bluuebunny/crossref_metadata_2025 huggingface dataset:
Ester derivatives of α‐hydroxymethylacrylates: Itaconate isomers giving high molecular weight polymers
Authors: Avci Duygu , Kūsefǧlu Selim H. , Thompson Robert D. , Mathias Lon J.
Published: April 2003

New ester derivatives of ethyl α‐hydroxymethylacrylate were synthesized using acid chlorides (traditional solution reactions), sodium salts of acids (with phase transfer catalysis), and trifluoroacetic anhydride (trifluoroacetate). The interfacial process gave high yields of clean products under very mild conditions. Derivatives obtained include the formate, acetate, hexanoate, stearate, benzoate, trifluoroacetate, and adamantanoate. Bulk polymerizations with 2,2′‐azobis (isobutyronitrile) gave high molecular weight polymers with intrinsic viscosities of over 2 dL/g and molecular weights of several million [based on size‐exclusion chromatography (SEC) comparison to polystyrene standards]. These high molecular weights were the result of autoacceleration in the bulk as shown by monitoring molecular weight with respect to conversion. Solution polymerization in benzene gave more typical polymer, e.g., the acetate derivative showed an SEC molecular weight of 52,000. Glass transition temperatures for the n‐alkyl esters decreased from the formate (77°C) to the hexanoate (15°C); the stearate showed a side‐chain melting point of 40°C but no Tg. Glass transitions were observed for the trifluoroacetate, benzoate, and adamantanoate polymers at 69, 130, and 214°C, respectively. Solution 13C‐NMR showed evidence of tacticity information for the formate and acetate derivatives with appaent preference for syndiotactic polymer formation similar to that of methyl methacrylate. FTIR and solid‐state 13C‐NMR analysis gave spectra with functional group peaks and chemical shift values expected based on composition. The stearate monomer and polymer gave solid‐state 13C chemical shifts of 34 and 33 ppm, respectively, for the central CH2 units consistent with monoclinic and orthorhombic crystal packing. © 1994 John Wiley & Sons, Inc.
Synthesis, characterization, and properties of colorless rigid‐rod poly(benzobisthiazole) derived from bicyclo[2.2.2]octane
Authors: Dotrong M. , Dotrong M. H. , Wang C. S. , Song H. , Moore G. J. , Evers R. C.
Published: April 2003

Polycondensation in polyphosphoric acid of 2,5‐diamino‐1,4‐benzene dithiol dihydrochloride with bicyclo[2.2.2]octane‐1,4‐dicarboxylic acid, as well as the corresponding dimethyl ester or diacid chloride, led to rigid‐rod benzobisthiazole polymers. Colorless and soluble polymers with intrinsic viscosities as high as 30.6 dL/g (methanesulfonic acid, 30°C) were obtained. The ultraviolet‐visible spectrum of a polymer film cast from methanesulfonic acid under reduced pressure displayed no absorptions in the visible range (400–900 °m). The polymer was thermooxidatively stable up to 420°C in air as determined by thermogravimetric analysis. Fibers spun from a lyotropic polyphosphoric acid solution exhibited a tensile strength of 300–450 Ksi, a modulus of 26 Msi, and a compressive strength of 53 Ksi. Wide‐angle X‐ray scattering patterns of polymer fibers indicated a 3‐dimensional crystal structure rather than a nematic liquid crystal structure. © 1994 John Wiley & Sons, Inc.
The comppen model: A combined complex‐participation/penultimate effect model for free‐radical copolymerization
Authors: Brown Paul G. , Fujimori Kiyohisa
Published: April 2003

The Comppen model for the mechanism of free‐radical copolymerization has been developed to account for both penultimate effects and the participation of 1:1 electron donor‐acceptor complexes during chain propagation. This was achieved by incorporating penultimate effects into the existing complex participation model of Cais, Farmer, Hill, and O'Donnell, using probability theory to derive new copolymer composition and sequence distribution equations that are solely functions of the reactivity ratios, the composition of the comonomer feed, and the equilibrium constant for 1:1 electron donor‐acceptor complex formation. The model was applied to experimental data from styrene/maleic anhydride copolymers prepared in methyl ethyl ketone at 50°C over a wide range of comonomer feed compositions, using nonlinear least‐squares curve fitting techniques to determine best estimates of the reactivity ratios. Copolymer compositions and sequence distributions for copolymers in this comonomer system were then predicted using the Comppen model and compared to those determined experimentally via 13C‐NMR spectroscopy. © 1994 John Wiley & Sons, Inc.
Investigation on the particle growth mechanism in propylene polymerization with MgCl2‐supported ziegler–natta catalysts
Authors: Noristi L. , Marchetti E. , Baruzzi G. , Sgarzi P.
Published: April 2003

To elucidate the particle growth mechanism in propylene polymerization with high‐yield MgCl2‐supported Ziegler‐Natta catalysts, observations have been carried out by electron microscopy on a series of samples having different degrees of polymer growth (from 0.1 to 1000 g/g of catalyst). Topics such as surface and bulk morphology, catalyst fragmentation, as well as distribution of the catalyst residues in the polymer have been investigated. The experimental data suggest that if the site distribution in the catalyst is uniform and the polymerization conditions are mild, the polymer growth starts uniformly throughout the catalyst particle, which then undergoes an even and progressive fragmentation into very fine units homeogeneously dispersed in the polymer matrix. The above results thus provide further experimental support to the particle growth mechanism outlined in the multigrain or polymeric flow models. © 1994 John Wiley & Sons, Inc.
Phenylethynyl‐terminated imide oligomers and polymers therefrom
Authors: Hergenrother P. M. , Bryant R. G. , Jensen B. J. , Havens S. J.
Published: April 2003

Two new phenylethynyl endcapping compounds, 3‐ and 4‐amino‐4′‐phenylethynylbenzophenone, were synthesized and used to terminate imide oligomers from 3,4′‐oxydianiline and 4,4′‐oxydiphthalic anhydride at a calculated molecular weight of 9000 g/mol and from 3,4′‐oxydianiline (0.85 mol), 1,3‐bis (3‐aminophenoxy) benzene (0.15 mol), and 3,3′,4,4′‐biphenyltetracarboxylic dianhydride at a calculated molecular weight of 5000 g/mol. Glass transition temperatures for the cured oligomers were ∼ 249°C for the former and 272°C for the latter. Films cured at 350°C for 1 h were tough and flexible and provided high tensile properties. The uncured oligomers were readily compression molded to provide tough, solve nt‐resistant moldings. © 1994 John Wiley & Sons, Inc.
Synthesis of rigid polymer containing pendant norbornadiene moieties and its photochemical valence isomerization
Authors: Iizawa Takashi , Sueyoshi Tomoko , Hijikata Chikara , Nishikubo Tadatomi
Published: April 2003

Polymers having pendant norbornadiene (NBD) moieties and rigid main chain were prepared from the reaction of partially brominated poly(2,6‐dimethyl‐p‐phenylene oxide) with a potassium carboxylate derivative of the corresponding NBD using a phase transfer catalyst in chlorobenzene. The photochemical valence isomerization of pendant NBD to quadricyclane (QC) moieties proceeded smoothly in the film state as well as polymer solution upon the irradiation by sunlight, xenon lamp, or high‐pressure mercury lamp. The rate of isomerization was affected by the structure of main chain in the polymer and the substituent groups of NBD derivatives. The catalytic reversion of the resulting QC moiety to the original NBD proceeded smoothly in the solution with (5,10,15,20‐tetraphenyl‐21H,23H‐por‐phine)cobalt(II) as the catalyst at room temperature; however, the reaction of NBD polymer containing poly(2,6‐dimethyl‐p‐phenylene oxide) (PPO) showed lower reactivity than that of the corresponding low molecular weight QC compound. When the cycle between the photochemical valence isomerization of NBD moiety to quadricyclane (QC) moiety and thermal reversion of QC moiety to NBD moiety at 160°C was repeated, the NBD polymer synthesized from PPO degraded gradually, whereas NBD polymer prepared from poly(4‐chloromethylstyrene) decomposed easily. Therefore, the rigid PPO structure showed high resistance for the degradation of NBD moiety. © 1994 John Wiley & Sons, Inc.
Synthesis and characterization of potentially biodegradable thermotropic polyesters based on p‐hydroxybenzoic acid and glycolic acid
Authors: Jin Xiaoming , Carfagna Cosimo , Nicolais Luigi , Lanzetta Rosa
Published: April 2003

The synthesis of novel thermotropic liquid crystalline copolyesters derived from aliphatic hydroxy acid (glycolic acid, GA) and aromatic hydroxy acid (p‐hydroxybenzoic acid, PHBA) via a melt‐copolycondensation process in the presence of various catalysts was explored. The following three possible routes were checked: PHBA and GA in different feed ratios with or without a catalyst; PHBA and GA in different feed ratios with or without a catalyst in the presence of acetic anhydride as a condensation agent; and different PHBA derivatives were used to examine the reactivity of aromatic hydroxy acid. The copolycondensability, chemical structure, liquid crystallinity, textures and morphology, phase transition behaviors and thermal stability, and solubility were investigated by FTIR, NMR, DSC, TGA, and polarized‐light microscope. It has been found that only the 60–70 mol % PHBA‐containing copolyesters could exhibit a nematic liquid crystallinity. The as‐prepared polymers were brittle due to relatively lower molecular weights. © 1994 John Wiley & Sons, Inc.
Solution polymerization of vinyl monomers in the presence of poly(N‐acetyliminoethylene) macroazoinitiators
Authors: Simionescu Cristofor I. , David Geta , Ioanid Aurelia , Paraschiv Vasile , Riess Gerard , Simionescu Bogdan C.
Published: April 2003

New block copolymers with poly(N‐acetyliminoethylene) and vinyl sequences were obtained by a two‐step synthetic approach. In the first stage macroinitiators of poly(N‐acetyliminoethylene) type, with azo groups inserted in the main chain, were prepared. They were latter used in the radical polymerization of some vinyl monomers [styrene, methacrylic acid, methyl methacrylate, butyl methacrylate, β‐(N‐carbazolyl)ethyl acrylate, β‐(methacryloyfoxy)ethyl 3,5‐dinitrobenzoate]. The resulting block copolymers were characterized by spectral methods, elemental analysis, gel permeation chromatography, and electron microscopy. The kinetic study of the thermal and photochemical decomposition of the synthesized macroazoinitiators, as well as the polymerization data, suggest a dependence of their initiating efficiency on the length of the poly(N‐acetyliminoethylene) segments. © 1994 John Wiley & Sons, Inc.
Chemical treatment of membranes of a polymer blend: Mechanism of the reaction of hypochlorite with poly(vinyl pyrrolidone)
Authors: Wienk I. M. , Meuleman E. E. B. , Borneman Z. , van den Boomgaard Th. , Smolders C. A.
Published: April 2003

Sodium hypochlorite solutions are used to treat membranes prepared from a polymeric blend containing poly(vinyl pyrrolidone) (PVP) to increase their water permeability. Sodium hypochlorite affects the membrane material in such a way that PVP is selectively removed from the membrane matrix. The mechanism of the reaction between hypochlorite and PVP is investigated by several chemical analysis techniques of the reaction products. Strong indications are found that the reaction involves chain scission of PVP according to a radical mechanism. © 1995 John Wiley & Sons, Inc.
Synthesis and properties of poly(phenylacetylenes) having o‐silylmethyl groups
Authors: Seki Hiroyuki , Masuda Toshio , Higashimura Toshinobu
Published: April 2003

Novel phenylacetylene (PA) monomers, which have o‐silylmethyl groups of different bulkinesses, i.e., o‐Me3SiCH2PA, o‐Et3SiCH2PA, and o‐t‐BuMe2Si‐CH2PA, polymerized with W and Mo catalysts in high yields. The MoCl5‐Ph4Sn catalyst achieved the highest weight‐average molecular weights (Mw 7 × 105 − 12 × 105), and the Mw increased as the ortho‐substitutent became bulkier (e.g., Mw of o‐t‐BuMe2SiCH2PA: 12 × 105). These monomers polymerized in a living fashion by the MoOCl4‐n‐Bu4Sn‐EtOH catalyst. The resulting polymers were soluble in common solvents such as toluene and chloroform. In the UV‐visible spectra, a tendency was observed that absorption maxima shifted to longer wavelengths as the substituents became bulkier. Membranes of the polymers were fairly permeable to gases (e.g., oxygen permeability coefficients 30‐80 barrers). Though o‐(Me3Si)2CHPA also polymerized with W and Mo catalysts, the product polymer was partly insoluble in any solvent. © 1995 John Wiley & Sons, Inc.
Synthesis, structure, and thermal properties of epoxy‐imide resin cured by phosphorylated diamine
Authors: Chin Wei‐Kuo , Shau Min‐Da , Tsai Wei‐Chun
Published: April 2003

New phosphorylated epoxy‐imide polymer was obtained using diimide‐diepoxide (DIDE) cured with bis(3‐aminophenyl)methylphosphine oxide (BAMP). In addition, composition of the synthesized diimide‐diepoxide (DIDE) with common curing agents, e.g., 4,4′‐diaminodiphenylether (DDE) and 4,4′‐diaminodiphenylsulfone (DDS), were used for making a comparison of its curing reactivity, heat and flame retardation with that of bis(3‐aminophenyl)methylphosphine oxide. The reactivity of those curing agents toward epoxy‐imide, as measured by differential scanning calorimetry (DSC), was of the order DDE > BAMP > DDS. Through the evaluation of thermal gravimetric analysis (TGA), the new phosphorylated epoxy‐imide polymer demonstrated excellent thermal properties as well as a high char yield. © 1995 John Wiley & Sons, Inc.
Synthesis and crosslinking of cyano‐substituted polyamides and polyimides prepared from 1‐(2,2‐dicyano‐1‐hydroxyviyl)‐3,5‐diaminobenzene, sodium salt
Authors: Mikroyannidis John A.
Published: April 2003

3,5‐Dinitrobenzoyl chloide was condensed with malononitrile in the presence of sodium hydroxide under phase‐transfer conditions to afford 1‐(2,2‐dicyano‐1‐hydroxyvinyl)‐3,5‐dinitrobenzene, sodium salt, which was catalytically hydrogenated to the corresponding diamine. The latter was used as starting material for the preparation of unsaturated cyanosubstituted polyamides and polyimides. The polymers were soluble in polar aprotic solvents, dilute sodium hydroxide, and certain strong inorganic and organic acids. Upon curing at 300°C for 65 h, crosslinked polymers were obtained that were stable up to 392–404°C in N2 or air and afforded an anaerobic char yield of 60–71% at 800°C. Their glass transition temperatures as determined by thermal mechanical analysis (TMA) were 221–275°C. © 1995 John Wiley & Sons, Inc.
Cyanate esters based on cardanol modified‐phenol‐formaldehyde resins: Syntheses and thermal characteristics
Authors: Nair C. P. Reghunadhan , Bindu R. L. , Joseph V. C.
Published: April 2003

Cardanol incorporated‐phenol‐formaldehyde novolac resins were synthesized by acid and base catalyzed reactions. The novolacs were transformed to their cyanate esters. The thermal cure characteristics of the cyanate esters depended upon the composition. The presence of cardanol proportionately facilitated the curing. The thermal characterization of the novolacs and the corresponding cured phenolic‐triazine networks indicated a dedicated a detremental effect of cardanol on the thermal stability and char residue of the resins. © 1995 John Wiley & Sons, Inc.
Study of bulk chain coupling reactions. III. Reaction between bisoxazolines or bisoxazlines and carboxy‐terminated oligomers
Authors: Douhi Abderrahim , Fradet Alain
Published: April 2003

2,2′‐Bis(2‐oxazoline) and 2,2′‐bis[5,6‐dihydro‐(4H)‐1,3‐oxazine] have been used as chain coupling reagents (CC) and reacted in the bulk with α,ω‐dicarboxy‐poly(2,2′‐oxydiethylene adipate) (PS) or with α,ω‐dicarboxy‐polyamide 12 (PA). The reactions have been followed by viscosimetry, titration of COOH groups and 1H‐ and 13C‐NMR spectroscopy. Either with the PS/CC or PA/CC systems, or with the model system dodecanoic acid (DA)/CC, the reactions were fast, since in most cases 80% conversion was reached after 15 min reaction. The expected DA dimer or high molar mass PA or PS polymers were obtained. No significant side reaction has been detected. The thermal stability of the resulting polymers is higher than that of starting oligomers. Due to the introduction of CC units in the chains, the crystallinity of PA/CC is slower than that of starting PA. © 1995 John Wiley & Sons, Inc.
Studies on thermotropic liquid crystalline polyurethanes. II. Synthesis and properties of liquid crystalline polyurethane elastomers
Authors: Sun Shih‐Jieh , Hsu Keh‐Ying , Chang Teh‐Chou
Published: April 2003

Three series of novel thermotropic liquid crystalline polyurethane elastomers (TLCPUEs) were studied. Hard segments were formed by using hexamethylene diisocyanate (HDI) reacted with a mesogenic unit, benzene‐1,4‐di(4‐iminophenoxy‐n‐hexanol), which also acted as a chain extender. Three diols: 1,10‐decanediol,poly(oxytetramethylene) glycol (PTMEG) Mn = 1000 and PTMEG Mn = 2000 were used as the soft segments. The effects of soft segments of polyurethanes on the liquid crystalline behavior were studied. Higher molecular weight TLCPUEs were obtained by adding 30−50 mol % of mesogenic segments to diisocyanates. In contrast to a conventional chain extender such as 1,2‐ethylene glycol or 1,4‐butyl glycol, the synthesized polyurethane elastomers exhibited a mesophase transition by using a mesogenic unit as the chain extender. Mesophase was found for all synthesized LC polyurethanes except of polymers H2‐A‐12 and H2‐A‐7. The structures and the thermal properties of all synthesized TLCPUEs were studied by using FTIR spectroscopy, wide‐angle x‐ray diffraction (WAXD) and DSC measurements, a polarizing microscope equipped with a heating stage, dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). Mechanical properties were also examined by using a tensilemeter. © 1995 John Wiley & Sons, Inc.
Demonstration of methylene‐ether bridge formation in melamine‐formaldehyde resins
Authors: Scheepers M. L. , Adriaensens P. J. , Gelan J. M. , Carleer R. A. , Vanderzande D. J. , De Vries N. K. , Brandts P. M.
Published: April 2003

1H and 13C NMR have been used for the quantitative determination of methylene‐ether bridges in melamine‐formaldehyde (MF) resins. The amount of methylene‐ether bridges was determined by 13C NMR from the number of monomethylolated amino groups consumed in the condensation reactions and is in agreement with that calculated from the condensation water contents. This latter method, which involves a combination of 1H and 13C NMR, is based on the amount of condensation water released during the formation of both methylene and methylene‐ether bridges. © 1995 John Wiley & Sons, Inc.
Thermosets obtained by chemical modification of epichlorohydrin‐ethylene oxide copolymer and their crosslinking through double bonds
Authors: Reina J. A. , Serra A. , Mantecón A. , Cádiz V.
Published: April 2003

The epichlorohydrin‐ethyleneoxide copolymer is modified with 10‐undecenoate and 4‐pentenoate moieties in order to obtain thermosets by cross‐linking through their double bonds. These polymers are then characterized using NMR, IR, chlorine elemental analyses, X‐ray powder diffraction, DSC, TGA, and viscosimetric measurements. Because the thermal crosslinking reaction overlaps in all cases with degradation processes, a free radical source (dicumyl peroxide) is necessary. The Arrhenius kinetic parameters are determined by DSC, using Ozawa and Kissinger expressions. Finally, the quality of cured materials is tested by TGA. © 1995 John Wiley & Sons, Inc.
Ferrocene as an effective initiator for copolymerization of styrene with maleic anhydride
Authors: Kuramoto Noriyuki , Ogino Hiroko , Kido Junji , Nagai Katsutoshi
Published: April 2003

Ferrocene (Fc) was found to be an effective initiator for copolymerization of styrene (ST) with maleic anhydride (MAH). Copolymerization could be initiated by charge transfer complex formed between MAH as an electron acceptor and Fc as an electron donor. A good relationship between the formation of charge transfer complex and initiation activity was observed in the copolymerization of ST with MAH in various solvents. Overall energy of activation determined from an Arrhenius plot in dioxane was found to be 21.8 kJ/mol. © 1995 John Wiley & Sons, Inc.
Olefin terpolymerizations. I. 1,4‐hexadiene
Authors: Yu Zhengtian , Marques Maria , Rausch Marvin D. , Chien James C. W.
Published: April 2003

Ethylene (E), propylene (P), and 1,4‐hexadiene (HD) were terpolymerized with rac‐1,2‐ethylenebis (1‐η5‐indenyl) zirconium(IV) dichloride and methylaluminoxane (Et[Ind]2ZrCl2/MAO), and compared with the copolymerizations of E/P, E/HD, P/HD, and terpolymerization using ethylidene norbornene (ENB) as the termonomer. HD lowers the polymerization activity, the effect is more pronounced for P/HD and E/P/HD using large amount of P, than for E/HD and E/P/HD using feed low in P. The polymer molecular weight is most strongly affected by the temperature of polymerization (Tp), whereas the E/P ratio in the feed has virtually no effect. The reactivity ratios rE and rP are 3.0 and 0.3, respectively, at 20°C but rP becomes larger than rE at TP = 70°C. 1H‐NMR spectra showed occurrence of cycloaddition in the homopolymerization of HD; on the other hand, HD is incorporated in the terpolymer only by linear 1,2‐addition. © 1995 John Wiley & Sons, Inc.
ansa‐Zirconocenium catalysis of syndiospecific polymerization of propylene: Theory and experiment
Authors: Yu Zhengtian , Chien James C. W.
Published: April 2003

The syndiospecific propylene polymerizations catalyzed by isopropylidene(cyclopentadienyl)(fluorenyl)‐ and (2,2‐dimethylpropylidene)(cyclopentadienyl)(fluorenyl)‐zirconocenium (1+ and 2+) have been investigated theoretically and compared with experimental observations. With the ab initio calculated structures for the transition state (TS) of 1+(M)P and 2+(M)P (M = propylene, P = 2‐methylpentyl), their steric energies (E°) have been computed using MM2 force‐field. The difference between steric energies E°(m) and E°(r) for the meso and racemic enchainment of propylene, respectively, is defined as the stereocontrol energy [δE°(m − r)] for syndiotactic propagation. The δE°(m − r) for the TS of 1+ (M)P is about 2.1 kcal/mol, the value is 1 kcal/mol greater for 2+(M)P. The observed steric pentad distributions of the syndiotactic poly(propylene) obtained by these catalysts are consistent with smaller effective stereocontrol energy, which is about two‐third as large as δE°(m − r) values calculated for the MM2 optimized structure. Syndiotactic enchainment is favored over isotactic enchainment for all combinations of site configurations in the catalyst. α‐Agostic interaction seems to enhance syndioselectivity, whereas γ‐agostic interaction changes the stereoselectivity to meso enchainment. The mirror plane symmetry of the syndiotactic propagating species renders the stereoselectivity of the polymerization insensitive to reaction conditions. These catalysts are also highly regiospecific. © 1995 John Wiley & Sons, Inc.
Modified horner–emmons reaction of polymeric phosphonates: Versatile synthesis of pendant stilbene‐containing polymers
Authors: Belfield Kevin D. , Wang Juexian
Published: April 2003

Poly[styrene‐co‐(diethyl vinylbenzylphosphonate)] and poly[methylmethacrylate‐co‐(diethyl vinylbenzylphosphonate)] were prepared and used in modified Horner‐Emmons reactions to synthesize polymers with covalently attached stilbene groups. This versatile new method allowed for the preparation of polymers with either electron‐donor (OCH3, CH3) or electron acceptor (Br, NO2) substituents on the stilbene aromatic ring. The resulting polymers were characterized by 1H NMR, FT‐IR, UV‐visible, DSC, and size exclusion chromatography. Efficient transformation of polymeric phosphonates to the polymeric stilbene derivatives was realized. Size exclusion chromatographic analyses demonstrated that the reaction conditions have no deleterious effect on the molecular weight distribution of the various polymers that were prepared. Photochromic behavior was demonstrated for one of the derivatives. © 1995 John Wiley & Sons, Inc.
An amphiphilic graft copolymer as a surface‐modifying additive for poly(methyl methacrylate)
Authors: Zhu Liming , Gunnarsson Omar , Wesslén Bengt
Published: April 2003

An amphiphilic graft copolymer was prepared by transesterification of poly(2‐ethylhexyl acrylate‐co‐methyl methacrylate) with poly(ethylene glycol) monomethyl ether (MPEG2000). The grafting reaction was performed in melt at 155°C. The purified graft copolymer was blended into poly(methyl methacrylate) in concentrations of 1.5‐30 wt %, either by mixing in chloroform solution or by melt mixing by means of a twin‐screw extruder or a Brabender blender. Films of the blends were prepared by solution casting onto glass plates or by hot pressing between polished Al plates. At concentrations up to 20% of the graft copolymer homogeneous blends were obtained. At higher concentrations the blends were heterogeneous, and side‐chain crystallinity was detectable by DSC analysis. The surface properties of the films were studied by measurements of water contact angles. The surface accumulation of the graft copolymer was demonstrated as a large increase in the wetting angle hysteresis, and found to depend on the procedure for film preparation as well as the casting substrate. © 1995 John Wiley & Sons, Inc.
Poly‐3‐Hydroxyalkanoates containing unsaturated repeating units produced by pseudomonas oleovorans
Authors: Kim Y. B. , Lenz R. W. , Fuller R. C.
Published: April 2003

Poly‐3‐hydroxyalkanoates (PHAs) containing repeating units with terminal alkene substituents at the 3‐position were produced by Pseudomonas oleovorans grown with either 7‐octeneoic acid [OA()] alone, or 10‐undeceneoic acid [UND()] alone, or mixtures of UND() and either nonanoic acid (NA) or octanoic acid (OA). For the latter, the biomass and PHA yields decreased as the fraction of UND() increased in the mixed carbon substrates. Essentially all of the repeating units in the PHA obtained from cells grown with UND() alone contained terminal alkene groups, including 3‐hydroxy‐10‐undeceneoate, 3‐hydroxy‐8‐noneneoate, and 3‐hydroxy‐6‐hepteneoate units, but less than half of the units in the PHA from OA() had alkene substituents. The PHAs obtained from cells grown with various mixtures of UND() and either OA or NA were random copolymers, and the fraction of units with alkene substituents in these polymers increased in proportion to the fraction of UND() in the mixed carbon substrates. © 1995 John Wiley & Sons, Inc.
Homogeneous polyesters of predetermined length, composition, and sequence: Model synthesis of alternating glycolic‐acid‐co‐(L)‐lactic‐acid oligomers
Authors: Huang Bin , Hermes Matthew E.
Published: April 2003

Methods for making monodisperse polyester copolymers of predetermined length, com‐position, and sequence are reported. Alternating oligomers of (L)‐lactic‐co‐glycolic acid (La‐co‐Gl), isosteric with polypeptides, are prepared by solution methods of protecting, coupling, and deprotecting alcohol and acid groups. The carboxylic acid is protected by benzyl ester formation and released by hydrogenation. The hydroxyl group is protected as the methoxyethoxyethyl ether and deprotected with sodium iodide and trimethylsilyl chlo‐ride. Coupling uses dicyclohexylcarbodiimide. End‐capped alternating oligomers containing (GILa)4 and (GILa)8 show polymer properties. They are noncrystalline oils that exhibit discernable Tg. The conformation of GILa and LaGl diads in the polyesters is shown to be similar to isosteric peptide diads GlyAla and AlaGly. Exactly structured, monodisperse polyesters suggest a chemical parallel to proteins. Designed struc‐tural templates combining sheet‐form (Gl)n and helical (La)n segments are at‐tractive synthesis targets. The solution preparations reported here can be applied, but it is suggested that biosynthetic methods for introducing single ester units into peptide chains be adapted to synthesize precisely fashioned polyesters. © 1995 John Wiley & Sons, Inc.
Crowned polyacetylene. I. Synthesis and characterization of poly(4′‐ethynylbenzo‐15‐crown‐5)
Authors: Kakuchi Toyoji , Matsunami Shigeyuki , Kamimura Hiroyuki , Ishii Fumiaki , Uesaka Takahiro , Yokota Kazuaki
Published: April 2003

4′‐Ethynylbenzo‐15‐crown‐5 (EB15C5) polymerized with high yields in the presence of (bicyclo[2.2.1] hepta‐2,5‐diene) rhodium(I) chloride dimer and triethylamine as a cocatalyst in chloroform at 30°C. Common catalysts for the polymerization of substituted acetylenes, WCl6 and MoCl5, did not produce any polymer from EB15C5. The structure of the main chain for poly(4′‐ethynylbenzo‐15‐crown‐5) (PEB15C5) was determined to be predomi‐nantly cis form, based upon the relatively sharp signals attributed to the main chain atoms that was observed in the 1H and 13C NMR spectra. The cation‐binding properties of PEB15C5 are very similar to that of poly(4′‐vinylbenzo‐15‐crown‐5), and the selectivity is in the order of K+> Rb+ ≫ Cs+ ⋙ Na+, Li+. The electrical conductivity of PEB15C5 increased from 1.3 × 10−10 to 1.3 × 10−6 S. cm−1, when the polymer was doped with iodine. © 1995 John Wiley & Sons, Inc.
Complex‐radical terpolymerization of allylglycidyl ether, maleic anhydride, and methyl methacrylate: Design of self‐crosslinking macromolecules
Authors: Yürük Hüseyin , Rzaev Zakir M. O. , Akovali Güneri
Published: April 2003

Radical copolymerization of donor–acceptor monomers, i.e., allylglycidyl ether (AGE), maleic anhydride (MA) and methyl methacrylate (MMA) are studied, where binary copolymerization of AGE...MA complex with MMA is obtained. Constants of charge transfer complex formation (Kc) and copolymerization (r1 and r2) are determined by 1H‐NMR and Kelen‐Tüdöş methods, respectively. It is found that synthesized film‐forming terpolymers with free epoxy and anhydride groups on side chain of macro‐molecules are being crosslinked easily under the effect of temperature and/or UV‐ir‐radiation. Observed crosslinking effect is proved by the DTA, TGA, and IR spectroscopic analyses. It is shown that complex‐radical terpolymerization is very convenient method for the designing of reactive functional macromolecules of linear structure with self‐crosslinking properties which can serve as a basis for the use in photolithographic applications. © 1995 John Wiley & Sons, Inc.
Preparation and properties of alkylated poly(styrene‐graft‐ethylene oxide)
Authors: Jannasch Patric , Wesslén Bengt
Published: April 2003

Poly(styrene‐graft‐ethylene oxide), having alkyl chains (C12 or C18) on the polystyrene main chain or on the poly(ethylene oxide) (PEO) side chains, were synthesized. The main chain was alkylated by first ionizing amide groups in a styrene/acrylamide copolymer with tert‐butoxide, and then using the amide anions as sites for reactions with 1‐bromoalkanes. An excess of amide anions was used in the reaction, and the remaining anions were subsequently utilized as initiator sites for the anionic polymerization of ethylene oxide (EO). Synthesis of poly(styrene‐graft‐ethylene oxide) with alkylated side chains was accomplished by polymerization of EO onto the ionized styrene/acrylamide copolymer, followed by an alkylation of the terminal alkoxide anions with 1‐bromoalkanes. The alkylated graft copolymers were structurally characterized by using elemental analysis, 1H NMR, GPC, and IR spectroscopy. DSC analysis showed that only graft copolymers with PEO contents exceeding about 50 wt % and side chain crystallinities comparable to those of homo‐PEO. Main chain alkylated graft copolymers generally had higher crystalinities, as compared to nonalkylated and side chain alkylated samples. The graft copolymers absorbed water corresponding to one water molecule per EO unit at low PEO contents. The water absorption increased progressively at PEO contents above 30 wt % for main chain alkylated samples and above 50 wt % for non‐alkylated samples. © 1995 John Wiley & Sons, Inc.
Synthesis and characterization of 3‐phenylethynyl endcapped matrix resins
Authors: Jayaraman S. , Srinivasan R. , McGrath J. E.
Published: April 2003

The synthesis of 3‐phenylethynylphenol, and its applicability as a high temperature cross‐linking endcap for high Tg polyarylene ethers is described. It was synthesized in high yields and purity using the palladium catalyzed coupling reaction between the protected 3‐bromo or iodo phenol and phenylacetylene. The yield of the reaction was found to be highly dependent on the structure of the halide used, the reaction temperature, and the concentration of phenylacetylene. The use of the protected phenol in the palladium catalyzed reaction was also extended to the high yield synthesis of 3‐ethynylphenol and protected 4‐ethynylphenols. The complete synthesis of 3‐phenylethynylphenol, 3‐ethynylphenol, and protected 4‐ethynylphenol in high yields has been demonstrated and is discussed herein. Three new phenylethynyl functionalized arylene ether matrix resins have been synthesized in high yields and purity by reacting 3‐phenylethynylphenol with 4,4′‐dichlorodiphenyl sulfone, 4,4′‐difluorobenzophenone, and bis(4‐fluorophenyl)phenyl phosphine oxide, via nucleophilic poly(arylene ether) synthesis conditions. These low molecular weight materials undergo thermally induced chain extension/branching to yield an insoluble three‐dimensional network at reaction temperatures of around 380°C. The low molecular weight arylene ethers endcapped with the phenylethynyl group demonstrate excellent flow characteristics and a wide processing window of about 250°C. Crosslinking of the 4,4′‐bis(3‐phenylethynyl phenoxy)diphenyl sulfone system for 30 min at 350°C in air afforded a Tg value of 265°C by differential scanning calorimetry measurements. Trace metal analysis for palladium and copper showed absence of these metals that would otherwise detract from the excellent thermal stability. The synthesis and characterization of these phenylethynyl endcapped arylene ether matrix resins is discussed. © 1995 John Wiley & Sons, Inc.
Poly(ethylene oxide)/poly(2vinylpyridne)/lithium perchlorate blends as solid polymer electrolytes: Composition/property/structure interrelationship
Authors: Li Jean , Pratt Lawrence M. , Khan Ishrat M.
Published: April 2003

Poly(ethylene oxide) (MW 600,000)/poly(2vinylpyridine) (MW 200,000)/LiClO4 blends have been prepared by the solution blending process. The ionic conductivities of the blends containing lower weight fractions (15, 17.5, 20 and 22.5%) of poly (2vinylpyridine) initially increases as the salt content is increased, reaches a maximum at an ethylene oxide/Li+ mole ratio of 10 and decreases as the salt content is further increased. Blends, which have higher weight fractions of poly(2vinylpyridine) (25 and 35%) display different electric behavior, i.e., the ionic conductivity continously increased as the salt content is increased to an ethylene oxide/Li+ mole ratio of 2. Thermal, 7Li solidstate NMR and semiempirical MNDO molecular orbital studies indicate that this contrasting behavior may be explained by the structure and ratios of the solvates (mixed solvate or homosolvate) of LiClO4 present in the blends. © 1995 John Wiley & Sons, Inc.
Chain extension of polyesters PET and PBT with N,N′‐bis (glycidyl ester) pyromellitimides. I
Authors: Bikiaris Demetris N. , Karayannidis George P.
Published: April 2003

Three N,N′‐bis (glycidyl ester imide) of pyromellitic acid (diepoxides) were prepared and were used as chain extenders for poly (ethylene terephthalate) (PET) and poly (butylene terephthalate) (PBT). The typical reaction conditions for the coupling of the polyester macromolecules were heating with the chain extender under argon atmosphere above the melting temperature (280°C for PET and 250°C for PBT) for several minutes. The Characterization of the samples, obtained at variable residence times in the reactor, was based on solution viscosity measurements and carboxyl and hydroxyl end‐group determinations. Two of the diepoxides used gave satisfactory results. Starting from a PET having intrinsic viscosity [η] = 0.60 dL/g, and carboxyl content CC = 42 eq/106 g, one could obtain PET with [η] = 1.15 dL/g and CC = 16 eq/106 g within 30 min at 280°C. Analogous results were observed for PBT. The hydroxyl content of polyester in all cases was increased. When the quantity of the chain extender used was higher than that theoretically required for its reaction with all carboxyl end groups of the polyester, this resulted in some gel formation indicative of crosslinking. © 1995 John Wiley & Sons, Inc.
Quantitative nuclear magnetic resonance imaging of liquids in swelling polymers
Authors: Hyde Thomas M. , Gladden Lynn F. , Mackley Malcolm R. , Gao Ping
Published: April 2003

The variation of nuclear magnetic resonance (NMR) relaxation parameters (T1,T2) within a polymer during swelling, limits the absolute accuracy with which liquid concentration profiles can be obtained using NMR imaging. In this article a study of the diffusion of decalin into ultra‐high molecular weight polyethylene (UHMWPE) is reported. The study illustrates the use of a method of analysis whereby quantitative solvent profiles can be obtained from data influenced by bothT1andT2contrast effects. AT1andT2map are obtained at a point in the uptake of liquid where the greatest range in liquid concentration is obtained at a point in the uptake of liquid where the greatest range in liquid concentration is observed. The intensity of signal corresponding to liquid in the polymer is compared to that of pure liquid in a reference sample, and correlations forT1andT2values versus signal intensity are used to deconvolve relaxation contrast, to yield the true liquid concentration. The technique was used to study the effect of degree of crosslinking of UHMWPE on the swelling kinetics and decalin transport within the polymer. A spin‐echo imaging technique was used with a recycle delay approximately equal to the average spin‐lattice relaxation time of the liquid, and an echo time approximately half the average spin‐spin relaxation time. Under these conditions the relaxation contrast was significant, yet the mass uptake data derived from the concentration profiles obtained, using the method of analysis described, agreed well with gravimetric data. © 1995 John Wiley & Sons, Inc.
Role of polycation promoters in the cobalt(II) phthalocyaninetetracarboxylic and ‐octacarboxylic acid‐catalyzed autoxidation of mercaptoethanol
Authors: Schipper Eugène T. W. M. , Heuts Johan P. A. , Pinckaers Ralph P. M. , Piet Pieter , German Anton L.
Published: April 2003

The promoting effects of 2,4‐ionene on the cobalt(II) phthalocyaninetetracarboxylic acid‐[CoPc(COOH)4] and cobalt(II) phthalocyanineoctacarboxylic acid‐[CoPc(COOH)8] cata‐lyzed autoxidation of 2‐mercaptoethanol were studied. Dimerization of the CoPc(COOH)4 catalyst, combined with the disappearance of the catalytically inactive μ‐peroxo complex and the appearance of substrate enrichment in the presence of 2,4‐ionene, results in a 40‐fold enhancement of the oxidation rate as compared with the polymer‐free system. UV‐VIS spectroscopy indicates that CoPc(COOH)8 is incapable of forming μ‐peroxo complexes or 2,4‐ionene‐induced dimeric catalyst species under normal reaction conditions. Thus, it was possible to study exclusively the ionene‐induced effect of substrate enrichment. Addition of 2,4‐ionene to an aqueous CoPc(COOH)8 solution results in an activity enhancement by a factor of 2‐3, which can be ascribed to substrate enrichment. Additionally, using mono‐disperse ionene oligomers showed a molecular weight dependence of 2,4‐ionene on the catalytic activity of CoPc(COOH)8, as was observed for the conventional 2,4‐ionene/cobalt phthalocyaninetetrasodiumsulfonate system. The optimal polycation/catalyst ratios of both systems decrease with increasing chain length of 2,4‐ionene, until a constant value is reached. This leads to the conclusion that the optimal polymer/catalyst ratios are predominantly determined by substrate enrichment. © 1995 John Wiley & Sons, Inc.
Thermotropic liquid crystalline polymers with low thermal transitions. II. Low melting thermotropic liquid crystalline homo‐ and co‐polyesters
Authors: Sacripante Guerino , Ober Cristopher K. , Bluhm Terry , Panettoni Mario , Alexandru Lupu
Published: April 2003

Thermotropic liquid crystalline (TLC) polymers with low melt transitions are useful for imaging technologies. This is the first report describing thermotropic liquid crystalline copolyesters of low melt transitions comprised of a mesogen with up to three different spacer moieties. We have noted that the smectic mesophase range decreased with increasing amounts of different spacer moieties, without altering the isotropic transition and thereby leading to a broader nematic range. © 1995 John Wiley & Sons, Inc.
The preparation and characterization of poly(urethane–peo‐polar siloxane) complexes as polymer electrolytes
Authors: Hewitt David G. , Jing Lin
Published: April 2003

A series of novel poly(urethane‐PEO‐polar siloxane) copolymers and their complexes with LiClO4 were prepared for assessment as polymer electrolytes and characterized by IR, GPC, and DSC, and their ionic conductivity and thermal stability were tested. The incorporation of polar siloxanes into U‐PEO greatly increased conductivity. The highest conductivity was 2.6 × 10−5 S cm−1 at 25°C. The correlation between Tg, conductivity, and the ratio of siloxane to PEO as well as stability of the polymers are discussed. © 1995 John Wiley & Sons, Inc.
Studies on thermotropic liquid crystalline elastomers. I. Synthesis and properties of poly (amide‐ester) elastomers
Authors: Sun Shih‐Jieh , Chang Teh‐Chou
Published: April 2003

Three series of novel poly(amide‐ester) (PAE) elastomers were prepared by direct poly‐condensation from terephthalic acid (TPA), polyols (Mn = 1000 or 2000), and various diamines. The structures and thermal properties of the synthesized PAEs were examined by FTIR spectroscopy, wide angle X‐ray diffraction (WAXD), differential scanning calo‐rimetry (DSC), thermal optical polarized microscopy, thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). The effects of kinds and amount of diamines and the molecular weight of polyols on the thermal properties of PAEs were studied. By introducing long flexible spacers (PE‐1000 or PE‐2000) into the polymer main chain, all polymers showed two‐phase morphology under the thermal optical microscopic observation. It was interesting that most of the synthesized polymers exhibited only one melting transition corresponding to the soft segments. The melting transition of hard segments could not be detected due to decomposition of the soft segments. However, a thermotropic liquid crystalline PAE (TLCPAE) prepared from methylhydroquinone and 2‐chloro‐5‐methyl‐phenylenediamine with PE‐1000 could be obtained by lowering the melting transition temperature of the hard segment. © 1995 John Wiley & Sons, Inc.
Polymers of carbonic acid. XIV. High molecular weight poly(trimethylene carbonate) by ring‐opening polymerization with butyltin chlorides as initiators
Authors: Kricheldorf Hans R. , Weegen‐Schulz Bettina
Published: April 2003

Numerous BuSnCl, Bu2SnCl, and Bu3SnCl‐initiated polymerizations of cyclo(tri‐methylene carbonate) (TMC) were conducted in bulk. In addition to the initiator, reaction time, temperature, and monomer/initiator (M/I) ratio were varied. Yields above 90% were obtained with all three initiators, but their reactivities decrease in the order BuSnCl3 > Bu2SnCl2 > Bu3SnCl. The maximum molecular weights decrease in the same order. With BuSnCl3 Mws up to 250,000 were obtained. These molecular weights were determined by GPC on the basis of the universal calibration method. In this connection Mark‐Houwink equations for two solvents, tetrahydrofuran (THF) and CH2Cl2 were determined and compared with literature data. Furthermore, mechanistic aspects were studied. 1H‐ and 13C‐ NMR spectra revealed that BuSnCl3 forms complexes with the CO‐group of TMC, whereas Bu2SnCl3 do not cause NMR spectroscopic effects. Kinetic studies in chloroform and nitrobenzene and a comparison with Bu3SnOMe suggest that at least BuSnCl3 initiates a cationic mechanism. However, in contrast to SnCl4 (or SnBr4), BuSnCl3 does not cause decarboxylation. Regardless of the initiator 1H‐NMR spectroscopy revealed CH2OH and CH2CI endgroups in all cases. © 1995 John Wiley & Sons, Inc.
Liquid‐Crystalline copolymers and polymer blends containing electron donor and acceptor groups: Effects of mesogenic structures on the smectic phase and the miscibility
Authors: Kosaka Yozo , Uryu Toshiyuki
Published: April 2003

Side‐chain liquid‐crystalline copolymers and polymer blends containing an electron‐donating (carbazolylmethylene)aniline group and electron‐accepting nitrophenyl groups with various central linking groups between aromatic groups in the mesogenic units, i.e., NCH, CHCH, NN, and COO, were prepared to examine effects of the mesogenic structure on thermal behaviours. The most remarkable effects of the central linking group on the thermal properties and the miscibility were observed for the polymer blends. The 1:1 miscible polymer blends were prepared from the electron‐donating polymer containing (carbazolylmethylene)aniline group (PM6Cz) and the electron‐accepting polymers with similar central linking groups, i.e., NCH, CHCH, and NN. For example, the 1: 1 polymer blend of PM6Cz and the electron‐accepting polymer containing the nitrostilbene group induced a smectic phase from 73 to 207°C. This isotropic temperature was 46°C higher than the calculated value (161°C) based on the composition without the electron donor‐acceptor interaction. On the other hand, the 1: 1 polymer blend of PM6Cz and the electron‐accepting polymer containing the nitrophenylbenzoate group showed phase separation. Thus, the remarkable thermal stability and the miscibility of the polymer blends containing the electron donor and acceptor groups might be caused by planar structures between the mesogenic side groups which have similar central linking groups through the electron donor‐acceptor interaction. A similar tendency was seen for copolymers and binary mixtures of both low‐molecular‐weight compounds containing the same mesogenic groups. © 1995 John Wiley & Sons, Inc.
Preparation and control of surface properties of monodisperse micrometer size beads by dispersion copolymerization of styrene and butyl methacrylate in polar media
Authors: Horák Daniel , Švec FrantiŠek , Fréchet Jean M. J.
Published: April 2003

The dispersion copolymerization of styrene and butyl methacrylate in ethanol‐water medium to afford micrometer‐size monodisperse beads has been investigated. Hydroxypropyl cel‐lulose, poly (acrylic acid), and poly (vinylpyrrolidone) have been used as steric stabilizers, benzoyl peroxide and azobisisobutyronitrile as initiators. A novel steric stabilizing system consisting of a mixture of poly (acrylic acid) and hydroxypropyl cellulose has also been shown to lead to monodisperse beads for which the surface charge can be controlled by the relative ratio of steric stabilizers. The effect of several variables, such as the solvency of the medium, the concentration of co‐monomers, the reaction temperature, and the type of steric stabilizer and initiator used on the bead size and size distribution are discussed. © 1995 John Wiley & Sons, Inc.