bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of polyamides by the polyaddition of bissuccinimides with diamines
Authors: Kagiya Tsutomu , Izu Masatsugu , Matsuda Takehisa , Fukui Kenichi 
Published: April 2003

AbstractPolyamides which contain succinamide units, NHCO(CH2)2CONH were prepared by the ring‐opening polyaddition of bissuccinimides with diamines at 200°C. in bulk. Nylon 24 and nylon 64 were prepared by the reaction of N,N′‐ethylenedisuccinimide with ethylenediamine and of N,N′‐hexamethylenedisuccinimide with hexamethylenediamine, respectively. It was suggested that the transamidation reaction by aminolysis influenced the detailed structures of the polymers prepared from N,N′‐ethylenedisuccinimide and hexamethylenediamine and from N,N′‐hexamethylenedisuccinimide and ethylenediamine. The detailed structures of the polymers are discussed on the basis of their melting points and x‐ray diagrams. It is concluded that the polymers contain a crystalline portion of \documentclass{article}\pagestyle{empty}\begin{document}$ \rlap{--}[{\rm NH \hbox{--} (CH}_2 {\rm)}_{\rm 2} {\rm \hbox{--} NHCO \hbox{--}}({\rm CH}_2)_2 {\rm \hbox{--} CONH \hbox{--}}({\rm CH}_2)_6 {\rm \hbox{--} NHCO \hbox{--}}({\rm CH}_2)_2 {\rm \hbox{--} CO\rlap{---}]} $\end{document} sequences.
Isotactic sequence lengths by ozonation of poly(propylene oxide)
Authors: Price Charles C. , Tumolo Anthony L. 
Published: April 2003

AbstractOzonation followed by lithium aluminum hydride reduction cleaved high molecular weight isotactic poly(propylene oxide) to crystalline polyglycols. From the melting point and molecular weight of the latter, the molar freezing point depression produced by end groups is found to be ca. 18°C./mole, as compared to that estimated for poly(ethylene glycols), Kf = 12°C./mole, from earlier data. By assuming syndiotactic placements (or other irregularities) would produce the same molar depression, the melting point of isotactic poly(propylene oxides) produced by various catalysts has been used to estimate the isotactic sequence lengths.
The initiation process in the polymerization of tetrahydrofuran with carbonium ion salts
Authors: Kuntz Irving 
Published: April 2003

AbstractThe initiation process for the polymerization of tetrahydrofuran with (C6H5)3C+SbCl6− has been studied. Two mechanisms have been considered: a cation‐addition process, and a process in which tetrahydrofuran donates a hydride ion to the cation of the initiator to form triphenylmethane. The biscarbonium salt [(C6H5)2C+C6H4CH2]2(SbCl6−)2 has been synthesized and used to initiate the polymerization of tetrahydrofuran. The results are consistent with the hydride‐ion mechanism but may be inconclusive because of chain transfer. NMR experiments with 0.05–0.2M solutions of initiator in tetrahydrofuran show that triphenylmethane is rapidly produced in an amount equal to the molar amount of initiator originally present. Some NMR evidence for the presence of an acetal end group in the polymer has been obtained. It is concluded that the initiation process in this system definitely involves the formation of triphenylmethane, although a detailed, unique mechanism cannot be selected at this time.
Influence of preparative conditions on molecular weight and stereoregularity distributions of polypropylene
Authors: Combs R. L. , Slonaker D. F. , Joyner F. B. , Coover H. W. 
Published: April 2003

AbstractThe influence of preparative conditions on the molecular weight and stereoregularity distributions of polypropylene was investigated. The stereoregularity distribution is narrowed by using a highly stereospecific catalyst, by decreasing the polymerization temperature, and for the three‐component catalyst by keeping the mole proportion of the electron‐donating third component at 0.5. The molecular weight distribution can be narrowed by using a highly stereospecific catalyst, a high monomer concentration, and a high polymerization temperature, and by having a lower conversion, particularly at low monomer concentration. The possibility of long‐chain branching in polypropylene was indicated by data from the fractionation of tritium‐labeled polymers.
Course of the terpolymerization of ethylene, propylene, and dicyclopentadiene. II. Two‐step addition of dicyclopentadiene
Authors: Cunningham Robert E. 
Published: April 2003

AbstractTerpolymerizations of ethylene, propylene, and dicyclopentadiene were carried out in which the dicyclopentadiene was added to the reaction system in two equal portions at the beginning and midpoint of each run, while the monoolefins were added continuously. In the resultant elastomers, unsaturation remains much more constant throughout the course of the polymerization than for terpolymers obtained when all dicyclopentadiene is added at the start of the reaction. Yield and molecular weight of the terpolymers produced by either technique are quite comparable, however. With VCl4 catalyst (with Al2Et3Cl3 cocatalyst) in heptane solvent, the two‐step addition of the diene gave terpolymers with little gel, in contrast to the high gel in terpolymers formed with the single initial addition of the diene. This system also produced terpolymer with the highest final unsaturation and molecular weight. Catalysts of VCl4, VOCl3, or V(C5H7O2)3 in benzene gave terpolymers of moderate unsaturations and molecular weights.
Electron spin resonance study of irradiated monomer and polymer of 3,3‐bis(chloromethyl)oxetane
Authors: Tsuji Kozo , Iwamoto Takeo , Hayashi Koichiro , Yoshida Hiroshi 
Published: April 2003

AbstractESR spectra were studied for irradiated 3,3‐bis(chloromethyl)oxetane (BCMO) single crystals and poly‐BCMO obtained by polymerizing BCMO single crystals in solid state. In both cases, the spectra consist of the superposition of two‐line and threeline components at −196°C. On warming the sample, only the former survived. From the examination of hyperfine coupling tensors, it is concluded that the two‐line spectrum is due to the free radicals
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for the monomer and C(CH2Cl)2ĊHO for the polymer sample, respectively. The orientation of the free radicals gives information about the mode of ring opening in the solid‐state polymerization of BCMO.
Preparation and polymerization of some vinyl monomers containing the 1,3‐dioxolane group
Authors: D'Alelio G. F. , Caiola R. J. 
Published: April 2003

AbstractThe synthesis and structure determinations of (2,2‐dimethyl‐1,3‐dioxolan‐4‐yl)‐methyl acrylate, 4‐(2,2‐dimethyl‐1,3‐dioxolan‐4‐yl)methyl itaconate, and [(2,2‐dimethyl‐1,3‐dioxolan‐4‐yl)methyl] methyl fumarate are described. Reactivity ratios in the copolymerization of these monomers with other comonomers are reported and the Alfrey‐Price Q and e values calculated. The post‐polymerization study of the effects of ultraviolet light and heat on these polymers and copolymers is presented. The 1,3‐dioxolane group when appended to the polymer chain performs as an internal ultraviolet sensitizer. A mechanism is offered to explain the crosslinking behavior of these polymers when treated with ultraviolet light.
Linear polymers of allyl acrylate and allyl methacrylate
Authors: D'Alelio G. F. , Hoffend T. R. 
Published: April 2003

AbstractAllyl acrylate and allyl methacrylate were polymerized by anionic initiators to soluble linear polymers containing allyl groups in the pendant side chains. The pendant unpolymerized allyl groups of the resulting linear poly(allyl acrylates) were shown to be present by: (1) the disappearance of the acrylyl and methacrylyl double bond absorptions in the infrared spectra in the conversions of monomers to polymers; (2) postbromination of the allyl bonds in the linear polymer; (3) the disappearance of the allyl groups absorptions in the infrared spectra of the brominated linear polymers; and (4) the thermal‐ and radical‐initiated crosslinking of the linear polymers through the allyl groups. Allyl acrylate and allyl methacrylate show great reluctance to copolymerize with styrene under anionic initiation, but copolymerize readily with methyl methacrylate and acrylonitrile. Block copolymers were prepared by reacting allyl methacrylate with preformed polystyrene and poly(methyl methacrylate) anions. The linear polymers and copolymers of allyl acrylate may be classified as “self‐reactive” polymers which yield thermosetting polymers. Bromination of the linear polymers offers a convenient method of producing self‐extinguishing polymers.
Synthesis of an arylene/alkylene polyether from diphenolic acid and rosenmund reduction to the polyether aldehyde
Authors: Fitch Robert M. , Chow Carl Da 
Published: April 2003

AbstractThe Williamson ether synthesis has been applied to the formation of an arylene/alkylene polyether with pendant carboxyl groups from 4,4‐bis(p‐hydroxyphenyl)pentanoic acid and 1,4‐dichlorobutane. The polymer was found to have a viscosity—molecular weight relationship following the equation, [η] = 1.30 × 10−4M0.94, in dimethylformamide at 25°C. Hydrogenolysis of the derived polyether acid chloride was found to proceed smoothly at atmospheric pressure in the presence of Pd–BaSO4 catalyst without poisoning of the catalyst by multiple absorption of polymer. The resulting polyether aldehyde undergoes typical aldehyde reactions. The infrared spectra of the polymers are also examined.
Photolysis of poly(ethylene terephthalate)
Authors: Marcotte F. B. , Campbell D. , Cleaveland J. A. , Turner D. T. 
Published: April 2003

AbstractThe photolysis of poly(ethylene terephthalate) films was studied in vacuo with light of wavelengths 2537 and 3130 A. A very stable filter system which cuts out the 3025 A. line was developed to isolate 3130 A. from a mercury spectrum. Despite the fact that the penetration of 2537 A. light was limited to a depth of a ca. 103 A. whereas 3130 A. light was more uniformly absorbed it was possible to demonstrate that the quantum yields for CO and CO2 formation were in agreement for the two wavelengths. Quantum yields for fractures and crosslinks were estimated by sol‐gel analysis. An absorption maximum which develops near 13 μ after exposure of poly(ethylene terephthalate) to light or γ‐rays was attributed to the formation of groups formed by elimination of CO and CO2. ESR spectra for trapped radicals were tentatively assigned to the components p‐C6H3· and ·OCH2CH2. It is suggested that the former radicals combine to form crosslinks. Quantum yields (× 104) with 3130 A. light are: CO, 6; CO2, 2; crosslinks, 5.5; trapped radicals, 1.5; With 2537 A. light, quantum yields are: CO, 6–9; CO2, 2–3; the network formed was not characterized as to crosslinks and fractures; trapped radicals were observed to exist but not determined.
Cyclo‐ and cyclized diene polymers. XIII. γ‐Ray‐initiated polymerization of 1,3‐dienes
Authors: S̆těpán Václav , Vodehnal Josef , Kössler Ivo , Gaylord Norman G. 
Published: April 2003

AbstractThe γ‐ray‐initiated polymerization of butadiene, isoprene, and 2,3‐dimethylbutadiene‐1,3 was carried out at temperatures of 20°C. and −78°C. Polymers of butadiene and isoprene with mixed linear and cyclic structure were proved to result from the polymerization at −78°C. A monocyclic structure was found for the 2,3‐dimethylbutadiene‐1,3 polymers initiated either at −78°C. or in the thiourea canal complex at 20°C.
Synthesis and evaluation of a series of regular polyampholytes
Authors: Neufeld C. H. H. , Marvel C. S. 
Published: April 2003

AbstractA series of three true polyampholytes with unequivocally alternating acidic and basic groups attached directly to the skeletal backbone of the polymer chain have been prepared. This was accomplished by copolymerizing 3,6‐diallyl‐2‐piperidone with the α,ω‐dithiols containing 2‐, 4‐, and 6‐methylene groups. The polymerization was carried out in an emulsion system initiated by 2,2′‐azobisisobutyronitrile (AIBN), yielding soluble piperidone‐containing polymers with molecular weights in the 20,000–30,000 range. The piperidone rings in the polymers were hydrolyzed by dilute sulfuric acid to yield the desired polyampholytes. Fibers were prepared by wet‐spinning formic acid solutions of the polyampholyte into saturated salt solution or by melt‐spinning. These fibers were quite elastic. We were unsuccessful in demonstrating that mechanical energy could be attained by the effect of pH on the fibers. Similarly, no pH effect could be elicited in Instron tests. The stress‐relaxation curve showed a marked positive force–temperature effect characteristic of rubberlike materials with few crosslinks. In a check of transition temperatures, it was noted that on repeated runs the second‐order transition temperature rose markedly, suggesting an irreversible change. Viscometric studies clearly demonstrated polyelectrolyte behavior. X‐ray diffraction studies of the polyampholytes showed that maximum crystallinity and orientation occurred in the polymer containing as part of the repeating unit the 1,4‐butane dithiol moiety.
Aromatic polysulfonamides
Authors: Arnold F. E. , Cantor S. , Marvel C. S. 
Published: April 2003

AbstractAromatic polysulfonamides have been prepared by solution polycondensation of aromatic disulfonyl chlorides and aromatic diamines with a suitable acid acceptor in such solvents as N,N‐dimethylacetamide and tetramethylenesulfone. The highest molecular weight polymers were obtained by using 2,6‐dimethylpyridine as the acid acceptor in tetramethylenesulfone as the solvent. Clear, translucent, brittle films of the polysulfonamides may be formed from solution or from melt.
Stereospecific polymerization of methacrylonitrile. I. Characterization of crystalline polymethacrylonitrile
Authors: Joh Yasushi , Kotake Yahide , Yoshihara Toshio , Ide Fumio , Nakatsuka Kazuo 
Published: April 2003

AbstractMethacrylonitrile (MAN) was polymerized with diethylmagnesium. Acetone‐insoluble portions of the polymers are found to be crystalline. Highly crystalline portions can be isolated by further extraction of the acetone‐insoluble parts with dimethylformamide (DMF). A film of DMF‐insoluble fraction can be oriented uniaxially by hot‐press rolling. The crystalline PMAN is insoluble in the usual solvents for amorphous PMAN because of their crystallinity and is easily soluble in CF3COOH or Cl2CHCOOH. The viscosity–molecular weight relationship was determined in Cl2CHCOOH at 30°C. as [η] = 3.24 × 10−3M0.520. We found several crystalline bands in the infrared spectra, for example, at 1192 and 885 cm.−1. Formation of the carbonyl group in the polymer is discussed, and it is concluded that it may be formed by the hydrolysis of conjugated cyclic imine or hydrolysis of the nitrile group in the polymer to acid amide.
Uranyl ion‐sensitized polymerization of acrylamide and methacrylamide in aqueous solution
Authors: Venkatarao K. , Santappa M. 
Published: April 2003

AbstractThe kinetics of polymerization of the vinyl monomers, acrylamide and methacrylamide, photosensitized by uranyl ions in homogeneous aqueous acid medium was studied systematically. Monochromatic radiation of wavelengths 365, 405, and 436 mμ was used for irradiation. Uranyl perchlorate in aqueous perchloric acid (pH = 0–2) was used as the sensitizer to ensure that only uncomplexed UO22+ ions existed in the solution. Polymerization was found to proceed without any induction period, the steady state being attained in about 10–20 min., and was followed by the measurement of the rate of monomer disappearance by bromine addition method. The chain lengths of the polymers were determined by viscometry. It was observed that there was no change in the initiator concentration, [UO22+], during polymerization. The dependence of the rate of polymerization on variables like light intensity, light absorption fraction by the active species, wavelength, monomer concentration, hydrogen ion concentration, temperature, nature of the acid used (HClO4 and H2SO4), viscosity of the medium etc., were studied. A kinetic reaction scheme is proposed and discussed in the light of the experimental results. Certain rate parameters were calculated. The mechanism of photosensitization by uranyl ions with specific reference to primary photochemical act, initiation of polymerization etc., are discussed.
Conformation of polyesters adsorbed on solid surfaces
Authors: Peyser Paul , Tutas Daniel J. , Stromberg Robert R. 
Published: April 2003

AbstractThe conformation of a polyester, poly(ethylene o‐phthalate), of relatively low molecular weight was studied after adsorption. The extension of the adsorbed molecule in a poor solvent on several planar metal surfaces was studied by ellipsometry and the fraction p of attached groups on colloidal silica particles in a good solvent was determined by the shift in the infrared absorption frequency between free and adsorbed carbonyl groups. In contrast to previously reported results for polystyrene, the extension normal to the surface remained constant (∼70 A.) while the concentration of polymer in the adsorbed film increased during the adsorption period. The value of p (0.34 for MW = 5400) is relatively high and was independent of surface population for the range of solution concentrations measured. Differences between these results and those for polystyrene are interpreted as resulting from differences in interaction energy and chain stiffness.
Synthesis of polyaryloxysilanes by melt‐polymerizing dianilino‐ and diphenoxysilanes with aromatic diols
Authors: Dunnavant W. R. , Markle R. A. , Stickney P. B. , Curry J. E. , Byrd J. D. 
Published: April 2003

AbstractA series of polyaryloxysilanes was prepared from aromatic diols and dianilino‐ and diphenoxysilanes. High molecular weight polymers were obtained at temperatures of 200°C. or higher by using melt‐polymerization procedures. The polymers, which combine the structures of silicones and polyaromatics, possessed high thermal stabilities and were obtained as materials which (1) failed to melt or soften at 350°C., (2) were gumlike at elevated temperatures, or (3) were soluble, film‐ and fiber‐forming polymers capable of being processed as conventional thermoplastics and having potentially useful mechanical properties. The preparation of monomers, general polymerization procedures, and certain structure‐property relationships for the thermoplastic polyaryloxysilanes are considered.
Chemical modifications of polycyclopentadiene
Authors: Meyersen Klaus , Wang Jean Y. C. 
Published: April 2003

AbstractPolycyclopentadiene, which is known to undergo extremely fast autoxidation resulting in insoluble products, was chemically modified, leading to derivatives no longer sensitive to oxygen. Soluble and stable products can be obtained in high conversions by Diels‐Alder addition of hexachlorocyclopentadiene (96.5 mole‐%), by epoxidation (93.5 mole‐%), and by addition of thioglycolic acid (97.9 mole‐%). A prerequisite is an efficient purification of polycyclopentadiene via reprecipitations in an oxygen‐free atmosphere. Other attempted alterations of the double bond were the hydroxyformylation and the free‐radical addition of haloalkanes, which, however, resulted in completely insoluble products. Typical addition reactions were carried out with the epoxy derivative of polycyclopentadiene, e.g., additions of hydrogen chloride, monochloracetic acid, chlorophenol, thiophenol, piperidine, hydrolysis to glycols. Easily initiated polymerization of the epoxy group is believed to be a conversion‐limiting side reaction in certain addition reactions, such as addition of hydrochloric acid or hydrolysis to glycols.
Role of heterogeneous Cr(AcAc)3–AlEt3 catalyst system in isoprene polymerization
Authors: Deshpande A. B. , Subramanian R. V. , Kapur S. L. 
Published: April 2003

AbstractPolymerization of isoprene in presence of a heterogeneous Ziegler‐type catalyst system, Cr(AcAc)3–AlEt3, has been studied in benzene medium. The rate of polymerization is first‐order with respect to catalyst as well as monomer concentration. The rate studies, activation energy, and polymer microstructures are reported in order to follow the probable mechanism of polymerization.
Effect of temperature and solvents on stereospecific polymerization of vinyl alkyl ethers catalyzed by aluminum sulfate–sulfuric acid complex
Authors: Lal Joginder , McGrath James E. , Trick G. S. 
Published: April 2003

AbstractThe effect of polymerization temperature and solvents was determined on the crystallinity of polymers of vinyl isobutyl ether and of vinyl n‐butyl ether prepared with aluminum sulfate–sulfuric acid complex catalyst. Principally, the methyl ethyl ketone (MEK)‐insoluble fractions of these polymers were used for characterization. Density, per cent crystallinity by x‐ray diffraction, infrared ratio, and dilatometric volume contraction of these polymer fractions were used as criteria of crystallinity. The MEK‐insoluble fractions of poly(vinyl n‐butyl ethers) prepared in carbon disulfide in the temperature range of −30 to +25°C did not show any significant difference in the values of the above crystallinity parameters. The polymer obtained at 50°C. was less crystalline than the rest of the polymers. The MEK‐insoluble fractions of poly(vinyl isobutyl ethers) prepared at 0–50°C. in carbon disulfide and n‐heptane solvents also did not significantly differ in their degree of crystallinity. They were, however, decidedly less crystalline than the MEK‐insoluble fractions of the corresponding polymers obtained at −20°C. These data a indicate that on increasing the temperature of polymerization the crystallinity of the polymers was either unchanged or decreased slightly. The polymerizations of vinyl n‐butyl ether and vinyl isobutyl ethers were also carried out in binary mixtures of carbon disulfide with n‐heptane, chlorobenzene, and MEK. Generally, increasing the concentration of carbon disulfide increased the inherent viscosities of polymers as well as the weight percentage of their MEK‐insoluble fractions. The MEK‐insoluble fraction of poly(vinyl isobutyl ether) prepared in carbon disulfide‐MEK mixture (volume ratio 2:1) was isotactic and highly crystalline. Likewise, the MEK‐insoluble fractions of two polymers of vinyl n‐butyl ether prepared in MEK itself were also isotactic and highly crystalline. Compared to poly(tetramethylene oxide), these latter fractions exhibited less dependence of rate of crystallization upon temperature. Consequently, at low degrees of supercooling they crystallize much more rapidly than does poly(tetramethylene oxide).
NMR studies on the stereospecific polymerization of methyl vinyl ether. Part I. Polymerization by metal halides: Penultimate effect
Authors: Ohsumi Y. , Higashimura T. , Okamura S. 
Published: April 2003

AbstractMethyl vinyl ether (MVE) was polymerized under various conditions by BF3·O(C2H5)2 and SnCl4·CCl3CO2H catalysts. The effect of polymerization conditions on the steric structure of poly(methyl vinyl ether) (PMVE) was studied by NMR spectra. It was found that the triad isotacticity of PMVE decreased and the syndiotacticity and heterotacticity increased with increasing polarity of the solvent and increasing polymerization temperature. This result coincided with the qualitative conclusion estimated from softening point and infrared spectra. However, the variation of tacticity by the change of the polarity of a solvent was not so large as expected. There was no large difference between the behavior of BF3·O(C2H5)2 and SnCl4·CCl3CO2H as catalysts. From the relation between the difference of free energy of monomer addition due to the steric structure of the polymer and the polymerization temperature, it was concluded that the penultimate effect really existed and was due to only the difference in enthalpy in the MVE–BF3. O(C2H5)2 or MVE–SnCl4·CCl3CO2H systems. The penultimate effect was not greatly changed by the polymerization conditions in these systems.