bluuebunny/crossref_metadata_2025 huggingface dataset:
Low‐ and high‐molecular‐weight polyacetylenes: Synthesis, characterization, and thermal isomerization
Authors: Chien James C. W. , Schen Michael A.
Published: April 2003

Procedures for the synthesis of polyacetylene ([CH]x) with Mn (number average molecular weight) from 400 to about 106 have been developed. This probably represents the largest range of molecular weight (MW) obtainable for a given monomer by a single initiator system. The catalyst residue level in [CH]x can be significantly reduced by acidic‐methanol purification. The very low MW polymer L‐[CH]x (polyacetylenes with Mn 400–500), has the same cis crystal structure as the higher MW polymers but is less ordered along the c‐axis. It is isomerized to the trans material with apparently a more compact unit cell than high MW polymers. There is annealing of crystallite which increases the longitudinal order during thermal isomerization. This process occurs more readily and with lower activation energy in L‐[CH]x than for polymers with higher MW. Isomerization of high MW polymers tends to trap cis units which can result in degradation as evidenced by the formation of sp3 carbon vibrations in IR spectra. This is true even for L‐[CH]x after prolonged heating. The results render credence to the proposal based on anamalous resonance Raman scattering profile that there can be very short trans segments in thermally isomerized trans‐[CH]x.
Oxidation of benzyl alcohol with Fe(III) using polymers containing the nitroxyl radical structure as a mediator
Authors: Miyazawa Takeo , Endo Takeshi
Published: April 2003

Some polymers containing the nitroxyl radical structure were prepared and applied to the electron transfer agents from Fe(III) to benzyl alcohol. Benzyl alcohol was also oxidized by Fe(III) in two‐phase or tri‐phase systems using hydrophobic or hydrophilic polymers, which contain 2,2,6,6‐tetramethylpiperidine‐1‐oxyl moiety, as an electron transfer catalyst. Especially, the hydrophilic polymers accelerated the oxidation of benzyl alcohol.
Vinyl polymerization by carbon black V. Solvent effect and the kinetics of the polymerization of N‐vinylcarbazole
Authors: Haque Shah A. , Biswas Mukul
Published: April 2003

The polymerization of N‐vinylcarbazole has been carried out at 60°C under nitrogen with different grades of carbon black, N220, N110, N330, and N660 as heterogeneous catalysts. The order of efficiency of the catalysts in regard to the polymerization is: N220 > N110 > N660 > N330. Effect of solvent polarity on the polymerization has been studied with acetonitrile, 1,2‐dichloroethane, and toluene‐nitrobenzene mixtures. Nitrobenzene, with highest polarity, affords the highest rate, which decreases with decreasing nitrobenzene percentage in the solvent mixture. These features suggest the polymerization to be cationic in nature. The relative viscosities of the polymers are low, but tend to increase only slightly with increasing nitrobenzene content. The rate of polymerization can be expressed by the relation

A suitable kinetic model has been presented in conformity with the experimental findings.
Mechanism of N‐vinylcarbazole polymerization on Co(II)–13X molecular sieve
Authors: Biswas Mukul , Banerjee Madhusudan , Maiti Mrinal M.
Published: April 2003

Kinetics of polymerization of N‐vinylcarbazole over Co(II)‐13X molecular sieves in toluene have been studied. The rate of polymerization (Rp) has been found to be second order with respect to percent exchange level of Co(II) and also to the NVC concentration at all the reaction temperatures of 40, 50 and 60°C. The rate increases with decreasing pH of the original exchanging salt solution up to a pH of about 3.5, beyond which it falls. The overall activation energy of polymerization has been found to decrease with increase in monomer concentration, exchange level of Co(II), and the hydrogen ion concentration of the original exchange solution. Average degree of polymerization also follows a similar trend. A mechanism of polymerization involving simultaneous propagation on both metal ion Co(II) and proton on a zeolite surface has been suggested. The two propagation routes are characterized by an average activation energy of 10.36 kcal/mol and 5.40 kcal/mol on the metal ion and proton centers, respectively.
Direct polycondensation of hydroxybenzoic acids with diphenyl chlorophosphate in the presence of ethers
Authors: Higashi Fukuji , Yamada Yukiharu
Published: April 2003

The effects of a modification of the relative reactivity of carboxyl groups to hydroxy groups in monomers on the direct polycondensation of hydroxybenzoic acids was investigated. Polycondensation with diphenyl chlorophosphate (DPCP) was largely promoted by carrying out the reaction in the presence of ethers which are capable of complexing with carboxyl groups in the monomers. The amount of alkyl ethers, such as, poly(ethylene oxide) (PEO) corresponding to an equivalent unit mole of carboxyl groups was effectively added. The molecular weights of the polymers produced increased with the higher molecular weights of PEO, showing maximum values by use of PEO of 1–2.5 × 105.
Synthesis of polyamides from active 5,5′‐isophthaloyldithiobis‐2‐aryl‐1,3,4‐oxadiazoles and diamines under mild conditions
Authors: Saegusa Yasuo , Akano Norihiro , Nakamura Shigeo , Chau Nguyen , Iwakura Yoshio
Published: April 2003

As model compounds for determining the potential adaptability of novel leaving group to polyamide synthesis, 2‐aryl‐5‐benzoylthio‐1,3,4‐oxadiazoles having various electron accepting and donating groups in the oxadiazole unit were successfully prepared from the benzoylation of the corresponding 2‐aryl‐1,3,4‐oxadiazoline‐5‐thiones under kinetically controlled conditions ( < −50°C). The aminolyses of all the benzoyl thioesters by aniline afforded quantitative yields of benzanilide at room temperature in a short reaction time. Polycondensations of new active dithioesters, 5,5′‐isophthaloyldithiobis‐2‐aryl‐1,3,4‐oxadiazoles, with both aliphatic and aromatic diamines occured quite rapidly even at room temperature to form polyamides with reduced viscosities up to 0.41 dL/g. The reactivities of the dithioesters having electron accepting groups such as p‐chloro and p‐nitro groups, particularly p‐nitro groups, toward diamines were much higher than that of the dithioester having no such groups, but the introduction of electron donating p‐methyl group had an adverse effect. The effects of reaction conditions such as solvent, temperature, and monomer concentration on the reduced viscosity of polyamides were also investigated. It was found that monomer concentration had a remarkable influence on the molecular weight of the resulting polyamides.
On the reaction mechanism of gamma‐ray solid‐state copolymerization
Authors: Hayakawa Kiyoshi , Kawase Kaoru , Yamakita Hiromi
Published: April 2003

The gamma‐ray induced solid‐state polymerization of binary mixtures consisting of a maleimide derivative as the first component and acenaphthylene or trans‐stilbene as the second component was investigated regarding the occurrence of copolymerization. The binary solid mixture of these compounds exhibited a phase‐equilibrium diagram including a simple eutectic mixture, and the irradiation caused the formation of a random copolymer together with that of homopolymers of component comonomers. The reaction rates and the composition of products suggested that the mobility of monomer molecules in the crystals affected the solid‐state polymerization significantly. The solid‐state copolymerization was supposed to take place by the diffusion of comonomer molecules via a vapor phase to the nuclei where the copolymerization proceeded.
pH‐induced reversible permeability control of the 4‐carboxy acrylanilide‐methyl methacrylate copolymer membrane
Authors: Ishihara Kazuhiko , Muramoto Naohiro , Fujii Hideyuki , Shinohara Isao
Published: April 2003

To develop a polymer membrane whose permeability of water‐soluble compounds could be controlled in response to a pH change of the medium, a polyelectrolyte membrane containing an aromatic carboxyl group, i.e., 4‐carboxyacrylanilide (CAAn)‐methyl methacrylate(MMA) copolymer membrane, was prepared. The water content of the CAAn‐MMA copolymer membrane increased with increasing pH owing to ionization change in the CAAn moiety. This increase was particularly remarkable in the pH range from 5 to 7. The change in water content was reversible and could be controlled by the CAAn composition in the copolymer. Permeation of 1,4‐bis(2‐hydroxyethoxy)benzene(DHEB) through the CAAn‐MMA copolymer membrane was investigated in solutions of various pH. Change in the permeability of DHEB in function of the pH was similar to the change in membrane water content. This was explained by an increase in the permeation pathway of DHEB in the membrane, in proportion to that in the water content. Moreover, when a pH‐sensitive membrane was placed in a solution in which an enzymatic reaction occurred, substrate‐induced permeation control of DHEB through the CAAn‐MMA copolymer membrane was possible.
Graft copolymerization of ethyl acrylate onto gelatin using hydrogen peroxide and ascorbic acid in aqueous medium
Authors: George Anne , Radhakrishnan Ganga , Joseph K. Thomas
Published: April 2003

Gelatin a derived protein from collagen can be modified at 60°C by allowing it to react with ethyl acrylate by use of a novel initiator technique. The polymeric ethyl acrylate side chain is chemically bonded to gelatin. The effects of synthetic variable in the graft copolymerization reactions have been discussed in the light of percent grafting, grafting efficiency, and the rate of polymerization.
Functional polymers and sequential copolymers by phase‐transfer catalysis. 15. Thermotropic copolyethers based on 4,4′‐dihydroxybiphenyl, bisphenol a and 1,9‐dibromononane
Authors: Shaffer Timothy D. , Jamaludin Mustafah , Percec Virgil
Published: April 2003

Thermotropic liquid crystalline (LC) copolyethers have been synthesized from 1,9‐dibromononane, a nonmesogenic bisphenol (4,4′‐isopropylidenediphenol [BPA]) and a mesogenic bisphenol (4,4′‐dihydroxybiphenyl [HB]) by a two‐phase (organic solvent—aqueous NaOH) phase‐transfer catalyzed polyetherification. LC polyethers were obtained for copolymers containing as much as 70 mol % BPA. Optical polarizing microscopy and DSC have revealed smectic mesomorphism for all the copolyethers. The influence of both copolymer composition and microstructural changes, including the nature of the chain ends, upon the mesomorphic properties of these copolyethers have been discussed.
Permeation through homopolymer latex films
Authors: Chainey M. , Wilkinson M. C. , Hearn J.
Published: April 2003

The helium permeabilities of homopolymer films cast from polymer solutions and latex dispersions have been measured as a function of time. The permeability coefficients of most polymer latex films started off at a value which was considerably higher than that of the corresponding solvent‐cast film, but then dropped at a rate dependent on the polymer concerned. The permeability coefficients levelled off at a value which was closer to, but still higher than that of the equivalent solvent‐cast film. Solvent‐cast film permeabilities remained constant for the period of several months over which time they were examined. The reduction in the permeability of latex films is attributed to ageing processes occurring within the film after casting. The fact that latex film permeability coefficients are always higher than those of solvent‐cast films suggests that latex films never become completely homogeneous. The effect on permeability of the latex type and characteristics, and preparation and storage conditions has been examined. The polymer molecular weight, particle size, and surface‐change density did not appear to exert any influence, within experimental error. However, the time‐dependent permeability behavior was affected by the film preparation and storage temperatures.
Efficiency of polymer sensitizer in photosensitized reaction of tris(bipyridine)ruthenium(II) complex‐containing polymer
Authors: Sumi Katsuhiro , Furue Masaoki , Nozakura Shun‐Ichi
Published: April 2003

Photochemical properties of Ru(bpy)2(poly‐4‐methyl‐4′‐vinyl‐2,2′‐bipyridine)Cl2 (2) were studied and compared with that of Ru(bpy)3Cl2. Continuous irradiation of a solution, which contains polymer 2 as a photosensitizer, methylviologen (MV2+) or 4,4′‐bipyridinium‐1,1′‐bis(trimethylenesulfonate) (SPV) as an electron acceptor and triethanolamine (TEOA) as a sacrificial donor, resulted in the formation of viologen radical ion (MV+ or SPV−). The rate of formation of MV+ or SPV− for the polymer 2 system was smaller than that for the Ru(bpy)3 Cl2 systems. The reason for this fact was kinetically analyzed by quenching experiments of excited Ru(II) complexes by MV2+ or SPV, the photosensitized reactions of the TEOA–Ru(II) complex–MV2+ or ‐SPV systems, and the dye laser photolysis of the Ru(II) complex–MV2+ or ‐SPV systems.
Polymerization of styrene by photoexcited safranine T without additives
Authors: Timpe Hans‐Joachim , Neuenfeld Steffen
Published: April 2003

Styrene can be photopolymerized with methanolic solutions of safranine T(STH+) in the absence of any additives. Under these conditions the monomer acts as an electron donor for the excited singlet state of STH+, and after electron transfer an initiating semireduced STH+ radical is produced. The experimentally determined monomer exponent of α = 2 indicates additional deactivation reactions of the primary radicals. The polymerization rate depends on the dye concentration also in those regions, in which all light is already absorbed. Presumably, this dependence is caused by a comproportionation reaction between STH+ and substituted leuco‐safranine T formed in the course of polymerization. © 1993 John Wiley & Sons, Inc.
Control of particle size in dispersion polymerization of methyl methacrylate
Authors: Shen S. , Sudol E. D. , El‐Aasser M. S.
Published: April 2003

Poly(methyl methacrylate) (PMMA) particles ranging in diameter from 2 to 10 μm were prepared by dispersion polymerization. The effects of various polymerization parameters on the size and monodispersity were systematically investigated. The particle size was found to increase with increasing polymerization temperature, concentration and decomposition rate of the initiator, and solvency of the dispersion medium. It also increased with increasing concentration and molecular weight of the polymeric stabilizer, poly(vinyl pyrrolidone) (PVP). As the monomer concentration was increased from 5 to 20 wt %, a minimum was found in the particle size at a monomer concentration of 10 wt %. A costabilizer was found to be necessary for preparing monodisperse particles at stabilizer concentrations below 2 wt %. A recycling experiment showed that the consumption of PVP was quite small in each cycle and the residual materials in this system could be reused readily. © 1993 John Wiley & Sons, Inc.
Polymeric phosphonium salts as a novel class of cationic biocides. II. Effects of counter anion and molecular weight on antibacterial activity of polymeric phosphonium salts
Authors: Kanazawa Akihiko , Ikeda Tomiki , Endo Takeshi
Published: April 2003

Various poly[tributyl(4‐vinylbenzyl)phosphonium salt]s with different counter anions were prepared and their antibacterial activities against Staphylococcus aureus were explored by the viable cell counting method in sterile distilled water. Antibacterial activity was found to be affected by the structure of the counter anions. The activity was low for a counter anion which tends to form a tight ion‐pair with phosphonium ion, while it was high for those facilitating ionic dissociation to free ions. Furthermore, the molecular weight dependence of the antibacterial activity was investigated for poly[tributyl(4‐vinylbenzyl) phosphonium chloride] with various molecular weights against S. aureus. Antibacterial activity was found to increase with molecular weight. Various copolymers were prepared in which the compositional ratio of tributyl(4‐vinylbenzyl)phosphonium chloride to acrylamide, N‐vinyl‐2‐pyrrolidone, or styrene was altered, and the effect of the positive charge density on the antibacterial activity was investigated against S. aureus. Antibacterial activity of the copolymers was much higher than that of the low‐molecular‐weight model compound and enhanced with the molar fraction of the phosphonium units in the copolymers. © 1993 John Wiley & Sons, Inc.
Intra–intermolecular gel‐free cyclopolymerization of nonconjugated diene with peroxodiphosphate/different activators redox pairs
Authors: Behari Kunj , Agrawal Uma , Das Rima
Published: April 2003

Gel‐free cyclopolymerization of N,N′‐methylenebisacrylamide has been carried out using potassium peroxodiphosphate (PDP) as initiator in combination with different activators such as mercaptosuccinic acid (MSA) and thioglycollic acid (TGA) in an inert atmosphere at 45 ± 1°C and 40 ± 1°C, respectively. The rate of polymerization was found proportional to the first power of the monomer and activator concentration and the half‐power of PDP in both redox systems. A mechanism involving cyclopolymerization in the propagation path has been proposed. © 1993 John Wiley & Sons, Inc.
Polymeric phosphonium salts as a novel class of cationic biocides. III. Immobilization of phosphonium salts by surface photografting and antibacterial activity of the surface‐treated polymer films
Authors: Kanazawa Akihiko , Ikeda Tomiki , Endo Takeshi
Published: April 2003

Immobilized polycationic biocides with phosphonium salt on the surface of poly(propylene) film were prepared by surface photografting and surface antibacterial activity of the resulting films against Staphylococcus aureus and Escherichia coli was explored by the viable cell counting method. These films with phosphonium salts were found to exhibit high antibacterial activity against S. aureus and E. coli—particularly against E. coli. Furthermore, morphological changes of the cells of S. aureus and E. coli in contact with the immobilized phosphonium salt were estimated by scanning electron microscopy. It was found that the immobilized biocides exhibited surface bactericidal activity against both strains as evidenced by shrunken and deformed cells of these species in contact with the immobilized biocides. © 1993 John Wiley & Sons, Inc.
One‐phase supported titanium‐based catalysts for polymerization of ethylene. II. Effect of hydrogen
Authors: Salajka Zdenĕk , Kratochvíla Jan , Hudec Pavel , Vĕc̆orek Petr
Published: April 2003

The relation between composition of the one‐phase titanium‐based silica supported catalysts for gas‐phase ethylene polymerization, and the ability of these catalysts to control the molecular weight of polymer using hydrogen has been studied. Halogen containing alkylaluminium compounds and alkoxy groups on titanium promote the chain transfer process. A significant polymerization rate lowering effect is caused by hydrogen. However, catalyst activity fully revives after hydrogen removal from the polymerization system. The proportion of active titanium was found to be 18±4% in the presence of hydrogen, and the value of propagation rate constant (kp) was calculated to be 190±45 L/mol.s. © 1993 John Wiley & Sons, Inc.
Polymerization behavior of 1,2,2,6,6‐pentamethyl‐4‐piperidinyl m‐isopropenyl‐α,α‐dimethylbenzyl carbamate
Authors: Lau Wayne W. Y. , Lee C. S. , Lee S. Y. , Goh S. H.
Published: April 2003

Copolymers of 1,2,2,6,6‐pentamethyl‐4‐piperidinyl m‐isopropenyl‐α,α‐dimethylbenzyl carbamate (CB) with styrene (S) and with methyl methacrylate (MMA) were synthesized using AIBN as initiator. S–CB copolymers made from feed ranging from 0.45–0.94 mole fractions S and MMA‐CB copolymers made from feed of 0.34–0.88 mole fractions MMA were used to determine the monomer reactivity ratios r1 and r2. The structure of S–CB copolymers was inferred to be mainly of a random nature and in the MMA–CB copolymerization system there is a stronger tendency to form alternating copolymers. © 1993 John Wiley & Sons, Inc.
Introduction of 2‐methoxycarbonylallyl end group by copolymerization of methyl α‐(phenoxymethyl)acrylate accompanying with addition‐fragmentation reaction
Authors: Yamada Bunichiro , Kobatake Seiya , Satake Masayuki , Otsu Takayuki
Published: April 2003

Copolymerizations of methyl α‐(phenoxymethyl)acrylate (MPMA) with methyl acrylate, methyl methacrylate, styrene, and methyl α‐ethylacrylate were carried out. Addition of a polymer radical to MPMA followed by the subsequent fragmentation of poly(MPMA) radical resulted in the 2‐methoxycarbonylallyl end group and phenoxy radical in the course of the copolymerization. The extent of the fragmentation determined by 1H‐NMR spectroscopy depends on reactivity of the MPMA radical toward the reference monomers. An increase in the addition rate of the MPMA radical to the reference monomer brought about suppression of the fragmentation. The addition of the MPMA radical to styrene seems to be sufficiently fast to prevent the fragmentation. Since the rate of the fragmentation relative to the propagation was considerably accelerated by raising the temperature to 110°C, MPMA can be used as a novel chain transfer agent to control molecular weight and end group at a temperature above 100°C. © 1993 John Wiley & Sons, Inc.
Synthesis and properties of novel aromatic polyamides derived from 1,5‐bis(4‐aminophenoxy)naphthalene and aromatic dicarboxylic acids
Authors: Yang Chin‐Ping , Chen Wen‐Tung
Published: April 2003

A new bis(phenoxy)naphthalene‐containing diamine, 1,5‐bis(4‐aminophenoxy)naphthalene, was synthesized in two steps from the condensation of 1,5‐dihydroxy‐naphthalene with p‐chloronitrobenzene in the presence of potassium carbonate, giving 1,5‐bis(4‐nitrophenoxy)naphthalene, followed by hydrazine hydrate/PdC reduction. A series of polyamides and copolyamides were synthesized by the direct polycondensation of the diamine with various aromatic dicarboxylic acids or with mixed dicarboxylic acids in N‐methyl‐2‐pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. The polymers having inherent viscosity of 0.81–1.25 dL/g were obtained in quantitative yield. Most of the polymers were generally soluble in aprotic solvent such as N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidone, etc. The polymers derived from rigid dicarboxylic acids such as terephthalic acid, naphthalene dicarboxylic acid, and 4,4′‐biphenyldicarboxylic acid exhibited crystalline patterns. Glass transition temperatures of polymers were in the range of 230–360°C, and 10% weight loss temperatures in nitrogen and air were above 492 and 470°C, respectively. © 1993 John Wiley & Sons, Inc.
Design of monomers for nonshrinking polymerizations, and synthesis of some N, S‐analogs of spiroorthocarbonates
Authors: Millich F. , Eick J. D. , Jeang L. , Byerley T. J.
Published: April 2003

The design of spiroorthocarbonate monomers (SOCs) and related structures is discussed with the aim of maximizing monomer polymerizability in the absence of undesirable byproducts. The successful syntheses of N,S‐analogs of aryl‐ and alkaryl‐SOCs are reported; these are monomers of structure
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where P and Q are O and OC(CH3)2−, mp 156–158°C; and P and Q are OCH2 and OCH2, mp 148–150°C. As is indicated by infrared spectra, the polymerization of both monomers is initiated by boron trifluoride etherate. © 1993 John Wiley & Sons, Inc.
Interaction between Na+ and polymer in aqueous solution of sodium salts of poly(2‐hydroxyethyl methacrylate‐co‐methacrylic acid) studied by 23Na‐NMR
Authors: Song Jin Deog , Jhon Mu Shik
Published: April 2003

The interaction between Na+ and polymer was studied by 23Na‐NMR for the aqueous solution of P(HEMA‐co‐MAANa), sodium salt of poly(2‐hydroxyethyl methacrylate‐co‐methacrylic acid), as a function of the polymer concentration, charge density of the polymer chain, and temperature. The NMR line width of 23Na‐NMR in 1% (w/v) aqueous solution of the P(HEMA‐co‐MAANa) narrowed with increasing temperature due to the rapid exchange of Na+ between free and polymer‐bound states with a rate of exchange exceeding the quadrupolar relaxation rate in the latter state. At high concentrations of the polymer above 1.0% (w/v) at 298 K, the 23Na‐NMR relaxation fits for a single Lorentzian due to the rapid exchange between two Na+ states. However, it follows a biexponential decay of magnetization in dilute solutions of polymer. The biexponential decay character of relaxation increased with the increase of the fraction of the MAANa monomer unit on the polymer chain. This feature of 23Na‐NMR relaxation was used to deduce the correlation time (τc), the degree of binding (pB), and the quadrupole coupling constants (X) of the polymer‐bound counterion. The χ and τc values show that the mobilities of the polymer chain are correlated with the motion of Na+ in aqueous solution of the polymer and there is a small degree of the specific binding between COO− and Na+. No evidence in support of the intramolecular conformational change by the charge density variation in P(HEMA‐co‐MAANa) was obtained. © 1993 John Wiley & Sons, Inc.
Preparation and properties of poly(alkyl vinyl ether‐2‐ethyl‐2‐oxazoline) diblock copolymers
Authors: Liu Q. , Konas M. , Davis R. M. , Riffle J. S.
Published: April 2003

A method for the synthesis of well‐defined poly(alkyl vinyl ether–2‐ethyl‐2‐oxazoline) diblock copolymers with hydrolytically stable block linkages has been developed. Monofunctional poly(alkyl vinyl ether) oligomers with nearly Poisson molecular weight distributions were prepared via a living cationic polymerization method using chloroethyl vinyl ether together with HI/ZnI2 as the initiating system and lithium borohydride as the termination reagent. Using the resultant chloroethyl ether functional oligomers in combination with sodium iodide as macroinitiators, 2‐ethyl‐2‐oxazoline was polymerized in chlorobenzene/NMP to afford diblock copolymers. A series of poly(methyl vinyl ether–2‐ethyl‐2‐oxazoline) diblock materials were found to have polydispersities of ≈ 1.3–1.4 and are microphase separated as indicated by two Tg's in their DSC thermograms. These copolymers are presently being used as model materials to study fundamental parameters important for steric stabilization of dispersions in polar media. © 1993 John Wiley & Sons, Inc.
Synthesis, characterization, and chiroptical property of optically active poly(urea‐urethane)s
Authors: Chen Yun , Tseng Hsien‐Hsiung
Published: April 2003

Five new optically active poly(urea‐urethane)s were synthesized by solution polyaddition of (1S,2S)‐(+)‐2‐amino‐3‐methoxy‐1‐phenyl‐1‐propanol (4) with diisocyanates (diphenylmethane‐4,4′‐diisocyanate, toluene‐2,4‐diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, m‐xylylene diisocyanate) at 80°C for 60 h. In some cases, the reaction mixture transformed into a gel when cooled to room temperature. The reduced viscosities are between 0.14 and 0.63 dL/g depending on the solvents and diisocyanates. Thermal behaviors of these polymers were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The Tg and crystallization temperature (Tc) were in the range of 80–200°C and 220–238°C, respectively. Thermal decomposition started at about 275°C, and the residual weights at 400°C were 15–60% depending on the polymers. The conformation of the polymers in film state was studied by circular dichroism (CD) spectra, by comparison with the corresponding model compounds which were synthesized from 4 and phenyl isocyanate or propyl isocyanate. Polymers derived from aromatic diisocyanates formed as ordered conformation in the film state, while those from aliphatic diisocyanates did not. After packing as chiral stationary phases of high‐performance liquid chromatography (HPLC), the polymers showed selective resolution to trans‐stilbene oxide and trans‐1,2‐cyclopentanedicarboxanilide. © 1993 John Wiley & Sons, Inc.
The effect of ionic electrolytes on hydrolytic degradation of biodegradable polymers: Mechanical and thermodynamic properties and molecular modeling
Authors: Pratt Lawrence , Chu Caryn , Auer Jeff , Chu Alfred , Kim Jennifer , Zollweg John A. , Chu C. C.
Published: April 2003

The purpose of this study was to examine the effect of electrolytes on the hydrolytic degradation of synthetic biodegradable polymers and fibers. Both Polyglycolic acid (PGA) and poly(glycolide–lactide) copolymer (PGL) were used for the study. Four different electrolytes were used: NaCl, LiCl, MgCl2, and ZnCl2. The electrolyte effect was evaluated in terms of the change in tensile properties, water uptake, and surface morphology of the polymers and fibers. It was found that the NaCl and MgCl2 solutions significantly retarded the hydrolytic degradation of both PGA and PGL as evidenced in the prolonged retention of tensile breaking strength of these fibers when compared to deionized water control. Increasing the concentration of the electrolyte retarded the hydrolytic degradation rate further. These mechanical property data agreed well with the rate and amount of water uptake of PGA and could be correlated with the chemical potential difference of water between the electrolyte solution and pure water. The effect of electrolyte was further analyzed by theoretical calculation. Semiemperical molecular orbital calculations indicated that hard cations like Mg, Li, and Zn strongly coordinated to the polar sites of the polymer chain segments (CO) and severely disrupted their solvation spheres. Such a disruption was reflected in the smaller amount and slower rate of water uptake by PGA, and thus a slower rate of hydrolytic degradation as evident in the retention of tensile breaking strength. © 1993 John Wiley & Sons, Inc.
Fully aromatic thermotropic liquid crystalline polyesters of substituted 4,4′‐biphenols. IV. Homopolyesters with terephthalic acid and copolyesters with terephthalic acid and 4‐hydroxybenzoic acid
Authors: Bhowmik Pradip K. , Lenz Robert W.
Published: April 2003

A series of fully aromatic thermotropic polyesters based on mono‐, di‐, and tetra‐substituted biphenols was prepared by the melt polycondensation method and examined for their thermotropic behavior by a variety of experimental techniques. The homopolyesters obtained from substituted biphenols containing either one phenyl or two phenyl groups as substituent(s) and TA formed nematic melts, but the homopolymers of the substituted biphenols containing either four sec‐butyl groups or two tert‐butyl groups with TA had melting transitions, Tm, above 400°C. Thus, it was not possible to determine whether they formed nematic melts. On copolymerization with 30 mol % HBA most of the resulting copolyesters had much lower Tm values, compared to those of respective homopolyesters, and the copolymers of the biphenol monomer containing the tert‐butyl groups formed a nematic melt at an observable temperature. However, the copolymer of the biphenol with sec‐butyl groups still had a Tm above 400°C. © 1993 John Wiley & Sons, Inc.
Ethylene–vinyl acetate semi‐batch emulsion copolymerization: Use of factorial experiments for improved process understanding
Authors: Scott P. J. , Penlidis A. , Rempel G. L.
Published: April 2003

A good working knowledge of the mechanism and an appreciation of the effects the process variables have on the properties of interest are required for optimization and control of polymerization processes. Despite the importance of ethylene‐vinyl acetate emulsion copolymers, limited kinetic information is available. Results from a series of factorial experiments are presented here which examine the emulsion polymerization of ethylene with vinyl acetate. Copolymers of up to 32 wt % ethylene have been produced at an ethylene pressure of 500 psig and a temperature of 20°C. The effects of the process variables on the rate of polymerization, copolymer composition, particle size and number, molecular weight averages, and gel content are discussed. The kinetic results obtained suggest process improvements for the production of homogeneous copolymer. Mechanistically, the locus of polymerization has been verified as the polymer particles and little water phase polymerization was observed. © 1993 John Wiley & Sons, Inc.
Polyimides with alicyclic diamines. I. Syntheses and thermal properties
Authors: Jin Qiu , Yamashita Takashi , Horie Kazuyuki , Yokota Rikio , Mita Itaru
Published: April 2003

The polyaddition reactions of alicyclic diamines such as 1,4‐diaminocyclohexane (1,4‐CHDA) or 4,4′‐diaminodicyclohexylmethane (DCHM) and configurational isomers of 1,4‐CHDA or DCHM with tetracarboxylic aromatic anhydrides in aprotic solvents were carried out to prepare high molecular weight poly(amic acid)s. Through the thermal imidization of poly(amic acid)s, several flexible polyimide films were prepared. Because of the stiffness of the alicyclic moieties in diamines, the resulting polyimides exhibit high glass transition temperatures (220–340°C) almost similar to those for corresponding aromatic polyimides which have phenylene groups in place of cyclohexyl groups, and show good thermal stability. The partial crystallization was observed for polyimides with trans‐cyclohexyl moiety during the heating in differential scanning calorimetry and ascertained by wide‐angle x‐ray diffraction. Thus, the inhibition of the occurrence of charge transfer in polyimides is accomplished by introducing alicyclic diamines in place of aromatic diamines without reducing their thermal stability. © 1993 John Wiley & Sons, Inc.
Synthesis of a stable, foamable, gold‐containing organic carboxylate polymer
Authors: Khan Md. Nazrul I. , Fackler John P. , Chum Steve P. , Paquet Andrew
Published: April 2003

The functionalized polyethylene acrylic acid copolymers Primacor 1430 (P1430, containing 9.5% acrylic acid) and Primacor 5980 (P5980, containing 20% acrylic acid) have been used to synthesize gold/polymer dispersions and gold/polymer ionomers, respectively. When [Ph3PAu]+ is bonded directly to the carboxylate, work‐up of the polymer leads to decarboxyation and metallic gold formation. However, ionic bonding of [(Ph3P)2Au]+, and related bis phosphine cations produce workable, foamable polymers. Analysis shows samples from these reactions to contain between 4–15 wt % of Au depending on the type of gold complex used and the reaction conditions. The gold/polymer (ionomer) sample with about 12% Au has been worked to mold sheets of foam. © 1993 John Wiley & Sons, Inc.
Sulfur‐containing polyacrylates. IV. The effect of Sand Olinkages on the photo‐ and thermally induced polymerization of dimethacrylates
Authors: Andrzejewska E. , Andrzejewski M.
Published: April 2003

The photo‐and thermally induced polymerization of four analogous dimethacrylates2,2′‐thiobisethanol dimethacrylate, 2,2′‐oxybisethanol dimethacrylate, pentanediol‐1,5‐dimethacrylate, and butanediol‐1,4‐dimethacrylatewas studied to determine the influence ofSandOlinkages on the polymerization course. Generally, the presence of the heteroatom in the monomer molecule results in higher reaction rates and yields but the extent of this influence highly depends on the polymerization conditions and the type of heteroatom. The effect of the thioether bond exceeds the effect of the ether bond at lower (40°C) temperature in the presence of oxygen but the reverse situation takes place at higher (75°C) temperature and/or in an inert atmosphere when photofragmentating and thermal initiators are used. The results are discussed mainly in terms of propensity of sulfides and ethers to act as hydrogen donors and chain‐transfer agents. © 1993 John Wiley & Sons, Inc.
On the formation and properties of a high‐temperature resin from a bisphthalonitrile
Authors: Burchill P. J.
Published: April 2003

When 4,4'‐bis (3,4‐dicyanophenoxy) biphenyl is heated with small amounts of aromatic amine or amidine salts, a highly crosslinked polytriazine is obtained. This polymer has been shown to be the same as that reported when bisphthalonitriles are heated with amines. Salts promote this reaction more readily and the glass transition temperature of the polymer after post‐cure at 315°C is generally 30°C higher than when free bases are used. The fracture properties and elasticity of the salt‐cured polymer have been measured at temperatures up to 250°C. As a model system, the self reaction of phthalonitrile promoted by amines and their salts has been studied. In both cases, poly[4‐(2‐cyanophenyl)‐1,3,5‐triazine‐2,6‐diyl‐1,2‐phenylene] is produced, and more efficiently using the salts. A reaction mechanism for this polymerization has been proposed. © 1994 John Wiley & Sons, Inc.
Fluorination of polymers by sulfur hexafluoride gas under electric discharge
Authors: Das Partha Sarathi , Adhikari Basudam , Maiti Sukumar
Published: April 2003

Fluorination of low‐density polyethylene, polyacetylene, and poly(vinyl alcohol) was carried out using SF6 gas under electric discharge. The polymers were partially fluorinated and the extent of fluorination was more in the case of poly (vinyl alcohol) than the other two polymers. The fluorinated polymers were characterized by elemental analysis (Fluorine), IR, and x‐ray diffraction. Optical transparency of the films was also measured. The fluorinated polymers show better solvent resistance and decreased transparency than the virgin polymer. © 1994 John Wiley & Sons, Inc.
Synthesis and characterization of polyesters from hindered biphenols and hydroquinones
Authors: Kim Whan‐Gi , Hay Allan S.
Published: April 2003

Polyesters have been synthesized by polycondensation of terephthaloyl dichloride or isophthaloyl dichloride with hindered biphenols and hydroquinones which contain bulky substituents (methyl and phenyl) on the arylene ring. Polymers derived from isophthaloyl dichloride have better solubility and lower glass transition temperatures than the corresponding polymers obtained from terephthaloyl dichloride. © 1994 John Wiley & Sons, Inc.
The effect of supporting electrolyte on the electrochemical synthesis, morphology, and conductivity of polyaniline
Authors: Duić L J. , Mandić Z. , Kovačiček F.
Published: April 2003

Electrochemical synthesis of polyaniline (PANI) was carried out under cyclovoltammetric conditions using H2SO4, HCl, HNO3, and HClO4 as supporting electrolytes. The observed different rate of PANI deposit growth depending on the acid in the solution has been explained on the grounds of a different degree of specific adsorption for particular anion. It has been found that morphology of the deposit depends greatly upon the anion present in the solution. Thus, PANI synthesized from the solution of oxyacids results in a dense sponge‐like structure while PANI from the hydrochloric acid solution results in a spaghetti‐like structure. The structure of the deposit influences the conductivity, being higher for a dense deposit from oxyacid solutions and three orders of magnitude lower in case of a deposit from hydrochloric acid solution. © 1994 John Wiley & Sons, Inc.
Synthesis and characterization of 1,3,4,‐thiadiazole‐containing polyethers from 2,5‐bis (4‐fluorophenyl)‐1,3,4‐thiadiazole and various aromatic diols
Authors: Saegusa Yasuo , Iwasaki Takeshi , Nakamura Shigeo
Published: April 2003

Seven 1,3,4‐thiadiazole‐containing polyethers with reduced viscosities of 0.27–1.44 dL/g were synthesized by the high‐temperature solution polycondensation of novel activated difluoride, 2,5‐bis (4‐fluorophenyl)‐1,3,4‐thiadiazole, with aromatic diols possessing a variety of ring structures. The expected chemical structures were confirmed by IR and 1H‐NMR spectroscopy and elemental analysis. Of all the polymers, three polyethers were highly crystalline and soluble only in limited solvents such as concentrated sulfuric acid. The other polyethers were amorphous and dissolved easily in a variety of organic solvents including N‐methyl‐2‐pyrrolidone (NMP), phenols, and chlorinated hydrocarbons. Colorless to slightly yellow‐colored, transparent, and tough films could be cast from the NMP solutions of the amorphous polyethers. The mechanical properties of the films were excellent, and their tensile strength, elongation at break, and tensile moduli were in the ranges of 48–72 MPa, 5–7%, and 1.3–1.9 GPa, respectively. The amorphous polyethers had high glass transition temperatures of 204–299°C. All the polyethers were highly thermally and thermooxidatively stable and exhibited no weight loss up to 400°C, with 10% weight loss being recorded at 464–513°C in air. © 1994 John Wiley & Sons, Inc.
Poly (2,6‐dimethyl‐1,4‐phenylene oxide)/poly (butadiene) diol interpenetrating polymer networks: Phase morphological characteristics and glass transition temperature behavior
Authors: Xue Yongpeng , Frisch Harry L.
Published: April 2003

The fracture surface topography of simultaneous interpenetrating polymer networks (SIN'S) of poly (2,6‐dimethyl‐1,4 phenylene oxide) (PPO)/poly (butadiene) diol was examined by scanning electron microscopy (SEM). The phase morphology of the IPNs is highly dependent on PPO/poly (butadiene) diol mass ratio. A single‐phase morphology of the IPNs was achieved when the content of poly (butadiene) diol is below 40 wt % in the initial composition. The SEM observations are also wholly consistent with the glass transition temperature behavior obtained in the differential scanning calorimetric (DSC) measurements. © 1994 John Wiley & Sons, Inc.
Interpolymer complex formation of some nonionogenic polymers with linear and crosslinked polyacrylic acid
Authors: Budtova T. V. , Suleimenov I. E. , Ya. Frenkel S.
Published: April 2003

The formation of interpolymer complexes on the surface of crosslinked poly (acrylic acid) with some nonionogenic polymers is compared with the complex formation in analogous linear polymer systems. The behavior of these systems is compared with that of complexes of two oppositely charged polyelectrolytes. The concentration redistribution of the linear polymer in the system polyelectrolyte network‐polymer solution and the degree of swelling of this network in these solutions were determined. © 1994 John Wiley & Sons, Inc.
Asymmetric polymerization of aromatic isocyanates with optically active anionic initiators
Authors: Okamoto Yoshio , Matsuda Masashi , Nakano Tamaki , Yashima Eiji
Published: April 2003

The asymmetric anionic polymerization of o‐, m‐, and p‐methylphenyl isocyanates, p‐methoxyphenyl isocyanate, p‐chlorophenyl isocyanate, 2,6‐ and 3,4‐dimethylphenyl isocyanates, and 1‐naphthyl isocyanate was carried out using chiral anionic initiators such as the lithium salts of (−) ‐menthol, (−) ‐(2‐methoxymethyl) pyrrolidine, and (+) ‐1‐(2‐pyrrolidinylmethyl) pyrrolidine. Although o‐methylphenyl isocyanate gave an insoluble polymer and 2,6‐dimethylphenyl isocyanate afforded no polymer, the other monomers gave soluble polymers, which showed optical activity due to the prevailing helicity of the polymer chain induced by chiral initiator residues attached to the α‐end of the polymer chain. The molecular mechanics conformational calculation for a tetramer of m‐methylphenyl isocyanate supported the helical conformation of the main chain. The optical rotation of the polymers depended significantly on temperature. © 1994 John Wiley & Sons, Inc.
Fully aromatic thermotropic liquid crystalline homopolyesters of 3,4′‐benzophenone dicarboxylic acid
Authors: Bhowmik Pradip K. , Han Haesook , Garay Raul O.
Published: April 2003

A series of fully aromatic, thermotropic homopolyesters, derived from 3,4′‐benzophenone dicarboxylic acid and various aromatic diols, was prepared by the melt polycondensation method and examined for thermotropic behavior by a variety of experimental techniques. The aromatic diols used in the study were hydroquinone, 2,6‐, 1,4‐, 1,5‐, 2,3‐, and 2,7‐naphthalenediol isomers. All of the homopolyesters of 3,4′‐benzophenone dicarboxylic acid with aromatic diols (except that with 2,7‐naphthalenediol) formed a nematic LC phase in the melt. They had the glass transition temperatures (Tg) in the range of 133–164°C, the melting transitions (Tm) in the range 305–360°C and the high thermal stabilities (Td) in the range of 410–483°C. The 2,6‐naphthalenediol based homopolymer had the highest Tm (360°C) and the 2,3‐naphthalenediol based homopolymer had the lowest Tm (305°C) among all of the homopolymers of naphthalenediol isomers. © 1994 John Wiley & Sons, Inc.
Preparation and properties of aromatic polyamides and polyimides derived from 3,3‐bis [4‐(4‐aminophenoxy) phenyl] phthalide
Authors: Yang Chin‐Ping , Lin Jiun‐Hung
Published: April 2003

3,3‐Bis[4‐(4‐aminophenoxy)phenyl]phthalide (II) was used as a monomer with various aromatic dicarboxylic acids and dianhydrides to synthesize polyamides and polyimides, respectively. The diamineIIwas derived by a nucleophilic substitution of phenolphthalein withp‐chloronitrobenzene in the presence of K2CO3. PolyamidesIVa‐ghaving inherent viscosities of 0.77–2.46 dL/g were prepared by the direct polycondensation of diamineIIwith diacidsIIIa‐gusing triphenyl phosphite and pyridine as condensing agents. The polyamides were readily soluble in a variety of solvents such asN, N‐dimethylformamide (DMF),N,N‐dimethylacetamide (DMAc), andN‐methyl‐2‐pyrrolidinone (NMP) and afforded transparent and flexible films from the polymer solutions. These polymers had glass transition temperatures (Tgs) in the 227–307°C range and 10% weight loss temperatures occurred up to 450°C. PolyimidesVIa‐ebased on diamineIIand various aromatic dianhydridesVa‐ewere synthesized by the two‐stage procedure that included ring‐opening, followed by thermal or chemical conversion to polyimides. Most of the polyimides obtained by chemical cyclodehydration procedure were found to soluble in DMF, NMP,o‐chlorophenol, andm‐cresol. TheTgs of these polyimides were in the 260–328°C range and showed almost no weight loss up to 500°C under air and nitrogen atmosphere. © 1994 John Wiley & Sons, Inc.
Synthesis of new linear polymers containing phosphorus atom in the main chain by the radical polyaddition: Addition polymers of phenylphosphine with 1,4‐divinylbenzene or 1,4‐diisopropenylbenzene and their properties
Authors: Obata Takatsugu , Kobayashi Eiichi , Aoshima Sadahito , Furukawa Junji
Published: April 2003

A polyaddition of phenylphosphine (PH) to 1,4‐divinylbenzene (DVB) or 1,4‐diisopropenylbenzene (DIPB) was carried out by radical initiations or UV irradiation at 60–80°C in toluene under a nitrogen atmosphere. The soluble polymer with higher molecular weight ($\[ \bar M_w = 2 \times 10^4 \]$) was obtained in a high yield with AIBN initiator for 95 h in the presence of 5% excess of PH to DVB (monomer feed ratio [DVB]0/[PH]0 = 1/1.05). On the other hand, a polyaddition of PH to DIPB proceeded much slower than the case of DVB, but the high polymer was obtained in a high yield by choosing polyaddition conditions such as polyaddition temperature and initiator concentration. From 1H‐NMR, IR analyses, and phosphorus content of the polymers, it was characterized that both polymers have the alternating structure consisting of PH and DVB or DIPB units in 1 : 1 ratio. The glass transition and decomposition temperatures of both polymers under a nitrogen atmosphere were almost similar: 15–30°C and 380–385°C, respectively; but, the polymers were oxidized by heating under an atmosphere of air. The polymers had a self‐extinguishing property and the polymer blend of the flammable polymers such as polystyrene and polyethylene with the phosphorus‐containing polymers exhibited an excellent flame resistance. © 1994 John Wiley & Sons, Inc.
Quinone‐amine polymers. XII. Synthesis and characterization of novel polymers from 2‐phenylbenzoquinone and aliphatic diamines
Authors: Reddy T. Ashok , Erhan S.
Published: April 2003

In order to study the effect of the presence of phenyl groups in poly (amino‐quinone) (PAQ) polymers, several novel poly(amino‐2‐phenylbenzoquinone) (PhPAQ) polymers have been prepared from 2‐phenylbenzoquinone and aliphatic diamines, such as 1,6‐diaminohexane, 1,8‐diaminooctane, 1,12‐diaminodod+++++, and 1,4‐diaminocyclohexane. Prior to the polymerization, 2‐phenylbenzoquinone was generated in situ from 2‐phenylhydroquinone in the presence of calcium hypochlorite as the oxidizing agent in dichloromethane. All of the polymers synthesized have been characterized with respect to their corresponding model compounds. It was also found that unlike their analogous PAQ polymers, PhPAQ polymers were highly soluble in many common organic solvents because of the presence of phenyl groups in their polymer backbone. © 1994 John Wiley & Sons, Inc.