bluuebunny/crossref_metadata_2025 huggingface dataset:
New poly(amide‐imide)s syntheses. VIII. Preparation and properties of poly (amide‐imide)s derived from 2,3‐bis(4‐aminophenoxy)naphthalene, trimellitic anhydride, and various aromatic diamines
Authors: Yang Chin‐Ping , Chen Wen‐Tung
Published: April 2003

The new polymer‐forming diimide‐diacid, 2,3‐bis(4‐trimellitimidophenoxy) naphthalene (I), was readily obtained by the condensation reaction of 2,3‐bis (4‐aminophenoxy) naphthalene with trimellitic anhydride. A series of novel aromatic poly (amide‐imide)s were prepared by the direct polycondensation of diimide‐diacid I with various aromatic diamines using triphenyl phosphite in N‐methyl‐2‐pyrrolidone (NMP)/pyridine solution containing dissolved calcium chloride. The resultant polymers have inherent viscosities in the range of 0.65–1.02 dL/g at 30°C in N, N‐dimethylacetamide. These polymers were readily soluble in various organic solvents and could be cast into transparent, tough, and flexible films. Their casting films showed tensile strength at break up to 86 MPa, elongation to break of 5–9%, and initial moduli up to 2.35 GPa. The wide‐angle X‐ray diffraction revealed that those polymers containing p‐phenylene or p‐oxyphenylene group are partially crystalline, and the other polymers are evidenced as amorphous patterns. These polymers show a glass transition in the range of 213–290°C in their differential scanning calorimetry (DSC) traces. The thermal stability of the polymers was evaluated by thermogravimetry analysis, which showed the 10% weight‐loss temperatures in the range of 508–565°C in nitrogen and 480–529°C in air atmosphere. © 1994 John Wiley & Sons, Inc.
Photo‐ and thermoinitiated oxidation of high‐impact polystyrene. I. Characterization by FT‐IR spectroscopy
Authors: Israeli Y. , Lacoste J. , Lemaire J. , Singh R. P. , Sivaram S.
Published: April 2003

The photo‐ and thermooxidative degradation of different grades of high‐impact polystyrene (HIPS) has been studied by FT‐IR spectroscopy. The oxidized films were treated with NH3 and SF4 for the rapid identification and resolution of the various carbonyl species, alcohols, and hydroperoxides. All the sample gave similar oxidation products, but in varying quantities. The heterogenity in the film was also determined by micro‐FT‐IR spectroscopy. The thermal degradation processes at different temperature were compared. © 1994 John Wiley & Sons, Inc.
Two reaction routes for the preparation of aromatic polyoxadiazoles and polytriazoles: Syntheses and properties
Authors: Hensema E. R. , Boom J. P. , Mulder M. H. V. , Smolders C. A.
Published: April 2003

Two reaction routes for the preparation of aromatic poly‐1,3,4‐oxadiazoles and poly‐1,2,4‐triazoles are studied and their influence on the physical properties, i.e., inherent viscosity, glass transition, degradation temperature, and film integrity of the final products are discussed. Aromatic poly‐1,3,4‐oxadiazoles are prepared by means of a polycondensation reaction of terephthaloyl chloride and isophthalic dihydrazide yielding a precursor polymer, poly(p, m‐phenylene) hydrazide, which is converted into the corresponding poly‐1,3,4‐oxadiazole by means of a cyclodehydration reaction. Poly‐1,3,4‐oxadiazoles are also prepared by means of a polycondensation reaction between terephthalic and isophthalic acid and hydrazine yielding poly‐1,3,4‐oxadiazoles with higher inherent viscosities. Flexible poly‐1,3,4‐oxadiazole films are obtained only if the inherent viscosities of the polymers used are higher than 2.7 dL/g. The thermal stability is found to increase with increasing content of p‐phenylene groups in the polymer backbone. Aromatic poly‐1,2,4‐triazoles are prepared using polyhydrazides with alternating para‐ and meta‐phenylene groups and poly‐1,3,4‐oxadiazoles with a random incorporation of para‐ and meta‐phenylene groups in the main chain as precursor polymers. The glass transition temperatures are found to increase with increasing content of p‐phenylene groups in the main chain of these polymers. Cold crystallization is observed only for the alternating polymer. © 1994 John Wiley & Sons, Inc.
Free radical exit in emulsion polymerization. I. Theoretical model
Authors: Casey Brendan S. , Morrison Bradley R. , Maxwell Ian A. , Gilbert Robert G. , Napper Donald H.
Published: April 2003

The exit or desorption of free radicals from latex particles is an important kinetic process in an emulsion polymerization. This article unites a successful theory of radical absorption (i.e., initiator efficiency), based on propagation in the aqueous phase being the rate determining step for entry of charged free radicals, with a detailed model of radical desorption. The result is a kinetic scheme applicable to true “zero‐one” systems (i.e., where entry of a radical into a latex particle already containing a radical results in instantaneous termination), which is still, with a number of generally applicable assumptions, relatively simple. Indeed, in many physically reasonable limits, the kinetic representation reduces to a single rate equation. Specific experimental techniques of particular significance and methods of analysis of kinetic data are detailed and discussed. A methodology for both assessing the applicability of the model and its more probable limits, via use of known rate coefficients and theoretical predictions, is outlined and then applied to the representative monomers, styrene and methyl methacrylate. A detailed application of the theory and illustration of the methodology of model discrimination via experiment is contained in the second article of this series. © 1994 John Wiley & Sons, Inc.
Free radical exit in emulsion polymerization. II. Model discrimination via experiment
Authors: Morrison Bradley R. , Casey Brendan S. , Lacik Igor , Leslie Gregory L. , Sangster David F. , Gilbert Robert G. , Napper Donald H.
Published: April 2003

In emulsion polymerizations, desorption (exit) from latex particles of monomeric radical species that arise from transfer can be an important determinant of the overall kinetics. An examination of various methodologies for the testing of postulated free radical exit mechanisms is made. These utilize the model descriptions for the exit process presented in the accompanying article of Casey et al., employing data consisting of conversion as a function of time for the approach to steady state polymerization conditions. Experimental data are presented on the exit rate coefficients as a function of such experimental parameters as: particle size, monomer concentration, and aqueous‐phase free‐radical concentration for a series of styrene polymerizations at 50°C, where the average number of free radicals per particle (n̄) never exceeds 0.5. It is demonstrated for these systems that while the conversion/time dependence from a single run, under conditions sensitive to exit, is insensitive to mechanistic assumptions as to the fate of desorbed free radicals, the variation of the exit rate coefficient with particle size so obtained suggests a second order dependence on n̄, implying complete re‐entry of desorbed free radicals under all conditions studied. Once the monomeric radicals have re‐entered, they are more likely to remain inside the particle where they will either propagate or undergo termination rather than re‐escape. The article also presents an estimate for the rate coefficient at 50°C of the first propagation step of the monomeric radical subsequent to transfer. The conclusions drawn here for seeded systems should prove useful for study of particle nucleation mechanisms, when exit is particularly likely in small, newly formed, particles. © 1994 John Wiley & Sons, Inc.
Syndioselective propylene polymerization catalyzed by rac‐2,2‐dimethylpropylidene (1‐η5‐cyclopentadienyl) (1‐η5‐fluorenyl) dichlorozirconium
Authors: Fierro Ricardo , Yu Zhengtian , Rausch Marvin D. , Dong Sizhong , Alvares Dellyo , Chien James C. W.
Published: April 2003

Syndioselective propylene polymerization has been promoted by rac‐2,2‐dimethylpropylidene (1‐η5‐cyclopentadienyl) (1‐η5‐fluorenyl) dichlorozirconium (1). The active catalytic species were generated using either triphenylcarbenium tetrakis (pentafluorophenyl) borate (2) (Zr+ method) or methylaluminoxane (MAO method). The former exhibited much higher activity than the latter, especially at low polymerization temperatures (Tp). Syndiotactic poly (propylene) (s‐PP) obtained at Tp = −20°C has Tm approaching 160°C, [rrrr] pentad fraction of 0.92 to 0.95, and 45% crystallinity (Xc). It crystallized in two antichiral unit cells B and C. The C structure is favored by low temperature of polymerization, slow crystallization from melt, and annealing. The s‐PP has M̄w/M̄n ranging from 3.6 to 4.4, which can be separated into stereoregular fractions soluble in heptane and hexane and stereoirregular fractions soluble in pentane, ether, and acetone. Therefore, this system cannot be considered to be a single‐site catalyst. A parallel study was made on the isopropylidene (1‐η5‐cyclopentadienyl) (1‐η5‐fluorenyl) dichlorozirconium (3)/MAO catalyst. Molecular mechanics calculations were performed for all combinations of the configuration of asymmetric centers. The steric energy favors syndiotactic enchainment for both catalysts 1 and 3, with 1 forming the more syndioselective catalyst. © 1994 John Wiley & Sons, Inc.
Synthesis of tert‐butyl‐substituted poly (ether ketone) by nickel‐catalyzed coupling polymerization of aromatic dichloride
Authors: Ueda Mitsuru , Seino Yoshikatu , Haneda Yuko , Yoneda Masanobu , Sugiyama Jun‐Ichi
Published: April 2003

tert‐Butyl substituted poly (aryl ether ketone)s with relatively high molecular weights were prepared by the Ni‐catalyzed polymerization of tert‐butyl substituted aromatic dichlorides containing ether ketone unit. These polymers were amorphous and soluble in common organic solvents, such as THF, dichloromethane, and chloroform. De‐tert‐butylation of the polymer by the treatment of trifluoromethanesulfonic acid in the presence of toluene proceeded smoothly and produced crystalline poly (aryl ether ketone). © 1994 John Wiley & Sons, Inc.
Chemical derivatization as a mean to improve contact angle goniometry of chemically heterogenous surfaces
Authors: Holländer A. , Behnisch J. , Zimmermann H.
Published: April 2003

Plasma‐oxidized polyethylene (O‐PE) was derivatized with various chemicals and the advancing and receding contact angles with water, formamide, and tricresylphosphate were measured. The contact angles were used to evaluate the surface free energy (SFE) components in terms of the Lifshitz‐van der Waals‐acid base (LW‐AB) model. The derivatization was directed to couple alkyl chains to carbonyl, hydroxyl, and carboxyl groups generated on the surface of O‐PE. Carbonyl groups were treated with hydrazine and then reacted with dodecanoyl chloride. Hydroxyl groups were first reacted with reactive dicarboxylic acid dichlorides or cyanuric chloride, respectively, and then with alkylamines because the direct bonding of long‐chain alkyl carboxylic acid chlorides proceeds slowly and is, therefore, completed by surface restructuring. Carboxyl groups were chlorinated and in a second step reacted with alkylamines. The bonding of C12‐alkyl chains can be sensitively detected by the LW part of the SFE. Concerning the receding contact angles, it is pointed out that the carbonyl groups are present on the surface in a higher concentration than hydroxyl and carboxyl groups. The combination of contact angle goniometry (CAG) and chemical derivatization reactions supplies semiquantitative information about functional groups in the uppermost surface layer. In this way, a major shortcoming of CAG can be overcome. © 1994 John Wiley & Sons, Inc.
Synthesis and characterization of polyarylates derived from 4,4′‐dihydroxy‐meta‐terphenyl and aromatic diacid chlorides
Authors: Nye S. A. , Swint S. A.
Published: April 2003

Polyarylates derived from 4,4″‐dihydroxy‐meta‐terphenyl (DHmTP) were prepared by the phase‐transfer catalyzed, two‐phase polycondensation with aromatic diacid chlorides. The resulting polymers were crystalline, solvent resistant, and produced brittle films. Copolymers with bisphenol‐A were also synthesized using isophthaloyl diacid chloride. At low to moderate levels of DHmTP in the copolymers (25–75%), the materials had high glass transition temperatures (186–201°C), good solvent resistance, and gave tough, clear films. Terpolymers of DHmTP and BPA with 50:50 isophthaloyl and terphthaloyl diacid chloride were prepared with not much improvement over Ardel D‐100®. All the DHmTP‐polyarylates had good thermal stability (5% weight loss in air > 415–460°C) and had a high % char (20–48%). © 1994 John Wiley & Sons, Inc.
Thermotropic copolyamides from triethyleneglycol bis (4‐carboxyphenyl) ether, aromatic diamines, and p‐aminobenzoic acid
Authors: Higashi Fukuji , Nakajima Khoji , Zhang Wen Xion
Published: April 2003

It is proposed that depression of the transition temperatures, especially the melting point (Tm), can be achieved by the introduction of a different amide bond structure into the copolyamides of dicarboxylic acids and diamines by copolymerization of aminocarboxylic acids, such as p‐aminobenzoic acid. The effect was examined by the amount and distribution of the structure in the copolylamindes. Copolycondensations of PEG3, p‐aminobenzoic acid, and diamines with different chain lengths showed that the structural change of the amide bond in the copolymers, especially its distribution, was more important than its total amount in them. Several types of aminocarboxylic acids were briefly examined to study the effect. © 1994 John Wiley & Sons, Inc.
Pyrazoles—A novel class of blocking agents for isocyanates
Authors: Mühlebach Andreas
Published: April 2003

Pyrazoles were found as a novel class of blocking groups for isocyanates. Adhesive mixtures of pyrazole blocked isocyanates and amine terminated prepolymers like Jeffamines® (Texaco Chem. Co.) combine excellent reactivities (gelation times within minutes at 100–120°C), good latencies (more than 170 days at 40°C), and good adhesion properties on many substrates. The reactivity of pyrazole blocked isocyanates toward nucleophiles increases with the number of electron donor substituents on the pyrazole nucleus and, thus, can be fine tuned by the appropriate substitution pattern. This behavior contrasts sharply with that of phenolic blocked isocyanates, where reactivities with the same nucleophiles decrease with more and stronger electron donor substituents on the phenol nucleus. Therefore, different deblocking reaction mechanisms were proposed for pyrazole vs. phenol blocked isocyanates. The excellent latency of pyrazole blocked isocyanate/Jeffamine® mixtures is due to the insolubility of the two components at ambient temperature and the slow endothermic dissolution process at higher temperature. The good adhesion of formulations with pyrazole blocked isocyanates as reactive components on most plastic and metal substrates is ascribed to the primer action of the released blocking group. © 1994 John Wiley & Sons, Inc.
Ion‐free latex films composed of fused polybutadiene and poly (vinyl pyrrolidone) particles as polymer electrolyte materials
Authors: Rutt J. Steven , Matsumoto Morihiko , Ichino Toshihiro , Nishi Shiro
Published: April 2003

Latex films composed of fused polybutadiene (PB) and poly (vinyl pyrrolidone) (PVP) particles that contain no ionic, hydroxyl, or amino groups were swelled with lithium salt solutions to yield new polymer electrolyte materials. The latex particle consists of a nonpolar, rubbery core that contains the PB component and a polar, glassy shell that contains the PVP component. The particle core‐shell morphology was retained in the solid state, after the latex dispersion medium was removed and the films dried at high temperatures, due to the high Tg of the PVP shell. The films swelled when immersed in lithium salt solutions, and ionic conductivity of swollen films was greater than 10‐3 S/cm. Swelling and ionic conduction occurred only in the polar PVP component. Extraction of PVP occurred with extended swelling. © 1994 John Wiley & Sons, Inc.
Thermal polycondensation synthesis of biomimetic serine‐containing derivatives of polyaspartate: Potent inhibitors of calcium carbonate and phosphate crystallization
Authors: Donachy Julie E. , Sikes C. Steven
Published: April 2003

Biocompatable, degradable polymers that are powerful inhibitors of mineral formation were synthesized by automated solid phase and thermal polycondensation techniques. These polymers are analogues of natural proteins isolated from CaCO3 biomineral and consist primarily of polyaspartic acid and serine or modified serine residues. Phosphorylation of the serine residues greatly enhanced the inhibitory activity of the polymers. Synthesis in the presence of orthophosphoric acid resulted in the decomposition and modification of serine. These modified residues when incorporated into the polyaspartic acid also enhanced inhibitory activity of the polymers. © 1994 John Wiley & Sons, Inc.
Oligomers of a polyester network
Authors: Fawcett Allan H. , Hania Majid , Lo Kwok‐Wing , Patty Alan
Published: April 2003

Oligomers of glycerol and succinic acid have been prepared by three different methods and characterised by solution 13C‐NMR spectroscopy at 125.8 MHz. The first series of five oligomers was prepared by reacting glycerol with succinic anhydride; only one acid function of each succinic acid residue formed an ester by this means. They were readily distinguished as the shifts of their glycerol residues were dispersed over 16 ppm, and their shifts provided a guide to the assignment of shifts in the more elaborate oligomers. The second set of oligomers was prepared by treating glycerol with a small quantity of succinic acid, ester links being promoted by means of the reagent dicyclohexylcarbodiimide (DCCDI). When we used 2 mol of DCCDI/mol of acid in the presence of an excess of glycerol, no free acid functions remained, and a new set of oligomers was obtained. Furthermore, within this set the proportion of ring molecules was enhanced by repeating the reaction under much more dilute conditions. In this way the shifts of two ring oligomers were recognized in the spectrum. A different set of oligomers again was obtained when the esterification was performed with 1 mol of DCCDI/mol of succininic acid. After the first generation of oligomers had been identified in the mixtures produced by these three experiments, the reactions continued to produce larger oligomers with new fine structure features in the spectra. Glycerol trisuccinate was prepared in a pure form and heated in a vacuum to eliminate succinic acid groups and allow the formation of oligomers with two and three branch points. The structures successively produced by this reaction were readily recognized. In all we were able to recognize the formation of component structures in at least 17 different oligomers. The shifts of the carbons of the glycerol residues are sensitive to the substitution pattern at that residue, to whether the succinic acid residue to which they are linked has reacted a second time, and in some cases the methine shift is sensitive to how the succinic acid residue attached to a neighboring methylene carbon has reacted. © 1994 John Wiley & Sons, Inc.
Role of added Lewis base and alkylaluminum halide on living cationic polymerization of vinyl ether
Authors: Aoshima Sadahito , Onishi Hideshi , Kamiya Masamichi , Shachi Kenji , Kobayashi Eiichi
Published: April 2003

In the living cationic polymerization of isobutyl vinyl ether (IBVE) by the CH3CH (OiBu) OCOCH3 (1)/EtAlCl2 initiating system in the presence of the added base in hexane at +40°C, the stability of the initiating system 1/EtAlCl2, which form initiating species CH3CH⊕ (OiBu) derived from 1, was investigated. In the presence of the Lewis base such as ethyl acetate or 1,4‐dioxane, the active species was stable for 300 min even at +40°C in the absence of IBVE, and the living polymers were quantitatively obtained by adding IBVE. However, the active species was partly consumed by side reactions during the standing time for 60 min in the presence of a less basic additive such as ethyl benzoate, and about 50% of the active species was deactivated in the presence of methyl chloroacetate. Consequently, in the case of a less basic additive such as methyl chloroacetate (which was effective for the fast living polymerization), it can be seen that the careful selection of polymerization conditions was required. The living polymerization rate was dependent on the second order of EtAlCl2 concentration. EtAlCl2 induced the cleavage of 1 into CH3CH⊕ (OiBu) and EtAl⊖Cl2(OCOCH3), and the reactivity of CH3CH⊕ (OiBu) and propagating carbocation may be controlled by EtAl⊖Cl2(OCOCH3) with the aid of other EtAlCl2. Et1.5AlCl1.5 exists as a bimetallic complex of EtAlCl2 and Et2AlCl, and it is expected that the polymers having a bimodal molecular weight distribution will be obtained due to two kinds of counteranions coming from EtAlCl2 and Et2AlCl. However, in the cationic polymerization of IBVE by 1/Et1.5AlCl1.5 in the presence of ethyl acetate, the living polymer exhibiting a unimodal and very narrow molecular weight distribution was obtained. Thereby, it was suggested that the counteranions, EtAl⊖Cl2(OCOCH3) and Et2Al⊖Cl(OCOCH3), exchange rapidly with each other. © 1994 John Wiley & Sons, Inc.
Dimethyltitanocene‐induced surface chemical degradation of synthetic biodegradable polyesters
Authors: Pratt Lawrence M. , Chu C. C.
Published: April 2003

The purpose of this research was to selectively alter the rate of surface degradation of linear aliphatic polyesters without adversely affecting their bulk properties by way of functional group transformation, where the surface ester linkages would be converted to vinyl ether functionalities with dimethyltitanocene. It has been observed that dimethyl titanocene causes surface degradation of poly (glycolic acid) without adversely affecting its bulk properties, such as Mv, bursting strength, and thermal properties The vinvl ether resulting from the conversion of the PGA ester groups was unstable under ambient conditions, and further reacted by polymer chain scissioning, as was observed from measurements of molecular weight. © 1994 John Wiley & Sons, Inc.
Kinetics of propylene polymerization in the initial acceleration stage
Authors: Kim Il , Choi Hong Ki , Kim Jae Ha , Woo Seong Ihl
Published: April 2003

The kinetics of propylene polymerization catalyzed over a superactive and stereospecific catalyst for the initial build‐up period was investigated in slurry‐phase. The catalyst was prepared from Mg(OEt)2/benzoyl chloride/TiCl4 co‐activated with AlEt3 in the absence or presence of external donor. Despite a very fast activation of the prepared catalyst the acceleration stage of polymerization could be identified by the precise estimation of polymerization kinetics for a very short period of time after the commencement of polymerization (ca. 2 min). The initial polymerization rate, (dRp/dt)0 extrapolated to the beginning of the polymerization was second order with respect to monomer concentration. The dependence of initial polymerization rate on the concentration of AlEt3 could be represented by Langmuir adsorption mechanism. The initial rate was maximum at about Al/Ti ratio of 20. The activation energy for the initiation reaction was estimated to be 14.3 kcal/mol for a short‐time polymerization. The addition of a small amount of p‐ethoxy ethyl benzoate (PEEB) as an external donor increased the percentage of isotactic polymer, which was obtained after 120 s of polymerization, to 98% and the initial polymerization rate decreased sharply as [PEEB]/[AlEt3] increased. © 1994 John Wiley & Sons, Inc.
Glycine/Glycolic acid based copolymers
Authors: In 't Veld Peter J A. , Shen Zheng‐Rong , Takens Gijsbert A. J. , Dijkstra Pieter J. , Feijen Jan
Published: April 2003

Glycine/glycolic acid based biodegradable copolymers have been prepared by ring‐opening homopolymerization of morpholine‐2,5‐dione, and ring‐opening copolymerization of morpholine‐2,5‐dione and glycolide. The homopolymerization of morpholine‐2,5‐dione was carried out in the melt at 200°C for 3 min using stannous octoate as an initiator, and continued at lower reaction temperatures (100–160°C) for 2–48 h. The highest yields (60%) and intrinsic viscosities ([η] = 0.50 dL/g; DMSO, 25°C) were obtained after 3 min reaction at 200°C and 17 h at 130°C using a molar ratio of monomer and initiator of 1000. The polymer prepared by homopolymerization of morpholine‐2,5‐dione was composed of alternating glycine and glycolic acid residues, and had a glass transition temperature of 67°C and a melting temperature of 199°C. Random copolymers of glycine and glycolic acid were synthesized by copolymerization of morpholine‐2,5‐dione and glycolide in the melt at 200°C, followed by 17 h reaction at 130°C using stannous octoate as an initiator. The morphology of the copolymers varied from semi‐crystalline to amorphous, depending on the mole fraction of glycolic acid residues incorporated. © 1994 John Wiley & Sons, Inc.
Dispersion polymerization of methyl methacrylate: Mechanism of particle formation
Authors: Shen S. , Sudol E. D. , El‐Aasser M. S.
Published: April 2003

The mechanism for the formation of micron‐size polymer particles in the dispersion polymerization of methyl methacrylate was investigated by applying dynamic light scattering to monitor the evolution of the average particle size in the early stages of the polymerization. In addition, the contributions of physically adsorbed stabilizer and graft copolymer were evaluated by measuring the bound, unbound (adsorbed), and free stabilizer, and by determining the amount of added stabilizer required in seeded dispersion polymerizations. Twenty nanometer particles (termed nuclei) were the smallest particles detected and are considered to be formed by aggregation of growing polymer chains precipitating from solution as they exceed their critical chain length. Aggregation of these nuclei with themselves and their aggregates continues until mature and stable particles are formed. This occurs when sufficient stabilizer occupies the particle surface which includes both the polymeric stabilizer [poly(vinylpyrrolidone)] and its graft copolymer which is created in situ. The effects of process variables are discussed based on this mechanistic picture of the dispersion polymerization process. © 1994 John Wiley & Sons, Inc.
New poly (amide‐imide) syntheses. IX. Preparation and properties of poly(amide‐imide)s derived from 2,7‐bis (4‐aminophenoxy) naphthalene and various bis (trimellitimide)s
Authors: Yang Chin‐Ping , Chen Wen‐Tung
Published: April 2003

Eleven bis(phenoxy) naphthalene‐containing poly(amide‐imide)s IIIa–k were synthesized by the direct polycondensation of 2,7‐bis (4‐aminophenoxy) naphthalene (DAPON) with various aromatic bis (trimellitimide)s IIa–k in N‐methyl‐2‐pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. Poly (amide‐imide)s IIIa–k having inherent viscosities of 0.70–1.12 dL/g were obtained in quantitative yields. The polymers containing p‐phenylene or bis(phenoxy) benzene units exhibited crystalline x‐ray diffraction patterns. Most of the polymers were readily soluble in various solvents such as NMP, N, N‐dimethylacetamide, dimethyl sulfoxide, m‐cresol, o‐chlorophenol, and pyridine, and gave transparent, and flexible films cast from DMAc solutions. Cast films showed obvious yield points in the stress‐strain curves and had strength at break up to 87 MPa, elongation to break up to 11%, and initial modulus up to 2.10 GPa. These poly(amide‐imide)s had glass transition temperatures in the range of 255–321°C, and the 10% weight loss temperatures were recorded in the range of 529–586°C in nitrogen. The properties of poly(amideimide)s IIIa–k were compared with those of the corresponding isomeric poly (amide‐imide)s III′ prepared from 2,7‐bis(4‐trimellitimidophenoxy) naphthalene and aromatic diamines. © 1994 John Wiley & Sons, Inc.
Anionic polymerization of propylene oxide: Isomerization of allyl ether to propenyl ether end groups
Authors: Yu Ga‐Er , Heatley Frank , Booth Colin , Blease Trevor G.
Published: April 2003

The isomerization of allyl ether to propenyl ether end group in anionically‐polymerized poly (propylene oxide) was monitored by 1H NMR spectroscopy. It was confirmed that the reaction followed a simple second‐order rate law: −d[allyl]dt = k2[allyl] [O−]. Values of k2 determined over the 90–130°C temperature range, indicated an activation energy of 116 kJ mol−1. © 1994 John Wiley & Sons, Inc.
Copolymerization of methacrylonitrile with p‐methylstyrene
Authors: Chen Junjie , Goh S. H. , Lee S. Y. , Siow K. S.
Published: April 2003

Methacrylonitrile was copolymerized with p‐methylstyrene in methyl ethyl ketone at 80°C initiated by azobisisobutyronitrile. Monomer reactivity ratios of methacrylonitrile and p‐methylstyrene were found to be 0.205 and 0.377, respectively, using the Kelen‐Tüdos method. Triad fractions and monomer sequence lengths of three copolymers were determined from 13C‐NMR spectra and were found to be in good agreement with those calculated from reactivity ratios. © 1994 John Wiley & Sons, Inc.
Photocrosslinked hydrogels based on copolymers of poly(ethylene glycol) and lysine
Authors: Vyavahare Narendra , Kohn Joachim
Published: April 2003

A group of new, water‐soluble poly(ether‐urethane)s, derived from poly(ethylene glycol) and the amino acid L‐lysine, provide pendent carboxylic acid groups along the polymer backbone at regular intervals. The carboxylic acid groups were utilized for the attachment of acrylate and methacrylate pendent chains (hydroxyethyl acrylate, hydroxyethyl methacrylate, aminoethyl methacrylate, and aminoethyl methacrylamide), leading to functionalized polymers. The pendent chains were attached via ester and/or amide bonds having different degrees of hydrolytic stability. The attachment reactions proceeded with high yields (up to 95%). The functionalized polymers were subsequently photopolymerized (UV irradiation) to obtain crosslinked hydrogels. Crosslinked membranes with the highest degree of mechanical strength were obtained when the crosslinking reaction was performed in dioxane with benzoin methyl ether (0.1 wt %) as the initiator. the crystallinity, thermomechanical properties, and hydrolytic stability of the crosslinked membranes were studied. All membranes were transparent and highly swellable (equilibrium water content: 64–88%). The tensile strength in the swollen state ranged from 0.15 to 1.09 MPa. Under physiological conditions (phosphate buffered water, 0.1M, pH 7.4, 37°C) the hydrolytic stability of the hydrogels varied depending on the bonds used in the attachment of the acrylate pendent chains: Hydrogels with hydroxyethyl acrylate pendent chains dissolved within 30 days, while hydrogels containing aminoethyl methacrylamide pendent chains remained unchanged throughout a 30 day period. Using high molecular weight FITC‐dextrans as model compounds, complete release from the swollen hydrogels required between 60 and 150 h. Overall, the evaluation of poly(ethylene glycol)‐lysine derived, photocrosslinked hydrogels indicated that these materials provide a range of potentially useful properties. © 1994 John Wiley & Sons, Inc.
Reaction of diphenyldiacetylene by annealing under elevated pressure
Authors: Kojima Yoshitsugu , Tsuji Masao , Matsuoka Takaaki , Takahashi Hideroh
Published: April 2003

Reaction of diphenyldiacetylene (1,4‐diphenylbutadiyne) by annealing under elevated pressure (0.1–500 MPa) was carried out. Diphenyldiacetylene reacted at 210°C with appearance of gas, and this temperature was independent of the pressure. The measurement of high pressure differential thermal analysis (DTA) revealed that the reaction temperature under elevated pressure was below 24–42°C of the exothermic peak temperature. This implied that exothermic reaction occurred under elevated pressure. Elementary analysis, gel permeation chromatography (GPC), FTIR, Raman scattering, and high resolution 13CNMR experiments were performed to characterize the structure of the product. It was indicated that the product was a mixture of derivative of condensed polycyclic aromatic compound with phenyl group and diphenyldiacetylene oligomer. The fraction of the derivatives increased with increasing pressure, and pressure accelerated the dehydrogenation of the derivatives. The number‐averaged molecular weight (Mn) of the diphenyldiacetylene oligomer was 470–610 and the weight‐averaged molecular weight (Mw) was 1700–2300. It was considered that the oligomer had a polyacene‐based structure. © 1994 John Wiley & Sons, Inc.
Cationic polymerization of diglycidyl ether of bisphenol A
Authors: Matĕjka L. , Chabanne P. , Tighzert L. , Pascault J. P.
Published: April 2003

The cationic nonlinear polymerization of diglycidyl ether of Bisphenol A (DGEBA) in the presence of a diluent γ‐butyrolactone (BL) was initiated by the BF3‐4‐methoxyaniline (MA) complex. The reaction was studied by size exclusion chromatography, DSC, and dynamic mechanical analysis. Reaction mechanism involves a fast formation of adducts of DGEBA with MA released from the initiator. Formation of spiro orthoesters (S) by reaction of BL with DGEBA and homopolymerization of DGEBA as well as copolymerization with S follow. Gelation occurs at 60°C within a few minutes at conversion of epoxy groups (ξE)c= 0.20–0.45. The networks cured under optimum conditions show high glass transition temperature,Tα= 178°C. The mechanism‐structure‐property relations are discussed. © 1994 John Wiley & Sons, Inc.
Dye distribution in fluorescent‐labeled latex prepared by emulsion polymerization
Authors: Sosnowski Stanislaw , Feng Jianrong , Winnik Mitchell A.
Published: April 2003

Emulsion polymerizations were used for preparing fluorescent‐labeled polymers. The labeled polymers were analyzed by gel permeation chromatography (GPC) using both fluorescence (FL) and refractive index (RI) as detectors. The uniformity of polymer labeling was measured by the ratio between FL and RI signals, calculated by a computer software, on the basis of each GPC chromatogram. It was found that in emulsion polymerizations, the semicontinuous process can produce a more homogenous dye distribution in the host polymer molecules than the batch method. Uniform labeling of a polymer with various dyes can be achieved by the semi‐continuous process. However, experimental conditions for polymerization, such as initiator concentration and the presence of surfactant or chain transfer agent, may influence the uniformity of dye distribution. © 1994 John Wiley & Sons, Inc.
Amphiphilic graft copolymers with poly(oxyethylene) side chains: Synthesis via activated ester intermediates—properties
Authors: Berlinova Iliyana V. , Amzil Aissa , Tsvetkova Svetlana , Panayotov Ivan M.
Published: April 2003

Amphiphilic graft copolymers were synthesized via activated ester substitution of derivatives of fumaric acid with amino‐functionalized methoxypoly (oxyethylene)s (MPEO‐NH2) of different molecular weights. The monomeric activated esters, isopropyl pentachlorophenyl fumarate (PCPFA) and isopropyl succinimido fumarate (SIFA), were copolymerized with styrene (St) or N‐vinyl pyrrolidone (VP) at equimolar ratio. The polymeric‐activated esters proved to be good precursors for grafting of definite amounts of MPEO‐NH2. The aminolysis of the succinimide esters and VP‐containing copolymers proceeded with gel formation due to extensive hydrogen bonding. The hydrodynamic behavior, the emulsifying ability, the thermal properties, and crystallinity of the graft copolymers were studied as a function of their molecular characteristics. The length of the PEO grafts and the degree of grafting are the factors which affect the melting parameters and the crystallinity of the side chains. © 1994 John Wiley & Sons, Inc.
Phase‐transfer catalytic activity of soluble polystyrenes containing crown ether moieties and hydroxyl groups adjacent to the macrorings
Authors: Gotoh Yoshitaka , Kohno Yutaka , Fukuda Wakichi , Tomoi Masao
Published: April 2003

Soluble polystyrenes with crown ether structures and hydroxyl groups adjacent to the macrorings were prepared by the reaction of epoxide‐containing polystyrenes with monoaza‐15‐crown‐5 or monoaza‐18‐crown‐6. Rate of formation of the polymer‐bound alkali cation‐crown alkoxide ion pair from the soluble polystyrenes and aqueous NaOH or KOH depended on the loading of crown ether and hydroxyl units and on the size of the macroring. The elimination of HCl from less reactive 2‐chloroethylbenzene with aqueous NaOH or KOH in the presence of the soluble polystyrene catalysts under two‐phase conditions was limited mainly by the intrinsic reaction rate. The elimination of HBr from more reactive 2‐bromoethylbenzene in the presence of the less (11%) ring‐substituted polymer catalyst with 18‐crown unit was limited by the alkoxide formation rate. © 1994 John Wiley & Sons, Inc.
Synthesis of saccharide‐conjugated polyamides by quasi‐living anionic polymerization of a bicyclic lactam
Authors: Hashimoto Kazuhiko , Sugata Tohru , Imanishi Shin‐Ichiro , Okada Masahiko
Published: April 2003

Several well‐defined graft copolymers (7) having a water‐soluble natural polysaccharide (dextran) stock and hydrophilic polyamide branches of different molecular weights were synthesized by using a quasi‐living anionic polymerization of a bicyclic lactam 1, namely by the reaction of the acyllactam group in the quasi‐living polyamide 2 with the hydroxyl and amino groups in the dextran derivative (6), of which the reducing end was converted to an amino group. An oligosaccharide‐terminated polyamide 3 was also prepared efficiently by similar coupling reaction of the corresponding quasi‐living polyamide 2, with the maltose derivative (5) having an amino group. © 1994 John Wiley & Sons, Inc.
New fluorinated polysiloxanes containing an ester function in the spacer. I. Synthesis and characterization
Authors: Beyou Emmanuel , Babin Pierre , Bennetau Bernard , Dunogues Jacques , Teyssie Dominique , Boileau Sylvie
Published: April 2003

Unsaturated perfluoroalkyl esters derived from undecylenic acid: CH2CH(CH2)8COOCH2CH2RF (with RFC6F13, 2a and RFC8F17, 2b) and C8F17(CH2)10COOCH2CHCH2, 2c were prepared with excellent yields. Their hydrosilylation by methylhydrodimethylsiloxane copolymers of various SiH contents gives new fluorinated polysiloxanes which were examined by 1H‐ and 13C‐NMR, GPC, differential scanning calorimetry, and optical polarizing microscopy. Polymers derived from compounds 2a and 2b exhibit mesomorphic structures. © 1994 John Wiley & Sons, Inc.
Effect of reaction conditions on the grafting of 2‐(dimethylamino)ethyl methacrylate onto hydrocarbon substrates
Authors: Shing J. B. Wong , Baker W. E. , Russell K. E. , Whitney R. A.
Published: April 2003

The grafting of 2‐(dimethylamino)ethyl methacrylate (DMAEMA) onto two model hydrocarbons, squalane and n‐eicosane, and to linear low density polyethylene (LLDPE) has been investigated. The results of the study indicate that a high reaction temperature, 160°C, and a low concentration of monomer, less than 0.3 M, are optimum conditions for the grafting reaction. Reaction products, which consisted of grafted hydrocarbons and poly(DMAEMA), were separated by solvent extraction and vacuum distillation; samples were then analyzed by NMR and FTIR spectroscopy and size exclusion chromatography. 1H‐NMR spectroscopy indicates that grafted squalane contained approximately 6 DMAEMA units per squalane residue. 1H‐ and 13C‐NMR and molecular weight studies strongly suggest that the grafts onto the model hydrocarbons consist of single DMAEMA units. Results of the melt grafting of DMAEMA onto LLDPE show that the grafting efficiency and degree of grafting are substantially lower than were expected from the model system. © 1994 John Wiley & Sons, Inc.
Acyloin condensation in aqueous system by durable polymer‐supported thiazolium salt catalysts
Authors: Yamashita K. , Osaki T. , Sasaki K. , Yokota H. , Oshima N. , Nango M. , Tsuda K.
Published: April 2003

We characterized three low‐molecular‐weight thiazolium salt analogues: N‐methyl‐5‐(2′‐benzyloxyethyl)‐4‐methylthiazolium iodide (MBMTI), N‐methyl‐4‐phenylthiazolium iodide (MPTI), and N‐methylbenzothiazolium iodide (MBTI). MBMTI, having high‐electron density on the thiezolium ring, was found to be a durable thiazolium salt in buffer solution. Then, the polymer‐supported thiazolium salt catalyst having MBMTI structure as a catalytic site for acyloin condensation was prepared by the polymerization of the corresponding thiazole monomer and the following quaternization. The polymer catalyst had excellent catalytic activity even in buffer solution, while the corresponding low molecular weight catalyst did not show any activity in aqueous system. Furthermore, the durable polymer catalyst could be reused under the aqueous condition. © 1994 John Wiley & Sons, Inc.
Synthesis and properties of superconductors prepared from ethylenediaminetetraacetic acid (EDTA)‐ethylenediamine (ED) polyamide YBC chelate
Authors: Maeda Shigeru , Tsurusaki Yoshiyuki , Tachiyama Yoshiyuki , Naka Kensuke , Ohki Akira , Ohgushi Tetsuya , Takeshita Toshio
Published: April 2003

Single‐phase Y1Ba2Cu3O7‐x has been synthesized by a polymer‐metal chelate precursor technique. Ethylenediaminetetraacetic acid (EDTA)‐ethylenediamine (ED) polyamide was used as chelating polymer for Y, Ba, and Cu. The titration curves of the polymer in the absence and presence of each metal ion showed the chelate formations. The polymer was dissolved in water and the metal nitrates of Y, Ba, and Cu (1:2:3 in mole ratio) were stoichiometrically added to form a homogeneous molecular complex. The clear polymermetal chealate film was obtained by removal of the solvent without phase separation. This precursor was dried, calcined, and sintered to develop the superconducting (1,2,3) phase. The 1,2,3 phase produced was found to be pure according to x‐ray diffraction pattern and it possessed good superconducting properties, i.e., the onset of superconductivity was seen at 90.0 K and the resistance rapidly decreased with decreasing temperature, reaching substantially zero at 88.6 K. Scanning electron microscope (SEM) and face and point analyses by electron probe microanalysis (EPMA) showed that Y, Ba, and Cu elements were uniformly dispersed at least micron order. © 1994 John Wiley & Sons, Inc.
Penetration of plasma surface modification. I. Cf4 and C2F4 glow discharge plasmas
Authors: Yasuda T. , Okuno T. , Miyama M. , Yasuda H.
Published: April 2003

Plasma treatment of a polymeric surface could involve at least three major mechanisms: (1) direct interaction of reactive species in the low‐temperature plasma state with the surface (line of sight irradiation effect), and (2) chemical reactions of plasma‐induced reactive species with the surface, and (3) reactions among reactive species and the surface (plasma polymerization). The first and the third effects are considered to be limited to the surfaces which directly contact with plasma (glow). The second effect is not limited to the surfaces that contact with plasma state but can penetrate beyond the plasma zone by diffusion. Using an assembly of fibers, of which only the top layer contacts with plasma (glow), the penetration of chemical changes caused by plasma exposure was investigated. Results indicate that the fluorination effect (incorporation of fluorine‐containing moieties on the surface of polymeric substrate) penetrates through a considerable thickness of the assembly of fibers, depending on the porosity (gas permeability) of the system. Chemical reactions of plasma‐induced (chemically) reactive but nonpolymerizing species with the substrate fibers seems to predominate. The direct interactions of energetic species, such as ions, electrons, and electronically excited species, with polymeric surfaces seems to play relatively minor roles in the plasma treatment investigated. The major role of plasma, in this case, seems to be creating such chemically reactive species. © 1994 John Wiley & Sons, Inc.
Synthesis of thiol chelating resins and their adsorption properties toward heavy metal ions
Authors: Lezzi Alessandro , Cobianco Sandra , Roggero Arnaldo
Published: April 2003

A series of chelating resins, derived from a macroreticular styrene‐divinylbenzene (2%) copolymer beads grafted with various poly(ethylene glycols) HO(CH2CH2O)nH(n = 0, 4, 9, 13) and containing thiol groups as chelating functions, have been synthesized in a three‐step reaction sequence. The structure of the functionalized resins was confirmed by IR spectrophotometry, elemental analysis, and differential scanning calorimetry. The complexation behavior of these thiol resins was investigated towards Hg(II), Cu(II), and Pb(II) ions in aqueous solution by a batch equilibration technique. The influence of pH on adsorption capacity was also examined. The adsorption values for metal ions' intake followed the order Hg(II) > Cu(II) > Pb(II). The affinity of these polymers towards Hg(II) ions was so high that the total mercury level in the liquid decreased from 20 ppm to below 10 ppb after 2 h of treatment. Polymers can be regenerated by washing with a solution of hydrochloric acid (6N) and 10% by weight of an aqueous solution of thiourea. © 1994 John Wiley & Sons, Inc.
Thermotropic copolyamides from triethyleneglycol bis(4‐carboxyphenyl)ether, aromatic diamines, and p‐aminobenzoic acid modified by the monomer sequences in the copolyamides
Authors: Zhang Wen Xiong , Higashi Fukuji
Published: April 2003

Copolycondensations of triethyleneglycol bis(4‐carboxyphenyl)ether (PEG3), p‐amino‐benzoic acid (PABA), and p‐phenylenediamine (PPD) were studied in order to examine the effect of monomer sequences in the copolyamides upon the transition temperatures of the resulting copolymers. Random copolymerization of these monomers resulted in the copolymers exhibiting a nematic mesophase in a wide range of PABA content. On the other hand, the sequential copolymers composed of PABA/PPD = 1/1 and 2/1, which were prepared from 4,4′‐diaminobenzanilide (DABA) and N,N′‐bis(4‐aminobenzoyl)‐p‐phenylenediamine (BAB‐PPD), respectively, did not show a mesophase. The copolymers of a diamine combination of DABA and PPD exhibited a nematic mesophase, despite the lack of a mesophase for each homopolymer. The combinations of DABA and other diamines were also examined. © 1994 John Wiley & Sons, Inc.
Cation exchange membranes by pre‐irradiation grafting of styrene into FEP films. I. Influence of synthesis conditions
Authors: Gupta Bhuvanesh , Büchi Felix N. , Scherer Günther G.
Published: April 2003

Gamma radiation‐induced grafting of styrene into FEP films was investigated by the pre‐irradiation method. The degree of grafting was found to be strongly dependent on the synthesis conditions, such as radiation dose, monomer concentration, crosslinker, temperature, and film thickness. The order of dependence of the rate of grafting on pre‐irradiation dose and monomer concentration was found to be 0.64 and 1.90, respectively. The activation energy for the grafting in the temperature range of 50–80°C was determined to be 27.9 kJ/mol. A negative first order dependence of grafting on film thickness was observed. The results suggest that the initial grafting takes place at the film surface and proceeds to the middle by progressive diffusion of monomer through the polystyrene grafted layers. © 1994 John Wiley & Sons, Inc.
Quinone‐amine polymers. XV. Syntheses and characterization of high‐temperature resistant poly(arylamino‐quinone)s
Authors: Reddy T. Ashok , Macaione D. , Erhan S.
Published: April 2003

Several poly(arylamino‐quinone)s (PAAQs) were prepared by the conventional solution polymerization of p‐benzoquinone with various aromatic diamines in tetrahydrofuran. Polymers prepared by this method were found to be more soluble in many organic solvents compared to the PAAQs prepared by other reported methods. The poly(arylamino‐quinone)s were obtained in 82.3–94.5% yield and had inherent viscosities in the range of 0.073–0.251 dL/g. Among the PAAQs, the polymer prepared from p‐benzoquinone and 1,3‐bis(3‐aminophenoxy)benzene (APB) had demonstrated exceptionally good solubility and thermal stability. © 1994 John Wiley & Sons, Inc.