bluuebunny/crossref_metadata_2025 huggingface dataset:
Cationic ring‐opening polymerization of bicyclic amide acetals
Authors: Lu Caixia , Odian George
Published: April 2003

Various bicyclic amide acetals were synthesized from the cycloaddition reactions of 2‐substituted‐2‐oxazolines with styrene oxide. Ring‐opening polymerization of the bicyclic amide acetals occurred upon heating in the presence of methyl tosylate. Characterization of the bicyclic amide acetals and their polymers was accomplished by NMR and elemental analysis. Vapor pressure osmometry showed the highest polymer molecular weight was only 2,400. The mechanisms for cycloaddition and polymerization are discussed. © 1994 John Wiley & Sons, Inc.
Multimonomer partitioning in latex systems with moderately water‐soluble monomers
Authors: Schoonbrood H. A. S. , Van Den Boom M. A. T. , German A. L. , Hutovic J.
Published: April 2003

Simple equations describing monomer partitioning in latices during intervals 2 and 3 in emulsion polymerization with any number of low to moderately water soluble monomers were derived from the extended Morton equation by making various assumptions. It appears that it is mainly the combinatorial entropy of mixing that governs the partitioning behavior, and that other contributions to the free energy of the monomers in the polymer particles are marginal. Experimental results with styrene, methyl methacrylate, and methyl acrylate confirm the validity of the assumptions. In interval 3 of emulsion polymerization the sum of all contributions to the free energy of the monomers in the particles other than the combinatorial entropy of mixing can be taken as a constant that is dependent only on the monomer composition in the particles and independent of the degree of swelling of the particles. The only parameters one needs to know to calculate the monomer concentrations in all phases with help of the derived equations, are the saturation concentrations of each monomer in the polymer particles, and the saturation concentrations of each monomer in the aqueous phase. © 1994 John Wiley & Sons, Inc.
Photografting of vinyl polymers onto ultrafine inorganic particles: Photopolymerization of vinyl monomers initiated by AZO groups introduced onto these surfaces
Authors: Tsubokawa Norio , Shirai Yukio , Tsuchida Hideyo , Handa Satoshi
Published: April 2003

The photografting of polymers onto ultrafine inorganic particles, such as silica and titanium oxide, initiated by azo groups introduced onto these surfaces was investigated. The introduction of azo groups onto the particles was achieved by the reaction of 4,4′‐azobis(4‐cyanopentanoic acid) with surface isocyanate groups, which were introduced by the treatment with tolylene 2,4‐diisocyanate. It was found that the photopolymerization of vinyl monomers, such as methyl methacrylate (MMA), styrene, and N‐vinylcarbazole, is initiated by ultrafine particles having azo groups. The corresponding polymers were effectively grafted onto these surfaces through the propagation of the polymer from the surface radicals formed by the photodecomposition of the azo groups: e.g., the percentage of grafting of PMMA and polystyrene onto silica was reached to 112 and 176%, respectively. The percentage of grafting onto silica in the graft polymerization initiated by photodecomposition of surface azo groups was much larger than that initiated by thermal decomposition. Polymer‐grafted ultrafine particles thus obtained gave a stable colloidal dispersion in good solvents for the grafted chain. © 1994 John Wiley & Sons, Inc.
Synthesis of soluble, thermosetting polymides derived from 1,4‐phenylenebis(phenylmaleic anhydride) and aromatic diamines
Authors: Moy T. M. , Konas M. , McGrath J. E. , Fields E. K.
Published: April 2003

The dianhydride monomer 1,4‐phenylenebis(phenylmaleic anhydride) was polymerized with various aromatic diamines in a one‐step solution polymerization to afford high molecular weight, soluble polyimides containing backbone phenylmaleimide structures. The polymides were soluble in amide solvents, chlorinated hydrocarbons, and tetrahydrofuran at 25°C at a concentration of 15% (w/v), displayed molecular weight distributions (Mw/Mn) of 2.0–2.2 as determined by absolute GPC and showed Tg values of 240°C and above as measured by differential scanning calorimetry. In addition, polyimide thermosets were prepared from these materials by thermal cure at 350–360°C. The crosslinked polyimides displayed Tgs 20–25°C higher than their soluble precursors, and chloroform extraction indicated gel fractions ranging from 74–100% after cure. © 1994 John Wiley & Sons, Inc.
Heat‐Resistant thermosetting polyamide and polymides with styrlpyridine segments derived from 2,2′‐(1,4‐phenylenedivinylene) bisaminoquinoline
Authors: Mikroyannidis John A.
Published: April 2003

The nitration of quinaldine by fuming nitric and sulfuric acid afforded nitroquinaldine. It was condensed with a half molar amount of 1,4‐benzenedicarbaldehyde in the presence of acetic anhydride to yield 2,2′‐(1,4‐phenylenedivinylene) bisnitroquinoline. The latter was catalytically hydrogenated to the corresponding diamine, PBAQ. The new polyamide and polymides bearing styrylpyridine segments were prepared utilizing PBAQ as starting material. In addition, a model diamide and diimide were synthesized and characterized IR and 1H‐NMR spectroscopy. Inherent viscosities of polymers ranged from 0.31 to 0.60 dl/g. Certain polymer precursors such as a bismaleimide and bisnadimide were synthesized from the reactions of PBAQ with maleic and nadic anhydride, respectively. Their curing behavior was investigated by DTA. Curing of polyamide, polyimides, and polymer precursors at 240°C for 15 h yielded crosslinked polymers. They were stable up to 329–310°C in N2 or air and afforded a char yield of 67–62% in N2 at 800°C. © 1994 John Wiley & Sons, Inc.
A highly conductive and crystalline graphite‐like polymer from 2,4‐hexadiyn‐1,6‐diol
Authors: Lee Heung Jae , Shim Sang Chul
Published: April 2003

Poly‐(2,4‐hexadiyn‐1,6‐diol) (PHDO), prepared by NbCl5/(n‐Bu)4Sn catalyzed metathesis of HDO, was pyrolyzed at various temperatures and electrical and structural properties of resulting polymers were investigated by FT‐IR, Laser Raman, CP/MAS 13C‐NMR and X‐ray diffraction methods. The polymer obtained by pyrolysis of PHDO at 800°C showed a conductivity of about 10 S/cm at room temperature. The structure of the polymer seems to be a graphite‐like crystal consisting of condensed aromatic layers. © 1994 John Wiley & Sons, Inc.
Hydroquinone oxidation catalyzed by pyridine–Cu(II) complexes attached to polyorganosiloxane. II. Elucidation of factors related to catalytic activity
Authors: Nemoto Nobukatsu , Ishii Hiroji , Ihara Manabu , Takamiya Nobuo , Ikeda Koji
Published: April 2003

The oxidation of hydroquinone catalyzed by pyridine‐Cu(II) complexes attached to polyorganosiloxane was investigated in the mixed solvent of methanol/water (vol. ratio 2/1). The catalytic oxidation followed Michaelis‐Menten‐like kinetics. The large k2 term related to a turnover number indicated that the present polymeric catalysts have a remarkable effect on the activation process. The methylene number between the side‐chain acid amido and pyridyl groups of the polymeric ligand was shown to be closely related to the appearance of hydrophobic effects in both the substrate‐binding and the activation processes as deduced from the Michaelis constant and the thermodynamic and activation parameters. The binding parameters for 4‐methoxyphenol with pyridyl‐functionalized polyorganosiloxanes supported that the flexible backbone is also effective in the oxidation of hydroquinone. The Cu(II) complexes with pyridyl‐functionalized polyorganosiloxane would have the structures distorted from square planar formation, which would promote the reduction of Cu(II) to Cu(I), as concluded from ESR spectroscopy and electrochemical measurement. © 1994 John Wiley & Sons, Inc.
Acyclic diene metathesis (ADMET) depolymerization of functionalized furan‐based polymers
Authors: Viswanathan T. , Gomez F. , Wagener K. B.
Published: April 2003

Acyclic dience metathesis (ADMET) depolymerization of functionalized furan‐based polymers prepared via aqueous ring‐opening polymerization of 7‐oxanobornenes has been investigated. Results indicate that while very high molecular weight poly [exo‐N‐methyl‐7‐oxabicyclo [2.2.1] hept‐2,5‐diene‐2,3‐dicarboximide] can be depolymerized to oligomers with ease, poly [2,3‐dicarbomethoxy‐7‐oxabicyclo [2.2.1] hept‐2,5‐diene] is more resistant to depolymerization under similar conditions. This difference may be due to differential interaction of the carbonyls in the side chains with the metal atom of the catalyst in the proposed metallacyclobutane intermediate. ADMET depolymerization of poly [2,3‐bis (trifluoromethyl)‐7‐oxabicyclo [2.2.1] hept‐2,5‐diene] was feasible, however, the extent of depolymerization was decreased due to the use of a coordinating solvent (THF) used during the depolymerization process. © 1994 John Wiley & Sons, Inc.
A comparative study of the silent discharge treatment of saturated and unsaturated hydrocarbon polymers
Authors: Greenwood O. D. , Tasker S. , Badyal J. P. S.
Published: April 2003

Dielectric barrier air discharge treatment of polyethylene, polypropylene, polyisobutylene, polystyrene, and polyisoprene substrates has been characterized by x‐ray photoelectron spectroscopy (XPS). The relative reactivities of these polymers towards silent discharge oxidation are rationalized in terms of ozone molecules interacting with an excited surface. © 1994 John Wiley & Sons, Inc.
Efficiency of radiation‐induced main‐chain scission of poly (methyl methacrylate) depends on the irradiation temperature because of coexisting monomer
Authors: Ichikawa Tsuneki , Oyama Ken‐ichi , Kondoh Tatsu , Yoshida Hiroshi
Published: April 2003

Effect of irradiation temperature on the main‐chain scission of poly (methyl methacrylate) (PMMA) caused by γ‐irradiation was studied by means of gel permeation chromatography and ESR spectroscopy. Although no temperature dependency was observed on the scission efficiency for purified PMMA, the efficiency for crude or monomer‐doped purified PMMA was decreased by decreasing the temperature below ca. 200 K. Above 200 K the efficiency was constant and did not depend on the purity of PMMA. ESR study of the irradiated PMMA revealed that the suppression of the scission below 200 K is induced by the addition of methyl methacrylate monomer to primary radical species, which otherwise cause the main‐chain scission by warming the polymer above 200 K. The primary radical generated above 200 K immediately converts to the scission‐type  CH2  Ċ(CH3) COOCH3 radical through the β‐scission of the polymer main chain, so that the efficiency of the scission does not depend on both the impurity and the irradiation temperature. © 1994 John Wiley & Sons, Inc.
Synthesis of poly(biphenylene ketone)s via palladium catalyzed cross‐coupling reactions with ketone diacetals
Authors: Bochmann Manfred , Lu Jianjun
Published: April 2003

Dibromobenzophenone diacetals (BrC6H4)2C(OR)2 undergo cross‐coupling reactions with (Bu3SnC6H4)2O in the presence of palladium catalysts to give poly (diacetal ether)s whose molecular weights reflect the solubility changes of the growing polymer chains as a function of the diacetal precursors, R = Me < 1/2 CH2CH2 < 1/2 CH2CHMe and are significantly higher than those of polymers derived from dibromobenzophenone. New di‐zinc reagents based on diacetal derivatives were synthesized and used as organometallic coupling reagents with a range of dibromoarenes, resulting in a series of previously inaccessible poly (biphenylene ketone)s and poly (biphenylene ketone sulfone)s. While poly (biphenylene ether ketone)s are insoluble, poly (biphenylene ketone)s readily dissolve in concentrated sulfuric acid. The effects of reaction parameters on the molecular weight of poly (biphenylene ketone) were determined. © 1994 John Wiley & Sons, Inc.
Annealing effects on the thermal properties of liquid crystalline polyurethanes
Authors: Szczepaniak Barbara , Frisch Kurt C. , Penczek Piotr , Rudnik Ewa
Published: April 2003

This work is a continuation of our earlier investigations of liquid crystalline polyurethanes prepared from 4,4′‐bis(2‐hydroxyethoxy) biphenyl (BHBP), 2,4‐tolylene diisocyanate (TDI), and poly (oxytetramethylene) diols (PTMO). The annealing effects on the thermal properties of the investigation polyurethanes are presented for three samples with the same BHBP content, different flexible spacer length, and different molecular weight of the polyurethanes. The annealed polyurethanes were investigated by means of DSC, and polarizing microscopy. The results of the thermal analysis show that the temperatures of phase transitions depend on the annealing temperature and time. These dependences are different for different molecular weights. © 1994 John Wiley & Sons, Inc.
Thermodynamic characterization of interpenetrating polymer networks of poly (carbonate‐urethane) and poly (methyl methacrylate)
Authors: Privalko V. P. , Azarenkov V. P. , Baibak A. V. , Korskanov V. V. , Frisch H. L. , Zhou P.
Published: April 2003

Crosslinked poly (methyl methacrylate) and poly (carbonate‐urethane) as well as full interpenetrating network on their base (IPN) were characterized by precise heat capacity measurements in the temperature interval 1.2–150 K. As judged by the positive sign of the excess Gibbs free energy in the whole temperature interval above 30 K, the apparently single‐phase state of IPN is thermodynamically unstable; however, its kinetic stability is ensured by permanent chamical crosslinks prohibiting the incipient phase separation. © 1994 John Wiley & Sons, Inc.
Reactivity and catalytic activity of cationic lonomers for the nucleophilic substitution reactions
Authors: Ohtani Noritaka , Nakaya Makoto , Shirahata Kenji , Yamashita Tsuyoshi
Published: April 2003

Polystyrene‐based crosslinked cationic ionomers containing ammonium or phosphonium chlorides (AxRCI and PxBuCI) were reacted with decyl methanesulfonate. The kinetic data were correlated with the swelling behavior of the ionomers and the solution viscosity of the corresponding linear ionomers. The reactivity of the ionomers was independent of the particle size of the ionomer beads, indicating no diffusion control of the reaction. The solvent and the ion content of the ionomers greatly affect the reactivity. In nonpolar solvents with a low acceptor number, AN, such as toluene, the aggregation of ionic groups with an increasing ion content reduces the reactivity. A solvent with a high value of AN, such as chloroform, led a very low reactivity independent of the ion content. Aprotic polar solvent, such as acetonitrila, promoted the dissociation of the ionic groups and furnished a relatively high reactivity independent of the ion content. Several catalytic substitution reactions were carried out under liquid‐solid‐solid triphase conditions. The kinetic results were accounted for in terms of slow nucleophile transport and fast chemical reaction within the ionomer particles. © 1994 John Wiley & Sons, Inc.
Acid catalyzed fullerenation of carbazole polymer
Authors: Thomas Rhys N.
Published: April 2003

A new homogeneous fullerenated carbazole polymer has been synthesized, revealing a new substitution pattern for carbazole and a new photodecomposition‐resistant substitution pattern for fullerenes. The synthetic method may be accomplished in one pot via acid catalyzed alkylation. The new polymer has several unusual photovoltaic, charge storage, and photoconductivity capabilities. © 1994 John Wiley & Sons, Inc.
Preparation of polymers with substituted allyl end group using dimer of α‐methylvinyl monomer as addition fragmentation chain transfer agent at high temperatures
Authors: Yamada Bunichiro , Tagashira Shinji , Aoki Shuzo
Published: April 2003

The dimerization of methyl methacrylate, ethyl methacrylate, methacrylonitrile, and α‐methylstyrene to 2‐substituted‐1‐allylic compounds [CH2C(X)CH2C(CH3)2X] (X = COOR, C6H5, or CN), and methyl α‐ethylacrylate to a 3‐substituted‐2‐allylic compound [CH3CHC(COOCH3)CH2C(CH3)(C2H5) COOCH3] was carried out by catalytic chain transfer using benzylbis (dimethylglyoximato) (pyridine) cobalt (III). These dimers were then used as addition‐fragmentation chain transfer agents in the polymerizations of methyl methacrylate and styrene at 800C or above. Cross‐dimers from methacrylic ester‐α‐methylstyrene and methacrylonitrile‐α‐methylstyrene mixtures were similarly prepared. Except for those from methyl α‐ethylacrylate and methacrylonitrile, all the dimers participated in the addition‐fragmentation and the copolymerization to different extents. The dimer of methyl α‐ethylacrylate was actually inactive during the styrene and methyl methacrylate polymerizations. The methacrylonitrile dimer was primarily incorporated in the polymer chain through copolymerization. Among the dimer and the cross‐dimers from α‐methylstyrene with the other monomers, those bearing the α‐methylstyrene moiety in the α‐substituent [CH2C(X)CH2C(CH3)2C6H5, XCOOCH3, COOC2H5, and CN] are noted as highly reactive chain transfer agents. © 1994 John Wiley & Sons, Inc.
Synthesis and photochemical properties of solar energy storage‐exchange polymers containing pendant norbornadiene moieties
Authors: Nishikubo Tadatomi , Kameyama Atsushi , Kishi Katsuhiko , Mochizuki Yasushi
Published: April 2003

New photoresponsive polymers 1–4 containing pendant norbornadiene (NBD) moieties with N,N‐disubstituted amide groups were synthesized with 97, 98, 92, and 94% conversions by the substitution reaction of poly (p‐chloromethyl) styrene] with potassium salts of 3piperidyloxo‐2,5‐NBD‐2‐carboxylic acid, 3‐(NN‐dipropylcarbamoyl) ‐2,5‐NBD‐2‐carboxylic acid, 3‐(N‐methyl‐N‐phenylcarbamoyl)‐2,5‐NBD‐2‐carboxylic acid, and 3‐(N,N‐dipheylcarbmoyl)‐2,5‐NBD‐2‐carboxylic acid, respectively, using tetrabutylammonium bromide as a phase transfer catalyst for all. Polymers 1–4 with N,N‐disubstituted amide groups on the NBD moieties were sensitized by adding appropriate photosensitizers such as Michler's ketone and 4‐ (N,N‐dimethylamino) benzophenone in the film state, although the reactivities of the polymers without photosensitizer were lower than that of our previously reported polymer 5 containing pendant 3‐ (N‐phenylcarbamoyl) ‐2,5‐NBD‐2‐carboxylate moiety. It was also found that the photo‐irradiated retaining polymers 1–4 containing the corresponding QC moieties can be stored about 80–86 kJ/mol of their thermal energy. © 1994 John Wiley & Sons, Inc.
Synthesis and characterization of novel organonickel–organosilicon alternating copolymers
Authors: Guo X. Andrew , Hunter Allen D. , Chen Jie
Published: April 2003

The synthesis and characterization of five novel organonickel‐organosilicon alternating copolymers having the repeating unit C6F4Ni‘PBu3’2C6F4SiR2 [where SiR2 = SiMe2, SiMe‘Hex’, SiPh2, SiMe2OSiMe2, and SiMe2‘CH2’6SiMe2] are reported. The model compounds Ni‘PR3’2‘1,4‐C6F4SiMe3’2‘PR3 = PMePh2 or PBu3’ were prepared via reactions of Ni‘PR3’2‘1,4‐C6F4Li’2 with 2 equiv of SiMe3Cl, and were characterized by conventional analytical and spectroscopic measurements. The Polymers were prepared from the reactions of Ni‘PBu3’2‘1,4‐C6F4Li’2 with 1 equivalent of SiMe2Cl2 ‘polymer 1, Mw = 15,800’, SiMe ‘Hex’ Cl2 ‘polymer 2, Mw = 7300’, SiPh2Cl2 ‘polymer 3, Mw = 8600’, O‘SiMe2Cl’2 ‘polymer 4, Mw = 13,900’ and ‘CH2’6‘SiMe2Cl’2 ‘polymer 5, Mw = 19,700’. The molecular weights for each polymer were fully determined by both GPC and VPO. The multinuclear ‘1H‐, 19F‐, and 31P [1H]’‐NMR, FTIR, and UV‐Visible spectroscopic data for each polymer unambiguously establishes its repeating unit structure. The observations indicate that introduction of the silyl or siloxane units into the organonickel backbones has remarkably decreased the chain rigidity of the organonickel‐organosilicon polymers compared to their rigid rod organonickel analogues ‘i.e., [C6F4Ni‘PR3’2]n’. © 1994 John Wiley & Sons, Inc.
Kinetics for the catalyzed formation of poly(ethylene 2,6‐naphthalate) (PEN) by various metal compounds
Authors: Park Sang Soon , Im Seung Soon , Kim Dong Kook
Published: April 2003

The catalyzed transesterification between dimethyl 2,6‐naphthalate and ethylene glycol and polycondensation of bis (2‐hydroxyethyl) naphthalate have been investigated in the presence of various metal compounds as catalysts. The effect of the nature and concentration of these catalysts on both reactions has been studied. The observed overall rate of the transesterification was third order; first order with respect to dimethyl 2,6‐naphthalate, ethylene glycol, and the catalyst including initial concentration of catalyst, respectively. The decreasing order in catalytic activity on the transesterification was the order of Pb(II) > Zn(II) > Mn(II) > Co(II) > Ti(IV) > Sn(II) > Mg(II) > Ca(II) > Na(I) > Sb(III). And also, the decreasing order in catalytic activity on the polycondensation was found to be Ti(IV) > mixtures of Ti(IV) and Sb(III) > Sn(II) > Sb(III) > Co(II) > Zn(II) > Pb(II) > Mn(II) > Mg(II). © 1994 John Wiley & Sons, Inc.
Polyamides based on diamines and N, N′‐dimethyldiamines derived from biphenol
Authors: McCarthy T. F. , Lenz R. W. , Kantor S. W.
Published: April 2003

Aromatic‐aliphatic polyamides containing a biphenyl mesogen were prepared by both interfacial and solution polymerization reactions. Substitution of the amide nitrogen with methyl groups yielded polymers with significantly different properties than the unsubstituted polyamides. The methyl‐substituted polyamides had improved thermal stability, significantly lower meltin temperatures, and greater solubility in common solvents. Copolyamides were also synthesized which contained different flexible spacer units that varied in the number of methylene groups. No evidence for the presence of liquid crystalline phases could be obtained in either the unsubstituted polyamides or polyamides containing N‐methylated amide units. © 1994 John Wiley & Sons, Inc.
Synthesis, characterization, and polymerization of propenyl ether analogues
Authors: Crivello J. V. , Carter A. M. , Bratslavsky S. A.
Published: April 2003

A series of aromatic monomers bearing cationically polymerizable propenyl groups were prepared and characterized using the readily available starting materials: isoeugenol and o‐allyl phenol. Monomers with both propenyl and vinyl ether functional groups were also synthesized by the reaction of these starting materials with chloroethyl vinyl ether. The reactivity of the resulting monomers in photoinitiated cationic polymerization was studied using differential scanning photocalorimetry and photogel point measurements. Their thermal properties were determined using thermogravimetric analysis. © 1994 John Wiley & Sons, Inc.
Synthesis and characterization of random semi‐flexible thermotropic liquid crystalline poly(ester‐imide)s
Authors: Adduci Jerry M. , Facinelli John V. , Lenz Robert W.
Published: April 2003

A series of novel poly(ester‐imide)s were prepared by the reaction of meta‐ and para‐substituted trimellitimide dicarboxylic diacid chlorides with various diols containing four, five, six, seven, eight, nine, 10, and 12 methylene groups by a solution polymerization technique utilizing refluxing 1,2,4‐trichlorobenzene as a solvent. The poly(ester‐imide)s were characterized by dilute solution viscosity, infrared spectroscopy, differential scanning calorimetry, and polarized light microscopy. The inherent viscosities of the meta‐substituted poly(ester‐imide)s ranged from 0.06 to 0.25 dL/g while those of the para‐substituted poly(ester‐imide)s ranged from 0.10 to 0.65 dL/g and were obviously of higher molecular weight. The meta series were amorphous and showed no mesophase formation. All para‐substituted poly(ester‐imide)s exhibited monotropic mesophase identified as smecticAorder. © 1994 John Wiley & Sons, Inc.
Copolymerization of ethylene and 1‐butene with highly active Ticl4/THF/Mgcl2, Ticl4/THF/Mgcl2/SiO2, and TiCl3.1/3AlCl3 catalysts
Authors: Kim Jae Ha , Jeong Young Tae , Woo Seong Ihl
Published: April 2003

Highly active catalysts for copolymerization have been prepared by the precipitation of MgCl2/ToCl4 complex with or without high surface area silica. Copolymerization of ethylene and 1‐butene has been tested by using the prepared catalysts at various concentrations of 1‐butene. The catalytic activities are 20–80 kg/g Ti h. The rate of copolymerization is strongly affected by the addition of 1‐butene. The decay rate of copolymerization is first order with respect to time. Analyses of copolymers with solvent extraction, DSC, IR, XRD, and NMR were performed. Ethylene reactivity ratio (k11) for TiCl4/MgCl2/THF catalyst is calculated to be about 26 by NMR spectrum. © 1994 John Wiley & Sons, Inc.
Synthesis of poly (ether‐sulfone‐amide)s by palladium‐catalyzed polycondensation of aromatic dibromides containing ether sulfone structure, aromatic diamines, and carbon monoxide
Authors: Ueda Mitsuru , Yokoo Takayoshi , Nakamura Takeo
Published: April 2003

A general method for the preparation of aromatic poly (ether‐sulfone‐amide)s has been developed. Polymerization is based on the palladium‐catalyzed polycondensation of aromatic dibromides containing ether sulfone structural units, aromatic diamines, and carbon monoxide. Reactions were carried out in N, N‐dimethylacetamide (DMAc) in the presence of palladium catalyst, triphenylphosphine, and 1,8‐diazabicyclo [5,4,0]–7–undecene (DBU), and gave a series of poly (ether‐sulfone‐amide)s with inherent viscosities up to 0.86 dL/g under mild conditions. The polymers were quite soluble in strong acids, dipolar aprotic solvents, and pyridine. Thermogravimetry of the polymers showed excellent thermal stability, indicating that 10% weight losses of the polymers were observed in the range above 470°C in air. The glass transition temperatures of the polymers were around 230°C, which are higher than those of poly (ether‐sulfone) analogues. These polymers also showed the good tensile strengths and tensile modulus. © 1994 John Wiley & Sons, Inc.
Alkali metal ion conductors based on sulfonated poly(p‐phenylene terephthalamide)
Authors: Foo Conrad , Kwei T. K. , Okamoto Yoshi , McBreen James , Lee H. S.
Published: April 2003

To obtain thermally stable and mechanically strong sodium and lithium conducting polymers, we prepared Na+ and Li+ poly(phenylene terephthalamide sulfonate salts) (MW ∼ 5500). We also synthesized oligo(ethylene oxide) (3, 5, or 7 units of ethylene oxide) substituted ethylene carbonate and poly[oxymethylene‐oligo(oxyethylene)]. These are high boiling point liquids with high dielectric constants as well as metal chelating properties. Polyelectrolyte systems were prepared by mixing Na+ or Li+ poly(phenylene terephthalamide sulfonate) salts with various amounts of modified ethylene carbonate and/or poly[oxymethylene‐oligo(oxyethylene)]. Films (0.1–0.5 mm thick) obtained from the blends were found to have considerable mechanical strength; forming free standing films. The ionic conductivities of the Na+ and Li+ polyelectrolyte systems were 10−6−10−5 S/cm at 25°C. Thermal properties of these blend systems were investigated in detail. © 1994 John Wiley & Sons, Inc.
Study on the thermotropic liquid crystalline polycarbonates. IV. Synthesis and properties of liquid crystalline poly(imide‐carbonate)s
Authors: Sun Shih–Jieh , Chang Teh–Chou
Published: April 2003

Two series of novel thermotropic liquid crystalline poly(imide‐carbonate)s were prepared by melt polycondensation from various arylene or alkylene bis(phenylcarbonate)s by using N,N′‐bis(hydroxyethyl)pyromellitimide and N,N′‐bis(hydroxypropyl)pyromellitimide as monomers. Thermotropic liquid crystalline properties were characterized by a polarizing microscope with a heating stage and a differential scanning calorimeter (DSC). Nematic melts were found for the synthesized aromatic poly(imide‐carbonate)s. In order to investigate whether the pyromellitimide unit could be used as a mesogenic unit for preparing LC polymers, a series of aliphatic poly(imide‐carbonate)s was prepared in this study. However, no significant LC textures were found under the observation by polarizing microscope. It was suggested that the aspect ratio of the pyromellitimide unit was too short to form liquid crystalline poly(imide‐carbonate)s. In addition, it was interesting that the aliphatic poly(imide‐carbonate)s with a longer spacer (n = 3) in the pyromellitimide unit showed better crystallinity. Thermostabilities of all synthesized poly(imide‐carbonate)s were measured by thermogravimetric analysis (TGA). © 1994 John Wiley & Sons, Inc.
Synthesis of polytitanosiloxanes and their transformation to SiO2–TiO2 ceramic fibers
Authors: Gunji Takahiro , Sopyan Iis , Abe Yoshimoto
Published: April 2003

A one‐pot synthesis of polytitanosiloxanes (PTS) and its transformation to SiO2–TiO2 ceramic fibers were investigated. PTS was prepared by the hydrolysis of tetraethoxysilane followed by the reaction with bis(2,4‐pentanedionato)titanium diisopropoxide in methanol in 33–95 SiO2 mol %. PTS was considered to be a ladder‐ or sheet‐type polymer consisting of SiOSi and SiOTi linkages as a main chain with pendant hydroxyl and 2,4‐pentanedionato groups. SiO–TiO ceramic fibers were prepared by the pyrolysis of SiO2–TiO2 precursor fibers, which were prepared by the dry spinning of PTS followed by steam treatment. The tensile strength was 610 MPa for the SiO2–TiO2 fibers (SiO2/TiO2 = 20) after the pyrolysis at 7000C. © 1994 John Wiley & Sons, Inc.
The interaction of poly(methacrylate) radicals with diphenyldiacetylenes
Authors: Canizal Gerardo , Burillo Guillermina , Muñoz Eduardo , Gleason Roberto , Ogawa Takeshi
Published: April 2003

The free radical polymerization of methyl methacrylate (MMA) in the presence of p,p′‐ disubstituted diphenylbutadiynes was studied. Both the rate and degree of polymerization are somewhat lowered by the presence of the diynes, but the propagating radicals were stabilized giving clear ESR signals of the interacted polyMMA radicals at the polymerization temperature of 70°C. The magnitude of the interaction depended on the electron density of the diynes; in the cases of diphenylbutadiyne and dimethoxycarbonyldiphenylbutadiyne, the intoraction was more enhanced showing ESR signals with smaller spectra widths and increasing the number of radicals with the polymerization time, while in the cases of electron donor‐substituted diynes the interaction was weaker and the radical concentration remained constant during the polymerization. These systems are considered to be examples of the stabilization of transient radicals by the direct interaction of radicals with additives without formation or breaking of chemical bonds. No diacetylenic group was found in the polyMMA obtained. © 1994 John Wiley & Sons, Inc.
A novel catalyst system for the production of polyacetylene and of blends of polyacetylene with some silicon‐containing polymers
Authors: Graczyk Tomasz , Harrod John F.
Published: April 2003

Dimethyltitanocene, in conjunction with a wide variety of compounds containing SiH bonds, is an excellent catalyst for the polymerization of acetylene to give free standing films. Polymerizations of acetylene in a variety of siloxane and silane matrices using this catalyst system are described. The polyacetylenes produced with a [(MeSiHO)3(Me2Si)17]n random copolymer showed very similar properties to those previously produced by Naarman et al. with a Shirakawa‐type catalyst in a polydimethylsiloxane matrix. Ring, or chain, poly(methylhydrosiloxanes) with higher proportions of (MeSiHO) undergo redistribution in the course of acetylene polymerization to give polyacetylene embedded in an insoluble polysiloxane glass. Polyacetylene produced in a poly(phenylsilane) matrix yielded a 2‐component material from which the polysilane could not be solvent extracted. The electrical conductivity of iodine doped samples of this material is somewhat lower than that of the pure polyacetylene, but its mechanical properties and its resistance to degradative oxidation are superior to those of either of the pure component polymers. © 1994 John Wiley & Sons, Inc.
Temperature dependence of the interaction between water and sodium polymethacrylate in water–methanol mixture
Authors: Kim Hyun Gi , Jhon Mu Shik
Published: April 2003

The information for the interaction between water molecules and a polyelectrolyte was obtained from 23Na‐NMR studies for sodium polymethacrylate in water‐methanol mixtures. The chemical shift and the line width of the 23Na nucleus give the information on the immediate magnetic environment and the motion of the nucleus, respectively. The change of the chemical shift for 23Na nucleus is investigated by decreasing the temperature and changing the mol fraction of water in the solvent. According to these results, the hydrogen bonding of water molecules and polyanions becomes weaker as the temperature of the system decreases, but the interaction increases when the temperature is below the freezing point for water in this system. This effect, due to the change of temperature, becomes higher as the water mol fraction increases in the solvent. © 1995 John Wiley & Sons, Inc.
Synthesis of cross‐conjugated polyketones by the crossed‐aldol condensation of cyclic ketones with aromatic dialdehydes
Authors: Hudson Lilith Gentles , Stevens Malcolm P.
Published: April 2003

Insoluble cross‐conjugated polyketones were prepared from terephthalaldehyde and a variety of cycloaliphatic ketones by the crossed‐aldol condensation. Elemental analyses and infrared spectra suggest that the polymeric aldol intermediates were not completely dehydrated. Evidence is also presented that suggests conjugate addition of the base to the α,β‐unsaturated ketone may occur. Soluble cross‐conjugated polyketones were prepared from terephthalaldehyde and 2‐indanone, which contains no beta hydrogens, and from cycloaliphatic ketones and 1,2‐bis(4‐formylphenoxy)ethane, a dialdehyde containing isolated aldehyde groups. It is proposed, therefore, that the lack of solubility in the terephthalaldehyde‐based polyketones arises from crosslinking via enolate anions formed at the beta position of the cyclic ketones, which are delocalized through the carbonyl groups of neighboring backbone repeating units. © 1995 John Wiley & Sons, Inc.
Reactivity ratios and microstructure determination of vinyl acetate–alkyl acrylate copolymers by NMR spectroscopy
Authors: Brar A. S. , Charan Shiv
Published: April 2003

(Vinyl acetate)/(ethyl acrylate) (V/E) and (vinyl acetate)/(butyl acrylate) (V/B) copolymers were prepared by free radical solution polymerization. 1H‐NMR spectra of copolymers were used for calculation of copolymer composition. The copolymer composition data were used for determining reactivity ratios for the copolymerization of vinyl acetate with ethyl acrylate and butyl acrylate by Kelen‐Tudos (KT) and nonlinear Error in Variables methods (EVM). The reactivity ratios obtained are rv = 0.03 ± 0.03, rE = 4.68 ± 1.70 (KT method); rv = 0.03 ± 0.01, rE = 4.60 ± 0.65 (EV method) for (V/E) copolymers and rv − 0.03 ± 0.01, rB − 6.67 ± 2.17 (KT method); rv = 0.03 ± 0.01, rB = 7.43 ± 0.71 (EV method) for (V/B) copolymers. Microstructure was obtained in terms of the distribution of V‐ and E‐centered triads and V‐ and B‐centered triads for (V/E) and (V/B) copolymers respectively. Homonuclear 1H 2D‐COSY NMR spectra were also recorded to ascertain the existence of coupling between protons in (V/E) as well as (V/B) copolymers. © 1995 John Wiley & Sons, Inc.
119Sn‐NMR evidence for 2,1‐initiation in the anionic polymerization of butadiene with trialkyltin lithium
Authors: Hergenrother William L. , Doshak John M. , Brumbaugh Dennis R. , Bethea Tristram W. , Oziomek James
Published: April 2003

Low molecular weight polybutadienes and styrene butadiene copolymers were anionically prepared with trialkyltin lithium initiator and end‐capped with either hydrogen or a trialkyltin group. These polymers were prepared with a variety of microstructures. Analysis by 119Sn‐NMR and comparison to model compounds showed no cis‐1,4‐initiation of the butadiene. The initiation sites found were trans‐1,4‐ and both 2,1‐ and 1,2‐additions of the tin‐lithium bound to a 1,3‐butadiene. At low levels of added polar modifier, the 2,1‐addition predominated. The 119Sn‐NMR spectra allowed the assignment of the sequence distribution associated with the nearest eight main chain carbon atoms (2‐4 monomer units) adjacent to the tin end groups. No initiation could be detected involving the styrene comonomer, but incorporation of styrene was detected as the first or second unit after initiation. The reaction of the allyl‐tin end groups of these polymers with 1,2‐napthoquinone was followed by NMR and was used to assign the peaks associated with 1,2‐addition of the trialkyltin lithium to 1,3‐butadiene. © 1995 John Wiley & Sons, Inc.
Poly(p‐Phenylenebenzobisoxazole) fiber with polyphenylene sulfide pendent groups
Authors: So Ying‐Hung , Bell Bruce , Heeschen Jerry P. , Nyquist Richard A. , Murlick Cheryl L.
Published: April 2003

Poly(p‐phenylenebenzobisoxazole) (PBO) fiber with polyphenylene sulfide (PPS) pendent groups was made to improve PBO fiber compressive strength by crosslinking. PPS moieties allowed the polymeric network to crosslink at heat‐treatment temperatures at which PBO does not thermally degrade. PBO‐PPS fiber heat‐treated for 30 s at 600°C did not dissolve or break up in methanesulfonic acid. Compressive strength of crosslinked fiber was about 20% better than that of unmodified PBO fiber. In another experiment, 10 mol % of 2,5‐diphenylsulfideterephthalic acid was incorporated into PBO fiber. The side chain of one phenyl sulfide unit was too short to enhance crosslinking, and the fiber had about the same compressive strength as unmodified PBO fiber. © 1995 John Wiley & Sons, Inc.
Synthesis and characterization of segmented liquid crystal poly(azoxy polyester‐co‐polyoxypropylene)
Authors: Huang Jaine‐Ming , Kuo Jen‐Feng , Chen Chuh‐Yung
Published: April 2003

In this study a series of a segmented copolyester, poly(4,4′‐dioxy‐2,2′‐dimethyl‐azoxybenzene dodecanedioyl) (PMABD)‐co‐polyoxypropylene 400 (POP), was prepared. The chain length of PMABD studied (n) was varied from 7.8‐18.2, and that of POP was unchanged. The intrinsic viscosity of the segmented copolyesters was 1.04‐1.30, and the number average molecular weight obtained was 2.53 × 104−3.49 × 104 g/mol. The mesophase texture and thermal properties of the segmented copolyesters were measured as functions of n. It was found that the insert of flexible POP between those liquid crystalline domains of PMABD did affect thermotropic properties of PMABD. As the n value was 9.0 and 7.8 (or 7.4 and 8.6% by weight POP) the texture appeared as cholesteric‐like oily streaks. The effect could not be attained by simply copolymerizing a mesogenic moiety with a pair of spacers of different lengths. The fluidity and domain structure of the flexible dodecanedioyl‐POP‐dodcanedioyl segments are taken into account for the obtained results. © 1995 John Wiley & Sons, Inc.
Characterization of a melt processable liquid crystal copolyester
Authors: Thammongkol Vivan , Warner Steven B. , Polk Malcolm B.
Published: April 2003

Poly[oxy(2‐methyl‐1,4‐phenylene)oxyterephthaloyl‐co‐oxymethylene‐1,4‐cyclohexylene‐methyleneoxyterephthaloyl] was synthesized using a solution‐based process. This copolyester has cyclohexylene dimethylene as a semi‐rigid spacer along the polymer main chain to interrupt the inherent rigidity of the system while preserving the mesogenicity of the macromolecules. Polymer characterization includes elemental analysis, Fourier transform infrared spectroscopy, nuclear magnetic resonance, hot‐stage polarized light microscopy, wide‐angle x‐ray diffraction, dilute solution viscometry, differential scanning calorimetry, and thermogravimetric analysis. This copolyester shows nematic liquid crystalline behavior in polarized light above about 240°C. The intrinsic and inherent viscosities are 0.88 and 0.68 dL/g respectively. The observed melting temperature of this copolyester is about 265°C, but melting begins as low as 215°C, making the polymer readily melt‐processable. The degradation temperature is about 340°C under a nitrogen atmosphere. © 1995 John Wiley & Sons, Inc.
Wholly aromatic thermotropic liquid crystalline polyesters of 4,4′‐biphenol, substituted biphenols, and 1,1′‐binaphthyl‐4,4′‐diol with 3,4′‐benzophenone dicarboxylic acid
Authors: Han Haesook , Bhowmik Pradip K.
Published: April 2003

Wholly aromatic, thermotropic homopolyesters, derived from 4,4′‐biphenol, substituted biphenols, or 1,1′‐binaphthyl‐4,4′‐diol and 3,4′‐benzophenone dicarboxylic acid, and two copolyesters, each of which contained 30 mol % of 6‐hydroxy‐2‐naphthoic acid, were prepared by acidolysis polycondensation reactions and characterized for their liquid crystalline properties. The solubility behavior of these polymers has also been investigated. The two homopolymers of phenyl‐substituted biphenols with 3,4′‐benzophenone dicarboxylic acid were soluble in many common organic solvents. All of the homopolymers had lower Tm/Tf values than those with terephthalic acid, which was attributed to the incorporation of the asymmetric 3,4′‐benzophenone dicarboxylate units in a head‐to‐head and head‐to‐tail fashion along the polyester chain. Two copolymers had lower Tm values than those of the respective homopolymers, as expected. They formed nematic phases which persisted up to 400°C, except those of phenyl‐substituted biphenols with 3,4′‐benzophenone dicarboxylic acid. Each of these two polymers also exhibited an accessible Ti transition, and had a broad range of LC phase. They had glass transition temperatures, Tg, in the range of 139‐209°C and high thermal stabilities in the temperature range of 465‐511°C. © 1995 John Wiley & Sons, Inc.
Microgel formation in the free radical crosslinking polymerization of ethylene glycol dimethacrylate (EGDMA). I. Experimental
Authors: Chiu Y. Y. , Lee L. James
Published: April 2003

An important feature of free radical crosslinking polymerization of ethylene glycol dimethacrylate (EGDMA) resin is the formation of heterogeneous structure through intramolecular reaction. Such structure formation affects not only the cure behavior and rheological changes of the resin but also the physical properties of the formed polymers. In this study, the reaction kinetics, morphological changes, and characteristics of formed polymers were examined by a differential scanning calorimeter, a Rheometrics Dynamic Analyzer, a dynamic light scattering goniometer, and a Fourier transfer infrared spectrometer. Experimental data showed the formation of bimodal polymers before gelation. These polymers are partially crosslinked and can be considered as microgel particles. © 1995 John Wiley & Sons, Inc.
Polymerization of 1‐ethynylcyclohexene by tungsten and molybdenum‐based catalysts
Authors: Gal Yeong‐Soon , Jung Bal , Kim Ji‐Heung , Lee Won‐Chul , Choi Sam‐Kwon
Published: April 2003

1‐Ethynylcyclohexene, an acetylene derivative having cyclohexenyl substituent, was polymerized by various W‐ and Mo‐based catalysts. WCl6‐EtAlCl2 catalyst system was found to be very effective for this polymerization. The effects of the monomer‐to‐catalyst mol ratio, the initial monomer concentration, the temperature, and the cocatalysts for the polymerization of 1‐ethynylcyclohexene by WCl6 were investigated. The catalytic activity of Mo‐based catalysts was found to be similar to that of W‐based catalysts. The polymer structure was identified to have a conjugated polymer backbone carrying a cyclohexenyl substituent. The resulting polymers were light‐brown powder and completely soluble in aromatic and halogenated hydrocarbon solvents such as chlorobenzene, benzene, chloroform, carbon tetrachloride, etc. Studies of the thermal properties and morphology of poly(1‐ethynylcyclohexene) were also carried out. © 1995 John Wiley & Sons, Inc.
Cyanated liquid crystals withtrans‐stilbene structure: Syntheses and their cyclotrimerizations
Authors: Ou Jiunn–Chih , Hong Yen–Long , Yen Fu–Shan , Hong Jin–Long
Published: April 2003

Liquid crystalline aromatic monocyanate (M) and dicyanates (D1andD2) withtrans‐stilbene (PhCHCHPh) structure were synthesized and their cyclotrimerization reactions were studied by differential scanning calorimetry and infrared spectroscopy. MonocyanateMunderwent cyclotrimerization to yield a trimerized material with discotic properties. DicyanateD2and its cured product failed to exhibit any mesophase. In contrast, polycyclotrimerization of dicyanateD1obtained a liquid crystalline thermoset with its schlieren texture prolonged over a wide temperature range. © 1995 John Wiley & Sons, Inc.
Peroxide generation and decomposition on polymer surface
Authors: Kulik Eduard A. , Ivanchenko Maria I. , Kato Koichi , Sano Shushi , Ikada Yoshito
Published: April 2003

Polymer peroxides were generated onto polypropylene and polyurethane films, and polyester fibers by ozonization, UV irradiation, and plasma treatment. Their thermal and redox decompositions were studied using two assays: peroxidase and iodide. They may differ in the sensitivity to access the peroxides, depending on their localization in the polymer substrates. It was found that the generated peroxides are likely to be distributed not only on the outermost surface, but also in the subsurface of the polymer substrates. Plasma treatment provided polyurethane film with easily accessible peroxides, while UV irradiation and ozonization generated peroxides that were mostly incapable of reacting with aqueous solution of peroxidase. Redox decomposition of the peroxide groups by ferrous ions at 25°C showed that less than 50% of peroxides could react with ferrous ions with a rate constant similar to that of hydrogen peroxide in aqueous solution. Thermal decomposition of the peroxides did not obey the first‐order kinetics, probably due to formation of not single peroxide species with different decomposition rate constants. The lowest decomposition rate constant observed at 65°C was 3 × 10−3 min−1, which did not depend on the polymer substrate nature and the method of peroxide generation. © 1995 John Wiley & Sons, Inc.
Synthesis of high molecular weight poly(ether ketone)s by polycondensation of activated bis(aryl chloride)s with bisphenolates
Authors: Percec V. , Grigoras M. , Clough R. S. , Fanjul J.
Published: April 2003

The ability to achieve high molecular weight poly(ether ketone)s from the polycondensation of bis(aryl chloride)s with bis(phenolate)s has been consistently demonstrated. The polymerizations presented here help to delineate for specific bis(aryl chloride)/bisphenolate pairs the reaction conditions required to obtain high molecular weight polymers. Polycondensation of 1,3‐bis(4‐chlorobenzoyl)‐5‐tert‐butylbenzene (6) and 2,2′‐bis(4‐chlorobenzoyl)‐biphenyl (15) with various bisphenolates as well as of 2,2′‐bis(4‐hydroxyphenoxy)biphenyl (33) with 4,4′‐dichlorobenzophenone (41) and 1,3‐bis(4‐chlorobenzoyl)benzene (43) were used as representative model systems to select reaction conditions that led to high molecular weight polymers. © 1995 John Wiley & Sons, Inc.
Reactions on polymers with amine groups. I. Reactions of vinylpridine polymers and of their model compounds with unsaturated carboxylic acids
Authors: Bărboiu Virgil , Streba Emilia , Luca Cornelia , Simionescu Cristofor I.
Published: April 2003

The reactions of vinylpyridine polymers with α,β‐unsaturated carboxylic acids such as acrylic, methacrylic, crotonic, itaconic, cinnamic, fumaric, and maleic acids were studied. It was found that, when reacted with acrylic, itaconic and fumaric acids. poly(4‐vinylpyridine) gave macromolecular betaine products while with maleic acid, betaine as well as the corresponding salt was obtained. Poly(2‐vinylpyridine) reacted with the same acids as poly(4‐vinylpyridine) gave only the salts. No significant changes were observed with the two polymers when reacted with methacrylic, crotonic, and cinnamic acids. To attempt to rationalize these observations with the two macromolecular tertiary amines, the reactions of 4‐methyl and 2‐methylpyridines with the same carboxylic acids were investigated. The 1H‐NMR methodology was generally applied to elucidate the chemical structure obtained. © 1995 John Wiley & Sons, Inc.