Rigid‐chain metallomesogenic polymers containing vanadyl or copper(II) ions coordinated in the main chain

Rigid‐chain metallomesogenic polymers containing Cu(II) or VO(II) were prepared and characterized. All the polymers were soluble and melted without decomposition. They showed a thermotropic liquid–crystal (LC) behavior, and the mesophases were invariably preserved for a long time at room temperature in a metastable condition, with respect to the semicrystalline state. The nature of the mesophases of the Cu(II)‐containing polymers was similar to that observed in analogous organic rigid‐chain polymers having long lateral alkyl chains packed as extended ribbons. The VO(II)‐containing polymers showed an LC polymorphism involving a smectic A and a nematic phase. For all the polymers in a smectic or smecticlike state at room temperature, X‐ray diffraction data suggested short mean distances among the metal ions arranged in layers. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2342–2349, 2001     

Preparation and properties of novel polyimides derived from 4‐aryl‐2,6 bis(4‐amino phenyl)pyridine

To prepare novel polyimides with enhanced thermal stability and high solubility in common organic solvents, diamine monomers, 4‐aryl‐2,6 bis‐(4‐amino phenyl)pyridine, were introduced. The diamines were reacted with three different conventional aromatic dianhydrides including pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, and hexafluoroisopropylidene‐2,2‐bis(phthalic‐dianhydride) (6FDA) in dimethylacetamide solvent to obtain the corresponding polyimides via the polyamic acid precursors and chemical imidization. The monomers and polymers were characterized by Fourier transform infrared spectroscopy, ¹H NMR, mass spectroscopy, and elemental analysis; and the best condition of polymerization and imidization were obtained via the study of model compound. The polyimides showed little or no weight loss by thermogravimetric analysis up to 500 °C, and those derived from 6FDA exhibited good solubility in various polar solvents. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3826–3831, 2001     

Laser light scattering study of the degradation of poly(sebacic anhydride) nanoparticles

Poly(sebacic anhydride) (PSA) is biocompatible and degradable in basic media. We micronized this water‐insoluble polymer into stable polymeric nanoparticles via a microphase inversion. Such PSA nanoparticles degraded much faster than bulk PSA. The influence of the surfactant, temperature, and pH on the degradation of the PSA nanoparticles was investigated by a combination of static and dynamic laser light scattering. Under each condition, the degradation rate was nearly constant up to a 75% weight loss; that is, the degradation was close to zero‐order. The degradation rate increased with the pH and temperature. Biomedical applications of such PSA nanoparticles are suggested. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 703–708, 2001     

Synthesis and specific biodegradation of novel polyesteramides containing amino acid residues

Novel polyesteramides were synthesized from p‐nitrophenyl esters of sebacic or adipic acids and diamines containing α‐amino acid ester groups. The optimal polymerization condition was 60 °C in N,N‐dimethylformamide. The structures of these polymers were confirmed by IR and NMR. The number‐average molecular weights of these polyesteramides ranged from 2280 to 23,600 (except for the polymers containing glycine residues), depending on the nature of the amino acid used. The biodegradability of the polyesteramides was investigated by in vitro hydrolysis with proteases and a lipase as catalysts in borate buffer solutions. The results indicated that the polymers containing L ‐phenylalanine were hydrolyzed most effectively by α‐chymotrypsin, subtilisin Carlsberg, and subtilisin BPN′. The polyesteramides containing other amino acid residues also underwent hydrolysis to different extents, reflecting the substrate specificity of the proteases. Lipase had almost no effect on the hydrolytic degradation of these polyesteramides. The polymers containing glycine residues were hardly decomposed by any of the enzymes used. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1318–1328, 2001     

Using carbon nanotubes to detect polymer transitions

Raman spectral shifts of single‐wall carbon nanotubes embedded in polymer systems were used to measure transitions in polymers. Glass‐transition temperatures and secondary transitions were observed, and Raman spectroscopic data were compared with dynamic mechanical tests for a thermosetting and a thermoplastic polymer. The data confirm that the Raman spectral response of carbon nanotubes embedded in polymers is sensitive to polymer transitions. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1492–1495, 2001     

Effect of the solvent polarity on the living ligated anionic polymerization of tert-butyl methacrylate and copolymerization with methyl methacrylate

An anionic polymerization of t-butyl methacrylate and a copolymerization with methyl methacrylate were initiated with an organolithium ligated with 10 equiv of LiCl. As a rule, the complexation of the active species by LiCl masked the effect that the polarity of the solvent might have on the molecular structure of the chains. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1774–1785, 2001     

Synthesis of aminosaccharide‐derived polymers with urea,urethane, and amide linkages

The synthesis of novel polyurethanes and polyureas based on modified glycosylamines and glucosamines has been successfully accomplished by catalytic polymerizations. Several modified glucosamine monomers were synthesized to study their reactivities during these polymerization reactions. It was found that the anomeric hydroxyl groups are more reactive than the amino groups. The resulting polymers were characterized by NMR and IR spectroscopy, elementary analysis, viscosimetry, and gel permeation chromatography. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2332–2341, 2001     

ESR studies in γ‐irradiated and PS‐radiation‐grafted poly(vinylidene fluoride)

The fluoropolymer poly(vinylidene fluoride) was irradiated with γ rays to induce a polystyrene (PS) radiation grafting via an indirect method. Electron spin resonance and Fourier transform infrared studies were performed to identify the species that initiated the PS grafting. Specific experiments were performed to prove separately the importance of each kind of radical. A localization of the radicals in this irradiated polymer is proposed, and a kinetic model of the grafting is given. © 2001 John Wiley & Sons, Inc. J Polym Sci B Part B: Polym Phys 39: 1437–1448, 2001     

Synthesis of chromophore‐embedded polyurethanes for electrooptical materials

We carried out the polyaddition of dye‐embedded diols with diisocyanates to obtain novel nonlinear optical (NLO) polyurethanes, where the NLO units were embedded in the polymer backbone. The obtained polymers showed high glass‐transition temperatures (138–184 °C) and thermal stability (temperature of 10% weight loss under nitrogen = 227–287 °C). The λ maximum of the polymers was 521–556 nm. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2620–2624, 2001     

Synthesis of new monofunctional and oligofunctional oxetane acetals

Derivatives of 3‐ethyl‐3‐(hydroxymethyl)oxetane (trimethylolpropane oxetane), potentially useful in cationic UV‐curable formulations, were prepared by the simple acid‐catalyzed addition of alcohols to 1‐alkenyl ethers. Examples include several difunctional oxetane derivatives along with one fluorinated and one acryloylated oxetane derivative. These new materials may find use as reactive diluents or binders in several applications. A preliminary assessment of the curing was made. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 613–619, 2001     

End‐capped AB3‐type hyperbranched carbosilane macromolecules

End‐capped carbosilane macromolecules were prepared via the hydrosilation and continual addition of phenylethynyl, amine, bis(trimethylsilyl)amine, and cholesterol groups on the AB₃‐type hyperbranched carbosilane polymer. The matrix‐assisted laser desorption/ionization time‐of‐flight mass spectroscopic views of the end‐capped hyperbranched carbosilanes agreed with the expected mass distribution, in close regularity. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3287–3293, 2001     

Orientation of cellulose triacetate films cast from solution in high magnetic field

Cellulose triacetate solutions with various solvents, including methylene chloride, methyl acetate, and their mixture with ethanol, were cast in high magnetic fields, and the obtained films were subjected to the optical and infrared measurements. The film cast from a solution with a methyl acetate/ethanol mixed solvent exhibited birefringence as well as infrared dichroism, whereas the films cast from the other solutions did not. The aligned structure was discussed by comparison with a mechanically stretched sample. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1942–1947, 2001     

Morphology of micron‐sized,monomer‐adsorbed,crosslinked polymer particles having snowmanlike shapes prepared by the dynamic swelling method

A series of monomer‐adsorbed, crosslinked polystyrene/polydivinylbenzene composite particles having snowmanlike shapes were prepared by the dynamic swelling method that the authors had proposed in 1991. The morphology of the snowman‐shaped particles was estimated with the contact angle of the monomer phase on the polymer particle. Influences of the kind of monomers and polyvinyl alcohol colloidal stabilizer on the morphology were obviously observed and discussed from the viewpoint of thermodynamic stability. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3106–3111, 2001     

Hydrogen uptake mechanism of a silicone‐rubber DEB getter mixture

The kinetics of the hydrogen getter 1,4‐bis(phenylethynyl)benzene (DEB) blended with carbon‐supported Pd (DEB‐Pd/C) dispersed uniformly in silicone [DEB‐Pd/C‐poly(dimethyl siloxane)] were studied with a thermogravimetric method as a function of the hydrogen pressure and temperature. A diffusion‐controlled reaction model was developed to explain the experimental results. The diffusion coefficient, solubility coefficient, and permeability of hydrogen through silicone rubber were determined. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 425–431, 2001     

Copolymerization of carbon dioxide and propylene oxide with Ln(CCl3COO)3‐based catalyst: The role of rare‐earth compound in the catalytic system

A highly alternative copolymer of carbon dioxide and propylene oxide was obtained using a lanthanide trichloroacetates‐based ternary catalyst. The rare‐earth compound in the ternary catalyst was critical to dramatically raise the yield and molecular weight of the copolymer in addition to maintaining a high alternating ratio of the copolymer. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2751–2754, 2001     

End‐capped carbosilane dendrimers with benzoxazole,quinoline, and pyrone derivatives

Dendritic carbosilanes containing benzoxazole, quinoline, and pyrone derivatives on the periphery were prepared. The parent dendrimers in the inner shell were prepared by the use of iterative hydrosilation and alkenylation cycles. The end generations were obtained by the reaction of terminal Si? Cl groups on each periphery with HOR [HOR = 2‐(2‐hydroxyphenyl)‐benzoxazole, 8‐hydroxyquinoline, and 3‐hydroxy‐2‐methyl‐4‐pyrone] in the presence of amine. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2308–2314, 2001     

Copolymerization with depropagation: A study of α-methyl styrene/methyl methacrylate in solution at elevated temperatures

In free-radical polymerization, solvents are routinely used to reduce the solution viscosity and molecular weight. In the case of the α-methyl styrene/methyl methacrylate copolymer system, reducing the monomer concentration also has significant effects on the copolymer composition and maximum conversion obtained. Reactivity-ratio studies as well as full-conversion-range data were provided, and the results were compared to similar data in the bulk phase from our earlier work. A 30 wt % toluene solution was used for all experimental conditions. Copolymer composition modeling results were also presented. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1753–1763, 2001     

Sequential poly(ester amide)s based on glycine,diols, and dicarboxylic acids: Thermal polyesterification versus interfacial polyamidation. Characterization of polymers containing stiff units

Sequential poly(ester amide)s derived from glycine were synthesized by a two‐step method, involving a final thermal polyesterification. Molecular weights were in general higher than those obtained with the previously reported synthesis on the basis of interfacial polyamidation. Polymers with stiff units like oxaloyl or terephthaloyl residues were thermally characterized and their degradability studied by using different types of enzymes. Polymers containing short diols are degradable in papain solutions, the degradation rate being higher for oxalic derivatives. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4283–4293, 2001     

Application of a model‐free isoconversional method to the cure of phenolic systems

The curing process of a phenolic resole was monitored with differential scanning calorimetry under nonisothermal and isothermal conditions, the curing kinetics were analyzed with a model‐fitting approach and a model‐free isoconversional method, and the activation energy of this phenolic system was found to be close to 46 ± 4 kJ mol^?1. For complicated cures, the model‐free isoconversional method was found to be a simpler and more reliable approach. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1525–1528, 2001     

Preparation of polythioamides from dialdehydes and diamines with sulfur by the Willgerodt–Kindler type reaction

Willgerodt–Kindler type reactions of dialdehydes and diamines in the presence of sulfur were investigated for preparation of polythioamides. The one‐pot, three‐component polycondensation afforded various polythioamides in moderate to good yields. The appropriate reaction conditions were examined for the separate monomers. The results led us to the proposed mechanism for the polycondensation including formation of the intermediate Schiff base polymers followed by the successive nucleophilic attack of polysulfide anions to the azomethine units to give the thioamide groups. Structure, solubility, and thermal properties of the polythioamides were also compared with those of analogous polyamides. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3739–3750, 2001