bluuebunny/crossref_metadata_2025 huggingface dataset:
Poly(arylsulfone imide) as E‐beam resist: Synthesis and radiolysis
Authors: Chien James C. W. , Cheng Z. S.
Published: April 2003

Aromatic diamines containing SO2 and S moieties have been used to prepare soluble polyimides with ditrifluoromethyl methane bis(phthalic anhydride) (F‐series polyimides) and polyamic acid with pyromellitic dianhydride (P‐series). Gamma radiolysis gave G(S) values for scission between 1 to 2 with no crosslinking. Significant weight loss occurred with radiolysis is attributable to efficient SO2 bond scission for the F‐series polyimides, as well as imidization in the cases of P‐series polyamic acids.
Circular dichroism and exciton effect of syndiotactic methacrylic polymers with chiral diacyl hydrazide side chain. II. Poly(methacrylic acid–Nβ (L‐(+)‐lactoyl) hydrazide)
Authors: Thevissen J. , Mano E. B. , Klesper E.
Published: April 2003

Syndiotactic poly(methacrylic acid hydrazide) has been condensed with L‐(+)‐lactic acid to form optically active side chains which are connected to the main chain by diacyl hydrazide moieties. A model compound was prepared in the same way from pivalic acid hydrazide. The CD spectra of polymer and model compound have been recorded in aqueous solution at different pH. In the acidic and neutral range, a strong Cotton effect is observed at 195 nm for the polymer which is not present for the model. This Cotton effect may be part of an exciton doublet, the second half of which may be located below 190 nm, the limit of the CD spectrometer employed. In the alkaline region, the diacyl hydrazide moiety is deprotonated and the polymer leads in contrast to the model to a well developed exciton effect centered around a crossover point of 241 nm. The influence of the addition of alcohols and salt on the CD spectra is studied, as well as the effect of temperature. For both the acidic to neutral range on one hand, and the alkaline region, on the other hand, ordered conformations are postulated. For the alkaline region a specific helical conformation is discussed.
Polyimides derived from 1,2‐bis(4‐aminophenoxy)propane
Authors: Tjugito Sukanto , Feld William A.
Published: April 2003

The diamine 1,2‐bis(4‐aminophenoxy)propane, containing the flexible 1,4‐dioxa‐2‐methylbutyl‐ene unit, was synthesized. Polyimidization was carried out with 5,5′‐[2,2,2‐trifluoro‐(trifluoromethyl)ethylidine]bis‐1,3‐isobenzofurandione in m‐cresol employing toluene as azeotroping agent to yield a polyimide that was soluble in a variety of solvents and had an inherent viscosity of 0.84 dL/g in N,N‐dimethylformamide. Poly(amic acid) formation with pyromellitic dianhydride, 4,4′‐carbonyldiphthalic anhydride, and 5,5′‐[ethanediylbis(oxy)]‐bis‐1,3‐isobenzofurandione was carried out in N,N‐dimethylformamide with imidization completed by heating at 160°C for 24 h under vacuum. All of the polyimides exhibited a 5% weight loss in air and in helium by 420°C.
Synthesis of poly(benzoxazinone)s by direct polycondensation of dicarboxylic acids with bis(anthranilic acid)s
Authors: Ueda Mitsuru , Komatsu Shinichi
Published: April 2003

A convenient method for the synthesis of poly(benzoxazinone)s of high molecular weights has been developed. These polymers were prepared readily by direct polycondensation of aromatic dicarboxylic acids containing phenyl ether structures with bis(anthranilic acid)s using phosphorus pentoxide/methanesulfonic acid (PPMA) as a condensing agent and solvent. Polycondensations proceeded smoothly and were completed within several hours at 140°C to produce poly(benzoxazinone)s with inherent viscosities up to 2.6 dL/g. The synthesis of 2‐substituted benzoxazinones by the reaction of aromatic carboxylic acids or dicarboxylic acid with anthranilic acid in PPMA was studied in detail to demonstrate the feasibility of the reaction for polymer formation. The thermogravimetry of the aromatic poly(benzoxazinone)s showed 10% weight loss in air and nitrogen around at 440 and 460°C, respectively.
Influence of thermal initiation on the radical polymerization of unsaturated monomers
Authors: Guzman J. , Madruga E. L. , Riande E.
Published: April 2003

The effect of thermal initiation of the radical polymerization of unsaturated monomers has been analyzed by considering a kinetic scheme that includes thermal‐ and catalyst‐induced formation of free radicals, propagation, and termination reactions. Expressions relating the different rate constants with the instantaneous monomer concentration are derived and they indicate the great influence of thermal initiation on the kinetic results. Application to a real case suggests that evaluation of kd and kp/k from experimental results using the method of dead‐end polymerization may lead to erroneous values of these constants.
Poly(vinyl acetate) as a template for the radical polymerization of acrylonitrile
Authors: Tewari N. , Srivastava A. K.
Published: April 2003

The template polymerization of acrylonitrile (AN) along with atactic‐poly(vinyl acetate) of Mv (47,090), at 60°C for 120 min in dimethyl formamide (DMF) has been studied dilatometrically to study the effects of template, monomer, and initiator (benzoyl peroxide) concentration upon kinetics. Viscometric measurements showed that complexation between at‐PVAc and PAN was maximum when template/polymer ratio was 1:1 and time required for complete complexation was 15 min. The overall energy of activation was 57.76 and 77.01 kJ/mol in the presence and absence of, PVAc, respectively. The overall system follows mechanism I, i.e., the monomer molecules get adsorbed on the surface of the template macromolecules and then propagation proceeds.
Water‐soluble graft copolymers from macromonomer method
Authors: Tsukahara Yasuhisa , Ito Katsuji , Tsai Hsi‐Chuan , Yamashita Yuya
Published: April 2003

Water‐soluble graft copolymers of well‐defined structure having hydrophobic polymethacrylate branches with different ester groups were prepared by the macromonomer method. Methacrylate macromonomers of controlled molecular weights having a methacryloyloxyl end group were synthesized by radical polymerization of the corresponding monomer in the presence of thioglycolic acid followed by the reaction of glycidyl methacrylate with the terminal carboxyl group. These macromonomers were copolymerized with methacrylic acid and methyl methacrylate to prepare tailor‐made graft copolymers composed of a hydrophlic backbone and different kinds of hydrophobic branches, which were characterized by elemental analysis, NMR, and GPC. The viscosities of the aqueous solutions of the sodium salts of these graft copolymers were measured. It was found that the viscosity of the dilute solution of the graft copolymer was remarkably high compared with the corresponding random copolymer irrespective of the ester group in branch segments. Solubilizing behavior of Orange‐OT in aqueous solutions of the graft copolymers and the random copolymer were also investigated to study the nature of the hydrophobic domain of the graft copolymers.
Synthesis of diols containing nucleic acid bases and their polyesters
Authors: Lu C. X. , Zhou Yan
Published: April 2003

Preparation of four diols containing nucleic acid bases derived from 3‐(thymin‐1‐yl)propanoic acid (3‐TPA) and 3‐(uracil‐1‐yl)propanoic acid (3‐UPA), and the corresponding model polymers of polynucleotides with linear polyester backbone and nucleic acid base derivative as pendant side chains are described. N‐(1′,3′‐Dihydroxy‐2′‐methyl‐2′‐propyl)‐3‐(thymin‐1‐yl)propionamide (VIa, 3‐HMPTPA), N‐(1′3′‐dihydroxy‐2′‐methyl‐2′‐propyl)‐3‐(uracyl‐1‐yl)propionamide (VIb, 3‐HMPUPA) and their isomers, N(β,β‐dihydroxyethyl)‐3‐(thymin‐1‐yl)propionamide (VIIa, 3‐HETPA), and N‐(β,β‐dihydroxyethyl)‐3‐(uracil‐1‐yl)propionamide (VIIb, 3‐HEUPA) were synthesized through the selective N‐acylation of 2‐methyl‐2‐amino‐1,3‐propanediol and diethanolamine with 3‐TPA and 3‐UPA, respectively, by the active ester‐N‐hydroxyl‐1,4‐epoxy‐5‐cyclohexene‐2,3‐dicarboximide (HOEC) method. The resulting diols were polycondensed with active diamide of benzotriazole (HBT) such as 1,1′‐(isophthaloyl)bis‐benzotriazole (IPBBT), giving polyesters containing thymine and uracil derivatives as the side group, by the selective O‐acrylation of active amide‐benzotriazole method.
Copolymer of trifluoroethylmethacrylate–N‐p‐methoxyphenyl citraconimide as high TgE‐beam resist
Authors: Gong Ben‐Min , Chien James C. W.
Published: April 2003

Copolymers of 2,2,2‐trifluoroethyl methacrylate (TFEMA) and N‐p‐methoxyphenyl citraconimide (MCM) have been synthesized. The Tg varies with composition reaching 150°C with 34% MCM. The copolymer has good radiation sensitivity according to both G values for chain scission and E‐beam measurements. Though they have lower contrast than PMMA, they have much higher resistance to plasma etching. The resistance increases markedly with MCM content to values comparable to that for polyimides. Therefore, TFEMA–MCM copolymers of high MCM content can be useful as high temperature plasma etchable positive E‐beam resists.
Aromatic rigid chain copolymers. I. Synthesis, structure, and solubility of phenyl‐substituted para‐linked aromatic random copolyamides
Authors: Jadhav J. Y. , Preston J. , Krigbaum W. R.
Published: April 2003

Four 2,5‐biphenylene based difunctional condensation monomers, such as 2,5‐diphenyldicar‐boxylic acid or phenylterephthalic acid (PTA), 2,5‐bis(carbonylimino‐4‐benzoic acid)biphenyl (2,5‐BCIBABP), 2,5‐diaminobiphenyl hydrochloride (2,5‐DABP.HCl) and 2,5‐bis(iminocarbonyl‐4‐benzoic acid)biphenyl (2,5‐BICBABP), have been synthesized and characterized. These monomers were polymerized in combination with terephthalic acid (TA) and p‐phenylenediamine (PPD) via the phosphorylation reaction to prepare a series of phenyl‐substituted random copolyamides having all amide groups attached to para‐positions of the benzene rings. All the copolyamides have been characterized by solubility, solution viscosity, and by differential scanning calorimetry (DSC). Some of these copolyamides have unusual solubility in organic solvents such as N,N‐dimethylacetamide (DMAc) and N‐methyl‐2‐pyrrolidinone (NMP) containing dissolved lithium chloride. A few copolyamides were tested for lyotropic behavior and found to form anisotropic solutions at critical concentrations in organic solvents. A randomly distributed unsymmetrical phenyl substituent on the benzene ring of para‐oriented wholly aromatic polyamides dramatically changes the solubility and melting point. The phenyl substituent on a terephthalic acid unit is more efficient in decreasing melting point and increasing solubility in organic solvents of aromatic polyamides than the one on a p‐phenylenediamine unit. However, the former also introduces a more flexible link in the extended polyamide chain.
Radiation effects on silicon‐containing polyacetylenes
Authors: Tang Ben‐Zhong , Masuda Toshio , Higashimura Toshinobu , Yamaoka Hitoshi
Published: April 2003

Si‐containing mono‐ and disubstituted polyacetylenes([CMeC(SiMe3)] n, [CHČH(nC5H11)SiMe3]n, etc.) underwent degradation in air; many of them exhibited relatively high yields of main‐chain scission (Gs > 1). The Gs values for the polymers having a long n‐alkyl group were usually large (ca. 2). In contrast, no polymer degradation occurred in vacuum, indicating that oxygen is necessary for the radiolysis. The polymers irradiated in air contained CO and SiO groups, and dissolved in polar solvents, which are nonsolvents of the starting polymers. From the radiation sensitivity and thermal degradability of these polymers, it is concluded that disubstituted polymers with high Si contents ([CMeC(SiMe3)]n, [CMeC(SiMe2CH2SiMe3)]n, etc.) are not only radiation‐sensitive but also thermally stable.
Polypyrazolinones from aromatic di(propynoic ester)s and aromatic dihydrazines
Authors: Andrews S. M. , Bass R. G.
Published: April 2003

Novel polypyrazolinones with inherent viscosities ranging from 0.12 to 0.44 dL/g were prepared by the Michael‐type nucleophilic addition‐cyclization of various dihydrazines with 3,3′‐(1,3‐ or 1,4‐phenylene)bis(ethyl propynoate) (1,3‐ or 1,4‐PEP) and 3,3′‐(1,4‐phenylene)bis(phenyl propynoate) (1,4‐PPhP) in N‐methylpyrrolidone (NMP) solution at 25–110°C. The polymers exhibited moderate thermal stability with initial weight loss in air about 200°C and in nitrogen about 300°C (TGA). No apparent Tg′s were observed by DSC analysis. The synthesis and characterization of the polypyrazolinones is discussed.
Multitechnique surface spectroscopic studies of plasma modified polymers III. H2O and O2/H2O plasma modified poly(methyl methacrylate)s
Authors: Vargo Terrence G. , Gardella Joseph A. , Salvati Lawrence
Published: April 2003

The surfaces of poly(methyl methacrylate) (PMMA) films modified by O2H2O and H2O radio‐frequency glow discharge plasmas were studied using electron spectroscopy for chemical analysis (ESCA or XPS), low energy ion scattering (LEISS or ISS), Fourier transform IR spectroscopy (FTIR) with attenuated total reflectance (ATR) sampling, and critical surface energy from contact angle measurements. The extent and nature of modification with respect to promotion of a hydrophilic surface compared to the hydrophobic surface of the unmodified PMMA has been probed. Results show drastic decreases in C/O ratio at the near surface, which increases to that of the unmodified PMMA as deeper cross sections are analyzed. In addition peak fitting of ESCA data correlated with FTIR functional group information allows for the qualitative and quantitative analysis of the resulting bonding and structure of the modified layer. From these results combined with the polarity and surface energy differences obtained from contact angle measurements, the structural changes are discussed with respect to plasma reaction mechanisms and differences in the structure of the modified polymer films.
Cyclotrimerization of butyl and cyclohexyl isocyanate—catalysis and kinetics
Authors: Šehović Hajrija , Sendijarević Aiša , Sendijarević Vahid , Frisch Kurt C.
Published: April 2003

The cyclotrimerization of model aliphatic and cycloaliphatic isocyanates (butyl and cyclohexyl isocyanate) was carried out using an ammonium carboxylate and a salicylaldehyde‐potassium complex as catalysts. The kinetics of the cyclotrimerization of butyl isocyanate in both 2‐ethoxyethyl acetate and dimethylformamide (DMF) using the 2‐ethylhexanoate salt of trimethylaminopropanol‐2 was found to be of first order with respect to the isocyanate and also of first order with respect to the catalyst. The reaction rate in DMF was considerably greater than in 2‐ethoxyethyl acetate, as could be expected. Employing the salicylaldehyde‐potassium catalyst, the cyclotrimerization of butyl isocyanate followed second‐order kinetics with respect to the isocyanate and first order with regard to the catalyst. Due to the fact that the cyclotrimerization of cyclohexyl isocyanate was found to be slower than that of butyl isocyanate, the cyclotrimerization of this isocyanate was carried out only in DMF using the 2‐ethylhexanoate salt of trimethylaminopropanol‐2 as the catalyst. The kinetics of this reaction was found to follow second order with respect to the isocyanate and first order with regard to the catalyst. The products of the reactions were identified by IR, 1H‐NMR, and mass spectrometry.
Allylnadic‐imides: A new class of heat‐resistant thermosets
Authors: Renner Alfred , Kramer Andreas
Published: April 2003

Allyl‐bicyclo‐(2,2,1)hept‐5‐en‐dicarboxylic(2,3)imides (allylnadic‐imides) are prepared by heating equivalent amounts of allylnadic anhydride and amines. Mixtures of isomers (1‐allyl‐endo, 6‐allyl‐endo and exo) were obtained, separated by flash chromatography and identified by 1H‐ and 13C‐NMR. A series of novel allylnadic‐imide monomers is described. Upon heating to 250°C oligomers are obtained. Diels—Aider rearrangement and “ene” type addition reactions seem to play a major role in oligomer formation. Bis‐ and tris‐allylnadic‐imides are viscous liquids resins or low melting solids, which are soluble in common solvents. Upon heating to 250°C insoluble, high Tg solids are obtained with good thermooxidative and environmental stability and with reduced burning rate. Cured allylnadic‐imide resins are excellent high temperature insulators and low permittivity dielectrics. Crosslinked copolymers with maleic‐imides and epoxy resins are described. Neat resin and carbon fiber composite properties are reported.
Syntheses of new thiazolium salt polymers and their catalytic activities
Authors: Yamashita Keiji , Tokuda Hiroyuki , Tsuda Kazuichi
Published: April 2003

Thiazolium salt polymers were synthesized for the purpose of obtaining a more efficient catalyst for the acyloin condensation. A new thiazolium salt, N‐methyl‐4‐vinylphenylthiazolium iodide was synthesized. However, this compound did not homopolymerize by radical initiator. Therefore, 4‐vinylphenylthiazole was polymerized and the obtained polythiazole was quarternized by methyl iodide. Poly(N‐methyl‐4‐vinylphenylthiazolium iodide) was examined as a polymer‐catalyst for the acyloin condensation of several aldehydes. This polythiazolium salt had an excellent catalytic activity in organic solvents, even in nonpolar solvents. Moreover, it was observed that the catalytic activity increases with the decrease of quarternization.
The block copolymers and polymer blends of nylon 6 with poly(4,4′‐diphenylsulfone terephthalamide). I. Preparation and thermal properties
Authors: Wang Huie‐Hsiung , Chen Wei‐Liang
Published: April 2003

In this study, the flexible nylon 6 was reinforced by the rigid‐chain aromatic polyamide, poly(4,4′‐diphenylsulfone terephthalamide) (PSA). Various high molecular weight block copolyamides were synthesized by solution polymerization using 4,4′‐diisocyanatodiphenylmethane (MDI) or p‐aminophenylacetic acid (p‐APA) as a coupling agent, respectively. Their thermal properties had shown that block copolyamides exhibited higher Tg and Tm, and better thermal stability, especially those using p‐APA as a coupling agent. Decrease in thermal stability of block copolyamides based on MDI coupling agent was due to its urea linkage which been explained and proved by the infrared spectra data. On the other hand, the PSA molecules could act as “nucleating agents” among the nylon 6 matrix in the polymer blends, and accelerated the growth rate of crystallization of nylon 6 molecules, even though high molecular weight of PSA was used.
Positron annihilation lifetime evaluation of thermal cycling effects in atactic polystyrene
Authors: Kasbekar Anand D. , Jones Phillip L. , Crowson Andrew
Published: April 2003

Positron annihilation lifetime spectroscopy (PALS) was used to investigate the thermal cycling characteristics of two different molecular weight atactic polystyrene resins. Annealed compression molded samples were thermally cycled over the temperature range 253 K to 393 K with PAL spectra taken in 10 K increments upon both cooling and heating. The longest lived component lifetime and intensity, indicative of orthopositronium pick‐off, exhibit thermal dependencies that can be interpreted in a manner consistent with anticipated free volume changes associated with structural transitions.
FT–IR spectroscopic and thermal studies of poly(styrene‐co‐1‐vinyl naphthalene) and poly(vinyl methyl ether) blends
Authors: Kang Dong‐Pil , Ha Chang‐Sik , Cho Won‐Jei
Published: April 2003

The FT–IR spectroscopic analysis and the thermal behavior of the blends of styrene‐1‐vinyl naphthalene copolymers [P(S‐co‐1VN)] and poly(vinyl methyl ether) (PVME) were investigated in this work. The copolymers containing 23, 50, and 80% by weight of styrene were synthesized by radical polymerization. The blend films of the P(S‐co‐1VN) and PVME were cast from the mixed solvent of benzene/trimethylbenzene [50/50 (v/v)]. It was found from the optical clarity and the glass transition temperature behavior that the blends of PVME with P(S‐co‐1VN) of 80 wt % styrene and 20 wt % 1‐vinylnaphthalene (1VN) show miscibility below 50 wt % of the copolymer concentration and the concentration range to show miscibility becomes wider as the composition of 1VN decreases in the copolymers. From the FT–IR results, the relative peak intensity of the 1100 cm−1region due to COCH3bond of PVME and the peak position of 774 cm−1region due to the naphthyl ring of 1VN were sensitive to the miscibility of the P(S‐co‐1VN)/PVME blends. The frequency differences of the phenyl ring and the naphthyl ring in the P(S‐co‐1VN) from each frequency in the P(S‐co‐1VN)/PVME blends increase with increasing composition of styrene in the copolymers and with increasing concentration of PVME in the blends. A threshold energy exists to induce molecular interaction between the naphthyl ring of 1VN and the COCH3of PVME and to result in the miscible blends, regardless of the copolymer composition as well as the blend concentration. The threshold energy was estimated as about 3.689 × 10−21cal (779 cm−1) for the P(S‐co‐1VN)/PVME blend system. It can be concluded that the miscibility in P(S‐co‐1VN)/PVME blends is largely affected by the composition of the copolymers, and the blends become more miscible as the composition of styrene in the copolymers increases.
Solid‐state CP/MAS 13C‐NMR studies of naphthalene‐based thermotropic polyesters and model compounds
Authors: Kato Takashi , Kabir Gazi M. A. , Uryu Toshiyuki
Published: April 2003

Thermotropic aromatic polyesters based on 2,6‐naphthalenedicarboxylic acid and 4,4′‐dihydroxy‐1,6‐diphenoxyhexane 1a and ‐decane 1b have been synthesized by solution polymerization. The solid‐state structures of these polyesters have been examined by high‐resolution solid‐state CP/MAS (cross polarization/magic angle spinning) and solution 13C‐NMR. For precipitated original samples, alkylene spacers were generally in the all‐trans form in the solid state. For once‐melted samples, torsional gauche conformations were introduced to the spacers. The mesophase of the polyesters was identified as nematic. The temperature ranges of the nematic state of 1a and 1b were much wider than those of analogous polymers 2a and 2b based on terephthalic acid. For these polyesters, the substitution of the 2,6‐naphthalene ring for the benzene ring induced no appreciable change in the conformation of the diphenoxy alkylene units in the solid state and on the melting points. Thermotropic ester model compounds, i.e., bis(4‐butoxyphenyl) 2,6‐naphthalate 3a and bis(4‐butylphenyl) 2,6‐naphthalate 3b have been prepared and characterized by both solid‐state and solution NMR, which helped the interpretation of the solid‐state structures of the polyesters. These spectra were compared with those of terephthalate‐based related compounds 4a and 4b. The solid‐state spectra suggest that the butoxyphenyl group of 3a and the butylphenyl group of 3b formed almost the same conformations as those of 4a and 4b, respectively.
Polyimide–polyformal block copolymers
Authors: Grade M. M. , Verbicky J. W.
Published: April 2003

In an effort to combine and tailor the properties of thermoplastic resins we have investigated the synthesis of polyimide–polyformal block copolymers prepared by the condensation reaction of α,ω‐diamino functionalized polyformal oligomers with α,ω‐dianhydride terminated polyimide oligomers. Amino functionalized polyformal oligomers were synthesized by displacement condensation reactions of various bisphenols with methylene dihalides in the presence of base and aminophenols. Oligomeric aromatic polyformals having weight average molecular weights (MWw) of 7500 to 40,000 were obtained. Anhydride terminated polyimide oligomers with molecular weights (MWw) ranging from 10,000 to 15,000 were obtained by the condensation of bisphenol‐A–dianhydride and aromatic amines. Combining the polyimide oligomers with the polyformal oligomers in dipolar aprotic or nonpolar solvents afforded the desired block copolymers. The polyimide–polyformal block copolymers generally display two distinct glass transition temperatures by differential scanning calorimetry. The (AB)n block copolymers were evaluated by TGA in both air and N2 for thermal/oxidative stability.
Further polymers derived from bisazlactones and tetraamino compounds
Authors: Katritzky Alan R. , Sakizadeh Kumars , Swinson Joel , Heilmann Steven M. , Rasmussen Jerald K. , Krepski Larry R. , Pathre Sadanand V.
Published: April 2003

New polymers containing benzimidazole in the polymeric backbone were obtained from the reaction of bis(oxazolones) with known and with a novel aromatic tetraamine. The polymers have inherent viscosities in the range of 0.1‐0.4 dL/g (in DMF 30°C).
Metallocene–methylaluminoxane catalysts for olefin polymerizations. IV. Active site determinations and limitation of the 14CO radiolabeling technique
Authors: Chien James C. W. , Wang Borg‐Ping
Published: April 2003

The initial active site concentrations, [C*]0, have been determined with CH3OT radiolabeling for the Cp2ZrCl2/MAO and CpZrCl3/MAO catalysts (Cp = η5 : cyclopentadienyl, MAO = methyl aluminoxane). Almost all the Zr are found to be catalytically active in 70°C ethylene polymerizations; [C*]0 = [Zr] and [C*]0 = 0.8[Zr] at Al/Zr ratios of 104 and 103, respectively. Lowering the temperature to 50°C and Al/Zr to 5.5 × 102 reduces [C*]0 to 0.2[Zr]. The rate constant of propagation at 70°C was calculated to be 1.6 × 103(M s)−1 for both catalysts at Al/Zr = 1.1 × 104; the values are decreased fivefold and tenfold, respectively, for the CpZrCl3 and Cp2ZrCl2 systems. The usage of 14CO to determine the propagating Zr–P species was investigated. With regard to the time of reaction of 14CO with the polymerization mixture, the initial phase is attributed to reversible CO complexation and reversible migratory insertion. The second slower phase may be due to the formation of enediolate. During the course of a batch polymerization the 14C radioactivity incorporated is small compared to the number of active sites found by CH3OT determination; it is only ca. 10% of [C*]0 at maximum rate of polymerization. Therefore, 14CO radiolabeling cannot be used to count C*.
Radiation induced radical reactions in poly(chloroalkyl methacrylate)s/triallylisocyanurate mixtures
Authors: Wuensche P. , Mueller S. , Lorkowski K.‐H.
Published: April 2003

Radical generation after γ‐irradiation at 77 K and radical reactions during temperature increase are discussed for the polymers poly(2‐chloroethyl methacrylate) and poly(1,2,2,2‐tetrachloroethyl methacrylate), mixed with triallylisocyanurate (TAIC). After the radiation interaction radicals are generated in the ester alkyl side groups of the polymer by chlorine abstraction in both polymer/TAIC mixtures. Radical transfer to TAIC occurs during temperature increase to produce allyl radicals. Hence, the high radiation sensitivity of chlorine‐containing polymers is combined with the reactivity of allyl radicals of TAIC in such polymer–TAIC mixtures.
Electroninitiated polymerization of bis(trichlorophenoxo)‐tetramethylethylene diamine copper(II)
Authors: Sacak M. , Akbulut U. , Kisakurek D. , Turker L. , Toppare L.
Published: April 2003

Electroninitiated polymerization of bis(trichlorophenoxo)‐N,N,N′,N′‐tetramethylethylene diamine copper(II) was achieved in acetonitrile at various peak potentials of the monomer. A constant potential approach was selected in polymerization reactions. Electrolyses were carried out under air, nitrogen, and oxygen atmospheres. Structural analyses of the polymers were done by 1H‐NMR and 13C‐NMR FT–IR spectroscopy. Molecular weights of the polymers were determined by vapor pressure (isopiestic) method.
Electron transport membrane: Preparation of polypeptide membrane with spacers between the polymer matrix and viologen moiety and their application to an electron transfer reaction
Authors: Ishikawa Kazunori , Nambu Yoko , Endo Takeshi
Published: April 2003

Polypeptide membranes with several lengths of spacers [(CH2)n; n = 3, 6, 12] between the polymer matrix and viologen moiety as a functional group were prepared. Reduction of K3Fe(CN)6 with Na2S2O4 across the obtained membrane in aqueous media were carried out and reduction rate of K3Fe(CN)6 across the membrane of n = 6 was faster than that of n = 3. However, the reduction of the membrane (n = 12) did not proceed chemically and electrochemically at all.
Studies on acoustic behavior of praseodymium soaps
Authors: Mehrotra K. N. , Sharma Meera , Gahlaut A. S.
Published: April 2003

The CMC and various acoustic parameters of praseodymium soaps in 1‐pentanol have been determined by ultrasonic velocity measurements. The results show that the ultrasonic velocity, specific acoustic impedance, apparent molal compressibility, and molar sound velocity increase while adiabatic compressibility and intermolecular free length decrease with increasing concentration and chain length of soap.
Copolymerization of furan with maleic anhydride initiated by thioglycolic acid
Authors: Kuramoto Noriyuki , Suda Kaoru , Nagai Katsutoshi
Published: April 2003

Copolymerization of furan (F) with maleic anhydride (MAH) initiated by thioglycolic acid (TGA) was studied in various solvents and temperatures in the presence of atmospheric oxygen. Copolymer between F and MAH was readily obtained by using thiol compounds as initiators. The atmospheric oxygen catalyses the copolymerization reaction. The rate of copolymerization is proportional to the concentration [TGA]0.55 at low concentrations (< 1.0 mol/L), at higher concentrations rates decrease gradually. The copolymerization rate increases with increase in copolymerization temperature and varies with the total monomer concentration as ([F] + [MAH])1.9. The overall energy of activation as calculated from the Arrhenius plot has been found to be 6.4 Kcal/mol within the temperature range of 25–50°C.
Preparation and properties of aromatic copolyamides from aromatic diisocyanates and aromatic dicarboxylic acids
Authors: Otsuki Toshihiro , Kakimoto Masa‐Aki , Imai Yoshio
Published: April 2003

Wholly aromatic random copolyamides of high molecular weights were prepared by the high‐temperature solution polycondensation of an aromatic diisocyanate, 4,4′‐methylenedi(phenyl isocyanate) or 2,4‐tolylene diisocyanate, with a mixture of isophthalic acid and 4,4′‐oxydibenzoic acid. Glass transition temperatures of the polyamides and copolyamides were between 229 and 273°C; this depended on the combination of diisocyanates and dicarboxylic acids used. These aromatic copolyamides showed better solubility in various organic solvents and reduced crystallinity, compared to the corresponding homopolyamides. The copolyamides prepared from 2,4‐tolylene diisocyanate had greater solubility and higher glass transition temperatures than those obtained from 4,4′‐methylenedi(phenyl isocyanate).
Functionalization of PMMA by a functional “iniferter”: Kinetics of polymerization of MMA using N,N′‐diethyl‐N,N′‐bis(2‐hydroxyethyl) thiuram disulfide
Authors: Nair C. P. Reghunadhan , Clouet G. , Chaumont P.
Published: April 2003

α,ω‐Dihydroxy‐terminated‐PMMA was synthesized by the bulk polymerization of methyl methacrylate in the presence of a functional “iniferter,” viz., N,N′‐diethyl‐N,N′‐bis(2‐hydroxyethyl)thiuram disulfide (DHTD). The kinetics of the polymerization were studied by determining the polymerization rate as a function of the “iniferter” concentration at 60, 70, 85, and 95°C. Evaluation of the data by a computerized multiple regression analysis led to calculation of the various kinetic parameters and the activation energies of the related phenomena. The maximum observed in the Rp–initiator concentration curve was found to shift to lower initiator concentration as the temperature increased. The formal reaction order with respect to the concentration of the initiator decreased with increasing temperature and concentration of DHTD. The chain transfer constants of DHTD with MMA were calculated from the molecular weights of the resulting polymers. The functionalities of the oligomers were calculated from the elemental analysis of the chain end groups. Thermogravimetric analysis revealed that the polymer chain ends were devoid of unsaturated groups and that the polymer underwent degradation only by random scission.
Polymerization of tetraallyl ammonium chloride
Authors: Matsumoto Akira , Mano Hisako , Oiwa Masayoshi , Butler George B.
Published: April 2003

The radical polymerization of tetraallyl ammonium chloride (TAAC) was carried out in water using azo‐initiator as compared to that of diallyl dimethyl ammonium chloride (DADMAC); the rate of polymerization was quite low for TAAC, around one‐third of DADMAC. Kinetic discussion revealed the importance of degradative chain transfer in the polymerization of TAAC. The cyclopolymerizability of TAAC was estimated kinetically as the ability of 5‐membered monocyclic radical to form a bicyclic ring, giving the cyclization constant of 21 mol/L at [M] = 2 mol/L. Gelation occurred at around 20% conversion.
Free radical copolymerization in the presence of lewis acids. I. Alternating copolymerization of vinyl acetate with acrylic acid in the presence of GeCl4 and BCl3
Authors: Xu Guo Jin , Meng Yue‐Zhong , Song Hong , Lin Qing‐Song
Published: April 2003

Alternating copolymers of vinyl acetate (VAC) and acrylic acid (AA) were obtained by free radical polymerization in the presence of GeCl4 and BCl3. For the GeCl4 system, the reaction rate was proportional to [initiator]1/2. Optimum rate was obtained when the molar ratio of the monomers was 1:1. The chain transfer agent CCl4 had no effect on the reaction. By means of ultra‐violet spectra analysis, it was concluded that both VAC and AA formed complexes with GeCl4. ESR analysis gave us the information that salt complexed acrylic acid radical had greater cationic characteristics than uncomplexed radical. Thus the nature of alternation may be due to both complexed AA radical and activated monomer complexes.
Studies in the formation of poly(oxazolidone)s. III. Catalysis and kinetics of the model oxazolidone formation from cyclohexyl isocyanate and phenylglycidyl ether
Authors: Žilić Mirjana , Sendijarević Aiša , Sendijarević Vahid , Frisch Kurt C.
Published: April 2003

The reaction of cyclohexyl isocyanate with phenylglycidyl ether was selected as model reaction for the synthesis of cycloaliphatic isocyanate‐based poly(2‐oxazolidone)s. The selectivity of AlCl3 and AlCl3‐triphenylphosphine oxide (AlCl3–TPPO) and AlCl3‐hexamethylphosphoric triamide (AlCl3–HMPA) complexes was studied for 2‐oxazolidone formation. The reaction products were identified by means of the melting point, 1H‐NMR, and IR spectroscopy. The kinetics of the model reaction was studied using AlCl3‐TPPO in o‐dichlorobenzene at 120 and 140°C.
Heterogeneous dilute acid hydrolysis of cellulose: A kinetic model for the hydrolysis of the difficultly accessible portion of cellulose based on donnan's theory of membrane equilibria
Authors: Zaranyika M. F. , Madimu M.
Published: April 2003

The effect of adding an electrolyte on the rate of the heterogeneous dilute acid hydrolysis of cellulose was studied using 1.3M hydrochloric acid containing varying amounts of sodium chloride up to 0.17M. A general increase in the rate of hydrolysis was observed. In particular, a linear relationship was observed between the rate of hydrolysis of the later portion of the hydrolysis curve and the concentration of added electrolyte, thus confirming that Donnan's theory of membrane equilibria can be applied to the heterogeneous hydrolysis of cellulose in dilute acid. A kinetic model, based on this theory and whose predictions are consistent with the above experimental results is presented.
Crosslinked polystyrene latexes prepared with 12‐(o‐styryloxy)dodecyltrimethylammonium bromide
Authors: Choubal Milind , Ford Warren T.
Published: April 2003

Crosslinked polystyrene latexes with high surface charge densities have been prepared with 1, 3, and 5 mol% divinylbenzene and 0.5–5.0 mol% of 12‐(o‐styryloxy)dodecyltrimethylammonium bromide (1). Within experimental error all of surfactant 1 was incorporated into the particles. Analysis of the latex particles by transmission electron microscopy showed nonspherical shapes, aggregates, and number average diameters ranging from 22 to 95 nm. The particle size decreases and the polydispersity increases with increasing amounts of surfactant 1 and of divinylbenzene in the monomer mixture. A mechanism is proposed for particle formation by precipitation of crosslinked polymer from monomer droplets to form primary particles, coagulation of the primary particles to colloidally stable aggregates, and growth by further polymerization.
Binding of methyl orange and the hydrophobic fluorescent probe, 2‐p‐toluidinylnaphthalene‐6‐sulfonate, by 2‐dialkylaminoethyl methacrylate‐N‐vinyl‐2‐pyrrolidone and related copolymers
Authors: Takagishi Toru , Hosokawa Toshitsugu
Published: April 2003

The copolymers of N‐vinyl‐2‐pyrrolidone and 2‐dimethylaminoethyl methacrylate, 2‐diethylaminoethyl methacrylate, 2‐dimethylaminoethyl acrylate, or 2‐dimethylaminopropyl acrylamide have been prepared. Studies were made of the binding of a “binding probe,” methyl orange, by the copolymers in aqueous solution. The first binding constants accompanying the binding were evaluated. Furthermore, the intensity of fluorescence of a hydrophobic fluorescent probe, 2‐p‐toluidinylnaphthalene‐6‐sulfonate, in the presence of these polymers was investigated. The nature and phenomena of dye binding and hydrophobic fluorescent probe binding with the polymers are discussed.
Radiation‐induced graft polymerization of metal‐containing monomers
Authors: Savostyanov V. S. , Pomogailo A. D. , Kritskaya D. A. , Ponomarev A. N.
Published: April 2003

Graft polymerization of acrylates and acrylamide complexes of Mn(II), Cr(III), Fe(III), Co(II), Ni(II), and Cu(II) from alcohol solutions onto a polyethylene powder preirradiated in air up to total doses of 10–300 kJ/kg was studied. Graft copolymers with a metal content of as high as 1.7 mass% were obtained. The addition of a σ‐ or a coordinate‐bound metal atom to the monomer molecule (acrylic acid, acrylamide) was shown to decelerate the process of thermal homopolymerization by 4 to 8 times, significantly reduce the reaction order in respect with monomer concentration in solution, and in most cases produce no effect on the polymer chain termination mechanism. The grafting of metal‐containing monomers was found not to alter the structure of the monomer unit, valent state, and coordination of the metal atom, either. The graft polymerization of the monomers from solution is distinguished by a weak effect of the radical reaction inhibitors. The effective activation energies for the grafting of the metal‐containing monomers lie within 42–60 kJ/mol.
Synthesis and polymerizability of 7,8‐dicyano‐7,8‐diphenylquinodimethane
Authors: Brandt M. W. , Mulvaney J. E. , Hall H. K. , Green G. D.
Published: April 2003

7,8‐Dicyano‐7,8‐diphenylquinodimethane (DCDPQ) was prepared by oxidation of the dianion of α,α′‐dicyano‐α,α′‐diphenylxylene. 1H‐NMR of a solution of the purified compound showed that the cis and trans isomers were present in a 1:1 ratio. Following further spectroscopic and electronic characterization the polymerizability of the title compound was investigated. DCDPQ did not homopolymerize at 65°C in the presence of AIBN. DCDPQ copolymerized with p‐methoxystyrene and p‐aminostyrene in the presence of AIBN at 65°C. Characterization of the latter two copolymers indicated that they were nearly alternating. The copolymerization between DCDPQ and p‐aminostyrene proceeded in the absence of AIBN.
Models for polyurethane hydrolysis under moderately acidic conditions: A comparative study of hydrolysis rates of urethanes, ureas, and amides
Authors: Chapman Toby M.
Published: April 2003

The hydrolysis of model structures found in the hard blocks of polyurethanes has been studied under moderately acidic and neutral conditions. These include a series of N‐alkyl and N‐phenyl urethanes and ureas; for comparison purposes the corresponding amides and a carbonate ester based on bisphenol A were also studied. Of all functional groups the urethane was the most resistant to hydrolysis and the amide the most labile. Also, the N‐phenyl compounds were hydrolyzed faster than the corresponding alkyl derivatives. The carbonate ester underwent relatively rapid hydrolysis. Polyether containing polyurethanes, known to be relatively stable to hydrolysis, are discussed as to which polymer segments provide the weakest links under hydrolytic conditions.
Functional polymers. XLIX. Copolymerization of ω‐alkenoates with α‐olefins and ethylene
Authors: Purgett Mark D. , Vogl Otto
Published: April 2003

The 2,6‐dimethylphenyl ester of 10‐undecenoic acid was copolymerized with 1‐dodecene, 1‐octene, 1‐hexene, propylene, and ethylene using coordination initiation systems based on “aluminum‐activated” titanium trichloride and dialkylaluminum chlorides. The copolymerizations with higher α‐olefins proceeded smoothly and gave copolymers incorporating from 60 to 90% of the 10‐undecenoate feed. Copolymerization with propylene gave incorporation of 5 mol % of 2,6‐dimethylphenyl 10‐undecenoate; with ethylene only 3 mol % of the ω‐alkenoate was readily incorporated. All copolymers were characterized by elemental analysis, dilute solution viscosity, and by their IR 1H‐ and 13C‐NMR spectra.
A kinetic study of the copolymerization of maleic anhydride with ethyl vinyl ether using the rotating‐sector technique
Authors: Pasquali R. E. , Rodriguez F.
Published: April 2003

The results of polymerization and initiation experiments at 25°C show that the alternating copolymerization of maleic anhydride (monomer 1) and ethyl vinyl ether (monomer 2) is consistent with a theoretical mechanism defined by the usual rate constants (in L/mol s): Propagation: (kp)11 = 0.00; (kp)12 = 1.66 × 105, (kp)22 = 2.0 × 103; and (kp)21 = 2.04 × 105. Termination (kt)11 = 7.40 × 1010; (kt)12 = 52.8 × 1010; (kt)22 = 1.33 × 1010. The relative magnitudes of the two cross‐propagation constants and the three termination constants are consistent with accepted theory with regard to polarity, resonance, and steric factors. The steady‐state and rotating‐sector experiments were carried out in a dilatometer using azobisdiisobutyronitrile as the initiator, acetone as the solvent, and UV light of 365 nm wave length.
Synthesis and polymerization of N‐(ethylene)‐phthalimidyl acrylate
Authors: Pyriadi Thanum M. , Alasli Nabeel J.
Published: April 2003

N‐(Ethylene)phthalimidyl acrylate was synthesized starting from phthalimide or phthalic anhydride using two different routes. Free radical or anionic polymerization of the ester resulted in low‐molecular‐weight polymers.
Biocatalytic synthesis of polymers. Synthesis of an optically active, epoxy‐substituted polyester by lipase‐catalyzed polymerization
Authors: Wallace J. Shield , Morrow Cary J.
Published: April 2003

The enantioselective polymerization of bis(2,2,2‐trichloroethyl) trans‐3,4‐epoxyadipate with 1,4‐butanediol using the enzyme porcine pancreatic lipase as a catalyst is described. The polymerization was carried out at ambient temperature in anhydrous ethyl ether. End group analysis provided MN = 5,300 daltons, whereas GPC provided Mw = 7,900 daltons for the polymer. The unchanged (+)‐enantiomer of the diester was shown to have an enantiomeric purity of > 95% by proton NMR in the presence of the chiral shift reagent Eu(hfc)3. The stereochemical purity of the (−)‐polymer was estimated at > 96% by consideration of the amount of the slower reacting enantiomer that could have been incorporated and still attain the observed degree of polymerization (25) when the starting ratio of racemic diester to diol was 2:1. Direct determination of the stereochemical purity of the polymer using Eu(hfc)3 was unsuccessful. Similar studies on polymer having random stereochemical orientations of the epoxide showed that such polymers do not behave as if they are racemic in the presence of the shift reagent. The polymer required for the latter studies was prepared by epoxidation of the product from enzyme catalyzed polymerization of bis(2,2,2‐trichloroethyl) trans‐3‐hexenedioate with 1,4‐butanediol.
Organic monomeric glasses: A novel class of materials
Authors: Molaire Michel F. , Johnson Roger W.
Published: April 2003

An amorphous monomeric glass is defined as a mixture of compatible organic monomeric molecules with an infinitely low crystallization rate under the most favorable conditions. These mixtures can be formed in a one‐part reaction of a multifunctional nucleus with a mixture of substituents. The “noncrystallizability” of the mixture is controlled by the structural dissymmetry of the nucleus and/or the substituents and the number of components making up the mixture. We have developed an equation to calculate the number of components in a given mixture, knowing the structure and functionality of the nucleus and the number of substituents. An HPLC characterization method was developed and used to investigate the effects of various reaction conditions on the component concentration distributions and physical properties of the resulting materials. A dissymmetry number defined as the total weight percent of odd‐substituted components is believed to be a potential measure of the “noncrystallizability” of the mixture. Physical properties such as glass‐transition temperature can be dramatically increased through controlled oligomerization at the price of a moderate increase in melt viscosity. The organic monomeric glasses, like amorphous polymers, have good film‐forming properties. However, unlike polymers, they display extremely low melt‐viscosities and large positive entropy‐of‐mixing values and can be ground easily into extremely small particles. These properties make them ideal for certain applications where compatibility, melt‐flow, and small particle size are important.
Functional monomers and polymers. CLIV. Application of nucleic acid base containing polymers to high performance liquid chromatography
Authors: Nagae Suguru , Suda Yasuo , Inaki Yoshiaki , Takemoto Kiichi
Published: April 2003

Poly‐L‐lysine (PLL) derivatives containing pendant nucleic acid base, such as thymine or adenine, were bonded successfully to 3‐aminopropylsilanized silica (APS‐silica) and silica gel. These resins were found to be useful as the column of high performance liquid chromatography (HPLC) for the selective separation of oligoethyleneimine derivatives having pendant thymine or adenine bases.
Chain propagation/step propagation polymerization. III. An XPS investigation of poly(oxyethylene)‐b‐poly(pivalolactone) telechelomer
Authors: Wagener K. , Batich C. , Kirsch B. , Wanigatunga S.
Published: April 2003

A combination of chain and step propagations is being used to prepare a series of segmented copolymers containing polyoxyethylene and polypivalolactone segments each with narrow molecular weight distributions. The incompatibility of the two segments coupled with the difference in surface energies of the two segments could result in good phase separation with the polyoxyethylene segment thereby being found on the surface. Poly(oxyethylene)‐co‐(pivalolactone) telechelomer, which is the precursor to the segmented copolymer, is used as a model to develop an XPS method for surface analysis. An angular resolution study shows that negligible amounts of poly(pivalolactone) segments are present near the surface. Core level spectra of the telechelomer and its model compounds are presented to indicate that poly(oxyethylene) segment is richer near the surface.
Preparation and characterization of plasma polymerized (ethylene + oxygen) thin films
Authors: Prohaska G. W. , Nickoson C. G.
Published: April 2003

This report describes the preparation and characterization of plasma polymerized (ethylene + oxygen) (PPEO) thin films. The PPEO films described herein represent a unique class of materials from the standpoint of stoichiometry, chemical functionality, and crosslink density. It will be shown that PPEO deposition rate and structure, evidenced both at the surface and in the bulk, are strongly dependent upon the flow rate of O2 in the ethylene/O2 feed gas mixture. High O2 flow rates produce films with relatively high oxygen concentrations. Furthermore, increasing O2 flow rates lead to film structures which increasingly favor the incorporation of highly oxidized carbon functionalities. These effects (increasing film concentrations of oxygen and highly oxidized carbon functionalities) appear to show no further increase for O2 flow rates greater than or equal to ca. 10% of the ethylene flow rate.