bluuebunny/crossref_metadata_2025 huggingface dataset:
Regular copolyamides. IV. Characterization of membrane morphology
Authors: Tirrell D. , Vogl O.
Published: April 2003

Asymmetric copolyoxamide films prepared via a solution‐casting/gelation process have been characterized by scanning electron microscopy, small‐angle light scattering, and measurements of surface area and hydrophilicity. The polymer selected for study is a regular copolyamide prepared from N,N‐bis(2‐aminoethyl) oxamide and isophthaloyl chloride, and shows promise as a membrane material for desalination by reverse osmosis. Scanning electron microscopy reveals a unique capillary structure in films cast from N,N‐dimethylacetamide‐LiCl mixtures, plus a variety of structures in trifluoroacetic acid‐cast membranes. Light‐scattering experiments on water‐swollen films have substantiated microscopic observations of desiccated samples; the gel structures of the copolyoxamide films do not appear to suffer severe collapse on dehydration. Measurements of surface area and water sorption have been conducted in an attempt to assess membrane‐water interaction.
The growth of polymer colloids
Authors: Lichti Gottfried , Gilbert Robert G. , Napper Donald H.
Published: April 2003

The traditional theoretical approach to emulsion polymerization is extended to include effects due to the size of each polymer latex particle. Specific account can thus be taken of the particle size distribution in considering the growth of the colloid. Coupled partial differential equations are derived to describe the system and shown to reduce to the conventional Smith‐Ewart equations under certain limits. Solutions are presented for simple models for the emulsion polymerization of styrene and vinyl acetate.
Permeability to oxygen of poly(methyl methacrylate) films containing silane‐treated glass flakes
Authors: Higashide F. , Omata K. , Nozawa Y. , Yoshioka H.
Published: April 2003

Permeability to oxygen of poly(methyl methacrylate) (PMMA) films containing glass flakes (GF) was investigated. The glass flakes were treated with five kinds of silanes and K2Cr2O7‐H2SO4 solution to improve the affinity with PMMA. The permeability curves were classified into five representative types, which depend on the pretreatment of the glass flakes and the type of silane used as a coupling agent. The factors which influence permeability were studied from the point of view of permeative retardation with the aid of several methods, such as determination of the apparent density of the glass flakes treated with the silanes, the shearing and tensile strength of the PMMA films containing the glass flakes, ESR spectra of films irradiated by γ‐rays, and x‐ray diffraction patterns of the films. It was found that the three very effective methods to retard the permeability are (a) pretreatment of the glass flakes with NaOH, (b) treatment with γ‐methacryloxypropyltrimethoxysilane or ditrimethylsiloxymethylsilane, and (c) heat pressing of the films. The lowest permeability constant which was attained in this study was about one‐eighth that with PMMA alone.
Substrate–polymer interactions in liquid exclusion chromatography (GPC) in N,N‐dimethylformamide
Authors: Dubin Paul L. , Koontz Steven , Wright Kenneth L.
Published: April 2003

The importance of nonexclusion effects in the GPC behavior of several stationary phases was investigated with DMF, 0.01M LiBr, as the mobile phase. Various low MW solutes and narrow MWD polymers, encompassing a wide range of polarities, were studied. The elution of the polymers was examined in terms of “universal calibration” behavior. Styragel and silanized glass both exhibit affinity for apolar polymers in DMF; for the former substrate this effect shows a strong inverse dependence on MW. As a consequence, application of polystyrene calibration curves to GPC analysis of more polar polymers with these substrates leads to overestimations of MW parameters. These errors are not corrected when universal calibration procedures are used. Ideal exclusion chromatography is exhibited by a number of polymers on untreated porous glass substrates. However, polymers with strong hydrogen‐bonding functionality appear to be susceptible to marked adsorption in this system.
High‐conversion polymerization. III. Kinetic behavior of ethyl methacrylate
Authors: Cardenas J. N. , O'Driscoll K. F.
Published: April 2003

The kinetics of free‐radical polymerization of ethyl methacrylate (EMA) have been experimentally studied in bulk and in 50% solution in DMF over the temperature range from 60 to 90°C. At low conversion, the kinetic parameters have been determined, including constants for chain transfer to monomer and solvent. These parameters have then been used to model the kinetic behavior at high conversion using previously derived equations. The results indicate that the equations satisfactorily predict the conversion and molecular weight averages and distributions as a function of time from zero to ca. 95% conversion.
Synthesis and properties of block poly(styrene amides) and poly(styrene esters)
Authors: Katayama Shitomi , Serita Hajime , Takahashi Yukio
Published: April 2003

Three 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

The 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

Polyaddition 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

The 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

Bisbenzils 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

Application 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

The 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

Photodegradation 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

The 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

The 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

The 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

The 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

By 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

Poly‐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

4‐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

A 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

Three 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

Three 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

The 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

The 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

Novel 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

A 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

The 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

Crosslinked 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.
An investigation of the thermolysis mechanism of model urethanes
Authors: Voorhees K. J. , Hileman F. D. , Einhorn I. N. , Futrell J. H.
Published: April 2003

The products of pyrolysis in a helium atmosphere of a model urethane foam based on PAPI and propoxylated trimethylol propane were investigated by using GC/MS and GC/CIMS. Chemical‐ionization mass spectrometry was used because it produces primarily protonated molecular ions (M + 1) with little fragmentation which facilitated the identification of the polyol decomposition products. Identification of the polyol pyrolysis fragments has led to the formulation of a detailed polyol thermolysis mechanism. This mechanism shows the polyol to decompose by a systematic route of reactions rather than by a random breakdown.
Distribution of polymer deposition in plasma polymerization. I. Acetylene, ethylene, and the effect of carrier gas
Authors: Yasuda H. , Hirotsu Toshihiro
Published: April 2003

Factors which influence the distribution of polymer deposition in an electrodeless glow‐discharge system were investigated for acetylene and ethylene. Under the conditions in which “full glow” is maintained, the distribution of polymer deposition from pure monomer flow systems is nearly independent of flow rate of monomer or of the system pressure in discharge, but is largely determined by the characteristic (absolute) polymerization rates (not deposition rate) of the monomers. Acetylene has a high tendency to deposit polymer near the monomer inlet, whereas ethylene deposits polymer more uniformly in wider areas in the reactor. The addition of carrier gas such as argon or partially copolymerizing gas such as N2, H2, and CCl2F2 was found to narrow the distribution of polymer deposition. The distribution of polymer deposition is also influenced by a glow characteristic which is dependent on flow rate and discharge power.
Dipole moment characterization of phenol–, o‐cresol–, and p‐cresol–formaldehyde resins
Authors: Tobiason Fred L. , Cain Greg H. , Anderson Jack W.
Published: April 2003

Dipole moments and their temperature dependence have been measured in p‐dioxane for fractionated novolac phenol–, o‐cresol–, and p‐cresol–formaldehyde polymers. The phenol–formaldehyde fractions covered a molecular weight range of 200 to 6100, and the limiting dipole moment ratio 〈μ2〉/xm2 is 1.48. The p‐cresol–formaldehyde dipole‐moment ratio at a DP of 4 is 2.47, whereas the phenol–formaldehyde dipole‐moment ratio is 1.40. That for o‐cresol–formaldehyde is intermediate in value. The dipole‐moment temperature coefficients are positive for p‐cresol chains and negative for the phenol–formaldehyde chains. These results indicate that the hydroxyl groups along the p‐cresol–formaldehyde polymer are highly ordered, with the aromatic rings closer to the sterically hindered planar position than in the phenol–formaldehyde polymers.
Poly‐α‐ester degradation studies. VII. Thermal degradation of poly(cycloalkylidene carboxylates)
Authors: Norton G. P. , Tighe B. J. , Molloy R.
Published: April 2003

The thermal degradation of poly(cyclopentylidene carboxylate) and poly(cyclohexylidene carboxylate) has been studied over the temperature range 200–500°C by using a combination of kinetic and analytical techniques. The results obtained indicate the simultaneous operation of mechanisms previously observed with different compounds in the series. Thus kinetic studies by thermogravimetric analysis and characterization of the products formed suggest the occurrence of an essentially first‐order hydrogen abstraction process with superimposed random scission reactions in the early stages. The main products are cyclopenten‐1‐carboxylic acid and cyclohexen‐1‐carboxylic acid, respectively. This corresponds to the behavior previously observed in the degradation of poly(3‐pentylidene carboxylate). On the other hand, in‐line pyrolysis directly linked to a gas chromatograph clearly indicates the production of cyclopentanone and cyclohexanone and, more importantly in the case of poly(cyclopentylidene carboxylate), the formation of dicyclopentyl glycollide. The appearance of these products in addition to the unsaturated acids suggests that some degradation occurs by the intramolecular ester‐interchange process previously postulated for poly(methylene carboxylate) and poly(isopropylidene carboxylate). The associated thermodynamic parameters and relative quantities of the different products observed by gas‐chromatographic methods indicate that the hydrogen‐abstraction process predominates.
Aqueous polymerization of acrylonitrile initiated by the bromate–thiourea redox system
Authors: Pati Nrusingha C. , Lenka Subasini , Nayak Padma L. , Mohanty Trijama R.
Published: April 2003

The aqueous polymerization of acrylonitrile initiated by an acidified bromate–thiourea redox system has been studied under nitrogen atmosphere. The rate of polymerization is independent of thiourea concentration over the range 2–9 × 10−3M and reaches maximum at 9 × 10−3M. The rate varies linearly with [monomer]. The initial rate of polymerization as well as the maximum conversion increases within the range of 4–22.5 × 10−3M KBrO3, but beyond 22.5 × 10−3M the rate of polymerization decreases. The initial rate and the limiting conversion increases with increasing polymerization temperature in the range 30–45°C; and beyond 45°C they decrease. The effect of certain neutral salts, water‐soluble solvents, and micelles of cationic, anionic, and nonionic surfactants on the rate of polymerization has been investigated.
Study of the mechanism of polysulfone decomposition by pyrolysis/gas chromatography and pyrolysis/gas chromatography/mass spectrometry
Authors: Gritter R. J. , Seeger M. , Gipstein E.
Published: April 2003

Both co‐ and terpolysulfones have been flash‐pyrolyzed at high temperature followed by separation and identification of the products by gas chromatography and/or gas chromatography/mass spectrometry. As expected, most of the products were the corresponding olefin and SO2. Additionally, higher molecular weight products, including aromatics, and olefin isomerization products, were produced. Mechanisms for initiation and formation of the higher molecular weight products are presented which include the back reaction of intermediate free radicals to abstract hydrogen or to form CC bonds followed by expulsion of SO2. The free‐radical intermediates formed by the SO2 expulsion undergo transformations to give the aromatic products. No breakdown products were found with either O or S present, nor was SO2H found.
Some aspects of plasma polymerization of fluorine‐containing organic compounds. II. Comparison of ethylene and tetrafluoroethylene
Authors: Yasuda H. , Hsu T. S. , Brandt E. S. , Reilley C. N.
Published: April 2003

Plasma polymerizations of ethylene and tetrafluoroethylene are compared. In the plasma polymerization of ethylene and of tetrafluoroethylene, glow characteristics play an important role. Glow characteristic is dependent on a combined factor of W/Fm, where W is discharge power and Fm is monomer flow rate. At higher flow rates, higher wattages are required to maintain “full glow.” In the plasma polymerization of tetrafluoroethylene, simultaneous decomposition of the monomer competes with plasma polymerization. Above a certain value of W/Fm, decomposition becomes the predominant reaction, and the polymer deposition rate decreases with increasing discharge power. ESCA results indicate that the plasma polymer of tetrafluoroethylene that is formed in an incomplete glow region (low W/Fm) is a hybrid of polymers of plasma polymerization and of plasma‐induced polymerization of the monomer. Polymers formed under conditions of high W/Fm to produce “full glow” are similar, regardless of the extent of decomposition of the monomer. They contain carbons with different numbers of F(CF3, CF2, >CF, >C<) and carbons bonded to other more electronegative substituents.
Catalytic activity of Cu(II)–poly(vinyl alcohol) complex for decomposition of hydrogen peroxide
Authors: Hojo Nobumasa , Shirai Hirofusa , Chujo Yoshiki , Hayashi Sadao
Published: April 2003

Decomposition of hydrogen peroxide was examined was examined by using Cu(II)–poly(vinyl alcohol) (PVA) as catalyst. The rates of decomposition were measured. Electronic spectra and infrared spectra of Cu(II)–PVA complex systems were determined at various stages of decomposition. Effect of addition of various amines to the Cu(II)–PVA system on catalytic action was considered. The relation between the initial rate and the initial concentration of hydrogen peroxide varied in accordance with the rate expression of Michaelis‐Menten type. Cu(II)–PVA complex was found to have a large catalytic activity, while the polymeric PVA ligand and copper(II) ion exhibited less activity than Cu(II)–PVA complex. For hydrogen peroxide decomposition, Cu(II)–PVA complex showed catalytic activity when a stable complex of planar structure formed, while many other polymer complexes reported by other authors showed the catalytic activity when they were in unstable complex forms. An amine substituent has a critical influence on the rate of hydrogen peroxide decomposition. The mechanism in the first step of reaction for hydrogen peroxide decomposition is discussed.
Block copolymers of styrene, isoprene, and ethylene oxide prepared by anionic polymerization. I. Synthesis and characterization
Authors: Koetsier D. W. , Bantjes A. , Feijen J. , Lyman D. J.
Published: April 2003

Anionic polymerization has been used as a technique for the synthesis of five‐block copolymers of polystyrene (PS), polyisoprene (PI), and poly(ethylene oxide) (PEO). Two types of such polymers, PEO‐PI‐PS‐PI‐PEO and PEO‐PS‐PI‐PS‐PEO with varying PEO block length, have been prepared, using potassium naphthalene as the initiator and tetrahydrofuran as the solvent. The polymers were purified by extraction with ethyl acetate, diethyl ether, and water. After the addition of each monomer, a sample from the living polymer solution was taken and analyzed by spectroscopy (infared (IR) and proton magnetic resonance (PMR)), osmometry, and gel‐permeation chromatography (GPC) to obtain information about composition, molecular weight and molecular weight distribution of the intermediate polymers. The five‐block copolymers have also been characterized by the same techniques and by elemental analysis.
Polypivalolactone grafts on EPDM
Authors: Thamm Richard C. , Buck Warren H.
Published: April 2003

Random copolymers of ethylene, propylene, and 1,4‐hexadiene (EPDM) were carboxylated by reaction with thioglycolic acid or with maleic anhydride. Treatment of these polymers in tetrahydrofuran solution with tetrabutylammonium hydroxide generated carboxylate anions, which initiated the graft polymerization of pivalolactone. Conversion and grafting efficiencies approached 100%. Polypivalolactone chains had an estimated DPn of 3 to 20 and the average distance between graft sites varied from 3000 to 7700 molecular weight units. On cooling from the melt, highly crystalline domains of polypivalolactone formed, which melted at 120–200°C depending on DPn. Electron microscopy and x‐ray analysis verified the presence of these domains, which serve as reinforcing tiepoints for thermally reversible network formation. The resultant thermoplastic elastomers have excellent elasticity and strength, and their compression set resistance is equivalent to that of conventionally cured and reinforced EPDM. This paper details the synthesis, morphology, and structure–property relationships of these elastomers.
Ionic polymerization of 1,2‐butylene oxide: GPC, NMR, and IR characterization of the reaction products
Authors: Malhotra Shadi Lal , Leborgne Alain , Blanchard Louis‐Philippe
Published: April 2003

The triphenylmethyl hexafluoroarsenate‐initiated cationic polymerization of 1,2‐butylene oxide in dichloroethane between −25 and +25°C and its sodium‐initiated anionic polymerization in bulk at 20°C have been carried out. Gel permeation chromatography (GPC) molecular weight distribution curves of the reaction products are multinodal. Nuclear magnetic resonance (NMR) and infrared (IR) analyses show that the cationically prepared polymers are composed of cyclic oligomers and linear high‐molecular‐weight products, while the anionically prepared polymers contain only linear products some of which include double bonds. NMR analyses further reveal that the cationically prepared polymers consist of monomer repeat units, while the anionically prepared polymers are essentially made of side products originating from the reaction of 1,2‐butylene oxide with the sodium mirror used as the anionic initiator.
Effect of homologous series of alkyl sulfate surfactants on the emulsion polymerization of styrene. I. Equal total concentrations
Authors: Al‐Shahib W. A. G. R. , Dunn A. S.
Published: April 2003

There is evidence in the literature that the rates of emulsion polymerization increase by a large factor as the alkyl chain length increases for a homologous series of surfactants. However, the area occupied by a surfactant molecule in a saturated monolayer at the polystryene/water interface is independent of chain length for alkyl sulfates so that, on the basis of Gardon's theory, equal rates of polymerization would be expected when equal concentrations of surfactants are used. There is a large increase in the number of polymer latex particles formed and in the rate of emulsion polymerization as the surfactant concentration is increased through the critical micelle concentration; this accounts for the large increases reported, because the lower members of the homologous series are below their critical micelle concentrations in most of the published studies. When a common concentration is chosen that is above the critical micelle concentration even for the lowest member of the series, only a relatively small increase in latex particle number and rate of emulsion polymerization with alkyl chain length of the surfactant is observed. This is attributable to an increase in the concentration of surfactant micelles. Good agreement with Gardon's theory is obtained when the concentration of micellar surfactant is used instead of the total surfactant concentration.
Application of mass spectrometry to copolymers of ethylenes and propylene oxides. I. Structural analysis
Authors: Lee A. K. , Sedgwick R. D.
Published: April 2003

Mass spectra of linear copolymers of ethylene and propylene oxides show features which are characteristic of the two monomers. Interpretation of the spectra of samples with and without modified end groups allows them to be classified as either random or blocked in structure and, in the latter case, permits determination of the order in which blocks are incorporated. Within a limited molecular weight range, the method can lead to a full determination of the distribution of molecular weights in the samples.
Vinylation and polymerization with trivinylaluminum. I. Vinylation of organic halides as a model for termination in cationic polymerization leading to vinyl end groups
Authors: Mandal Broja M. , Kennedy Joseph P. , Kiesel Rodney
Published: April 2003

An improved synthesis of trivinylaluminum (V3Al) is described. The proton magnetic resonance (PMR) spectrum of V3Al was recorded and analyzed. A new vinylation method involving the use of V3Al as the vinylating agent has been developed, and the vinylation of organic halides by V3Al was studied at −30, −50 and −70°C. Primary alkyl chlorides, such as methyl and methylene chloride, do not react with V3Al and were used as solvents. Secondary chlorides such as 2‐chloropropane also do not react. t‐Butyl chloride gives rise to t‐butylethylene (70–98%), depending on reaction conditions, and the allylic chlorides, 3‐chloro‐1‐butene, and 3‐chloro‐3‐methyl‐1‐butene, yield the expected vinylated products and their isomers (∼90%). Allyl and benzyl chloride do not react under the conditions tried. The reaction between V3Al and the ditertiary dichloride 2,6‐dichloro‐2,6‐dimethylheptane yields several isomeric C13H24 and C11H20 hydrocarbons; however, surprisingly, C9H16 does not form. The C13 hydrocarbons arise by divinylation at the termini of the dichloride, while the C11 hydrocarbons are formed by vinylation at one and proton elimination at the other terminus of the dichloride. The presence of unsaturated C13H24 and C11H20 isomers is most likely due to proton induced isomerization. These results are explained by a proximity effect involving vinylation at one end of the dichloride by V3Al followed by rapid reaction of the second chlorine (mostly) by V2AlCl generated in situ during the first vinylation in the proximity of the chloride. At the other chlorine terminus V2AlCl causes either a second vinylation (leading to C13 hydrocarbons) or a proton elimination (leading to C11 hydrocarbons). The absence of C9H16 among the reaction products indicates that V3Al exclusively effects vinylation. The RCl + V3Al ← RV + V2AlCl reaction may be regarded as a model for initiation followed by immediate termination in cationic olefin polymerization, a process leading to vinyl‐ended polymers.
Photochemical addition of maleic anhydride derivatives and related compounds to benzene and polystyrene sensitized by low‐ and high‐molecular carbonyls
Authors: Hrdlovič P. , Záhumenský L. , Lukáč I. , Sláma P.
Published: April 2003

The photochemical addition of maleic anhydride to benzene initiated by radiation with λ > 340 nm is sensitized by low and high‐molecular carbonyls. Only those copolymers of para‐substituted acrylophenones with methyl methacrylates are effective sensitizers that have a triplet energy ET higher than 276 kJ/mole. The efficiency of maleic anhydride addition was found to be higher for copolymers of acrylophenone with styrene (ET > 276 kJ/mole) than that with polystyrene in the presence of low‐molecular ketone. The copolymer 4‐phenylacrylophenone–styrene exhibits maleic anhydride addition in solution and in film, although ET < 276 kJ/mole, possible caused by energy transfer from higher triplet level. The derivatives of maleic anhydride and structurally related compounds react under the conditions of sensitized photoaddition in a different way from the parent compound. Vinylene carbonate is added to polystyrene sensitized by acetophenone; 2,3‐dichloromaleic anhydride and 1,2‐dichlorovinylene carbonate initiated crosslinking of polystyrene in solution and in film; 2,3‐dimethylmaleic anhydride mainly underwent dimerization (88% w/w); dimethyl maleate does not react at all. Maleic anhydride and other related compounds take part in these reactions in the lowest triplet state. Addition of maleimide and its derivatives to polystyrene proceeds as a nonsensitized reaction from the singlet state and is more effective than maleic anhydride addition to polystyrene in solution and in film. 2,3‐Dichloromaleimide dimerized (15% (w/w)) as well as undergoing addition to polystyrene.