bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel synthesis of photocrosslinkable polymers
Authors: Kato Masao , Ichijo Taro , Ishii Keizo , Hasegawa Masaki
Published: April 2003

A new preparative route to photocrosslinkable polymers in which the polymers are produced directly from the polymerization of vinyl monomers having photocrosslinkable groups has been investigated. The photosensitive resins thus produced have higher sensitivity and resolution than conventional photosensitive resins. The monomers were synthesized from the esterification of vinylphenols or vinyl β‐chloroethyl ether with cinnamic acid, β‐styrylacrylic acid, and their homologs, and from the etherification of vinyl β‐chloroethyl ether with hydroxychalcones. Homopolymerizations of these monomers and their copolymerizations with other comonomers were investigated with the use of both radical and ionic initiators. It is shown that radical polymerization of the monomers gave soluble polymers only at low conversion. Anionic initiators did not initiate polymerization. Cationic polymerization imparted soluble polymers in high yield, except for the monomers bearing cyano groups, which generally gave insoluble polymers. Infrared and NMR spectroscopic investigation of the cationically obtained soluble polymers and comparative investigation by cationic polymerization of model compounds indicated that polymerization of the monomers proceeds through the vinyl double bond without affecting the photosensitive unsaturated bond. Thus, linear photocrosslinkable polymers with an intact photoreactive group may be produced by cationic polymerization. In general, these polymers have uniform structure and modifiable physical properties depending on the monomer used. The polymer thus obtained from β‐vinyloxyethyl cinnamate has been shown to have excellent properties for use as a photo‐resist.
Synthesis and thermal degradation of some ferrocene‐containing polyazines and poly‐schiff bases
Authors: Gamper R. G. , Funke P. T. , Volpe A. A.
Published: April 2003

A series of ferrocene‐containing polymeric azines and polymeric Schiff bases have been synthesized by means of acid‐catalyzed solution polycondensations. The molecular structures of the polymers synthesized have been determined, and information concerning their thermal behavior has been obtained. Comparative thermal stabilities of the products of polymerization of aliphatic and aromatic diamines with 1,1′‐diformylferrocene and 1,1′‐diacetylferrocene were investigated by thermogravimetric analysis both in air and in an inert atmosphere. In the inert atmosphere, initial weight loss due to thermal stress did not occur below 300°C in all cases, and in many cases 50–70% residue of polymer sample remained at 700°C. The use of a fluorinated diamine led to the synthesis of a polymer which did not exhibit any significant enhancement of thermal properties. Investigation of the polymer products by direct inlet mass spectroscopy led to the observation that several of the systems contained significant amounts of cyclic dimers, although linear polymers were the major products in most cases. Extraction of the cyclic dimers followed by molecular weight determination by vapor phase osmometry confirmed their molecular structures.
Relative reactivities of some dienes and acetylenes in copolymerization with sulfur dioxide
Authors: Ivin K. J. , Walker N. A.
Published: April 2003

The reactivities of isoprene, piperylene,2,3‐dimethylbutadiene, hex‐1‐yne, and phenylacetylene, at −20°C, relative to that of cyclohexene, have been determined for the radical‐initiated copolymerization with sulfur dioxide to form 1:1 polysulfones. The unsaturated hydrocarbons were copolymerized with sulfur dioxide in pairs and the composition of the terpolymers determined from the 100 MHz NMR spectra. The dienes react 11–15 times as fast as hex‐1‐ene, while hex‐1‐yne reacts 16 times more slowly. Phenylacetylene reacts 21 times as fast as hex‐1‐yne. The relative reactivities are interpreted mainly in terms of the effect of electron delocalization on the stability of the product radical.
Studies with inorganic precipitate membranes. IV. Evaluation of apparent fixed charge on membranes
Authors: Siddiqi Fasih A. , Lakshminarayanaiah N. , Beg Mohammad N.
Published: April 2003

Membrane potentials arising across four parchment‐supported ferrocyanide membranes of manganese, cobalt, silver, and cadmium when they separate 1:1 electrolyte solutions of concentration C1 and C2 such that C1 = 10C2, have been measured. The data have been used according to the procedure prescribed by one of the theories of membrane potential due to Teorell and Meyers and Sievers to derive values for the quantity of charge present on the membranes. An alternative procedure employed by Altug and Hair has been considered and found to overestimate the value for the charge on the membranes.
Chain folding in poly‐trans‐1,4‐butadiene crystals grown from various solvents
Authors: Stellman J. M. , Woodward A. E.
Published: April 2003

Crystals of poly‐trans‐1,4‐butadiene of uniform size have been grown from three solvents (n‐heptane, methyl isobutyl ketone, and toluene) by using a minimum dissolution temeprature technique. The percentage of double bonds available for reaction in the crystals was determined by epoxidation in suspension; crystal thicknesses were measured by electron microscopy. These values were used to calculate the number of monomer units per fold. The number of available double bonds was found to increase with decreasing molecular weight, evidence for the presence of non‐reentrant chains (cilia) at the crystal surfaces. The nature of the chain fold in poly‐trans‐1,4‐butadiene crystals is discussed.
Scattering of light by deformed three‐dimensional spherulites
Authors: Van Aartsen J. J. , Stein R. S.
Published: April 2003

A theoretical calculation of the Hv light‐scattering patterns for deformed three‐dimensional spherulites is presented. Affine deformation is assumed. The optic axis of the scattering element is allowed to lie at an arbitrary angle ß to the radius which is permitted to change in the course of the deformation in a manner that may depend upon the angular location in the spherulite. The consequences of twisting of the optic axis about the spherulite radius are also explored.
Crystallite size in highly drawn polyethylene
Authors: Glenz W. , Peterlin A. , Wilke W.
Published: April 2003

The size and distortion of crystallites in samples of linear polyethylene were determined before and after plastic deformation. A slowly cooled sample, a quenched sample, and highly drawn films (draw ratio 16) were investigated by different methods. Wide‐angle x‐ray patterns were analyzed to study the average size of the crystalline mosaic blocks and their distortion. In addition, the longitudinal crystal thickness (in the chain direction) was evaluated by two other approaches, determination of the long period, and the melting temperature of irradiated samples. The results show clearly that the size of the crystalline mosaic blocks changes substantially with drawing of polyethylene. Not only is the lateral crystal thickness affected, but the longitudinal crystal dimensions also change during the drawing process. By the three independent methods we find that the longitudinal crystal thickness after drawing is independent of the value for the undrawn samples, as was reported earlier by Peterlin. The change in crystallite size after drawing is accompanied by a large decrease in crystal volume to about 10% of the value for the undrawn sample. The degree of distortion in the crystals seems not to be affected by the deformation process. These experimental data can be considered evidence for high chain mobility and for the possibility of rearrangement of chain molecules during the process of plastic deformation.
Scattering of light by disordered spherulites. II. Effect of disorder in the magnitude of the anisotropy
Authors: Hashimoto T. , Stein R. S.
Published: April 2003

The contribution to the disorder scattering by imperfect spherulites resulting from fluctuations in the magnitude of the anisotropy is analyzed for two‐dimensional spherulites. The fluctuations are described in terms of a parameter characterizing the meansquare amplitude of the fluctuation and a correlation function describing the distance over which the correlation occurs. Cases considered are those where the correlation depends on either the radial or the angular separation of the scattering volume elements. As with the case of disorder in orientation, one finds that disorder in anisotropy may result in a nonzero value of intensity at μ = 0° and 90°, a decrease in the higher‐order variation of scattered intensity with θ, and an increase in the intensity of scattering at higher values of θ over that for a perfect spherulite. In addition, disorder in the angular direction leads to an increase in the scattered intensity at small values of θ as compared with the zero intensity of scattering from a perfect spherulite at θ = 0°.
Diffusion mechanisms in solid and molten polyethylene
Authors: Lowell P. N. , McCrum N. G.
Published: April 2003

The diffusion coefficient D and solubility coefficient k of small molecules [C3H6, C4H10, (CH3)4C] are determined at very low solute concentrations in annealed linear polyethylene over a wide range of temperature above and below the melting point Tm. For measurements above Tm the specimen was lightly crosslinked by irradiation from a 60Co source. The diffusion data fit equations of the form D = D0 exp {–ΔHD/RT}. An abrupt change in ΔHD occurs at Tm: representative values (for C4H10) are 4.53 and 14.9 kcal/mole above and below Tm. At Tm, D0 also changes abruptly: representative values (for C4H10) are log D0 = −2.65 above Tm and log D0 = +2.70 below Tm. The mechanism of diffusion therefore changes at the melting point. The melt exhibits typical liquidlike characteristics (negative values of activation entropy ΔSD). The ratio ΔSD/ΔHD = 4β (β denoting the isobaric coefficient of volume expansion) holds below but not above Tm. Equations of the form k = k0 exp {–ΔHk/RT} fit the solubility data. The log k versus T−1 plots above and below Tm are parallel but separated by a step at Tm. If crystallization followed by annealing is assumed to leave a weight fraction of polymer αk (the amorphous fraction) in which the solute can absorb and if the specific solubility coefficient of the amorphous fraction is identical to that of the melt, then log αk Equals the magnitude of the step at Tm. Values of αk determined from the observed step are very close to values of amorphous fraction determined by measurement of density. The solubility experiments support the concept of polyethylene as a two‐phase solid with the amorphous fraction of specific volume equal to the extrapholated specific volume of the melt. The passage of a solute molecule from one potential well to another, however, occurs by processes in the melt and the amorphous fraction which are entirely different.
Polymerization of α‐amino acid N‐carboxy anhydride. IX. Copolymerization of α‐amino acid N‐carboxy anhydride in heterogeneous system
Authors: Oya Masanao , Uno Keikichi , Iwakura Yoshio
Published: April 2003

Copolymerization of NCA's was undertaken in a heterogeneous system in acetonitrile, which is not a solvent of the polypeptides. The reactivity ratio was calculated by using the Lewis‐Mayo equation. Further, the conversion rate in the copolymerization and the configuration of the copolymer produced were compared with those of the copolymerization in the homogeneous system in nitrobenzene, in which the copolypeptides are swollen. The rate of copolymerization in acetonitrile was between the rates of polymerization of the individual monomers. It has been reported that the configuration of the copolymer obtained in dimethylformamide, in which the copolypeptides are swollen, is of the block type. On the other hand, many polypeptides obtained in acetonitrile, which is not a solvent of the copolypeptides, had a random configuration near to an alternating configuration.
Tractable polyfluoral
Authors: Temple S. , Thornton R. L.
Published: April 2003

Low‐temperature polymerizations of fluoral with the use of ionic initiators in inert diluents have produced high molecular weight polyfluoral which is amorphous and tractable. The polymer can be end‐capped by standard techniques to give material which is thermally stable to 350–400°C. The stabilized polymer can be fabricated from solution or melt‐pressed at temperatures as low as 125°C to give clear films and coatings which are oil‐and water‐repellent but highly permeable toward oxygen and water vapor.
Radiation‐induced postpolymerization of trioxane in the solid state. IV. Copolymerization of trioxane with dioxolane
Authors: Ishigaki Isao , Ito Akihiko , Hayashi Koichiro
Published: April 2003

The radiation‐induced postpolymerization of trioxane with 1,3‐dioxolane has been investigated. Trioxane and 1,3‐dioxolane were carefully purified in a rigorously dry, high‐vacuum system. In the present study it was found that trioxane can be easily copolymerized with 1,3‐dioxolane to give a copolymer having high molecular weight and excellent thermal stability. Typically, the isothermal weight loss after heating for 60 minutes under nitrogen at 222°C was 3.5% for a copolymer of trioxane and 1.0 wt‐%1,3‐dioxolane preirradiated with a dose of 1.0 × 105 Rad. The thermal stability of the copolymer was scarcely affected by the polymerization temperature and time, although it decreased slightly with increasing preirradiation dose. The dependences of the yield and inherent viscosity of the polymer on the preirradiation dosage, polymerization temperature and time were quite similar to those found for the homopolymerization of trioxane. The results were analyzed by using the kinetic scheme previously reported, and it was found that no chain transfer reaction occurs in this system. These results are discussed in comparison with those of homopolymerization reported previously.
Surface changes during polypropylene photo‐oxidation: A study by infrared spectroscopy and electron microscopy
Authors: Blais P. , Carlsson D. J. , Wiles D. M.
Published: April 2003

The surface oxidation of polypropylene films which occurs during ultraviolet irradiation in air was found to result in extensive surface restructuring. This restructuring was detected by changes in surface infrared spectra, as measured by attenuated total reflection spectroscopy, and by electron microscopy. The 997 cm−1/974 cm−1 absorbance ratio of the film surfaces increased steadily during ultraviolet degradation and was interpreted as an increase in helical ordering which resulted from backbone scission during irradiation. This scission probably also results in the increase in crystallinity detected by density changes. Electron microscopy of direct surface replicas and replicas of material detached from the oxidized film surfaces showed that surface cracking resulted during photo‐oxidation, and that this oxidation penetrated selectively into the polymer structure. The replicas of detached, oxidized material showed periodic structures related to the interior morphology of the films. The observed restructuring is believed to be entirely responsible for the decrease in percentage elongation at break which results from photodegradation.
Amide–quinoxaline copolymers
Authors: Duffy James V. , Augl Joseph M.
Published: April 2003

A series of new amide–quinoxaline ordered copolymers derived from phthaloyl, isophthaloyl, and terephthaloyl chlorides have been synthesized and characterized. The isophthaloyl and terephthaloyl polymers had decomposition temperatures between 445–495°C and were soluble in a variety of solvents. These high molecular weight polymers were prepared by reacting aromatic bis‐o‐diamines with bis(benzilyl)amides. Phthaloyl chloride yielded low molecular weight polymers due to competing side reactions.
Photopolymerization of methyl methacrylate in the presence of tertiary amines
Authors: Yokota Kenji , Tomioka Hideo , Ono Teruyuki , Kuno Fumimasa
Published: April 2003

The sensitization effect of tertiary amines on the photopolymerization of methyl methacrylate was studied. N,N‐Dimethylbenzylamine, triethylamine, and N,N‐dimethylaniline increased the rate of polymerization in this order, but pyridine did not show any effect. A free‐radical mechanism was confirmed by the tacticity of polymer, the retarding effect of hydroquinone, and the copolymer composition with styrene. On the basis of the detailed kinetics of the sensitized polymerization and the ultraviolet spectra of the reaction mixtures, a sensitization mechanism is proposed, in which the excited monomer and the amine form a complex and generate an initiating radical.
Radiation‐induced postpolymerization of trioxane in the solid state. V. Studies on copolymer composition
Authors: Ishigaki Isao , Ito Akihiko , Iwai Tadashi , Hayashi Koichiro
Published: April 2003

Studies on the composition of copolymers obtained by the radiation‐induced solid‐state postpolymerization of trioxane with 1,3‐dioxolane have been carried out. Gas‐chromatographic analysis of the reaction mixtures showed that most of the 1,3‐dioxolane disappears rapidly from the reaction system in an early stage of polymerization, and that the fraction of ethylene oxide units in the copolymer chain [E] decreases markedly with increasing polymer yield. This finding was confirmed by NMR spectra of the copolymer. DSC thermograms of the copolymer indicated that the relationship between the melting point and the average composition of copolymers prepared in this study differed from that found for copolymers in which comonomer units are distributed statistically in the polymer chain. It was suggested that the copolymer formed by the radiation‐induced solid‐state postpolymerization of trioxane–1,3‐dioxolane is characterized by a heterogeneous distribution of ethylene oxide units in the copolymer chain. It was also found that, in the radiation‐induced solid‐state postpolymerization of trioxane–1,3‐dioxolane, the amount of tetraoxane formation increased linearly with increasing polymer yield. Although it is extremely small compared with that obtained in solution polymerization, it is slightly larger in the trioxane–1,3‐dioxolane system than in the trioxane system.
NMR and ESR studies of the solid‐state polymerization of vinyl monomers. I. Acrylamide
Authors: Chachaty C. , Forchioni A.
Published: April 2003

The kinetics of the solid‐state polymerization of acrylamide, γ‐irradiated at 77°K, has been studied by wide line NMR and by ESR at temperatures above 300°K. This reaction may be followed by the growth of a narrow line superimposed on the NMR spectrum of the monomer. The amplitude of this narrow line has been found to be proportional to the polymer yield. By long continued annealing, the conversion yield approaches a limiting value, generally lower than 50% under most of our experimental conditions. The activation energy of post‐polymerization is 19 ± 1 kcal/mole. The radiochemical yield of radicals, determined by ESR, is 0.27 ± 0.03 at 77°K before warming. In the course of annealing above 300°K, the overall concentration of radicals is reduced to about one tenth of its initial value at 77°K. However, the local concentration of the remaining radicals is constant and equal to 1.2 × 1019 spins/g, i.e., more than 100 times their overall concentration. The recombination of radicals does not seem to intervene in the kinetics of post‐polymerization, so that it may be assumed that only the radicals remaining after annealing, have actually contributed to the reaction.
Effects of trivalent phosphorus compounds on vinyl polymerizations. II. Photopolymerization of acrylonitrile in the presence of triphenylphosphite
Authors: Ogawa Takeshi , Taninaka Takumi
Published: April 2003

It was found that acrylonitrile is polymerized by UV irradiation in the presence of triphenylphosphite under conditions where acrylonitrile alone does not polymerize. The rate of polymerization was found to be proportional to the monomer concentration, the phosphite concentration, and the light intensity. It was thought that a donor‐acceptor complex formed between triphenylphosphite and acrylonitrile absorbs light and initiates the radical polymerization.
Graft modification of poly(vinyl chloride) and related reactions
Authors: Thame N. G. , Lundberg R. D. , Kennedy J. P.
Published: April 2003

Cationically polymerizable olefins can be efficiently grafted onto poly(vinyl chloride) in the presence of alkylaluminum compounds. The substitution of labile chlorines in PVC by various branches yields a product of improved thermal stability as compared with unmodified PVC. Thus the grafting of a few per cent of polyisobutylene or poly‐butadiene onto PVC gives graft copolymers superior in thermal stability to the PVC backbone, as determined by thermogravimetric and differential thermal analyses as well as color development of molded films. At advanced stages of thermal degradation the thermal stability of poly(vinyl chloride)‐g‐isobutylene) (PVC‐g‐PIB is some 40°C superior to the unmodified PVC. In addition to grafting of polymer chains onto the PVC backbone, other methods are also available to achieve improved thermal stability. In pentane suspension, alkylaluminum compounds efficiently alkylate labile chlorines in PVC, and the product exhibits improved thermal stability. Alternatively, PVC carbonium ions can alkylate aromatic compounds, and these products also exhibit high heat stability. Based on the assumption that certain alkylaluminums quantitatively react with labile chlorines in PVC, it was estimated that 2–3% of the chlorines present in suspension‐grade PVC are labile.
Morphological study of crystals formed in films obtained by evaporation and deposition of polyethylene
Authors: Satou M. , Watanabe Y. , Hayashi H.
Published: April 2003

From thin films produced by vacuum evaporation and condensation of polyethylene, single crystals were grown by subsequent heat treatment of the films in xylene. Extended molecular chains composing the crystals are approximately 150 Å in length, i.e., about 1.5 times the thickness of the crystal layers. Electron microscopic examination of the crystals revealed that they were morphologically similar to ordinary polyethylene and paraffin single‐crystals, e.g., they sometimes exhibited a hollow pyramidal shape or typical spiral growth.
Melting behavior of polyethylene crystallized in a pressure capillary viscometer
Authors: Southern John H. , Porter Roger S. , Bair H. E.
Published: April 2003

The Melting of various polyethylene structures is compared by using data obtained on the Perkin‐Elmer differential scanning calorimeter (DSC). Transparent, high‐density samples crystallized under both orientation and pressure in the Instron capillary rheometer are compared with samples crystallized from dilute solution by stirring and with samples crystallized under high pressure. The latter two structures are assumed to contain extended‐chain crystallites. By comparison, the melting points and the superheatability of the Instron samples are consistent with the presence of an extended‐chain crystal component. The melting of irradiated samples crystallized in the rheometer is also observed to be consistent with this conclusion. In addition, DSC data are compared with the melting points defined with a polarized light microscope equipped with a hot stage.
Polymer photoprotection by copolymerized triplet quenchers
Authors: George G. A.
Published: April 2003

From a model of delocalized triplet energy in an aromatic vinyl polymer, the relative efficiency of triplet‐energy transfer to either an added or copolymerized quenching molecule is determined. It is found that copolymerization can increase the photoprotective efficiency only if the quenching rate is determined by the final energy transfer step. A study of the quenching of polystyrene phosphorescence by added or copolymerized naphthalene indicates that there is no enhancement of quenching efficiency by copolymerization.
Temperature dependence of the conformation of isotactic polystyrene in toluene
Authors: Helms J. B. , Challa G.
Published: April 2003

In order to obtain information about a possible helix–coil transition of isotactic polystyrene (i‐PS) at 80°C in toluene, as has been reported in other solvents, solution properties were examined at temperatures between 10 and 110°C. Use was made of viscometry, high‐resolution nuclear magnetic resonance, infrared spectroscopy, calorimetry, and light scattering. No distinct transition was found at 80°C but rather a second‐order transition between 62 and 65°C. A similar transition occurred in toluene solutions of atactic polystyrene. The transition may be attributed to a sudden change in the mobility of the phenyl side‐group of the polymer. From this study it is concluded that i‐PS has a helical conformation in toluene, the mean helix length decreasing smoothly with increasing temperature.
Observations of slip traces in polyethylene single crystals
Authors: Petermann Jürgen , Gleiter Herbert
Published: April 2003

Single crystals of polyethylene are investigated by transmission electron microscopy. A pattern of lines is observed in the crystals. The properties of these lines suggest that the lines represent slip traces (slip steps) generated by the movement of dislocations in the polyethylene crystals.
Alkylated polypyrazines
Authors: Biehle Richard P. , Higgins Jerry
Published: April 2003

The syntheses of four new monomers and two new polyaromatic pyrazines are described. The monomers; bis‐p,p′‐(octanoyl)diphenyl ether (Ia), bis‐p,p′‐(hexadecanoyl)diphenyl ether (Ib), bis‐p,p′‐(α‐bromooctanoyl)diphenyl ether (IIa), and bis‐p,p′‐(α‐bromohexadecanoyl)diphenyl ether (IIb), were produced by Friedel‐Crafts acylation of diphenyl ether with the corresponding acyl chloride and subsequent α‐bromination. Prepolymers were synthesized by the condensation of (IIa) and (IIb) with ammonia in N,N‐dimethylformamide (DMF), and polymers were prepared by subsequent melt condensation of the prepolymer to produce poly[2,5‐(oxydiphenylene)‐3,6‐(dihexyl)pyrazine] (IIIa), and poly[2,5‐(oxydiphenylene)‐3,6‐(ditetradecyl)pyrazine] (IIIb). Polymer IIIa was thermally (stable at >400°C while polymer IIIb was a tacky substance). The inherent viscosity of IIIa produced by 12 hr of melt condensation was 0.30 dl/g in formic acid. Additional heating in excess of 24 hr gave a slightly soluble polymer. The inherent viscosity of IIIb produced by 40 hr of melt condensation was 0.37 dl/g in formic acid.
Radiation‐induced copolymerization of tetrafluoroethylene with vinyl ethers
Authors: Hikita Tomoji , Tabata Yoneho , Oshima Keichi , Ishigure Kenkichi
Published: April 2003

Radiation‐induced copolymerization of tetrafluoroethylene with various vinyl ethers has been studied. It was found that tetrafluoroethylene can be copolymerized with vinyl ethers to give alternating copolymers over a wide range of the initial monomer concentration in the monomer mixture. The monomer reactivity ratios were determined for the copolymerization of tetrafluoroethylene with n‐butyl vinyl ether as 0.005 (rTFE) and 0.0015 (rNBVE). The rate of copolymerization is extremely high and has a maximum at an equimolar concentration of two monomers. The alternating structure of the copolymers was confirmed by the analysis of NMR spectra. Some thermal properties of the copolymers were measured by DSC and DTA.
Polymers having stable radicals. I. Synthesis of nitroxyl polymers from 4‐methacryloyl derivatives of 2,2,6,6‐tetramethylpiperidine
Authors: Kurosaki Toshikazu , Lee Kyu Wan , Okawara Makoto
Published: April 2003

Polymers having stable nitroxyl free radicals, poly‐4‐methacryloylamino‐ and poly‐4‐methacryloyloxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyls, were synthesized from their precursor polymers by oxidizing them in a methanolic solution of hydrogen peroxide. The precursor polymers were prepared by radical polymerization of 4‐methacryloyl‐amino/oxy‐2,2,6,6‐tetramethylpiperidines in various solvents. These polymerizations in acetic acid were found to yield polymers of high molecular weight. The copolymers of the precursor monomers with styrene and methyl methacrylate were also prepared as precursor copolymers. These precursor polymers of a piperidine type were converted to the polymers having stable nitroxyl free radicals by the hydrogen peroxide method. In this report, it was assumed that the post‐oxidation reaction introduced a nitroxyl group smoothly and quantitatively at room temperature. Elucidations of the stable radical formation and the electron spin behavior of the stable radical polymers were made in terms of elemental analyses, infrared, ultraviolet, and ESR spectroscopy.
Syntheses of polyurethanes derived from oximes and their photodegradation
Authors: Hong Sung Il , Kurosaki Toshikazu , Okawara Makoto
Published: April 2003

Polyoxime‐urethanes have been synthesized from dioximes and diisocyanates, and their structures have been ascertained by elemental analysis and infrared spectroscopy. They can be represented by the general formula:
magnified image
These polymer films were photolyzed by using a high‐pressure 100‐W mercury lamp, and the rate of decomposition of the NO bond was determined by use of ultraviolet and infrared spectra, or comparing the photochemical behavior with that of corresponding model compounds. Upon irradiating these polymers in the presence or absence of sensitizers or a hydrogen donor, there were obtained photolyzed polymers of low molecular weight, of which the molecular weights were estimated by observing the viscosity changes. To deduce the mechanism of photodegradation of polyoxime‐urethane, photolysis of benzophenone oxime‐phenyl urethane was investigated as a model compound.
Initiation and termination mechanism in the cooligomerization of the styrene–methyl methacrylate–carbon tetrachloride system
Authors: Tsuchida Eishun , Yao Takamu , Kitamura Kiwamu , Shinohara Isao
Published: April 2003

The analysis of the endgroups of the oligomers produced in the styrene (A)–CCl4(S) system (system I), the methyl methacrylate(B)–CCl4 system (system II), and the styrene–methyl methacrylate–CCl4 system (system III) was carried out in order to clarify the mechanism of the initiation, transfer, and termination. In system I, the number of Cl atoms per oligomer molecule NCl increases with the molar ratio of [S]/[A] when the molar ratio of [S]/[A] is below unity and is about four when the molar ratio of [S]/[A] is above unity, and the number of initiator fragments per oligomer molecule NI decreases with the increase in the molar ratio of [S]/[A]. In system II, NCl is about 0.45 over a considerably wide range of the molar ratio of [S]/[B]. In system III, NCl increases and NI decreases with the increase in the molar ratios of [S]/([A] + [B]) and [A]/[B]. From the data of NCl and NI, the fraction ICC14 of the initiation by the tri‐chloromethyl radical in the overall initiation reactions and the fraction TCC14 of the chain transfer reaction of the growing radical of styrene in all the reactions which produce the cooligomer in the system III were calculated. ICCl3 and TCC14 both increase with the molar ratios [S]/([A] + [B]) and [A]/[B].
Structural studies of polyformals. II. Crystal structure of poly‐1,3‐dioxolane: Modification II1
Authors: Sasaki Shintaro , Takahashi Yasuhiro , Tadokoro Hiroyuki
Published: April 2003

The structure of poly‐1,3‐dioxolane, [OCH2O(CH2)2]n was studied by x‐ray diffraction and infrared spectroscopy. Three crystal modifications were found. The crystal structure of modification II was determined: four molecular chains of glide type pass through the orthorhombic unit cell; Pbca‐D2h15, a = 9.07 Å, b = 7.79 Å, and c (fiber axis) = 9.85Å. The molecular conformation is
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The molecular chain consists of regular head‐to‐tail sequences. This fact shows that the ring opening of 1,3‐dioxolane occurs exclusively at the same type of CO bond in the cationic polymerization, just as in the case of 1,3‐dioxepane.
Calibration of an optical self‐beating spectrometer by polystyrene latex spheres and confirmation of the stokes‐einstein formula
Authors: Lee S. P. , Tscharnuter W. , Chu B.
Published: April 2003

The Rayleigh linewidth Γ of light scattered by dilute aqueous solutions of polystyrene latex spheres has been measured by using time‐dependent photocurrent signal correlation with a precision typically of 0.5–1% over a range of scattering angles θ. With independent measurements of the diffusion coefficient D from D = lim K → 0 (Γ/K2), the diameter of the sphere d by means of electron microscopy, and the hydrodynamic shear viscosity η, we have confirmed the Stokes‐Einstein relation D = kT/3πηd to within 1% if we take into account the effect of polydispersity on our Rayleigh linewidth data. We also find that dEM = 907 ± 56 Å for sample LS‐1132‐B as reported by the Dow Chemical Company differs from our dSB = 847 (±1.6%) Å ≈ dEM = 851 (±2%) by about 7%, which is outside the limits of error of our experiments. The subscripts EM and SB denote electron microscope and self‐beating, respectively, while K ≡ (4π/λ)sin(θ/2) is the magnitude of the momentum transfer vector.
Polyamine polymers from pyrrole, formalin, and amines by use of the mannich reaction
Authors: Tsuchida Eishun , Tomono Tsugikazu
Published: April 2003

It was found that pyrrole, one of the active hydrogen compounds, easily condensed with formalin and amine in the presence of acid catalyst to yield a new type of polyamine polymer containing pyrrole nuclei in the main chain of the polymer. This polymerization method was also confirmed to be applicable to the other active hydrogen compounds, such as N‐methylaniline, acetone, malononitrile, and hydroquinone. The structures of the polymers obtained were determined by infrared NMR and elementary analyses.

We named this reaction a Mannich polymerization and the polymers obtained the Mannich base polymer.
Heterotactic poly(vinyl alcohol)
Authors: Nozakura Shun‐Ichi , Ishihara Shigeichi , Inaba Yoshiaki , Matsumura Keiji , Murahashi Shunsuke
Published: April 2003

Bulky substituents in vinyl trialkylsilyl ethers and vinyl trialkylcarbinyl ethers led to heterotactic polymers (H = 66%). The polymers were converted into poly(vinyl alcohol) (PVA) and further to poly(vinyl acetate), and tacticity was determined as poly(vinyl acetate). Vinyl triisopropylsilyl ether in nonpolar solvents yielded a heterotactic polymer with a higher percentage of isotactic triads than syndiotactic triads (Hetero‐I). Vinyl trialkylcarbinyl ethers in polar solvents gave a heterotactic polymer with more syndiotactic triads than isotactic (Hetero‐II). Heterotactic PVA was soluble in water and showed characteristics infrared absorptions. Interestingly, Hetero‐I PVA showed no iodine color reaction, but Hetero‐II showed a much more intense color reaction than a commercial PVA. The mechanism of heterotactic propagation was discussed in terms of the Markóv chain model.
Polyaspartimides: Condensation of aromatic diamines and bismaleimide compounds
Authors: Crivello James V.
Published: April 2003

A detailed investigation of the condensation of aromatic amines and maleimide compounds was conducted by the use of model compounds. Weak Brönsted acids were found to have a marked catalytic effect on the reaction. By using glacial acetic acid as the reaction medium, a number of model aspartimide compounds were prepared. Aromatic diamines and bismaleimide compounds were condensed to high polymers in cresol containing a small amount of a protonic acid catalyst. Polymers having a variety of novel backbone structures were prepared and their physical properties studied.
Kinetics of polymer decomposition
Authors: Danforth Joseph D. , Takeuchi Tsugio
Published: April 2003

Kinetic equations have been developed for polymers that decompose by the zipper mechanism. The usual assumption of steady state kinetics has not been made. Plots of the fraction decomposed α, as a function of time demonstrate a variety of patterns depending upon the relative values of the fraction k1, of chains becoming activated per second and the fraction k2 of an activated chain that decomposes per second.
Kinetics of the decomposition of poly(vinyl chloride)
Authors: Danforth Joseph D. , Takeuchi Tsugio
Published: April 2003

Equations derived on the basis of a zipper mechanism under conditions where steadystate kinetics did not apply were found to represent the kinetics of the thermal decomposition of poly(vinyl chloride) in the temperature range 220–240°C.
Crystallization‐induced reactions of copolymers. II. Cis‐trans isomerization of 1,4‐poly‐1,3‐butadiene
Authors: Lenz R. W. , Ohata K. , Funt J.
Published: April 2003

The cis‐trans photoisomerization reaction of 1,4‐polybutadiene was carried out below the melting points on films of polymers containing high trans‐1,4 contents. Under the proper conditions of temperature and polymer composition, the reaction was observed to undergo an anti‐equilibrium behavior, which was attributed to an irreversible crystallization of repeating units after isomerization from cis to trans structure. As a result, the trans composition passed through a minimum with reaction time while crystallinity increased throughout the reaction, and unexpectedly the β crystalline form was observed well below the α–β transition temperature. The composition–time behavior observed was rationalized on the basis of incorporation of trans units into crystalline regions on the lamellar fold surfaces and discussed within the framework of the proposed requirements for crystallization‐induced reactions of copolymers.
Condensation polymers from 1,2,5‐thiadiazole‐3,4‐dicarboxylic acid
Authors: Macdonald Robert N. , Sharkey W. H.
Published: April 2003

A series of polyamides was prepared by interfacial polymerization of diamines with 1,2,5‐thiadiazole‐3,4‐dicarbonyl chloride. Polyamides from secondary cycloaliphatic diamines and aromatic diamines have high softening points, high glass transition temperatures, and good thermal stability. Secondary amines, in particular cycloaliphatic secondary amines, form very high molecular weight polyamides. The polyamide from trans‐2,5‐dimethylpiperazine and 1,2,5‐thiadiazole‐3,4‐dicarbonyl chloride is soluble in chloroform and 1,1,2‐trichloroethane and has been cast into films and spun into fibers from those solvents. Fibers of this polymer are strong and have very high work recovery from small strains. In addition, these fibers show good retention of strength and work recovery over a range of temperatures and humidities.
Evaluation of the crystallinity of copolyamide fibers
Authors: Włochowicz Andrzej , Jeziorny Andrzej
Published: April 2003

Density and x‐ray diffraction measurements of the degree of crystallinity have been made on copolymers of polyamide 6 PA‐6 with hexamethylenediamine terephthalate and ethylenediamine terephthalate ranging composition from 4 to 35 mole‐% of the terephthalates. The degree of crystallinity can be determined from the ratio of the sum of mass contribution products of the crystalline regions for each of the comonomers to the total copolymer mass. Such a procedure can be used when the molar fractions of comonomers in copolymer are known. The results obtained are in agreement with the theoretical values.
Poly(arylene sulfides) with pendant cyano groups as high‐temperature laminating resins
Authors: Haddad Ibrahim , Hurley Shaun , Marvel C. S.
Published: April 2003

Poly(phenylene sulfides) were synthesized from m‐benzenedithiol and aromatic dibromides in a basic medium of potassium carbonate in dimethylformamide or dimethylacetamide. The products obtained were slightly off‐white with relatively low melting ranges and had inherent viscosities in the 0.2–0.4 dl/g range in hexamethylphosphoric triamide. Similar poly(phenylene sulfides) containing pendant cyano groups along the polymer chains were obtained by the use of 5 mole‐% of either 2,4‐dichlorobenzonitrile or 3,5‐dichlorobenzonitrile. The products were similar to the pure polyphenylene sulfides, except that they showed lower melting ranges and gave insoluble products when heated alone or in the presence of zinc chloride.
Aging and degradation of polyolefins. II. γ‐initiated oxidations of atactic polypropylene
Authors: Decker Christian , Mayo Frank R.
Published: April 2003

Oxidations of bulk atactic polypropylene (PP) have been carried out at 22 and 45°C, and the dependence of rate of formation of each product on rate of initiation has been determined. The principal product is PP hydroperoxide, formed in a half‐order reaction. One termination product is polymeric dialkyl peroxide, formed in a first‐order reaction. Other termination and propagation products, alcohols and carbonyl compounds, are formed in reactions that are mostly first‐order in initiation. At 22°C, G is 9–63. G is about three times as great at 45°C as at 22°C. Experiments with 2,6‐di‐tert‐butyl‐p‐cresol shows that it can inhibit all non‐cage propagation and all formation of PP hydroperoxide, but that it does not affect cage reactions of initiating radicals and their successors. Only about 16% of the initiating PPO2· radicals escape the cage at 45°C. Oxidations of PP, n‐hexane, and their mixture with both peroxide and γ‐ray initiation show that nearly all the initiating radicals escape the cage in solution but that the concentration of PPO2· radicals is much less than in bulk because of a much faster chain termination. Both the propagation and termination constants for PP oxidation are much faster in solution, but the changes compensate so that kp/(2kt)½ is about the same in solution as in bulk.
Etude de copolymères ABS (acrylonitrile–butadiène–styrène): Solvatation préférentielle du polybutadiène par les promoteurs
Authors: Locatelli J. L. , Riess G.
Published: April 2003

ABS resins formed by copolymerization of styrene and acrylonitrile (AN) in presence of polybutadiene, consist of a mixture of SAN graft copolymer on polybutadiene (PBut) and of ungrafted SAN copolymer (styrene‐co‐acrylonitrile). The kinetic study was completed by showing a preferential solvation of polybutadiene by the initiator. This solvation effect was studied as a function of the concentration ratio SAN/PBut and in relation with the type of initiator. The adsorption of initiator appeared to be maximum when its solubility parameter (σ) is close to that of polybutadiene. As a function of the polybutadiene characteristics, this selective adsorption can be given by

where I1 is the quantity of initiator in the polybutadiene medium, I is the total amount of peroxide, [PBut] is the concentration of polybutadiene, and M̄n its molecular weight. It has been shown furthermore that the preferential solvation of polybutadiene by the benzoyl peroxide can be increased by addition of SAN or acrylonitrile. The consequences of this solvation effect on the characteristics of the grafting reaction, more precisely on the molecular weight of grafted and ungrafted SAN and on the rate of polymerization, were examined.
Some comments on domain structures in block copolymers
Authors: Krigbaum W. R. , Yazgan S. , Tolbert W. R.
Published: April 2003

Although samples of amorphous polymers cast from solution are usually assumed to be isotropic, they may, in fact, have some anisotropy due to the Bénard effect, in which the convection currents produced by evaporation are organized into a regular arrangement of cells. A pattern of hexagonal convection cell is easily visible during casting of SBS triblock copolymers. The anisotropy is demonstrated by comparing the small‐angle x‐ray diffraction diagrams taken through the face and edge of the films. The domain structures in two SBS copolymers are characterized by diffraction measurements. The smallangle diagram of a triblock polymer containing 50% styrene indicated a lamellar structure, while that from a 28% styrene copolymer is interpreted as arising from a hexagonal array of polystyrene cylinders dispersed in a continuous polybutadiene phase. Published diffraction data for block copolymers and other amphiphiles are surveyed in an attempt to place some limitations on the composition ranges over which the various types of domain structure exist. The factors which determine the dimensions of the two domains in lamellar phases formed from diblock copolymers are examined theoretically, and the predicted dimensions are compared with experimental results.
Structure of some ethylene–phosphonic acid copolymers
Authors: Johnson R. G. L. , Delf B. W. , MacKnight W. J.
Published: April 2003

An x‐ray study has been made of the structure of a series of ethylene–phosphonic acid copolymers and the parent low‐density polyethylene from which they were derived. The phosphonic acid contents (groups per 100 carbon atoms) of the copolymers were: A, 0.8; B, 1.8; C, 2.8; and D, 8.0. Small‐angle x‐ray scattering (SAXS) results show that the phosphonic acid substituents do not incorporate into the crystal lattice to any appreciable extent, that the substituents have the effect of decreasing the average thickness of the crystal lamellae and increasing the breadth of the size distribution of thicknesses, and that a two‐phase model does not adequately account for the observed SAXS invariant. Wide‐angle x‐ray scattering (WAXS) results show that specimens, A, B, and C are partially crystalline with the polyethylene crystal structure and that D is amorphous. The observed broadenings of the 110 and 200 crystal reflections in the copolymers indicate that the substituents decrease the lateral dimensions of the crystalline lamellae and/or increase the deformation of the lattice due to external strain. Specimen D, completely amorphous according to the WAXS criterion, exhibits the largest value of the SAXS invariant of all the copolymers studied and must thus possess a multiphase structure consisting of small ordered regions and a disordered phase. The results of the study show the structure of the copolymers to be consistent with the fringe‐micelle model but do not rule out the folded‐chain model, although a regular fold surface is unlikely.
Effect of water on the mechanical properties of collagen films
Authors: Tanioka Akhiko , Jojima Eiichiro , Miyasaka Keizo , Ishikawa Kinzo
Published: April 2003

The effect on water on mechanical properties of collagen films has been studied. The S‐shaped sorption isotherm is separated into an adsorption curve C1 and a solution curve C2. From the C2 curve, a value of 0.8 is calculated for the Flory‐Huggins interaction parameter χ1. The dynamic shear modulus G′, loss modulus G″, and loss tangent tan δ determined as functions of water content indicate two dispersions at low and at high water content. The region of water content from about 0.05 to 0.1 g/g, G′ decreases suddenly, G″ has a peak, and tan δ increases, corresponds to the region where the C2 component of sorption becomes detectable. Another dispersion occurs at water contents above 0.2 g/g. A composite curve can be obtained by shifting stress‐relaxation curves obtained at different humidities along the log time axis. When only the C2 component of sorbed water is taken into account, the shift factor ac is explained by a relation of Fujita and Kishimotos' based on free‐volume theory. Shift factor for the relaxation curves of wool fibers, except for an initial part at times of less than 1 sec, are described by the same equation. The parameter β in the equation has the same value of 0.16 for both collagen and wool.