bluuebunny/crossref_metadata_2025 huggingface dataset:
Syntheses and properties of cured epoxy resins containing the perfluorobutenyloxy group. I. Epoxy resin cured with perfluorobutenyloxyphthalic anhydride
Authors: Sasaki S. , Nakamura K.
Published: April 2003

Perfluorobutenyloxyphthalic anhydride (PFPA) has been synthesized as a new curing agent for epoxy resins, and the properties of epoxy resin cured with PFPA have been investigated. Good PFPA synthesis yields were realized by a dehydrating ring closure of perfluorobutenyloxyphthalic acid, which was obtained through the reaction of hexafluoropropene trimers with 4‐hydroxyphthalic acid. Epoxy resin cured with PFPA was found to have several excellent properties. Its boilding water absorption was 0.45%, which is about a one‐fourth that for conventionally cured epoxy resin. Its heat resistance was excellent, and its critical surface tension was almost the same as for PTFE.
Phosphorus‐containing polyurethanes and copolyurethanes based on 1,2‐dihydroxy‐1,2‐bis(diethoxyphosphinyl)ethane
Authors: Mikroyannidis John A.
Published: April 2003

The reactions of 1,2‐dihydroxy‐1,2‐bis(diethoxyphosphinyl)ethane (DBE) with various diisocyanates, such as tolylene diisocyanate, methylenebis(4‐phenylisocyanate), and hexamethylene‐1,6‐diisocyanate, were studied for the synthesis of phosphorus‐containing polyurethanes. In addition, DBE and ethyleneglycol or butanediol‐1,4 were copolymerized with the diisocyanates. The synthesized poyurethanes were characterized by Fourier transform‐infrared (FT‐IR), proton nuclear magnetic resonance spectroscopy (1H‐NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). Their thermal properties were compared with those of the corresponding common polyurethanes. The fire resistance of the copolyurethanes was evaluated by determining their limiting oxygen index and smoke evolution.
Aminopropylcellulose, synthesis and derivatization
Authors: Daly William H. , Munir Arshad
Published: April 2003

The preparation of 3‐aminopropylcellulose from cyanoethylcellulose is readily achieved. Reduction of the cyano groups with borane‐dimethyl sulfide in tetrahydrofuran or a borane‐tetrahy‐drofuran complex proceeds quantitatively in 3 h to a corresponding 3‐aminopropylcellulose. The presence of primary amine functions is confirmed by spectroscopy and a positive ninhydrin test; the concentration of amino substituents, as ascertained by titration, ranged from 1.2 to 6.4 meq/g. Because the derivatives are neither soluble nor excessively swollen in water, applications as ion‐exchange resins or chromatographic supports can be envisioned. Treatment of 3‐aminopropyl‐cellulose with acetyl chloride, phenyl isocyanate, or p‐toluenesulfonyl isocyanate produced 3‐acetamido‐, 3‐(N′‐phenyluredo)‐, or 3‐(N′‐p‐toluenesulfonyluredo)‐N‐propylcellulose. Alkylation with methyl chloride yielded a water‐soluble quaternary ammonium salt.
Synthesis of aromatic polythioamide‐oxothioxoquinazolines from bis(1,3,4‐thiadiazoline‐5‐thione) and aromatic bis‐o‐amino esters
Authors: Saegusa Yasuo , Iida Sakayu , Nakamura Shigeo , Chau Nguyen , Iwakura Yoshio
Published: April 2003

Aromatic polythioamide‐oxothioxoquinazolines were synthesized by the polycondensation of 2,2′‐(m‐phenylene)bis‐1,3,4‐thiadiazoline‐5‐thione with aromatic bis‐o‐amino esters. The polymerizations were carried out at 160°C in acidic media such as m‐cresol, sulfolane, and polyphosphoric acid to produce polymers with reduced viscosities up to 0.5 dL/g. These polymers were soluble in polar aprotic solvents like N‐methyl‐2‐pyrrolidone and some acidic media including m‐cresol. The polythioamide‐oxothioxoquinazolines showed relatively good thermal stability with 10% weight loss at 344–394°C in air.
Interpenetrating polymer networks from polyurethanes and methacrylate polymers. II. Interpenetrating polymer networks with opposite charge groups
Authors: Xiao H. X. , Frisch K. C. , Frisch H. L.
Published: April 2003

Interpenetrating polymer networks (IPNs) with opposite charge groups (tertiary amine and carboxyl groups) made from polyurethanes and methacrylate polymers have been synthesized and their properties and morphology, studied. With increasing carboxyl group concentration the mechanical properties and compatibility between the component networks were significantly improved, possibly because of the negative (or zero) free energy produced by the interaction contribution between the tertiary amine groups in the polyurethanes and the carboxyl groups in the methacrylate polymers determined by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The improved molecular mixing in these IPNs was thought to be due to the influence of the opposite charge groups in these systems.
Synthesis and investigation of polymers based on the nitriles of polycarboxylic acids and diamines
Authors: Vinogradova S. V. , Korshak V. V. , Siling S. A. , Solovyov V. N.
Published: April 2003

The influence of the reaction medium on the polycondensation of the tetranitriles of tetracarboxylic acids and diamines has been investigated. The reaction in phenol and cresols yields polymers with macroheterocycles in the chain—polyhexasocyclanes. If phenols with electron‐accepting substituents are used as reaction medium, nonmacrocyclic polymers with side aroxyl groups in the chain, polyisoindoxazenes—are formed. The properties of these polymers were studied. Macroheterocyclic compounds formed by condensation of phthalodinitrile with diamines can be used as one of the initial substances in polyhexasocyclane synthesis. Polyamidohexasocyclanes were prepared by polycondensation of macroheterocycles with dicarboxylic acid dichlorides. Some regularities of their formation and their properties were investigated.
Fire‐resistant polyimides and copolyimides based on 1‐[(dialkoxyphosphinyl)methyl]‐2,4‐ and ‐2,6‐diaminobenzenes
Authors: Mikroyannidis John A.
Published: April 2003

Various phosphorus‐containing polyimides were prepared by the reaction of 1‐[(dialkoxyphosphinyl)methyl]‐2,4‐ and ‐2,6‐diaminobenzenes (1) with a tetracarboxylic dianhydride like pyromellitic dianhydride (PMDA) and benzophenone tetracarboxylic dianhydride (BTDA). In addition, copolyimides that contained approximately 3% phosphorus were prepared by the reaction of 1 and m‐phenylenediamine (MPD) with the aforementioned tetracarboxylic dianhydrides. Elemental analysis, inherent viscosity, infrared (IR) spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) studies were performed to characterize the polymers. Their thermal properties were compared with those of the corresponding common polyimides. It was shown that the molecular weight and thermal stability of the polymers were reduced as the concentration of the phosphorus moieties increased. The fire‐resistance of the copolyimides was evaluated by determining their limiting oxygen index (LOI) value. Copolyimides that contained about 3% phosphorus showed an LOI value approximately 30% higher, than the value of the corresponding common polyimides. In addition, a model diamic acid and diimide was synthesized by the reaction of 1‐[di(2‐chloroethoxyphosphinyl)methyl]‐2,4‐ and ‐ 2,6‐diaminobenzene (DCEPD) with phthalic anhydride and characterized by elemental analysis, IR, proton nuclear magnetic (1H‐NMR) spectroscopy, DSC, and TGA. The pyrolysis behavior of the model compounds was investigated by gas chromatography‐mass spectrometry (GC‐MS). A direct cleavage of the PC bond and a possible rearrangement to diisocyanates occurred during their pyrolysis.
Anionic polymerization of norbornene trisulfide (exo‐3,4,5‐trithia‐tricyclo[5.2.1.02.6]decane)
Authors: Baran Teresa , Duda Andrzej , Penczek Stanisław
Published: April 2003

The anionic polymerization of norbornene trisulfide initiated with sodium thiophenoxide (sodium cation solvated with dibenzo‐18‐crown‐6 ether) was studied. Polymers with high molecular weights were obtained (Mn up to 105, osmometrically). Molecular weights calculated for living polymerization conditions (i.e., one molecule of initiator yields one macromolecule) agree well with Mn measured by osmometry. 1H‐NMR, 13C‐{1H}‐NMR, and Raman spectra of the polymer are given. Thermodynamics of polymerization in toluene solvent is described. Enthalpy ΔHss = −(1.39 ± 0.17) kcal mol−1 and entropy ΔSss = −(7.52 ± 0.55) cal mol−1 deg−1 coefficients of polymerization were evaluated from the temperature dependence of the equilibrium monomer concentration determined dilatometrically.
Fire‐ and heat‐resistant polymer based on maleimido‐substituted 2,2‐bis(anilino)‐4,4,6,6‐tetrakis‐(4‐aminophenoxy)‐cyclotriphosphazene
Authors: Kumar Devendra , Fohlen George M. , Parker John A.
Published: April 2003

A fire‐ and heat‐resistant polymer was obtained by the thermal polymerization of bismaleimido‐substituted 2,2‐bis(anilino)‐4,4,6,6‐tetrakis‐(4‐Aminophenoxy)‐cyclotriphosphazene. The thermal stabilities of the polymer were evaluated in nitrogen and in air by thermogravimetric analysis. This polymer was stable to 345°C and had char yields of 78% at 800°C in nitrogen and of 71% at 700°C in air. The structures of cyclotriphosphazene precursors and the polymer were characterized using Fourier‐transform infrared and proton nuclear magnetic resonance spectroscopy.
Living reversible anonic polymerization of N,N‐diethylamine‐1,3,2‐dioxaphosphorinan
Authors: Pretula Julia , Kałużyṅski Krzysztof , Penczek Stanisław
Published: April 2003

Polymerization of the cyclic amide of PIII is described for the first time. The N,N‐diethylamine‐1,3,2‐dioxaphosphorinan was shown to give living reversible polymerization with anionic initiators. Lithium and sodium derivatives were found to be inactive. 1H‐, 13C‐, and 31P‐NMR indicated that the polymer strictly reflects the monomer structure and is formed without any isomerization, the polymer chain being $\rlap{--} ({\rm OP}\left( {{\rm NR}_{\rm 2} } \right){\rm O(CH}_{\rm 2} \rlap{--} )_3 )_n $. Initiation involves attack of the anion on the P atom. From the dependence of the equilibrium monomer concentration on temeprature ΔH1s = 1.5 ± 0.2 kcal·mol−1 and ΔS1s = 4.6 ± 0.6 cal·mol−1·°K−1.
Preparation and properties of high transition temperature aromatic polyphosphonates by phase‐transfer‐catalyzed polycondensation of phenylphosphonic dichloride with bisphenols
Authors: Imai Yoshio , Kamata Hiroshi , Kakimoto Masa‐Aki
Published: April 2003

Aromatic polyphosphonates of high molecular weights were prepared from phenylphosphonic dichloride and bisphenols having rigid ring structures by the two‐phase polycondensation in organic solvent–aqueous alkaline solution system with phase‐transfer catalyst at 0°C or below. The effects of reaction solvent and catalyst on the inherent viscosities of the polymers formed are studied. The glass transition temperatures of the polyphosphonates with biphenyl, phenylindane, and diphenylfluorene units are 120, 124, and 188°C, respectively. These polymers are self‐extinguishing and are readily soluble in solvents such as N,N‐dimethylacetamide, pyridine, tetrahydrofuran, and chloroform. They began to lose weight above 300°C in air. Copolyphosphonates from combinations of bisphenols and phenylphosphonic dichloride are also prepared and characterized.
Photochromism of 4‐acryloxyazobenzene/(−)‐menthyl acrylate copolymers
Authors: Altomare A. , Carlini C. , Ciardelli F. , Solaro R. , Rosato N.
Published: April 2003

Copolymers of trans‐4‐acryloxyazobenzene (AAB) with (−)‐menthyl acrylate (MtA) have been prepared by free radical initiation; comonomer reactivity ratios have been found to be rAAB = 0.89 and rMtA = 0.53. Dependence of chiroptical properties on copolymer composition has been investigated and contribution to circular dichroism by azobenzene chromophores of isolated and sequence AAB units, as well as the influence of the trans to cis photoisomerization, have been determined. Kinetics of photoinduced trans → cis and thermally induced cis → trans isomerization of azobenzene side chains have also been examined and the kinetic parameters evaluated with relation to copolymer structure. The results have been discussed in terms of light‐induced secondary structure reversible modifications.
Functional metal‐porphyrazine derivatives and their polymers. VIII. Catalase‐like activity of Fe(III)‐ and Co(II)‐2,9,16,23‐tetracarboxyphthalocyanine supported on poly(2‐vinylpyridine‐CO‐styrene)
Authors: Shirai H. , Higaki S. , Hanabusa K. , Kondo Y. , Hojo N.
Published: April 2003

The decomposition reaction of hydrogen peroxide by Fe(III)‐ and Co(III)‐2,9,16,23‐tetracarboxyphthalocyanine supported on poly(2‐vinylpyridine‐CO‐styrene) and the quaternized one, was studied at pH 7.0 in aqueous media. The kinetics of this reaction was also investigated at pH 7.0 by measuring the initial velocity V0 of the increasing concentration of O2 with a Warburg respirometer. The reaction proceeded according to the catalaselike mechanism. Fe(III)‐2,9,16,23‐tetracarboxyphthalocyanine supported on poly(2‐vinylpyridine‐CO‐styrene) was a remarkably effective catalyst for a H2O2 decomposition reaction. The coordination sphere around the Fe(III)‐phthalocyanine ring was characterized by electronic and ESR spectroscopy. Fe(III)‐phthalocyanine supported on the copolymer dispersed in water was the five‐coordinated, high‐spin type. A typical competitive inhibition in respect of H2O2 by CN‐ was observed. ESR spectrum of this system showed the low spin iron(III) in the octahedral ligand field. The polymer coils hindered undesirable dimerization of metal‐phthalocyanine molecules by the shielding effect.
Graft polymerization of acrylic monomers onto starch fractions. III. Effect of carbohydrate structure
Authors: Goñi I. , Gurruchaga M. D. , Valero M. , Guzman G. M.
Published: April 2003

Grafted PMMA was isolated by the acid hydrolysis method. Weight‐average and number‐average molecular weights were determined by gel permeation chromatography. The number‐average molecular weight of the grafted chains was about 475,000 for amylopectin and 403,000 for amylose. The number of grafted chains (mmol) ranged from 2.4 × 10−3 to 4.6 × 10−3 for amylopectin graft copolymers and from 2.9 × 10−3 to 6.8 × 10−3 for those of amylose. These results were related to others obtained from ceric ion consumption studies. The values suggest that amylopectin, because of its complex structure, favors a higher consumption of ceric ion in homopolymerization reactions and inhibits the initiation reactions of the copolymerization.
Functionalization of an amorphous ethylene‐propylene copolymer by free radical initiated grafting of unsaturated molecules
Authors: De Vito G. , Lanzetta N. , Maglio G. , Malinconico M. , Musto P. , Palumbo R.
Published: April 2003

Functionalization of an amorphous ethylene‐propylene copolymer, EPM, has been performed by means of homogeneous grafting reactions of unsaturated molecules such as dibutylmaleate, diethylfumarate, itaconic anhydride, and maleic anhydride, initiated by free radicals. Dicumylperoxide and dibenzoylperoxide have been used as a free radical source and their efficiency has been compared. A different reactivity of the unsaturated molecules has been evidenced. The influence of the nature of the solvent on the functionalization degree has been investigated, revealing a noticeable effect of the solvent either on the amounts of grafted molecules or on the secondary reactions which lead to partial degradation of the functionalized EPM chains.
The preparation and characterization of homogeneous copolymers of ethylene and 1‐alkenes
Authors: Hunter B. K. , Russell K. E. , Scammell M. V. , Thompson S. L.
Published: April 2003

Homogeneous copolymers of ethylene and 1‐alkenes have been prepared using an ethyl aluminum sesquichloride–vanadium oxychloride catalyst system. Branches were varied from CH3 to C16H33 by appropriate choice of 1‐alkene. Size exclusion studies of copolymers of ethylene‐d4 and 1‐alkenes show that the comonomer content of a given sample is essentially constant over the whole molecular weight range. A random distribution of branches is inferred from the simplicity of the 13C‐NMR spectra and from the melting behaviour of the copolymers. Comonomer contents varying from 1 mol% to 15 mol% were readily determined by 13C‐NMR spectroscopy. The copolymers can be used to study the separate effects of branch length, branch frequency, and molecular weight on physical properties including melting point and crystallinity.
Addition polyimides. III. Thermal behavior of bismaleimides
Authors: Varma I. K. , Sangita  , Varma D. S.
Published: April 2003

This article describes the synthesis of N,N′‐bis(3,3′‐maleimidophenyl) sulfone (S) and its Michael addition products with (4,4′‐diaminodiphenyl) methane (S‐M), 4,4′‐diaminodiphenyl ether (S‐E), (3,3′‐diaminodiphenyl) sulfone (S‐DDSm), (4,4′‐diaminodiphenyl) sulfone (S‐DDSp), (3,3′,3″‐tris aminophenyl) phosphine oxide (S‐TAP), and 9,9‐bis(p‐aminophenyl) fluorene (S‐B). Curing behavior of these bisimides was investigated by differential scanning calorimetry. Activation energy of curing reaction was determined by using isothermal and multiple heating rate method. Thermal stability of bisimides was evaluated by thermogravimetric analysis. Better char yields were obtained in S‐TAP resins.
Molecular weight phenomena at high conversions in the Ziegler–Natta polymerization of butadiene
Authors: Honig J. A. , Burford R. P. , Chaplin R. P.
Published: April 2003

A Comparison between two different feedstocks in the homogeneous polymerization of butadiene has been conducted. The conversion and molecular weight trends were essentially the same for both feedstock systems. Changes in polydispersity at high conversions could not be explained by a living polymerization mechanism. A reaction scheme involving reuse of active cobalt centres combined with termination has been proposed.
The crosslinking of epoxy resins at interfaces. I. Germanium, germanium dioxide, and silane‐treated germanium
Authors: Garton Andrew
Published: April 2003

The chemical changes that accompany the crosslinking of an epoxy resin by an anhydride curing agent were followed by internal reflection spectroscopy (IRS). The crosslinking process was carried out on the surface of a germanium IRS element and the effects of various surface treatments of the germanium (humid aging, oxidation, and silane coating) on the reaction kinetics were examined. The reaction kinetics in the first 3000–4000 Å of the resin adjacent to dry, freshly polished germanium were similar to the reaction kinetics in the bulk of the resin. However, humid aging or oxidation of the germanium surface produced a local acceleration in the rate of anhydride consumption and reduced the yield of ester products. The aminosilane coating accelerated the consumption of anhydride, decreased the yield of ester, and resulted in the formation of amide groups in the interfacial region.
Thermal properties and morphology of α‐methylstyrene‐butadiene‐α‐methylstyrene triblock copolymer
Authors: Hsiue Ging‐Ho , Yang Wen‐Rong
Published: April 2003

Poly(α‐methylstyrene‐butadiene‐α‐methylstyrene) (mSBmS) was synthesized by two stages living anionic polymerization. Sodium naphthalene was used as initiator and HMPT as promoter to accelerate cross‐over reactions. The microstructure and composition of mSBmS were identified by infrared and nuclear magnetic resonance spectroscopes. The domain size was roughly calculated from TEM observation. It was observed that the morphology changed with the composition. The mSBmS exhibited two Tgs, −4 and 172°C, that associated with polybutadiene and poly‐α‐methylstyrene, respectively. Comparing stress relaxation behaviors of mSBmS and styrene‐butadienestyrene (SBS) at various temperatures, mSBmS showed a better thermal stability and degradation resistance than SBS. From the thermal gravimetric analysis, at 200°C, mSBmS gave a weight loss less than 1%, which provided a further evidence of better thermal stability of this material than of SBS.
The nature of active sites in butadiene polymerization catalyzed by organotitanium(III) derivatives
Authors: Dolgoplosk B. A. , Tinyakova E. I. , Guzman I. Sh. , Afinogenova L. L.
Published: April 2003

The stereospecificity of benzyl derivatives of trivalent titanium (Rn TiX3–n, where X = Cl, I, n = 1–3) in butadiene polymerization was studied. It was found that dibenzyltitaniumiodide is an efficient catalyst of the 1,4‐cis‐polymerization of butadiene and that tribenzyltitanium forms 1,2‐units. In both cases all the titanium‐benzyl bonds participated in the initiation reaction and the active sites were polymeric analogues of crotyl derivatives of Ti(III); namely, bis‐π‐oligobutadienyltitaniumiodide and tris‐π‐oligobutadienyltitanium. These sites are stable at room temperature. The nature of the active sites in the polymerization of butadiene with Ziegler's 1,4‐stereo‐specific systems Til4 (or Til2Cl2) + AIR3 are described.
Block copolymers derived from azobiscyanopentanoic acid. IV. Synthesis of a polyamide–polystyrene block copolymer
Authors: Ueda Akira , Nagai Susumu
Published: April 2003

Polyamides 6.10 and 6.6 (PA* 6.10 and 6.6) containing small amounts of NN units in the main chains were prepared by interfacial polycondensation between hexamethylenediamine and sebacoyl chloride or adipoyl chloride with addition of azobiscyanopentanoyl chloride. Polyamide–polystyrene block copolymers (PA‐b‐PSt) were then prepared by decomposition of the NN units of PA*, initiating radical polymerization of styrene in m‐cresol. The average PA block length of PA‐b‐PSt thus formed was longer than that expected from the initially present PA segments between the NN units. This is probably due to recombination of PA radicals whose initiation efficiency is as low as 15%. The PSt blocks also had higher molecular weight (7000–79,000) in comparison with homopolystyrene produced from monomeric azobiscyanopentanoic acid used as an initiator due to higher viscosity of polymerization system. Variation of intrinsic viscosity and turbidimetric titration behavior along with the change in composition were also discussed.
Direct polycondensation of aromatic dicarboxylic acids and bisphenols with tosyl chloride and N,N‐dimethylformamide in pyridine
Authors: Higashi Fukuji , Akiyama Naoki , Takahashi Ikuo , Koyama Tsugio
Published: April 2003

A Vilsmeier adduct derived from arylsulfonyl chlorides and DMF in pyridine was successfully used as a new condensating agent for the synthesis of aromatic polyesters by the direct polycondensation of aromatic dicarboxylic acids and bisphenols and also of hydroxybenzoic acids. Polymers of high molecular weights (M̄w = 78,000) with relatively narrow molecular weight distribution (M̄w/M̄n ≈ 3.0) were prepared by reacting aromatic dicarboxylic acids with the adduct in pyridine, followed by addition of bisphenols. The polycondensation was significantly affected by the amount of DMF, the nature of the arylsulfonyl chlorides, the conditions of initial reaction of the acids with the adduct, and the rate of reaction with bisphenols. The process was adaptable to the direct polycondensation of hydroxybenzoic acids, affording polymers of high molecular weight (ηinh = 1.73).
Cope elimination and complexation of poly(dimethylaminoethyl methacrylate N‐oxide)
Authors: Sato Tsuneyuki , Ito Osamu , Mori Shigeki , Otsu Takayuki
Published: April 2003

Poly(dimethylaminoethyl methacrylate N‐oxide) (poly(DMAEMNO)) was prepared by oxidation of poly(dimethylaminoethyl methacrylate) with hydrogen peroxide in methanol. From thermogravimetric and IR spectroscopic investigations Cope elimination of amine oxide group in poly(DMAENO) was found to occur at 120–150°C. The postpolymerization of partially pyrolyzed polymer carrying vinyl ester group as pendant was performed with azobisisobutyronitrile at 60°C in methanol to give cross‐linked polymer that was found to form hydrogel. Poly(DMAEMNO) gave metal–polymer complexes with CuCl2, ZnCl2, and CoCl2. Cobalt–polymer complex had a constitution of 1:2 of metal ion to amine oxide group, while copper– and zinc–polymer complexes seemed to have structures of 1:1 and 1:2 of metal ion to amine oxide group. Furthermore, polymer complexes of poly(DMAEMNO) with poly(methacrylic acid) and poly(acrylic acid) were found to be formed by mixing aqueous solutions of both polymers and also by radical polymerization of the acid monomers in the presence of poly(DMAEMNO). From elemental analysis, thermogravimetric investigation, and measurement of turbidity it was concluded that the resulting polymer–polymer complexes contained more than one acid monomer unit per one N‐oxide unit.
Synthesis and properties of polyamides of p‐phenylenedioxydiacetic acid
Authors: Srinivasan M. , Scariah K. J. , Krishnamurthy V. N. , Rao K. V. C.
Published: April 2003

Several polyamides of p‐phenylenedioxydiacetic acid (PDDA) were synthesized by the low‐temperature solution polycondensation techniques. Six different diamines were condensed independently with p‐phenylenedioxydiacetyl chloride (PDC) in a mixture of N‐methyl pyrolidone (NMP) and hexamethyl phosphoramide (HMPA). The polymers were obtained in 80–95% yield and possessed inherent viscosities in the range 0.32–0.81 dL/g. The polymers were characterized by infrared (IR) and H1‐NMR spectra. The solubility, density, crystallinity, and thermal stability of the polyamides were also determined. A model diamide (MDA‐1) was also synthesized from aniline and PDC to confirm the formation of polyamides from diamines.
Solution properties of ion‐containing polymers in polar solvents
Authors: Peiffer D. G. , Lundberg R. D.
Published: April 2003

The placement of ionic groups within the molecular structure of a polymer produces marked modification in physical properties. A large number of studies have been performed on these ion‐containing polymers, but few have focused on the effects of anion–cation interactions (i.e., counterion binding or ionization) on hydrodynamic volume, especially as the molecular structure of the solvent and nature of counterion are varied. In this study changes in hydrodynamic volume are followed through reduced viscosity measurements as a function of the abovementioned molecular parameters.

The dilute solution properties of various polyelectrolytes that contain sulfonate and carboxylate groups were investigated as a function of the counterion structure, charge density, molecular weight, and solvent structure. The polymeric materials were selected because of their specific chemical structure and physical properties. In the first instance a (2‐acrylamide‐2 methylpropanesulfonic acid)‐acrylamide‐sodium vinyl sulfonate terpolymer was synthesized and subsequently neutralized with a series of bases. Viscometric measurements on these materials indicate that the nature of the cation affects the ability of the polyelectrolyte to expand its hydrodynamic volume at low polymer levels. The magnitude of the molecular expansion is shown to be due in part to the ability of the counterion to dissociate from the backbone chain, which, in turn, is directly related to the solvent structure. The changes in solution behaviour of these inomers lend support for the existence of ion pairs (i.e., site binding) and ionized moieties on the polymer chains. Measurements performed in a variety of solvent systems further confirm this interpretation. In addition, and acrylamide‐sodium vinyl sulfonate copolymer was partially hydrolyzed with sodium hydroxide to study the effect of varying the charge density at a constant degree of polymerization and counterion structure. The results show that the charge density has a significant effect on the magnitude of the reduced viscosity and dilute solution behaviour. These observations, made in aqueous and nonaqueous solvents, are related to the interrelation of hydrodynamic volume, counterion concentration, and site binding. Again the controlling factor is the degree of site binding of the counterion onto the polymer backbone. Finally, we observe that the increased hydrodynamic volume affects viscosity behavior beyond the polyelectrolyte effect regime. If the average charge density on the macromolecule is relative high and/or the molecular weight is large (≥ 106) sufficient intermolecular interactions will occur to produce rapid changes in reduced viscosity.
Permanganate/glycine‐initiated polymerization of acrylamide
Authors: Bajpai U. D. N. , Bajpai A. K.
Published: April 2003

The kinetics of aqueous polymerization of acrylamide with KMnO4/glycine redox pair was studied in an atmosphere of nitrogen at 35 ± 0.2°C. The rate of polymerization was found to be first power on monomer, activator, and catalyst concentration. The overall energy of activation was calculated to be 15.66 kcal/deg mol (65.54 kJ/mol) between 30 and 50°C. The effects of various additives (alcohols, neutral salts, complexing agents, addition of catalyst) were studied. The dependence of the polymerization rate on the activator and catalyst concentration was studied in DMF‐water mixture also. The molecular weight of polymer was determined at various temperatures of the reaction medium.
Glycidyl methacrylate–tert‐butyl acrylate copolymers: Synthesis, characterization, and thermal studies
Authors: Dhal Pradeep K. , Babu Gaddam N.
Published: April 2003

Glycidyl methacrylate was copolymerized with tert‐butyl acrylate in bulk at 60°C using benzoyl peroxide as free radical initiator. The copolymer composition was determined by chemical analysis as well as from 13C‐NMR data. The monomer reactivity ratios were calculated by using the YBR method. The number average sequence length of the copolymers was determined from 13C‐NMR data and compared with those obtained from reactivity ratios. The intrinsic viscosity of the copolymers was determined in DMF, and thermal stability as well as mechanism of thermal degradation of the copolymers were evaluated.
Two‐component interpenetrating polymer networks (IPNs) from polyurethanes and epoxies. I. Studies on full IPN, pseudo‐IPN, and graft polymer alloys of polyurethanes and epoxies
Authors: Cassidy Edward F. , Xiao Han X. , Frisch Kurt C. , Frisch Harry L.
Published: April 2003

In this article we review the synthesis and morphology and the physical and mechanical properties of two‐component interpenetrating polymer networks (IPNs) from polyurethane and epoxy polymers; the corresponding pseudo‐IPNs and grafted IPNs are also discussed. A comparison was made of full IPNs, pseudo‐IPNs, grafted IPNs, and related homopolymers by examining their mechanical properties, mechanical spectra, and electron microscopy on an investigation of the effects of interpenetration or permanent entanglement in the IPN and related systems. This interpenetration has resulted in improved compatibility between the two polymer systems and has caused a decrease in the degree of phase separation. An observed shift in the dynamic glass transition temperatures (Tgs) of the two components which yielded a single IPN Tg further substantiates our results.
A regenerable immobilized NADH model. II. Reduction of α,α,α‐trifluoroacetophenone by immobilized 1,4‐dihydronicotinamide in aprotic solvent
Authors: Eling Berend , Challa Ger , Pandit Upendra K.
Published: April 2003

A regenerable dihydronicotinamide, immobilized on a macroreticular polystyrene resin was used for the reduction of trifluoroacetophenone (TFA) in acetonitrile. Practical reutilization of the polymeric reagent (91% per cycle) was obtained when magnesium perchlorate was added to the reaction of the immobilized dihydropyridine with TFA. A possible explanation of the role of Mg ion in the reaction of benzyldihydronicotinamide and its polymeric analog is presented. This explanation also accounts for the results of other NADH model reactions, described in the literature, and for the role of the Zn ion in the enzyme liver alcohol dehydrogenase (LADH).
Solution behavior of ampholytic styrene ionomers
Authors: Salamone J. C. , Tsai C. C. , Anwaruddin Q. , Olson A. P. , Arnold M. , Nagabhushanam T. , Sawan S. , Watterson A. C.
Published: April 2003

In this article are described the solution properties of ampholytic ionomers obtained by the radical copolymerization of styrene with the ion‐pair comonomer 3‐methacrylamidopropyltrimethylammonium, 2‐acrylamido‐2‐methylpropanesulfonate. The solution properties were studied in mixed solvents, with a good solvent for the polystyrene backbone and another for the ionic moieties, and in the individual good solvent of benzyl alcohol. The data obtained strongly support extensive intermolecular ionic interactions in solution.
Differential scanning calorimetry studies of irradiated polyethylene: I. Melting temperatures and fusion endotherms
Authors: Zoepfl F. J. , Markovic̀ V. , Silverman Joseph
Published: April 2003

The effect of ionizing radiation on the melting behavior of high‐density and low‐density polyethylene was examined with data obtained by differential scanning calorimetry. Melting temperatures and fusion endotherms were obtained after absorbed doses of gamma radiation up to 3 MGy. The changes in melting temperatures and heat of fusion for the first and second meltings are related to the radiation chemistry of polyethylene. The changes in the first melting temperature are caused by radiation‐induced links that decrease the melt entropy and increase the flod surface free‐energy‐per‐unit area of chain‐folded polyethylene crystals. These effects are dependent on the lamellar thickness distribution and on the types of links formed (intramolecular or intermolecular). The changes in melting temperature and heat of fusion obtained in the second melting are related to the inhibition of crystallization caused by the presence of radiation‐induced links.
Synthesis, characterization, and properties of novel aromatic bispropenyl ethers
Authors: Crivello James V. , Conlon David A.
Published: April 2003

Aromatic bispropenyl ethers are a new class of highly reactive thermosetting monomers that have been prepared and characterized. Two synthetic routes to their preparation have been developed. The first of these involves the base‐catalyzed isomerization of bisallyl ether precursors that gives predominantly the Z bispropenyl ether isomers. The second method employs tris(triphenylphosphine)ruthenium(II) dichloride as an isomerization catalyst and produces predominantly the E isomers. Using these methods, a number of bispropenyl ether monomers containing different aromatic groups have been synthesized. The cationic polymerization of these novel monomers to give crosslinked network polymers using diaryliodonium salts as photo and thermal initiators has been studied.
Direct polycondensations of hydroxybenzoic acids by use of diphenyl chlorophosphate in the presence of N,N‐dimethylformamide
Authors: Higashi Fukuji , Yamada Yukiharu , Hoshio Atsushi
Published: April 2003

Direct polycondensation reaction of hydroxybenzoic acids with diphenyl chlorophosphate (DPCP) in pyridine was largely improved by carrying out the reaction in the presence of a formamide. Among the formamides examined, N,N‐dimethylformamide (DMF), N,N‐dimethylformamide, and N,N‐dimethylacetamide were favorably used. A Vilsmeier adduct thus derived from DPCP and DMF was very effective especially for the preparation of high‐molecularweight copolyesters from hydroxybenzoic acids. Copolymers of several combinations of hydroxybenzoic acids were prepared and their solubility and thermal properties were investigated. The polycondensations of aromatic dicarboxylic acids and bisphenols with the adduct were also studied.
Synthesis and characterization of soluble polymides from 2,5‐bis(4‐aminophenyl)‐3,4‐diphenylthiophene and aromatic tetracarboxylic dianhydrides
Authors: Imai Yoshio , Maldar N. N. , Kakimoto Masa‐Aki
Published: April 2003

2,5‐Bis(4‐aminophenyl)‐3,4‐diphenylthiophene, a polyimide‐forming monomer, was prepared in three steps starting from benzyl chloride and sulfur. Novel polyimides were synthesized from the diamine and pyromellitic dianhydride or 3,3′, 4,4′‐benzophenonetetracarboxylic dianhydride (BTDA). Polymerization was carried out either by the usual two‐step procedure that included ring‐opening polyaddition giving polyamic acids, followed by cyclodehydration to polyimides, or by the direct one‐pot procedure involving cyclodehydration in situ. The polyimide derived from the diamine and BTDA, especially that prepared by the one‐pot procedure in m‐cresol containing isoquinoline, is soluble in various organic solvents and gave a yellow, transparent, tough, and flexible film. Solubility of this polyimide varied by the preparative method and by the copolymerization with bis(4‐aminophenyl) ether. All the polyimides are highly thermally stable and exhibited no appreciable decomposition up to 450°C in air and nitrogen atmospheres.
Polymerization of methyl methacrylate up to high degrees of conversion: Experimental investigation of the diffusion‐controlled polymerization
Authors: Stickler M. , Panke D. , Hamielec A. E.
Published: April 2003

The kinetic model given by Marten and Hamielec that describes the bulk polymerization of methyl methacrylate (MMA) and accounts for diffusion‐controlled termination and propagation was modified to include termination by combination and reaction diffusion and was then tested using isothermal conversion/time and molecular weight data obtained dilatometrically at various temperatures and with three different initiators. For each series of measurements two adjustable parameters were fitted to the conversion/time data. Excellent fits were obtained and the adjustable parameters were found to be the same for all concentration levels of the three initiators and to vary in a simple manner with temperature. The predicted molecular weight averages and molecular weight distributions were in satisfactory agreement with those found experimentally considering the difficulty of measuring high molecular weight PMMA by GPC. This model thus satisfies the specifications for a polymer reactor model that can be used to optimize commercial production systems.
Linear polythioesters. IX. Products of interfacial polycondensation of 4,4′‐dimercaptobenzophenone with some aliphatic acid dichlorides
Authors: Podkościelny Wawrzyniec , Kultys Anna
Published: April 2003

By interfacial polycondensation of 4,4′‐dimercaptobenzophenone with oxalyl, succinyl, adipolyl, suberoyl, and sebacoyl chlorides new polythioesters were obtained. To determine the optimal conditions of interfacial polycondensation the influence of the following factors on yield and value of reduced viscosity was studied: type of organic phase, the quantitative ratio of aqueous to organic phase, concentration of hydrogen chloride acceptor, molar ratio of reagents, temperature of reaction, rate of acid chloride addition, and contribution of catalyst. A thorough examination of the polycondensation of dithiol with adipolyl and sebacoyl chlorides was carried out. The structure of all polythioesters obtained under model conditions was determined by elemental analysis and infrared spectra. Initial decomposition and intensive decomposition temperature were defined by the curves of thermogravimetric analysis. Mechanical and electrical properties of the polythioesters obtained from 4,4′‐dimercaptobenzophenone and adipoyl and sebacoyl chlorides were determined. The molecular weight was not measured because of the low solubility of the polythioesters.
Probes of the microenvironments of the cationic copolymers of styrene and vinylbenzenetrialkylammonium halides
Authors: Herkstroeter W. G.
Published: April 2003

The microenvironments of the cationic copolymers of styrene and vinylbenzenetrialkylammonium halides were explored by use of fluorescence spectroscopy. 5‐Dimethylamino‐1‐naphthalenesulfonate (DANS) and 1‐pyrenebutyrate (PB) were the fluorescent probes selected to bind to the polymers. The fluorescence energy of the former responds to the polarity or hydrophobicity of the microenvironment, whereas the absorption and fluorescence of the latter reveal the extent of ground‐state and excited‐state interactions. Polyelectrolyte coiling occurs in proportion to the fraction of binding sites occupied with charge‐neutralizing, probe molecules. The bound DANS probe shows that coiling makes the binding‐site environment more hydrophobic, and the bound PB probe shows that coiling facilitates excimer formation not only with nearest‐neighbor pyrene moieties, but also with non‐nearest neighbors. With methyl groups at the quaternary nitrogen binding sites, pyrene moiety interactions preceding excimer fluorescence occur in both ground and excited states. When the methyl groups are replaced with butyl or pentyl groups, pyrene excimers still form in the excited state, but the weak, hydrophobic interactions of the pyrene ground state decrease, because the longer alkyl groups serve as hosts for the hydrophobic pyrene moieties.
Functional monomers and polymers. CX. Methylation and interaction studies on uracil‐containing polymethacrylate derivatives
Authors: Fang Shi‐Bi , Inaki Yoshiaki , Takemoto Kiichi
Published: April 2003

A polymethacrylate derivative containing uracil bases was methylated by using methyl iodide or dimethyl sulfate to give polymers containing 3‐methyluracil derivatives. In the case of methylation with dimethyl sulfate, sulfonation at 5‐position of the bases occurred in addition to the methylation at N‐3 position. The methylated polymers thus obtained were used further for the study of polymer complex formation with polymethacrylate containing adenine base.
Complexation and rate of polymerization of acrylic acid and methacrylic acid in the presence of poly(4‐vinylpyridine) in dilute methanol solution
Authors: Fujimori Kiyohisa , Trainor Gregory T. , Costigan Marion J.
Published: April 2003

A 1:1 hydrogen‐bonded complex was formed between acrylic acid (AA) or methacrylic acid (MA) and the pyridine group of poly(4‐vinylpyridine) (P4VP) in dilute solutions. A shift of infrared absorption of the hydrogen‐bonded acid OH to a lower energy direction and an upfield shift of acid proton in the NMR were observed when the monomers were added with pyridine. The equilibrium constants of the 1:1 complexation with P4VP measured by using a semipermeable membrane were 0.58 and 0.26 for AA and MA, respectively, at 25°C in methanol. The bromometrically measured initial rate of radical polymerization showed only a slight enhancement in the presence of P4VP, the rate being maximum at the 4VP unit:monomer mole ratio of 0.25 and 0.5 for AA and MA, respectively, in dilute methanol solution at 60°C.
Poly(alkylene oxide) ionomers. VII. Use of triethylaluminum/water/acetylacetone (1.0:0.5:1.0) for the polymerization of oxiranes
Authors: Bansleben Donald A. , Hersman Marie J. , Vogl Otto
Published: April 2003

Polymerization studies of oxiranes were conducted using a modified aluminumalkyl initiator, derived from the low‐temperature reaction by chelating agents (5°C) and hydrolysis products of triethylaluminum. The stoichiometric reaction product of acetylacetone and triethylaluminum, after partial hydrolysis with water, gave a homogeneous initiator that polymerized the oxides of ethylene, propylene, 1‐butene, 1‐hexene, 3‐chloro‐1‐propene, and 4,4,4‐trichloro‐1‐butene to the corresponding high molecular weight poly(alkylene oxides). The initiator, similar in nominal composition to the classical trialkylaluminum/water/acetylacetone (1.0/0.5/1.0) initiator developed by Vandenberg, retained a high level of activity, when properly stored, for nearly 4 weeks. The composition was inactive when the sequence of chelation and hydrolysis was reversed. Inclusion of a proton‐trapping agent in polymerization experiments of propylene oxide provided evidence that protons do not play a role in the initiation of oxirane polymerizations with modified organoaluminum oxides. Characterization of the various alkylene oxide polymers was carried out by spectroscopic, solution, and thermal techniques.
Optical rotatory dispersion and circular dichroism studies of copoly(propyl‐L‐aspartate‐benzyl‐L‐aspartate)
Authors: Tsujita Yoshiharu , Fujii Nobuaki , Imoto Yoshiko , Takizawa Akira , Kinoshita Takatoshi
Published: April 2003

Copoly(propyl‐L‐aspartate‐benzyl‐L‐aspartate)s with various compositions were synthesized by propylation of a parent poly(β‐benzyl‐L‐Aspartate). The variation of helix sense of copolyaspartate obtained against a degree of propylation and temperature was examined by optical rotatory dispersion and circular dichroism method. Copolyaspartate of propylation less than about 70% is in a left‐handed α helix conformation and its Moffitt parameter b0 and molecular ellipticity [θ]222 decreased gradually with increasing propylation. On the other hand, a different temperature dependence of b0 and [θ]222 was observed for copolyaspartate of propylation more than about 80%, i.e., the reversible transition of the helix sense from right‐ to left‐handed α helix took place by temperature increasing. These features were basically similar to the variation in helix sense of copoly(ethyl‐L‐aspartate‐benzyl‐L‐aspartate), although a slight difference was seen for copoly(propyl‐L‐aspartate‐benzyl‐L‐aspartate). The thermodynamic treatment indicating larger entropy of right‐handed α helix suggests much mobile side chain of the right‐handed α helix than the left handed one.
Determination of carbonyl‐containing functional groups in oxidized polyethylene
Authors: Fodor Zs. , Iring M. , Tüdős F. , Kelen T.
Published: April 2003

A combined (chemical and infrared (IR) spectrophotometric) method is discussed for the simultaneous determination of concentrations of carboxyl (A), ketone (K), and ester (E) groups formed in the oxidation of polyethylene (PE). The IR absorptivities of these functional groups were determined by using model compounds [stearic acid, stearone, poly‐(1,4‐butylene sebacate)]. The integral absorption of the CO band of polymer samples which contained several oxo groups of different types was found to be additive. This method was applied to the determination of the carboxyl, ester, and ketone content of samples oxidized at different oxygen pressures.
Catalyseurs Ziegler‐Natta supportés sur MgCl2 pour la polymérisation du propène. I. Etude de la réaction entre le triéthylaluminium et le benzoate d'ethyle
Authors: Spitz Roger , Lacombe Jean‐Loup , Primet Michel
Published: April 2003

In this article we describe a study of the reaction between triethylaluminium (TEA) and ethylbenzoate (BE) in a heptane solution by Fourier transform, infrared (IR), and ultraviolet (UV) spectroscopy. These compounds were chosen as a model of the cocatalytic solution used with a Ziegler‐Natta catalyst supported on MgCl2 for the stereospecific polymerization of propene. In the polymerization concentration range a 2 TEA:1 BE yellow complex was added to the solution and no free BE could be detected at a AI/BE molar ratio above 2: the solution contained only free and complexed TEA. The complex decomposed spontaneously to a colorless aluminium alcoholate. The rate of decomposition remained slow at room temperature and the reaction was enhanced by heating or by a high AI/BE ratio or high AI concentration. The decomposition was inhibited in the presence of an olefin.
Three‐component interpenetrating polymer networks (IPN's) from polyurethanes, epoxies, and poly(methacrylates)
Authors: Cassidy Edward F. , Xiao Han X. , Frisch Kurt C. , Frisch Harry L.
Published: April 2003

Three‐component IPN systems made from polyurethanes, epoxies, and poly(methacrylates) containing charge groups in the backbones of the constituent networks have been prepared. Specific attractive forces that occurred among the various networks helped to compatibilize them and aided in the formation of true homogeneous topologically interpenetrating polymer networks. These three‐component polymer alloys, including full‐IPN's, pseudo‐IPN's, and graft‐IPN's, were characterized by means of mechanical spectroscopy, electron microscopy, and stress–strain properties. In addition, some adhesion studies were carried out (lap shear strength and peel strength). A comparison of the different types of three‐component polymer alloys showed that better properties were generally exhibited by the graft‐IPN's and full‐IPN's containing opposite charge groups.