bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and properties of block poly(styrene amides) and poly(styrene esters)
Authors: Katayama Shitomi , Serita Hajime , Takahashi Yukio 
Published: April 2003

AbstractThree series of block copolymers, namely, polystyrenecaproamide (I), polystyrenehexamethyleneadipamide (II), and poly(styreneethylene terephthalate) (III), were prepared, and the properties of the copolymers in relation to the block sequence lengths and the compositions were studied. Styrene was polymerized in the presence of aluminum chloride and thionyl chloride to give ω,ω′‐dichloropolystyrenes of various degrees of polymerization from 12.0 to 51.0, which were either ammonolyzed to ω,ω′‐diaminopolystyrene or hydrolyzed to ω,ω′‐dihydroxypolystyrene. ω,ω′‐Diaminopolystyre was treated with adipic acid to give the corresponding salts, namely, ω,ω′‐diammoniumpolystyrene adipate, which was melt‐polymerized either with ε‐amino‐n‐caproic acid to give polystyrenecaproamide (I) or with hexamethylenediammonium adipate to give polystyrenehexamethyleneadipamide (II). ω,ω′‐Dihydroxypolystyrene was melt‐polymerized with dimethyl terephthalate and ethylene glycol to give poly(styreneethylene terephthalate) (III). All the block copolymers were of high enough molecular weight to be cast or spun into films or filaments. Upon polymerization, the increase of the block sequence of PSt units increased the amide content but decreased the ester content of the resulting copolymers. Also, an increase inndecreased the inherent viscosities of the copolymers at a constant monomer feedfccounted by the polymer equivalent of PSt but increased the inherent viscosities at a constant monomer feedrccounted by the monomer equivalent of PSt. The melting points of the copolymers decreased with increasingnvalues. Also, an increase inndecreased the densities of I and III but increased the density of II at a constant amide or ester compositionFccounted by polymer units but increased the densities of I, II, and III at a constant amide or ester compositionRccounted by the monomer unit.
Kinetics of anhydride formation in poly(acrylic acid) and its effect on the properties of a PAA‐alumina composite
Authors: Greenberg A. R. , Kamel Ihab 
Published: April 2003

AbstractThe kinetics of anhydride formation of poly(acrylic acid) (PAA) in porous PAA–alumina composites have been investigated by using a thermogravimetric technique (TGA). Three distinct reaction peaks at 200°C (I), 250°C (II), and 390°C (III) were identified in the dynamic TGA thermogram. These peaks were attributed to bound water removal (I), anhydride formation (II), and polymer degradation (III). The kinetics of the anhydride reaction were studied in a temperature range of 220–240°C and found to follow a second‐order mechanism with an activation energy of approximately 38 kcal/mole. In addition, the bound water was found to inhibit the onset of anhydride formation. The degree of conversion to anhydride was correlated with the equilibrium swelling level attained by the composite in water.
Polyaddition of bisketenimines. I. Synthesis of polyamidines from bisketenimines and diamines
Authors: Kurita Keisuke , Kusayama Yasukazu , Iwakura Yoshio 
Published: April 2003

AbstractPolyaddition of bisketenimines with various diamines was carried out in dioxane or toluene to afford linear polyamidines. The aliphatic diamines were fairly reactive toward the bisketenimines, and polyamidines having inherent viscosities up to 0.45 dl/g were obtained. The aromatic diamine, on the other hand, showed only poor reactivity, and the derived polyamidines had low inherent viscosities. All the polyamidines were found to be soluble in such polar solvents as dimethylacetamide and m‐cresol. The thermogravimetric analysis (TGA) showed that thermooxidative decomposition started at 230–350°C.
Melamine–formaldehyde resins: Molecular species distributions of methylolmelamines and some kinetics of methylolation
Authors: Tomita Bunichiro 
Published: April 2003

AbstractThe addition reaction between melamine and formaldehyde has been studied by the direct observation with NMR spectroscopy and high‐speed liquid chromatography. All of the nine methylolmelamines, including two isomers of di‐, tri‐ and tetramethylolmelamine could be assigned. The liquid‐chromatographic technique was applied to the quantitative analysis of methylolmelamines and the free formaldehyde contents in the reaction mixtures, and the molecular species distributions were determined. By using these quantitative methods, the equilibrium constants and rate constants for the individual reversible reactions were estimated.
Diether polyphenylquinoxalines. Monomers via nitro displacement–13C‐NMR analysis of monomers and polymers
Authors: Relles H. M. , Orlando C. M. , Heath D. R. , Schluenz R. W. , Manello J. S. , Hoff S. 
Published: April 2003

AbstractBisbenzils have been prepared by nucleophilic aromatic nitro displacement reactions. These materials, some model compounds, and some polyphenylquinoxaline polymers prepared from them were rigorously analyzed by 13C‐NMR spectroscopy. The observed chemical shifts were in excellent agreement with calculated values based on model systems. This served as the strongest evidence to support the proposed structures and gave additional intimate structural information on the polyphenylquinoxalines.
Polymerization initiation by In Situ initiator formation. I. Initiation of vinyl chloride–propylene copolymerization with peroxydicarbonates and diacyl peroxides formed In Situ
Authors: Ravey M. , Waterman J. A. 
Published: April 2003

AbstractApplication of the in situ initiator formation technique to the vinyl chloride–propylene system has been examined for peroxydicarbonates, acyl peroxycarbonates, diacyl peroxides, and a peroxy ester. Of these the peroxydicarbonates were found to be the most effective. Of the peroxydicarbonates examined, diethyl, diisopropyl, and di‐sec‐butyl were the most efficient, all being more efficient than lauroyl peroxide. A comparison between the in situ mode and the use of preformed initiator showed the latter to be the more efficient of the two techniques when diethyl peroxydicarbonate was used for the homopolymerization of vinyl chloride.
Multifunctional hydrolytic catalyses. IX. Hydrolysis of p‐nitrophenyl acetate by bifunctional polymer catalysts containing zwitterionic (hydroxamate) nucleophiles
Authors: Okahata Yoshio , Kunitake Toyoki 
Published: April 2003

AbstractThe hydrolysis of p‐nitrophenyl acetate by bifunctional polymer catalysts was studied in 28.9% EtOH–H20 at 30°C. Partial (ca. 10 mole%) quaternization of poly(4‐vinylpyridine) and poly(1‐vinyl‐2‐ethylimidazole) with benzyl N‐benzyl chloroacetohydroxamate and the subsequent removal of the benzyl group produced water‐soluble polymers containing zwitterionic hydroxamate groups and free pyridine (or imidazole) groups. The zwitterionic hydroxamate was a nucleophile more than 10 times as effective as simple hydroxamate anions, and the acetyl hydroxamate intermediate was efficiently hydrolyzed by the intrapolymeric pyridine (or imidazole) group. Thus, the catalytic efficiency of these bifunctional polymers was much better than monofunctional polymers which contain either hydroxamate or imidazole, and amounted to 10–20% of that of α‐chymotrypsin under a comparable condition.
Photodegradation behavior of tert‐butyl vinyl ketone polymers and copolymers with styrene and α‐methylstyrene
Authors: Tanaka Hitoshi , Otsu Takayuki 
Published: April 2003

AbstractPhotodegradation behavior of atactic and isotactic polymers of tert‐butyl vinyl ketone (t‐BVK) and its copolymers with styrene and α‐methylstyrene was studied in dioxane as a solvent at room temperature. The quantum yield of main‐chain scission of atactic poly(t‐BVK) was found to be larger than that of isotactic poly(t‐BVK) and atactic poly(methyl vinyl ketone). From the Stern‐Volmer plots on the quenching study of atactic poly(t‐BVK) with naphthalene and 2,5‐dimethyl‐2,4‐hexadiene, it was found that 60–70% of its photochemical reaction underwent main‐chain scission from the triplet state. It was also found that the increase in t‐BVK contents of both copolymers accelerated the photodegradation, and the copolymer with styrene was more photodegradable than that with α‐methylstyrene. These results seemed to suggest that the main‐chain scission of these vinyl ketone polymers and copolymers proceeded through a Norrish type II photoelimination mechanism.
Syntheses of polyamides and polypyrrolones from 2,2′‐disubstituted bis(3‐buten‐4‐olides) and diamines
Authors: Ueda Mitsuru , Yabuuchi Masahiko , Imai Yoshio 
Published: April 2003

AbstractThe ring‐opening polyaddition of 2,2′‐disubstituted bis(3‐buten‐4‐olides) with aliphatic diamines in m‐cresol at room temperature afforded in quantitative yields polyamides with a pendant ketone moiety having inherent viscosities of up to 0.7. On the other hand, the polymerization in m‐cresol at 80°C with acidic catalysts and at 160°C without any catalyst yielded directly polypyrrolones, a novel class of polyheterocycles. The cyclodehydration of the open‐chain polyamides to polypyrrolones was also achieved by simply treating the polyamide films with methanolic hydrochloric acid at room temperature. Both of the polymers were generally soluble in hot polar solvents such as dimethylformamide, m‐cresol, and nitrobenzene. The polypyrrolones began to lose weight gradually at around 250°C in nitrogen as determined by thermogravimetric analysis, while the thermograms in air showed an appreciable weight increase at about 230°C.
Nonoxidative crosslinking reactions in natural rubber. II. Radiotracer study of the reactions of amino acids in rubber latex
Authors: Burfield D. R. , Gan S. N. 
Published: April 2003

AbstractThe reaction of amino acids with functional groups in natural rubber has been studied by use of tritium labeled glycine as a tracer. The rate of reaction, in the latex phase, is found to be pH‐dependent with optimum rate at about pH 8. Reaction is considered to occur with rubber epoxide groups, since the level of incorporation of glycine correlates closely with the epoxide groups concentration. Competitive reactions with other amino acids and the effect of dimedone on glycine incorporation are also reported.
Cationic polymerization with boron halides. III. BCl3 coinitiator for olefin polymerization
Authors: Kennedy J. P. , Huang S. Y. , Feinberg S. C. 
Published: April 2003

AbstractThe polymerization of isobutylene with BF3, BCl3, and BBr3 coinitiators has been investigated. The polymerization with BCl3 requires the presence of a cationogen, e.g., H2O. The presence of a polar solvent is also necessary. Surprisingly, large quantities of polar solvent are required for effective polymerization. To obtain high conversions, the mixing sequence of the reagents is critical: BCI3 must be added last to charges containing the monomer and H2O in a polar solvent. Ultimate conversions increase by decreasing the temperature. Kinetic termination exists. Experiments with BF3 and BBr3 revealed that polymerizations induced with BF3 proceed in nonpolar and/or polar media. Polymerization stops with BF3 at less than complete conversion (termination exists). In contrast to findings with BCl3, polymer yields with BF3 increase with increasing temperatures. BBr3 is a very inefficient coinitiator, even in the presence of polar solvent, over the −10 to −90°C temperature range. A hypothesis which explains these observations has been developed.
Polyreactions in ordered systems: Polymerization of octadecyl methacrylate in monolayers at the gas–water interface
Authors: Naegele D. , Ringsdorf H. 
Published: April 2003

AbstractThe ultraviolet‐initiated polymerization of octadecyl methacrylate (ODMA, octadecyl 2‐methyl‐2‐propenoate) as a monomolecular layer at the gas‐water interface was studied. The polymerization was carried out at 27°C at the nitrogen‐water interface; air inhibits the polymerization. At 27°C the ODMA monolayer exhibits three different states which were characterized by surface pressure‐area diagrams and by surface potential measurements. The ODMA monolayer was polymerized under constant surface pressure in the range between 0 and 10 dyne/cm. The polymerization was followed by recording the contraction of the film. The conversion was determined by comparison of the area per monomer unit during polymerization with the area of mixed monolayers formed from ODMA and poly‐ODMA as well as by infrared spectroscopy. The polymerization in the condensed state of the monolayer (at high surface pressure) is considerably faster than in the expanded state (at low surface pressure). As the polymer has a condensing effect on the monomer in the mixed monolayer, autocatalysis is suggested at low surface pressures. The resulting polymer was studied by x‐ray diffraction. The structure of the freshly collapsed film is determined by the conformation of the polymer at the interface; the data after crystallizing the same sample from the melt point to higher tacticity of the poly‐ODMA prepared in monolayers than that of poly‐ODMA prepared by normal radical polymerization in solution.
Studies on the structure and resistance to thermooxidation of graft copolymer of polycaproamide with polyacrylonitrile and sulfur‐containing derivatives
Authors: Marupov R. , Kalontarov I. Ya. , Asrorov Y. , Mavlyanov A. M. , Niyazi F. F. 
Published: April 2003

AbstractBy the methods of infrared and mass spectroscopy, the structure of grafted copolymer of polycaproamide (PCA) with polyacrylonitrile (PAN) was examined. It is shown on the grounds of analysis of infrared absorption bands and mass spectrum of the volatile products of grafted copolymer thermodestruction that the graft copolymerization in the redox system Fe+3/H2O2 is carried out at the expense of the radicals, formed on COOH groups of PCA. The structure of grafted chains PAN changes owing to formation of cycles containing S and CN groups at the grafted copolymer treatment with Na2S. By the means of complex thermal analysis, the steadiness of the obtained products to thermooxidizing destruction was investigated. It was found that the presence of sulfur in the grafted copolymer PCA–PAN considerably intensifies the processes of grafted‐chain PAN cyclization as compared with the PAN homopolymer. It was shown that Na2S treatment brings to the product with the minimized absorption of oxygen at the isothermal heating that indicates its stability with regard to thermooxidizing destruction
Polymerization of acetylenic derivatives. XXVII. Synthesis and properties of isomeric poly‐N‐ethynylcarbazole
Authors: Dumitrescu Svetlana , Percec V. , Simionescu Cr. I. 
Published: April 2003

AbstractPoly‐N‐ethynylcarbazole (PEC) was prepared thermally, by using Ziegler‐Natta catalysts, and also by using TiCl4 and phosphine complexes for initiation. The spectral data (infrared, NMR, x‐ray diffraction, and ultraviolet) were best interpreted based on a cis‐transoidal/cis‐cisoidal stereoblock structure for (both soluble and insoluble) polymers prepared by Ziegler‐Natta catalysts and on a trans‐cisoidal structure for the polymers prepared with the other catalysts. The cis‐transoidal/cis‐cisoidal stereoblock structure isomerized thermally into a trans‐cisoidal structure, at temperatures which were dependent on the type of initiation.
Polymères à propriétés pharmaceutiques potentielles. III. Etude sur molécules modèles
Authors: Pinazzi C. , Rabadeux J. C. , Pleurdeau A. 
Published: April 2003

Abstract4‐Methyl, 4‐octene model molecules of the 1–4 polyisoprenic chain have been chemically modified in corresponding alcohol and chloroformate. These model molecules have been allowed to react with pharmaceuticals such as testosterone, cholesterol, and quinine to link the drug with a carbonate bound. Spectral data of these compounds are compared to those of previously synthetized polymers with potential pharamaceutical properties.
Copolymerization of 2‐phenylvinyl alkyl ethers and maleic anhydride
Authors: Vuković R. , Kureševič V. , Fleš D. 
Published: April 2003

AbstractA series of 2‐phenylvinyl alkyl ethers (I) having as alkyl group methyl, ethyl, n‐propyl, n‐butyl, 2‐methylbutyl, 3‐methylpentyl, and optically active 1‐methylpropyl of (S) absolute configuration, were copolymerized with maleic anhydride to alternating copolymers. The copolymerizations were carried out in bulk at 70°C in the presence of AIBN as initiator. Monomer I (R = Et) was also polymerized with lauroyl and benzoyl peroxide as initiator. The yield and molecular weight were highest when equimolar amounts of both monomers were used. The equilibrium constant of charge‐transfer complex of monomer I (R = Et) and maleic anhydride was determined by the transformed Benessi‐Hildebrand NMR method and has a value of 0.28 mole/1.
Ether polyphenylquinoxalines. II. Polymer synthesis and properties
Authors: Clair Anne K. St. , Johnston Norman J. 
Published: April 2003

AbstractThree polyphenylquinoxalines were prepared by the one‐step solution cyclopolycondensation of 3,3′,4,4′‐tetraaminobenzophenone with three novel bisbenzils containing oxyphenylene groups. High molecular weight polymers were obtained that exhibited good solubility in chlorinated solvents and m‐cresol and formed tough, flexible films from solution. Glass transition temperatures Tg which were determined by thermomechanical analysis, torsional braid analysis, and dielectric loss measurements showed that the inclusion of oxyphenylene units into the polymer chain was effective in reducing the Tg. However, the onset of polymer decomposition, as determined by thermogravimetric analysis and isothermal aging, disclosed that the oxyphenylene units also decreased the thermooxidative stability for two of the polymers studied.
Acetylation of DMSO:PF solutions of cellulose
Authors: Seymour Raymond B. , Johnson Earl L. 
Published: April 2003

AbstractThree different techniques for esterifying solutions of cellulose dissolved in mixtures of dimethyl sulfoxide (DMSO) and paraformaldehyde (PF) were evaluated and are herein described. The evaluation and development of suitable synthetic procedures and the characteristics of the resulting acetylated cellulose are reported. Glacial acetic acid (glacial HOAc), acetyl chloride (AcCl), and acetic anhydride (Ac2O) were compared as acetylating agents for solutions of cellulose in DMSO:PF, and it was demonstrated that mixtures of pyridine (Py) and Ac2O rapidly acetylated the cellulose to yield beige to amber acetone‐soluble cellulose acetates which were partially oxidized. These thermoplastic resins exhibited softening points between 80 and 110°C and thermal stabilities (in nitrogen atmospheres) similar to those of native celluloses (350 to 375°C). Degree of acetyl substitution (DS) values ranged from 0 to 2.0 as a function of acetylation time.
Role of polymer morphology in the oxidation of polypropylene
Authors: Garton A. , Carlsson D. J. , Wiles D. M. 
Published: April 2003

AbstractThe γ‐initiated oxidation and presensitized photooxidation of polypropylene films and fibers are shown to be insensitive to sample thickness (if <150 μm) and a range of morphological parameters such as molecular orientation (in drawn samples) and fibrillar and void content. The relevance of these observations is discussed in the light of the many previous assertions as to the influence of morphological effects on oxidation rates. The γ‐initiated oxidation was studied in preference to conventional thermal or photoinitiated oxidation because of the greater control over the rate of radical production available by this method.
Effects of chlorophosphines on the radical polymerization of methyl methacrylate
Authors: Uemura Hideaki , Taninaka Takumi , Minoura Yuji 
Published: April 2003

AbstractThe effect of chlorophosphines (phosphorus trichloride, dichlorophenylphosphine, chlorodiphenylphosphine) on the radical polymerization of methyl methacrylate was investigated in benzene solution. The polymerization was carried out at 50°C by the standard solution method, α,α′‐azobisisobutyronitrile being used as an initiator. These chlorophosphines accelerated the polymerization of methyl methacrylate but did not affect the rate of decomposition of α,α′‐azobisisobutyronitrile. Ultraviolet and infrared spectral data suggested that the acceleration effect was due to the complex formation of methyl methacrylate with each chlorophosphine. From the result of a copolymerization with styrene, it was found that the reactivity of methyl methacrylate monomer increased in the presence of dichlorophenylphosphine.
Preparation and properties of polyamides from 2,2′‐p‐phenylenebis‐5‐oxazolones with diamines
Authors: Ueda Mitsuru , Kino Kohsuke , Yamaki Kiyoshi , Imai Yoshio 
Published: April 2003

AbstractNovel phenylated polyamides having inherent viscosities in the range of 0.2–0.4 were prepared by the ring‐opening polyaddition of 2,2′‐p‐phenylenebis(4,4‐diphenyl‐5‐oxazolone) with aliphatic diamines in polar aprotic solvents. Similarly, unsubstituted polyamides were obtained from 2,2′‐p‐phenylenebis‐5‐oxazolone and both aliphatic and aromatic diamines. The phenylated polyamides were highly soluble in a wide range of solvents including tetrahydrofuran and dioxane, while the unsubstituted polymers showed limited solubility in the solvents. No marked differences in thermal stability between the phenylated and unsubstituted polyamides were noted, and all the polyamides began to decompose at around 250°C in both air and nitrogen.
Hydrocarbon formation in the pyrolytic decomposition of methacrylate copolymers
Authors: Gritter R. J. , Seeger M. , Johnson D. E. 
Published: April 2003

AbstractA series of methyl methacrylate (MMA)–methacrylic acid (MAA) copolymers containing up to 50% methacrylic acid and the respective homopolymers were reproducibly pyrolyzed at 900°C and the fragments identified by gas chromatography (GC) or GC–mass spectroscopy. It was shown that PMMA and the MMA portions of blocky or random copolymers yielded 99% MMA, while a large portion (50–60%) of the MAA broke down to give a wide variety of hydrocarbons via decarboxylation and/or anhydride formation. Both unsaturated aliphatic and aromatic hydrocarbons, as well as the minor products of the MMA decomposition, support free‐radical processes for these decompositions. It was also shown that the copolymers readily complex oxygenated solvents (which did not affect decomposition) and metal ions (which markedly affected the products).
Effect of preswelling of polymers in radiation‐induced graft copolymerization
Authors: Omichi Hideki , Araki Kunio 
Published: April 2003

AbstractThe graft copolymerization of styrene onto preirradiated poly(isobutylene oxide) was studied. An alkyl radical, C(CH3)2CHO, was mainly observed by the irradiation of preswelled poly(isobutylene oxide) in aerated methanol. Kinetic analysis of the graft copolymerization indicated that the preswelling influenced ktr and kt and did not influence of ∫ Ridt and kp.
Optical resolution of mandelic acid derivatives by column chromatography on crosslinked cyclodextrin gels
Authors: Harada Akira , Furue Masaoki , Nozakura Shun‐Ichi 
Published: April 2003

AbstractCrosslinked α‐ and β‐cyclodextrin gels (α‐CD‐E and β‐CD‐E) were used for the chromatographic resolution of racemic mandelic acid and its derivatives. β‐CD‐E bound L‐(+)‐isomers preferentially over D‐(−)‐isomers and resolved DL‐methyl mandelate to give a D‐(−)‐isomer of 100% optical purity in the first fraction. Mandelic acid, ethyl mandelate, and O‐methylated mandelic acid yielded resolutions of 65–83% in initial fractions. α‐CD‐E, on the contrary, bound D‐(−)‐isomers more strongly than L‐(+)‐isomers, resolving DL‐methyl mandelate to a smaller extent than β‐CD‐E. Binding of DL‐mandelic acid and DL‐methyl mandelate on β‐CD‐E was studied quantitatively by the equilibrium method. β‐CD‐E has a similar binding capacity to starch with 1:1 stoichiometry but bound much more strongly than starch. β‐CD‐E has the same mode of selectivity as starch for the asymmetric binding of the mandelic acid derivatives, but α‐CD‐E has a reverse selectivity to β‐CD‐E and starch.