks in the pyrogram, the numberaverage molecular weight (Mn) of the polymer can be estimated. The observed Mn values of PSts estimated by this method are compared with those determined by size exclusion chromatography (SEC). By this method it was possible to make direct determination of Mn values of PSts with MWs between 1000 and ca. 1 million. Furthermore, the calibration curve produced by the relative intensity of one of the most characteristic peaks (2‐phenyl‐1‐heptene; C4H9CH2C (Ph) = CH2) for the end group to total intensity of all the peaks in the pyrogram, gave rapid and highly reproducible Mn values. © 1994 John Wiley & Sons, Inc.