bluuebunny/crossref_metadata_2025 huggingface dataset:
2‐Hydroxy‐3‐ionene chloride
Authors: Noren G. K.
Published: April 2003

The condensation of dimethylamine with epichlorohydrin gave an almost quantitative yield of 2‐hydroxy‐3‐dimethylaminopropyl chloride which was polymerized via the Menschutkin reaction to give 2‐hydroxy‐3‐ionene chloride. This cationically charged polymer was obtained in greater than 90% yields as a white to tan solid when precipitated into acetone. Number‐average molecular weights of up to 10,000 and intrinsic viscosities of up to 0.11 dl/g in 0.4M potassium bromide were found. These low molecular weights were attributed to several impurities that were identified as being produced by side reactions. Thermal analysis of the polymers showed an endothermic transition at 32–39°C with the onset of decomposition occuring at about 200°C.
Thermal and photo‐induced phenomena in γ‐irradiated poly(methyl methacrylate)
Authors: Torikai Ayako , Asai Toshihiro , Suzuki Toshio , Kuri Zen‐Ichiro
Published: April 2003

ESR spectra and optical absorption spectra of γ‐irradiated poly(methyl methacrylate) (PMMA) at 77°K and the photo‐ and thermal bleaching behavior have been studied. γ‐Irradiation of PMMA yields a singles spectrum with a line width of 6 G which is bleachable with visible light. This species is assigned to the polymer cation. The unbleached species consists mainly of a four‐line spectrum and is assigned to a polymer radical having a different CH2 conformation from the usual nine‐line spectrum. On subsequent warming to room temperature, the spectrum changes into the nine‐line spectrum. γ‐Irradiation of PMMA containing biphenyl as an additive at 77°K gives biphenyl cation. Yield of polymer radical is reduced by the addition of biphenyl and 2‐methyltetrahydrofuran. A mechanism is proposed which is consistent with the experimental results.
Polyfluoroethers from 2,2,3,3,4,4‐hexafluoropentanediol and bis(chloromethyl) ether and bishalomethyl‐substituted aromatic compounds
Authors: Johncock Peter , Hewins Maurice A. H.
Published: April 2003

The polyfluoroethers \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm \rlap{--}[OCH}_{\rm 2} {\rm XCH}_{\rm 2} {\rm OCH}_{\rm 2} ({\rm CF}_{\rm 2} )_3 {\rm CH}_{\rm 2} \rlap{--} ]_n $\end{document} (X = O, 1,3‐C6H4, 1,4‐C6H4 or 4,4′‐C6H4OC6H4) and copolymers (X = 1,3‐ and 1,4‐C6H4) having inherent viscosities in acetone >0.5 dl/g were prepared in good yields by treatment of the mixture of sodium salts obtained from 2,2,3,3,4,4‐hexafluoropentanediol and an excess of sodium hydride in tetramethylene sulfone (TMS)‐tetrahydrofuran or TMS‐petroleum ether with the appropriate bishalomethyl compound. The polymers varied from highly extensile elastomeric gums when X = O or 1,3‐C6H4 to a leathery material when X = 4,4′‐C6H4−OC6H4. Glass transition temperatures ranged from ‐43°C when X = 0 to 6°C when X = 4,4′‐C6H4OC6H4. The polymers started to lose weight (by thermogravimetry) at 220–250°C in oxygen and at 250–290°C in nitrogen. However, the xylylene polymers underwent structural changes even at room temperature, as reflected by changes in solution viscosity. Attempts to cure the polymer when X = O with peroxides were unsuccessful.
Effect of copolymers of 4(5)‐vinylimidazole and quaternary imidazolium salts on the hydrolysis rates of charged and neutral esters. II
Authors: Overberger C. G. , Pacansky T. J.
Published: April 2003

The effects of copolymeric catalysts containing hydrophobic binding sites (quaternary imidazolium salts) and catalytically active nucleophilic sites (imidazole) on the hydrolysis of long‐chain anionic esters were investigated. The quaternary imidazolium salt groups contained hydrocarbon chains of varying length. Their solubility relationships and viscosity measurements followed a trend governed by the hydrocarbon chain length of the quaternary imidazolium salt. These investigations revealed that increasing the hydrocarbon chain length of the quaternary imidazole groups along the copolymer chain or the chain length of the ester substrate resulted in an increase of the catalytic rate of ester hydrolysis. Increasing the ethanol content decreased the catalytic activity and greatly reduced the apolar binding between the catalyst and substrate. For the cases of low ethanol content and high chain length of the substrate, the ester hydrolysis reactions in the presence of the copolymeric catalysts preceeded by a Michaelis‐Menten kinetic scheme.
Formation of free radicals in photoirradiated cellulose. II. Effect of moisture
Authors: Hon Nyok‐Sai
Published: April 2003

The effect of moisture content upon free radical formation in celluloses irradiated with ultraviolet light has been studied by means of ESR spectroscopy at 77°K. As studied from the variation of the line‐shape and the relative signal intensity of the spectra observed, it is clear that moisture content in the sample greatly influences the formation of free radicals when irradiated with ultraviolet light. The moisture content in the range of 5–7% leads to a significant decrease of radical formation; and alternatively, when moisture content is lower or higher than this range, the formation of free radicals is increased.
Enhancement of stereospecificity in isoprene polymerization with alkylaluminum–titanium chloride catalysts through use of carbon disulfide
Authors: Perry Dale C. , Farson Frank S. , Schoenberg Emanuel
Published: April 2003

The effect of CS2 on isoprene polymerization with triisobutylaluminum‐titanium tetrachloride catalysts was studied at Al/Ti ratios of optimum (0.9) and higher values. In the absence of CS2, appreciable amounts of low molecular weight oils (“extractables”) were formed at the expense of cis‐1,4‐polyisoprene with higher than optimum Al/Ti ratios. Small amounts of CS2 were found to prevent extractables formation and allow attainment of higher yields of cis‐1,4‐polyisoprene. The optimum CS2/Ti chloride molar ratio (0.1) was independent of the Al/Ti ratio of the catalyst. Polymer microstructure and dilute solution viscosity were unaffected by CS2. The results support the theory that the catalyst surfaces hold two types of active sites: p‐sites, which initiate polymerization, and o‐sites, which lead to oligomerization. CS2 appears to enhance polymerization by coordinating selectively at the o‐sites. The predominance of oligomerization at the higher Al/Ti ratios was attributed to a destruction of p‐sites by excess trialkyl‐aluminum.
Aromatic polyethers, polysulfones, and polyketones as laminating resins. IV. Polymers with p‐cyclophane units for crosslinking
Authors: Sivaramakrishnan K. P. , Samyn C. , Westerman Ira John , Wong Daniel Ting‐Man , Marvel C. S.
Published: April 2003

1,3‐Bis(p‐phenoxybenzenesulfonyl)benzene, 4,4′‐bis(p‐phenoxybenzenesulfonyl)diphenyl ether, and 4,4′‐diphenoxydiphenyl sulfone were polymerized with isophthaloyl or terephthaloyl chlorides in Friedel‐Crafts type polymerizations. These polymers had [2,2]p‐cyclophane units in the backbone, introduced by employing 3,9‐bis(p‐phenoxybenzoyl) [2.2]p‐cyclophane as part of the polyaryl ether component. Thermolysis of the dimethylene bridge of the [2.2]p‐cyclophane monomer produced diradicals which combined across polymer chains to provide crosslinks. p‐Cyclophane polymers with 1,3‐bis‐(p‐phenoxybenzenesulfonyl)benzene showed potential as high performance, thermally stable laminating resins.
Aromatic polyethers, polysulfones, and polyketones as laminating resins. V. Polymers containing acetylenic side groups
Authors: Samyn C. , Marvel C. S.
Published: April 2003

1,3‐Bis(p‐phenoxybenzenesulfonyl)benzene and 4,4′‐diphenoxydiphenyl sulfone were polymerized with isophthaloyl and terephthaloyl chloride in Friedel‐Crafts type polymerizations. These polymers had 2,4‐diphenoxyacetophenone in the backbone. The acetyl group was then converted into an acetylene group. They were crosslinked effectively by cyclization of the acetylene groups with a catalyst or by cyclo‐addition with bisnitrile oxides.
Synthesis and characterization of poly‐n‐alkylmalonamides: Formation of a partially disordered layer structure
Authors: Corradini P. , Lanzetta N. , Maglio G. , Palumbo R. , Riva F.
Published: April 2003

Polyamides from n‐alkylmalonic acids and linear aliphatic diamines, with paraffinic side chains of 3–18 carbon atoms, were prepared by melt polycondensation or by low‐temperature interfacial polycondensation and were characterized by infrared, differential scanning calorimetry (DSC), and x‐ray diffraction techniques. First‐order transitions were found in the range of 130–210°C, depending on the number of carbon atoms in the side chain. The x‐ray diffraction indicated substantially amorphous systems for polyamides with 8–18 carbon atoms in the side chain. However, long‐range order arises in these polymers from a solid‐state structure in which polyamide and hydrocarbon layers having partially disordered chain conformations alternate.
Synthesis and polymerization of optically active trans‐(R)(–)‐5‐phenyl‐1,3‐hexadiene and trans‐(R)(–)‐6‐phenyl‐1,3‐heptadiene
Authors: Radovanović‐Kiprijanova R. , Fleš D.
Published: April 2003

The monomers trans‐(R)(–)‐5‐phenyl‐1,3‐hexadiene (I) and trans‐(R)(–)‐6‐phenyl‐1,3‐heptadiene (II) were prepared by dehydration of (R)(–)‐3‐acetoxy‐5‐phenyl‐1‐hexene and (R)(–)‐3‐acetoxy‐6‐phenyl‐1‐heptene, respectively. Monomers I and II were polymerized in heptane with three catalyst systems: γ‐TiCl3–Al(i‐Bu)3, VCl3–Alet3, and nBuLi. Polymers of identical structures were obtained with all three catalysts; according to infrared and NMR spectra, only the 1,4 structure was present. Acetone‐insoluble fractions of poly‐I and poly‐II have higher optical rotations than the corresponding monomers ([M]D of poly‐I, ‐46.45°, of monomer I, ‐28.6°: [M]D of poly‐II, ‐46.8°, of monomer II, ‐32.55°). There is no difference in the rotation of poly‐I and poly‐II.
Reactivity of methacrylates in anionic copolymerization with methyl methacrylate by n‐BuLi
Authors: Yuki Heimei , Okamoto Yoshio , Ohta Koji , Hatada Koichi
Published: April 2003

Monomer reactivity ratios, r1 and r2 were determined in the anionic copolymerizations of methyl methacrylate (MMA, M1) with ethyl (EtMA), isopropyl (i‐PrMA), tert‐butyl (t‐BuMA), benzyl (BzMA), α‐methylbenzyl (MBMA), diphenylmethyl (DPMMA), α,α‐dimethylbenzyl (DMBMA), and trityl (TrMA) methacrylates (M2) by use of n‐BuLi as an initiator in toluene and THF at ‐78°C. The order of the reactivity of the monomers towards MMA anion was DPMMA > BzMA > MMA > EtMA > MBMA > i‐PrMA > t‐BuMA > TrMA > DMBMA in toluene and TrMA > BzMA > MMA > DPMMA > EtMA > MBMA > i‐PrMA > DMBMA > t‐BuMA in THF. Except for the extremely low reactivity of TrMA and DPMMA in toluene due to steric hindrance, the order was explained in terms of the polar effect of the ester groups. A linear relationship was found between log (1/r1) and Taft's σ* values of the ester groups, where the ρ* value was 1.1. The plots of log (1/r1) vs. the 1Ha (cis to the carbonyl) and 13Cß chemical shifts of the monomers were also on straight lines. The polymer obtained in the copolymerization of MMA with TrMA in toluene by n‐BuLi at ‐78°C was a mixture of poly‐MMA and a copolymer, suggesting that there exist two kinds of growing centers.
Determination of the elementary rate constants of autoacceleration reactions on polymers
Authors: Stoy V.
Published: April 2003

Equations describing the course of an autoacceleration reaction on a polymer in the low conversion region were derived and used to obtain relationships between the curvature of the conversion curve at the beginning and the elementary rate constants k1 and k′2. Calculations carried out by using our relationships are compared with the procedure suggested by Kawabe and Yanagita, and the applicability of the individual methods for the determination of the elementary rate constants is discussed.
Estimation of molecular weight distribution based on chain length dependence of termination rate
Authors: Ito Katsukiyo
Published: April 2003

When a chain length dependence of polymer‐polymer termination is given by kt,ns = const. (n−2a + s−2a) where n and s are the chain lengths for the polymer radicals and a is parameter, an instantaneous weight fraction of the non‐reacting polymers is derived as:

where h and k̄ are the kinetic parameters, p is a parameter depending on a, and pn is instantaneous number‐average chain length. Such a weight fraction corresponds to the experimental one over a wide range of conversion in the polymerization of styrene. On the scope of this correspondence, the polymer‐polymer termination rate is estimated as: k̄t = 8πR0D1/100 ( = 4πRsDs) where R0 is reaction radius between monomer radicals and D1 is the diffusion coefficient of the monomer; Rs is reaction radius between segment radicals with n ≅ 100 and Ds is the diffusion coefficient of the segment. The Fujita‐Doolittle theory applies to such a rate. Further, the rate also yields 1.5 × 1071./mole‐sec, which is the observable extent at conversions less than 0.2.
Gel‐permeation chromatography: A procedure that corrects for imperfect resolution
Authors: Timm D. C. , Rachow J. W.
Published: April 2003

Gel‐permeation chromatography is an excellent tool for obtaining polymer fractionation data. Inasmuch as chromatograms are functions of instrument operating conditions, an interpretation procedure must be employed to yield correct molecular distributions of macromolecular materials. A procedure is described that corrects for imperfect resolution. Extensive experimental testing of polymeric materials with kinetically known molecular distributions demonstrates its validity in regions where poor resolution is experienced.

Applications will allow one to utilize equipment with inherently poor resolution or to operate instruments with high resolution in regions of poor resolution (e.g., rapid analysis).
Effects of acids on vinyl polymerization initiated by chromous acetate‐alkyl halide
Authors: Lee Munam , Minoura Yuji
Published: April 2003

Effects of various acids, i.e., acetic, chloroacetic, hydrochloric, and sulfuric acids on the polymerization of styrene initiated by Cr2+–CHCl3 in DMF was studied. These acids reduced the rates of polymerization by Cr2+–CHCl3 initiator systems. This phenomenon could be explained by a decrease of the reducing power of Cr2+ for alkyl halide. On the other hand, chloroacetic acids could initiate the polymerization of styrene without CHCl3 because these acids have active chlorine in the molecule for Cr2+. It was found that the polymer obtained by this initiator system had an endgroup containing chromium carboxylate, therefore this polymer was green in color and insoluble in benzene.
Interpolymer complex between poly(ethylene oxide) and poly(carboxylic acid)
Authors: Ikawa Takeo , Abe Koji , Honda Kenji , Tsuchida Eishun
Published: April 2003

An interpolymer complex was prepared by mixing aqueous solutions of poly(ethylene oxide) (PEO) and of a poly(carboxylic acid), i.e., poly(acrylic acid)(PAA), poly(methacrylic acid)(PMAA), or styrene‐maleic acid copolymer(PSMA). The complexation mechanism was discussed on the basis of results of such experimental methods as viscosity, potentiometric titration, and turbidimetry. The hydrogen bond is primarily involved in these complexations, but the influence of hydrophobic interaction on complexation can not be ignored. If the degree of dissociation α of carboxylic acid or the degree of polymerization Pn of PEO was perceptibly changed, a stable complex was obtained at about α 0.1 or Pn(PEO) = 40 for PMAA, 200 for PAA. This fact indicates that more than a definite number of binding sites are necessary for a stable interpolymer complex to be formed and that cooperative interaction among active sites plays an important role in complex formation.
Radiation‐induced polymerization of tetrafluoroethylene and 1,2,3,4,5‐pentafluorostyrene at high pressure
Authors: Brown Daniel W. , Lowry Robert E.
Published: April 2003

Tetrafluoroethylene (A) and 1,2,3,4,5‐pentafluorostyrene (B) were irradiated at 15°C at autogenous pressure by use of 30–92 mole‐% A and at 5000 atm by use of 42–99.9 mole‐% A. The high‐pressure results indicate that the reactivity ratio rA for monomer addition to A‐ended radicals is 0.005; the other reactivity ratio rB appears to vary from 15 to 60 generally increasing with the A content of the charge. At autogenous pressure rA is small, but a precise determination is not possible because of the very low polymerization rate when the A content of the charge is high. However, if rA is less than 0.01, then values of rB vary from 15 to 50, again generally increasing with the A content of the charge. Mixtures of A and B exhibit positive deviations from Raoult's Law. Activity coefficients were measured at autogeneous pressure and used in an attempt to correct rB for the nonideality of solution. The range of rB was reduced only slightly to 8–27, and charges with high A contents now generally gave low values of rB; consequently, this approach was not regarded as a success. Another attempt was made to account for the apparent variation in rB by ascribing influence to the penultimate units of the radicals. Improved agreement between theoretical and observed compositions resulted, but significant discrepancies remained unexplained. Rate data agreed well with those calculated from a theoretical copolymer rate equation using values of rA and rB of 0.0045 and 40, respectively. The equation predicts an almost proportional decrease in rate with increasing proportions of A in the charge from 0 to 99 mole‐% A.
Copolymerization of fluorinated acrylic monomers with p‐vinylphenol and hydroxyethyl methacrylate
Authors: Overberger C. G. , Sincich Eugene
Published: April 2003

Copolymers of p‐vinylphenol were prepared in bulk with heptafluorobutyl and pentadecafluorooctyl acrylates and trifluoroethyl, hexafluoroisopropyl, heptafluorobutyl, octafluoropentyl and pentadecafluorooctyl methacrylates using azobisisobutyronitrile as the initiator in sealed tubes. Intrinsic viscosities of the copolymers ranged from 0.44 to 1.85. Monomer reactivity ratios for copolymers of trifluoroethyl methacrylate (M1) were: with hydroxyethyl methacrylate (M2), r1 = 0.47, r2 = 1.0; with methyl methacrylate (M2), r1 = 0.82, r2 = 0.50; with styrene (M2), r1 = 0.29, r2, = 0.20; and with p‐vinylphenol (M2), r1 = 0.096, r2 = 1.5. Q and e values of trifluoroethyl methacrylate were 1.30 and 0.92, respectively. Monomer reactivity ratios of octafluoropentyl methacrylate (M1) were: with styrene (M2), r1 = 0.26, r2 = 0.20; and with p‐vinylphenol, r1 = 0.21, r2 = 1.5. Q and e values for octafluoropentyl methacrylate were 1.27 and 0.92, respectively. Critical surface tensions of the homopolymers ranged from 17.9 to 14.8 dyn/cm. A copolymer of hexafluoro‐i‐propyl methacrylate and p‐vinylphenol exhibited a critical surface tension of 16.5 dyn/cm.
Synthesis of hydrophilic polyamide from L‐tartarate and diamines by active polycondensation
Authors: Ogata N. , Hosoda Y.
Published: April 2003

Dimethyl L‐tartarate underwent polycondensation reaction with hexamethylenediamine in solutions at 30°C to form polyamide having pendent hydroxyl groups. Solvents had a great influence on polymer yields and diglyme, tetrahydrofuran (THF) or dimethylsulfoxide (DMSO) were favorable in respect of polymer yields. Solution viscosities of resulting polyamide were as low as 0.1 to 0.2. However, post‐polycondensation of the precursor polyamide at solid phase yielded hydrophilic polyamide having film‐forming ability. The polyamide decomposed at 210°C by heating.
Polyimidothioether–polysulfide block polymers
Authors: Crivello James V. , Juliano Peter C.
Published: April 2003

The synthesis of a new class of block polymers that contain alternating polyimidothioether “hard” blocks and polysulfide elastomer “soft” blocks is described. Compositions with 70% and greater polysulfide component are solvent‐resistant, thermoplastic elastomers exhibiting room temperature tensile strengths of up to 1500 psi and ultimate elongations of nearly 800%. The physical properties are a strong function of test temperature due to relatively short polyimidothioether blocks, 850 ≤ M̄n≤ 3500 g/mole. These short polyimidothioether blocks were necessary to minimize degradation of the polysulfide elastomer blocks during thermal processing at temperatures ∼100°C above the “hard” block domainTg.
Radiation copolymerization of vinyl acetate with the diethyl esters of maleic and fumaric acids
Authors: Du Plessis T. A. , Schnautz N. G. , Lustig A.
Published: April 2003

The radiation‐induced copolymerization of vinyl acetate with diethyl maleate and with diethyl fumarate was investigated in the temperature range from −40 to 90°C over a wide range of comonomer compositions. Both the rates of copolymerization and the molecular weights of the resulting copolymers were found to depend strongly on the initial comonomer compositions. The apparent activation energy was found to change at 13°C with an increase in temperature from a value of 1.76 kcal/mole to a value of 4.31 kcal/mole in the copolymerization with diethyl maleate, while in the case of the copolymerization with diethyl fumarate the apparent activation energy changed at 21°C from a value of 1.76 kcal/mole to a value of 5.98 kcal/mole. Scavenger studies indicate that a free‐radical mechanism prevails over the entire temperature range investigated in the case of both copolymerizations.
Thermal cis–trans isomerization and decomposition of polyacetylene
Authors: Ito Takeo , Shirakawa Hideki , Ikeda Sakuji
Published: April 2003

Thermal cis‐trans isomerization and decomposition of polyacetylene film prepared with a Ti(OC4H9)4–Al(C2H5)3 (Al/Ti = 4) system were investigated under inert gas or in vacuum by means of thermal analysis and infrared spectroscopy. Thermograms of differential thermal analysis of cis‐polyacetylene revealed the existence of two exothermic peaks at 145 and 325°C and one endothermic peak at 420°C which were assigned to cis‐trans isomerization, hydrogen migration accompanied with crosslinking reaction, and thermal decomposition, respectively. The isomerization was followed by infrared spectroscopy over the temperature range 75–115°C. The reaction did not obey simple kinetics. The apparent activation energy for the cis‐trans isomerization was 17.0 kcal/mole for the polymer containing 88% cis configuration and increased with increasing trans content up to 38.8 kcal/mole for 80% trans content.
Hydroxamic acid polymers
Authors: Winston Anthony , Mazza Edward T.
Published: April 2003

A polymer bearing hydroxamic acid groups and having a high affinity for iron(III) was prepared through the following procedure. Acryloylalanine (III), prepared by the reaction of acryloyl chloride with alanine, was treated with N‐hydroxysuccinimide in the presence of dicyclohexylcarbodiimide to give the N‐hydroxysuccinimide ester (IV). The ester IV was polymerized by using AIBN in dioxane to give polymer V. Treatment of polymer V with methylhydroxylamine in DMF gave the hydroxamic acid polymer II. The water‐soluble polymer II was purified by dialysis or by gel‐permeation chromatography (GPC) on Sephadex G‐25. Analytical GPC on Sephadex G‐200 and Sepharose 4B indicate that the average molecular weight of the polymer is in the range of 5 × 105 to 1 × 106. The presence of hydroxamic acid groups is confirmed by the intense red‐brown color produced by the addition of iron(III) to a 50% aqueous DMF solution of the polymer under acidic conditions. In pure water the polymer‐iron complex precipitates as a tan solid. Iron‐binding studies of the polymer reveal that the iron(III) trihydroxamic acid complex FeA3 forms at low concentrations of iron. At higher iron levels a lower order of stability is apparent, which can be accounted for by the conversion of FeA3 to FeA2+. In contrast, the FeA3 complex of the trihydroxamic acid deferoxamine‐B is stable at all iron levels. These results are consistent with the polymer structure, which for steric reasons would favor a stable complex, FeA2+, between iron and two adjacent hydroxamic acid groups. An FeA3 complex would be expected to have a lower stability as a result of either bond angle strain and atomic compression, or a lower probability in bringing a third hydroxamic acid into position to form the octahedral complex.
N‐Aryltetramethylguanidines, living catalysts for polyurethane foams
Authors: Ulrich Henri , Reymore Harold E. , Sayigh A. A. R.
Published: April 2003

N‐Aryltetramethylguanidines catalyze the formation of polyurethane foams by a novel exchange reaction involving CN double bond of the guanidines and the isocyanate groups of the polyisocyanates. The catalyst sites are transferred to the growing polymer network, achieving a rapid catalytic build‐up of the foam.
Stereoregulation in the polymerization of methyl α‐ethylacrylate by n‐BuLi in toluene
Authors: Hatada Koichi , Kokan Susumu , Niinomi Toshikazu , Miyaji Koh , Yuki Heimei
Published: April 2003

The polymerization of methyl α‐ethylacrylate was carried out in toluene by n‐BuLi at various temperatures. The yield of the polymer decreased with increase in the polymerization temperature and at 30°C and above no polymer was obtained, indicating that the ceiling temperature of this monomer lay between 0 and 30°C. The isotacticity increased with an increase in the polymerization temperature and at 0°C a highly isotactic polymer was obtained. The fractionation of the polymer obtained at −78°C showed that the polymer was a mixture of isotactic and syndiotactic ones. Upon the addition of a small amount of methanol or water in the polymerization mixture the isotacticity of the polymer increased while the yield decreased. Syndiotactic polymer was obtained in the polymerization by n‐BuLi in tetrahydrofuran as well as by diisobutyl aluminum diphenylamide in toluene.
Analysis of the linear methods for determining copolymerization reactivity ratios. II. A critical reexamination of cationic monomer reactivity ratios
Authors: Kennedy Joseph P. , Kelen Tibor , Tüdös Ferenc
Published: April 2003

A thorough examination of some cationic copolymerization systems by a new method has shown that many published r values have to be corrected significantly and that some are erroneous and meaningless, because for these systems the conventional copolymer compositions equation does not hold. Available information in regard of cationic copolymerizations has been treated in terms of three classes: (a) Systems in which the conventional copolymer composition equation adequately describes the copolymerization mechanism and previous authors justifiably used the two parameter model to calculate reactivity ratios. Our results show that the discrepancy between published r values and the more precise values obtained in this work is about ±23%. (b) Systems in which the approximations implicit in the conventional copolymer composition equation do not hold and the calculated r values are erroneous and misleading. Monomer pairs comprising monomers of significantly different reactivities belong to this class indicating that in copolymerizations in general and in cationic copolymerizations in particular a strong cast system exists, i.e., copolymerization can readily occur within the cast (between monomers of similar reactivities); however, only with difficulty if at all between casts (between monomers of differing reactivities). (c) Systems in which the use of the copolymer composition equation is completely unjustified, the calculated r values are meaningless and in some cases the existence of true copolymers is questioned.
Kinetic study of radical polymerization of acrylonitrile in the presence of triphenyl phosphite
Authors: Taninaka Takumi , Minoura Yuji
Published: April 2003

In the presence of triphenyl phosphite (TPP), the radical polymerization of acrylonitrile (AN) with α,α′‐azobisisobutyronitrile (AIBN) as the initiator was carried out at 50°C, and the effects of TPP on the polymerization were kinetically investigated. The rate of polymerization was found to be proportional to the first order of the AIBN concentration and the AN concentration, respectively, at all concentrations of TPP. However, the rate of polymerization was proportional to the reciprocal of the TPP concentration at low concentrations, but to the first order of the TPP concentration at high concentrations. On assuming two termination reactions, i.e., the usual unimolecular termination by occlusion of the polymer radical and a bimolecular termination between the propagating radical and TPP, and the formation of the weak n‐π complex between AN and TPP which accelerates propagation step, the rate of polymerization and the degree of polymerization were kinetically discussed. The equations derived were in good agreement with the experimental results.
Low‐angle x‐ray fine structure investigation of tussah protein fiber
Authors: Ratho T. , Patel A.
Published: April 2003

Low‐angle x‐ray methods have been used to evaluate some macromolecular parameters of the scattering particles in tussah, a silk fiber. A low‐angle Kratky camera of recent design has been used for the experimental measurements of the scattering intensities. The sample under investigation is taken as a densely packed colloidal system belonging to general micelle system and the well known theories of Kratky and Kratky and Porod have been utilized. The parameters determined are specific inner surface of the dispersed phase (O/V), transverse lengths like the length of inhomogeneity (lr) and the length of coherence (lc), and the air fraction of the scattering particles in tussah fiber; these were found to be 7.084 × 10−6Å−1, 100.6 Å, 367.7 Å, and 0.02%, respectively.
Formation of free radicals in photoirradiated cellulose. V. Effect of temperature
Authors: Hon Nyok‐Sai
Published: April 2003

ESR spectra of purified and ferric ion‐sensitized celluloses irradiated with ultraviolet light in vacuo at 45, 20, −80, and −196°C were recoreded and compared. Generally, several kinds of spectra, viz., singlet, three‐line, five‐line, and seven‐line spectra, were observed. At higher temperatures, only singlet and three‐line spectra of stable free‐radical species were detected, whereas at lower temperatures such as at −196°C, two doubled spectra of formyl radicals and hydrogen atoms were also detected in addition to cellulose radicals. It is believed that the intricate spectra observed at low temperatures are superimposed upon spectra generated by free radicals which may or may not be stable at high temperatures. During reirradiation at −196°C with an alternative light sources, i.e., λ > 2537 Å and λ > 3400 Å, of samples which were irradiated at 20°C or at −196°C, phenomena indicative of radical transformation and formation of new radicals or of decay of radicals in terms of ultraviolet bleaching were observed on studying the changes of line‐shapes and relative signal intensities of the spectra.
Chemical reactions in monomolecular layers solid‐state polycondensation of octadecyl urea formaldehyde
Authors: Rosilio C. , Ruaudel‐Teixier A.
Published: April 2003

Evidence is given for solid‐state polycondensation reactions in octadecyl urea multilayers, built up by the Langmuir‐Blodgett method. The disappearance and infrared frequency modifications of characteristic functional groups are followed by spectroscopy in transmitted and reflected light and in ATR. The crosslinked polymer thus obtained on a solid substrate is compared with the polymer obtained at the liquid‐air interface. The chemical reactions are accompanied by molecular reorientation phenomena in multilayers.
Synthesis and radical ring‐opening polymerization of spiro o‐carbonates
Authors: Endo Takeshi , Bailey William J.
Published: April 2003

Syntheses and radical ring‐opening polymerization of spiro o‐carbonates(I‐IV) were investigated.
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These polymers were yellow powders and soluble in common organic solvents. The infrared and NMR spectra indicated that the polymers were alternate copolymers of either and carbonate containing double bonds. The polymerization mechanism is discussed.
Structure and reactivities of alkyl vinyl ketones in their radical copolymerizations with styrene
Authors: Otsu Takayuki , Tanaka Hitoshi
Published: April 2003

To clarify the effect of the alkyl substituents in alkyl vinyl ketones (RVK) on their radical copolymerizations, the copolymerizations of six such alkyl vinyl ketones with styrene were investigated. From the results obtained, the relative reactivities of RVK toward the polystyryl radical were correlated with the Taft equation: log (1/r1) = ρ*σ* + δEs, in which σ* and Es are polar and steric substituent constants, respectively, and ρ* and δ are reaction constants. The values of ρ* and δ obtained were 0.40 ± 0.05 and 0, respectively. It was observed that the Q and e values obtained for RVK increased with increasing of σ* values, and that both relative reactivities and Q,e values of methyl vinyl ketone also increased with increasing of the ET values of the solvents used. From the spectral determination of the RVK monomers, it was also found that their n–π interactions were related to the copolymerization reactivities. Furthermore, the radical polymerization of tert‐butyl vinyl ketone (t‐BVK) with azobisisobutyronitrile (AIBN) was investigated, and its rate Rp was found to be expressed by the following rate equation: Rp = k [AIBN]0.5[t‐BVK]1.0.
Thermal polymerization of styrene in the presence of some ferrocene derivatives. II. Low concentrations of vinylferrocene and ethylferrocene
Authors: Tinker A. J. , George M. H. , Barrie J. A.
Published: April 2003

Styrene has been polymerized thermally at 60°C in the presence of low concentrations of vinylferrocene and in the presence and absence of 2,2′‐azobisisobutyronitrile (AIBN). The polymerizations were studied in bulk and also in benzene solution. The thermal polymerization of styrene in the presence of ethylferrocene, but without added AIBN or solvent, was also examined. The bulk polymerizations exhibited high initial rates of polymerization followed by a decrease in rate. Initial rates of polymerization for bulk polymerizations in the absence of AIBN have been interpreted by means of a kinetic scheme involving propagation with styrene participating in a specific interaction with the ferrocene derivative and some kinetic parameters associated with this scheme have been evaluated. The decrease in the rate of polymerization is due to the formation of a retarder. The benzene solution polymerizations fitted a simple kinetic scheme and the transfer constant for vinylferrocene with respect to polystyryl radicals Cs, has been evaluated as 1.98 × 10−3.
Formation of free radicals in photoirradiated cellulose. VI. Effect of lignin
Authors: Hon Nyok‐Sai
Published: April 2003

The effect of lignin on free‐radical formation in photoirradiated pulp was studied by means of electron spin resonance spectroscopy. Samples were irradiated with light of wavelength longer than 3400 Å as well as longer than 2537 Å. Radical formation in aspen lignin was observed before and after irradiation with light of wavelength longer than 3400 Å. Upon irradiation, free radicals were formed in a pulp sample with 0% lignin content only when oxygen was present. On irradiation with light longer than 2537 Å, in the presence of nitrogen, oxygen, and under vacuum, free‐radical formation was found in all cases. The largest concentration of radicals was obtained under vacuum, the smallest in oxygen. It is evident that cellulose was protected from radiation by the presence of lignin. Increased aspen lignin content in pulp led to a decrease in the relative signal intensity of ESR spectrum, that is, a decrease of the yield of free radicals in the cellulose fraction in pulp. Irradiation with light in the presence of oxygen caused significant yellowing of the pulp sample, and these photooxidation and discoloration reactions occurred primarily on the surface of the sample irradiated.
Nonoxidative crosslinking reactions in natural rubber. I. Determination of crosslinking groups
Authors: Burfield D. R. , Gan S. N.
Published: April 2003

The presence of both epoxide and amine groups as integral constituents of the natural rubber macromolecule have been demonstrated, by application of an HBr double titration technique. The number of such groups is dependent on the clonal source of the rubber and is found to decrease on storage in step with an increase in the plasticity of the rubber. The groups are believed to be involved in nonoxidative crosslinking reactions which occur in rubber on storage. Possible crosslinking mechanisms are proposed.
Synthesis of polyhydrazides by ring‐opening polyaddition reaction of N,N′‐biisomaleimide with dihydrazine and dihydrazides
Authors: Ueda Mitsuru , Kanno Susumu , Imai Yoshio
Published: April 2003

The ring‐opening polyaddition reaction of N,N′‐biisomaleimide with a dihydrazine and dihydrazides was carried out in polar aprotic solvents at room temperature to afford a new class of polyhydrazides having inherent viscosities in the range of 0.1–0.5 in nearly quantitative yields. Almost all of the polyhydrazides were soluble in dimethylformamide, dimethyl sulfoxide, and other polar aprotic solvents. They did not show any clear melt temperature and began to decompose at around 200–300°C.
Isobaric temperature dependence of radical generation in poly(methyl methacrylate)
Authors: Szőcs F. , Plaček J. , Borsig E.
Published: April 2003

In this study the effect of temperature on the generation of free radicals accompanying the decomposition of benzoyl peroxide in poly(methyl methacrylate) was studied. The concentration of the chain‐end radicals was determined by the ESR method. The known nine‐line spectrum of the chain‐end radicals of poly(methyl methacrylate) was observed. This spectrum was affected by the contribution of chain radicals at higher temperatures. The dependence of the chain‐end radical concentration on the annealing temperature of polymer found for different pressures gives information on the conditions under which free radicals arise and decay in the temperature range between 90 and 170°C at pressures ranging from 2000 to 12000 atm.
Polyamide‐imides from 3′,4′‐dicarboxy‐4″‐chloroformyl terephthaloylphenone anhydride
Authors: Tagle L. H. , Neira J. F. , Diaz F. R. , Ramirez R. S.
Published: April 2003

Novel polyamide‐imides were prepared from 3′,4′‐dicarboxy‐4″‐chloroformyl terephthaloylphenone anhydride and various aromatic and aliphatic diamines. The polymers were characterized by viscosity, infrared spectra, TGA, DSC, and elemental analysis. The thermal stability of the films was comparable to that of polyamide‐imides previously reported.
Polymerization of alkylene oxides with aluminum alkyl–strong phosphoric acid–lewis base catalyst
Authors: Kida Yasuji , Miura Yuichi , Shikata Kazuo , Azuma Keiichi
Published: April 2003

Polymerization of epichlorohydrin (ECH) and copolymerization of propylene oxide–allyl glycidyl ether were studied by using a catalyst consisting of aluminum alkyl–strong phosphoric acid–Lewis base. This system showed high polymerization activity for alkylene oxides, and it was elucidated by x‐ray diffraction analysis that the resultant ECH polymer was completely amorphous. The polymerization was presumed to be of the coordinated anionic type. The physical properties of the vulcanized polymers were studied.
Temperature‐induced transformations of peroxide radicals formed in polytetrafluoroethylene with γ‐ray irradiation
Authors: Tagawa Tōru , Amemiya Hideo , Shinohara Isao , Hagiwara Miyuki , Kagiya Tsutomu
Published: April 2003

At 200°C, temperature‐induced transformations of peroxide radicals from CF2CF(OO·)CF2 (radical I) to CF2CFCF2 (radical 1) and CF2CF2OO· (radical II) to CF2CF2 (radical 2) in vacuo, and from I to II in oxygen atmosphere were observed. In these thermal transformations, the evolution of CO2 with a small amount of CO and CF2O was observed. Further, measurements of the heat of crystallization of the treated polytetrafluoroethylene suggest that a reduction of polymer molecular weight occurs during the transformations from I to 1 and I to II.
Inorganic coordination polymers. XVIII. Observations on brittle and flexible films of {Cr[OP(CH3)(C6H5)O]2[OP(C8H17)2O]}x
Authors: Nannelli Piero , Gillman H. D. , Block B. P.
Published: April 2003

Films of {Cr[OP(CH3)(CH6H5)O]2[OP(C8H17)2O]}x, formed during the reaction of {Cr(OH)[OP(CH3)(C6H5)O]2}x with dioctylphosphinic acid, are either brittle or flexible depending on the details of the preparation of the chromium(III) bisphosphinate precursor. Both kinds of film appear to contain mainly triple‐bridged chains. Differing degrees of randomness in distribution of the two kinds of phosphinate bridges and, hence, of the internally plasticizing octyl groups along the chain account for the observed differences in flexibility, x‐ray diffraction patterns, and birefringence. The observed intrinsic viscosities of 9–18 dl/g indicate that these trisphosphinates form microgels rather than true solutions. The thermal degradation of these films proceeds by the oxidation and cleavage of the organic side groups. Addition of antioxidants to the flexible films significantly increases the longevity of their flexibility at 200°C.
Study of radiation‐induced polymerization of vinyl monomers adsorbed on inorganic substances. IV. Dose rate and temperature dependences in the styrene–silica gel system
Authors: Fukano Kazuyuki , Kageyama Eiichi
Published: April 2003

In order to elucidate the mechanism of radiation‐induced polymerization of styrene adsorbed on silica gel, the effects of dose rate and irradiation temperature were studied in detail. Monomer conversion increased with increasing dose rate and temperature. At the same conversion, the percent grafting increased with decreasing dose rate and also with increasing temperature. In general, GPC spectra of graft polymers and homopolymers showed two peaks; the ratio of the two peaks changed with dose rate and irradiation temperature. The dose‐rate exponents of the polymerization rate of four peaks were different from each other. The activation energies of radical polymerization and cationic polymerization were about 2.6 kcal/mole and 0 kcal/mole, respectively. Based on the results obtained, a reaction mechansim is proposed.
Polymer degradation during radiation‐induced emulsion polymerization of styrene
Authors: Sato K. , Rudin A. , Huang R. Y. M.
Published: April 2003

Styrene was polymerized in emulsion with initiation by γ‐rays at a dose rate of 0.6 Mrad/hr. Polymerization rates were as expected from previous reports by others. No branching or crosslinking was detectable, and the Mw/Mn ratio of the polystyrene did not change significantly during the course of the polymerization reaction. The molecular weight of the product polymer decreased with increasing conversion, in contrast to the behavior of chemically initiated emulsion polymerizations. Monomer‐free polystyrene does not degrade under the same radiation conditions, and the progressive decrease of polymer molecular weight with conversion is shown to result from the presence of monomer.
Siloxane‐modified heterocyclic polymers
Authors: Breed L. W. , Wiley J. C.
Published: April 2003

Fully aromatic, siloxane‐modified polybenzimidazoles and polybenzoxazoles were prepared by a single‐stage melt polymerization and characterized. These polymers, which have good solubility in pyridine and N‐methylpyrrolidinone, undergo thermooxidative decomposition above 300°C. Model compounds for these two classes as well as polypyromellitimides were also prepared.
Effect of gegen ion in cationic polymerization and copolymerization of trioxane
Authors: Chen Catherine S. Hsia
Published: April 2003

p‐Chlorophenyldiazonium hexafluorophosphate
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has been reported to be a superior catalyst for cationic polymerization and copolymerization of trioxane as compared to boron trifluoride dibutyl etherate (BF3·Bu2O)1. In the present investigation the effect of anions derived from elements in Group VA, AsF and SbF, has been ascertained. It has been concluded that p‐chlorophenyldiazonium hexafluoroarsenate
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is also a superior catalyst to boron trifluoride dibutyletherate (BF3·Bu2O), while p‐chlorophenyl‐diazonium hexafluoroantimonate
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is inferior.

Copolymers with the highest polymer yield (>95%) and molecular weight (intrinsic viscosity = 4 to 5) were obtained with
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Simple dependences on catalyst concentration have been observed to hold for a wide catalyst concentration range ([M]/[C]) = (1 to 20) × 105:

For
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the same relationships hold. However, the polymer yield (75%) and molecular weights (intrinsic viscosity ≃1) are considerably lower while the extent of chain transfer is higher. Furthermore, the polymerization proceeds with explosive violence.

The quantitative aspects resulting from polymerization, for the most part, can be interpreted in terms of the extent of dissociation of the propagating ions.
Degradation of polymer mixtures. VI. Blends of poly(vinyl chloride) with polystyrene
Authors: Dodson B. , McNeill I. C.
Published: April 2003

The degradation of films containing both PS and PVC has been examined by TVA and TG. Stabilization of both polymers, more notably PS, is observed, but the degradation products are the same as when the polymers are degraded alone. Molecular weight measurements indicate a more rapid decrease in the molecular weight of PS when PVC is present. The possibility of grafting or other processes leading to chlorine incorporation in PS has been excluded by the results of experiments using 36Cl‐labeled PVC. The mechanisms of possible interactions between the degrading polymers are discussed. Processes involving reaction of chlorine radicals with PS at lower temperatures and reaction of PS radicals with the residue of PVC dehydrochlorination or its decomposition products at higher temperatures appear probable.
Urea‐formaldehyde resins: NMR study on base‐catalyzed reaction of formaldehyde with urea in deuterium oxide
Authors: Tomita Bunichiro , Hirose Yoshiyuki
Published: April 2003

High‐resolution nuclear magnetic resonance has been used in order to investigate the base‐catalyzed reaction of formaldehyde with urea in deuterium oxide. We investigated the effects of temperature and concentration on the chemical shift of glycol species in formalin under basic condition. Assignment of all the signals appearing in the addition reaction was completed. The formation of N,N‐dimethylolurea, uron, monomethyloluron, and dimethyloluron was observed for the first time, as well as the formation of monomethylolurea, N,N′‐dimethylolurea, and trimethylolurea, which had been observed previously: the formation of presumptive tetramethylolurea could not be observed. The rate constants and equilibrium constant for urea, monomethylolurea, N,N′‐ and N,N‐dimethylolurea, and trimethylolurea were estimated by analysis of the decomposition reactions of monomethylolurea and N,N′‐dimethylolurea.
Determination of interaction parameter χ1, for poly(vinyl alcohol) and water in gels crosslinked from solutions
Authors: Peppas Nikolaos A. , Merrill Edward W.
Published: April 2003

The Flory interaction parameter χ1 of poly(vinyl alcohol)‐water systems has been estimated as a function of temperature and volume fraction of PVA, the polymer having been crosslinked from solutions of the same in water. Values are reported for temperatures between 0°C and 90°C and polymer volume fractions between 0.03 and 0.12.