bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and properties of carboxyl‐functional mixed esters of hydrolyzed starch
Authors: Rudolph Stephen E. , Glowaky Raymond C.
Published: April 2003

Mixed esters of hydrolyzed starch represent a new class of chemically modified natural polymers demonstrating a broad range of properties. Members of this class of polymers have both neutral aliphatic ester side chains and carboxyl‐functional half‐ester side chains. Use of hydrolyzed starch as the backbone polymer results in products that are considerably lower in molecular weight than whole starch derivatives, but which are still polymeric in character. Synthesis proceeds smoothly in pyridine using anhydrides as acylating agents and the pure solid mixed ester products are isolated by precipitation in water. Measurement of degree of substitution (D.S.) by NMR or hydrolysis characterizes the chemical composition of the polymers. The actual D.S. achieved in the synthesis depends upon the competition between starch and residual water for anhydrides, which can be quantitatively evaluated by monitoring the acid content of the reaction mixture. The Tg and Ts of starch mixed esters vary with both D. S. and length of the aliphatic ester side chain. As the composition changes from acetate—phthalate to butyrate—phthalate a Tg range of greater than 100°C is observed. Hydrolyzed starch mixed esters are hydrophobic and organic‐soluble, but may be readily solubilized in aqueous base through the half‐ester groups. Solutions show surface activity which varies according to the type and extent of substitution.
Cationic polymerization with boron halides. VI. Polymerization of styrene with BF3, BCl3, and BBr3
Authors: Kennedy J. P. , Feinberg S. C.
Published: April 2003

The polymerization of styrene with BF3, BCI3, and BBr3 coinitiators and CH2Cl2 solvent has been investigated. The effects of temperature, monomer concentration, and the nature of the boron halide on molecular weights, molecular weight distribution, and conversion were determined. Molecular weights were found to decrease in the order BCl3 >BF3 >BBr3. This sequence was discussed in terms of system ionicity and counterion stability. The overall energies of activation for polymerization (ΔE) were −1.6 ± 0.3, −1.9 ± 0.8, and −0.9 ± 0.5 kcal/mole for BF3, BCI3, and BBr3, respectively, which indicated similar overall polymerization mechanisms in the range of −20 to −80°C. The predominant molecular‐weight‐governing event in polymerizations with BCl3, and BBr3 was chain transfer to monomer, whereas with BF3 chain transfer and termination were nearly equal. Chain termination in BCl3‐coinitiated polymerizations involves chlorination of the growing polystyryl cation by BCl3OH⊖ and leads to benzylic chlorine termini.
An analytical evaluation of anhydrosugar polymerizations
Authors: Ito Hiroshi , Schuerch Conrad
Published: April 2003

1,6‐Anhydro‐2,3,4‐tri‐O‐(p‐methylbenzyl)‐β‐D‐glucopyranose (TXGL, M1) has been copolymerized with 1,6‐anhydro‐2,3,4‐tri‐O‐benzyl‐β‐D‐glucopyranose (TBGL, M2). Reactivity ratios, calculated by the Mayo and Lewis procedure, are r1 = r2 = 1.25 ± 0.25. Within experimental error these values represent azeotropic copolymerization. Therefore preceding interpretations of the relative reactivity of TXGL and other benzylated anhydrosugars are not incorrect because the possible effect of p‐methyl substitution was ignored. Analysis of this copolymerization system and the reported copolymerizations of TXGL with 1,6‐anhydro‐2,3,4‐tri‐O‐benzyl‐β‐D‐manno‐(TBMN) and galactopyranoses (TBGA) by the linear method recently proposed by Kelen and Tudos has confirmed that true copolymerization takes place in all the systems mentioned above and that the classical copolymerization theory adequately describes the copolymerization mechanism. Physical properties of the copolymers of TXGL and TBGL indicate the usual high stereoregularity of structure.
Polyepiiodohydrin
Authors: Schacht E. , Bailey D. , Vogl O.
Published: April 2003

Polyepiiodohydrin was prepared from polyepichlorohydrin by the Finkelstein reaction with sodium iodide in butanone. An 88% degree of replacement of chlorine by iodine was obtained. The reaction of iodides with polyepichlorohydrin was accompanied by a substantial drop in molecular weight. The copolymer, which contains eight epiiodohydrin units per epichlorohydrin unit, has a glass transition temperature of 1°C and a density of 2.2 g/cm3. Properties of epiiodohydrin homopolymer were estimated by extrapolation of copolymer data.
Photodegradation of aramids. II. Irradiation in air
Authors: Carlsson D. J. , Gan L. H. , Wiles D. M.
Published: April 2003

A series of isomeric fully aromatic polyamides (aramids) were photodegraded in the presence of oxygen. Films and fibers of these aramids gave carboxylic acids as the major products when measured by infrared spectroscopy and potentiometric titration. These acids probably resulted from the oxygen interception of the radicals generated by photocleavage of the amide bonds. In contrast to results found upon irradiation in the absence of oxygen, carboxylic acid formation was accompanied by a rapid loss in molecular weight, and a decrease in useful mechanical properties. Quantum yields for carboxylic acid formation were ≤5.5 × 10−5 mole/einstein and decreased along the aramid series roughly in agreement with increases in Tg. The photo‐Fries rearrangement product was observed in aramid fibers irradiated in air, whereas no rearrangement product was seen in films irradiated in air.
Olefin polymerization in liquid sulfur dioxide initiated by m‐chloroperbenzoic acid. I. Homopolymerization of styrene and α‐methylstyrene
Authors: Akcelrud L. , Gomes A. S.
Published: April 2003

Homopolymerizations of styrene (Sty) and α‐methylstyrene (AMS) in liquid sulfur dioxide were carried out in the temperature range from −10°C to −78°C, using m‐chloroperbenzoic acid as initiator. It is shown, through the effect of initiator concentration, temperature, and times of reaction on the conversion and molecular weight of the polymers, that AMS is more reactive than Sty because it requires a smaller amount of initiator for the same conversion to be reached, although the molecular weight of the resulting polymer is lower. A linear relationship has been observed for Sty between the degree of polymerization and the initiator concentration. Within the experimental conditions employed, the presence of polysulfones has been discarded by elemental analysis. The polymerization reactions are considered to be cationic in mechanism.
Olefin polymerization in liquid sulfur dioxide initiated by m‐chloroperbenzoic acid. II. Copolymerization of styrene and α‐methylstyrene
Authors: Akcelrud L. , Gomes A. S.
Published: April 2003

Copolymerizations of styrene (Sty) and α‐methlstyrene (AMS) were carried out in liquid sulfur dioxide at −10°C and at −40°C with m‐chloroperbenzoic acid (MCPBA) as initiator. Reactivity ratios were determined by the methods of Fineman–Ross and Kelen–Tüdös, from polymer composition obtained by nuclear magnetic spectroscopy. As indicated by thermogravimetric analysis, a block copolymer was obtained at −40°C.
Copolymerization of styrene with vinyl acetate in presence of tributyl amine (TBA)
Authors: Bataille P. , Charifi‐Sandjani N.
Published: April 2003

This work presents the results of solution and emulsion copolymerization of vinyl acetate and styrene in the presence of a tertiary amine such as tributyl amine. This amine increases the stability of the vinyl acetate free radicals and favors copolymerization reaction. Emulsion polymerizations in the presence of TBA resulted in a terpolymer of styrene‐vinyl acetate‐vinyl alcohol. Vinyl alcohol is due to hydrolysis in the basis aqueous medium.

The homo‐and copolymers obtained by precipitation from the reacting mixtures were fractionated according to procedures devised from solubility trials and from the work of Soen et al.13

Fractions were characterized by nuclear magnetic resonance (NMR), infrared (IR), gel permeation chromatography (GPC), and thermal analysis.

Heteropolymers were obtained with both techniques, and a terpolymer was obtained by emulsion polymerization, due to ester hydrolysis. The monomer conversion was more than 26%; 15% of the motives in the polymer were alcohols and 4%, acetates. With solution polymerization the conversion was more than 11%; 14% of the motives, as indicated by NMR, were acetates and the rest styrene.
Polymerization of α,α‐disubstituted‐β‐propiolactones and lactams. 10. Crystalline structure, thermal and mechanical studies of statistical and block copolymers of pivalolactone and α‐methyl‐α‐propyl‐β‐propiolactone
Authors: Allegrezza A. E. , Lenz R. W. , Cornibert J. , Marchessault R. H.
Published: April 2003

AB and ABA block copolyesters based on racemic poly(α‐methyl‐α‐n propyl‐α‐propiolactone) (PMPPL) as a “soft” or elastomeric segment and polypivalolactone (PPL) as a “hard” or crystallizable segment have been synthesized and compared with random copolymers of the same composition. X‐ray studies show the coexistence of polymorphic crystal forms for a given polymer in a given sample. Thermal and dynamic mechanical properties give clear evidence of heterophase structure corresponding to segregation of PPL and PMPPL. The crystalline phase clearly provides thermally reversible crosslinking in the ABA block copolymers. On stretching, the planar zigzag form of PMPPL is observed. Because of the domain structure, moduli of ABA samples are higher than those of PMPPL and their tensile strengths are similar to those of comparable styrene‐butadiene block copolymers.

The polymer synthesis was achieved by sequential monomer addition with tetrahexyl ammonium benzoate as initiator. For the ABA polymers the diammonium salt of sebacic acid provided a di‐functional initiator. The agreement between calculated and observed molecular weights testify to the “living” character of this polymerization reaction.
ESR study of γ‐irradiated 1,3,5‐trithiane and its derivatives
Authors: Andrzejewska E. , Żuk A. , Pietrzak J. , Krzyminiewski R.
Published: April 2003

Radicals formed in γ‐irradiated 1,3,5‐trithiane and its derivatives at room temperature have been studied by ESR spectroscopy. ESR evidence establishes that 1,3,5‐trithiane as well as α‐ and β‐2,4,6‐trimethyl‐1,3,5‐trithiane yield radicals mainly by loss of the hydrogen atom, whereas α‐ and β‐2,4,6‐triphenyl‐1,3,5‐trithiane and 2,4,6‐trimethyl‐2,4,6‐triphenyl‐1,3,5‐trithiane produce radicals that are parent radical cations, which are also present in small amounts in aliphatic trithianes. Furthermore, in all the spectra examined R–S.‐type radicals are observed. The probable initiation process of radiation‐induced 1,3,5‐trithiane polymerization is discussed briefly.
Radical block polymerization of vinyl chloride. II. Synthesis and characterization of vinyl chloride block copolymers
Authors: Weinand G. , Smets G.
Published: April 2003

Peroxidized polypropylene has been used as a heterofunctional initiator for a two‐step emulsion polymerization of a vinyl monomer (M1) and vinyl chloride with the production of vinyl chloride block copolymers. Styrene, methyl‐, and n‐butyl methacrylate and methyl‐, ethyl‐, n‐butyl‐, and 2‐ethyl‐hexyl acrylate have been used as M1 and polymerized at 30–40°C. In the second step vinyl chloride was polymerized at 50°C. The range of chemical composition of the block copolymers depends on the rate of the first‐step polymerization of M1 and the duration of the second step; e.g., with 2‐ethyl‐hexyl acrylate block copolymers could be obtained with a vinyl chloride content of 25–90%. The block copolymers have been submitted to precipitation fractionation and GPC analysis. Noteworthy is the absence of any significant amount of homopolymers, as well as poly(M1)n as PVC. The absence of homo‐PVC was interpreted by an intra‐ and intermolecular tertiary hydrogen atom transfer from polypropylene residue to growing PVC sequences. The presence of saturated end groups on the PVC chains is responsible for the improved thermal stability of these block polymers, as well as their low rate of dehydrochlorination (180°C). Molecular aggregation in solution has been shown by molecular weight determination in benzene and tetrahydrofuran.
Poly(dimethyl biphenylene)
Authors: Krigbaum W. R. , Krause Kenneth J.
Published: April 2003

Two methods were investigated for the preparation of poly(dimethyl biphenylene) in a search for polymers combining good solubility with sufficiently high chain extension to produce a lyotropic nematic phase. The Ullmann reaction was used to condense 4,4′‐diiodo‐3,3′‐dimethyl biphenyl and the corresponding 2,2′‐dimethyl derivative with copper, and 4,4′‐dibromo‐2,2′‐dimethyl biphenyl was polymerized using the coupling reagent, bis(1,5‐cyclooctadiene)nickel(0), developed by Semmelhack. The Ullmann polymers were completely soluble in CHCl3 but only partially soluble in toluene, whereas earlier work had indicated similar polymers of higher molecular weight to be completely soluble in toluene. All the polymers produced were of low molecular weight and no evidence of the nematic phase was found by polarized light microscopy for CHCl3 solutions over the concentration range 6.8–25% by weight.
The chemistry of THPC–urea polymers and relationship to flame retardance on wool and wool–polyester blends. II. Relative flame‐retardant efficiency on wool, polyester, and wool‐polyester blends
Authors: Basch Avraham , Nachamowitz Benjamin , Hasenfratz Sarah , Lewin Menachem
Published: April 2003

Optimum flame retardance in THPC‐urea‐type formulations was achieved by approximately 1—0.9 THPC‐urea mole ratio and slow urea addition. A phosphonium salt structure is more efficient in flame retarding 100% wool and wool‐polyester blends than a phosphine oxide structure. Both structures are equivalent in flame retarding 100% polyester. It is considered probable that a vapor‐phase mechanism is predominant in the phosphorus‐based flame retardancy of wool, whereas a mixed solid‐vapor phase mechanism operates for 100% polyester.
Reaction of poly(vinyl chloride) with superoxide anion
Authors: Osawa Zenjiro , Nakano Hiroko , Mitsui Eiichi , Nakano Minoru
Published: April 2003

Reaction of poly(vinyl chloride) (PVC) with superoxide anion was carried out in tetrahydrofuran (THF) at 40°C in a nitrogen atmosphere. Remarkable changes in infrared (IR) spectra of the samples treated with superoxide anion were observed in the following regions: ca. 3300, 1680, 1620, and 765 cm−1, which suggested the formation of hydroxyl groups, α,β‐unsaturated ketone groups, and ethylenic structures. Ultraviolet–visible spectra also showed the formation of polyene structures. The content of chlorine in the polymer decreased and that of oxygen increased with reaction time. The reaction mechanism was discussed on the basis of these results.
Functional monomers and polymers. XXXXVI. A copolymerization study of methacryloyl‐type monomers containing nucleic acid bases in chloroform solution
Authors: Akashi M. , Kita Y. , Inaki Y. , Takemoto K.
Published: April 2003

Behavior of the free radical copolymerization of N‐β‐methacryloyloxyethyl derivatives of adenine with that of thymine was studied in chloroform solution, taking account of the specific base‐base interaction of these monomers. Hydrogen bonding interaction between such monomers was observed by NMR spectroscopy. The acceleration of copolymerization was found to be greater either at lower monomer concentration or at lower polymerization temperature. When N‐β‐methacryloyloxyethylcarbazole was used as a comonomer, the rate of copolymerization showed a similar trend as in the case of usual free radical copolymerizations. From r1 and r2 values obtained, the copolymerization was found to be alternating, particularly in the case of copolymerization between monomers having complementary nucleic acid bases. The results suggest that the hydrogen bonding interaction between adenine and thymine plays a role in the propagation step.
Cyclopolymerization. VI. Polymerization mechanism of N‐methyl‐N‐allylmethacrylamide at lower temperature
Authors: Kodaira Toshiyuki , Murata Osamu
Published: April 2003

Mechanistic investigations on the polymerization of N‐methyl‐N‐allylmethacrylamide (MAMA) at lower temperature were carried out based upon the ESR studies of MAMA and its monofunctional counterparts irradiated with 60Co γ rays. Cyclopolymerizability of MAMA was also studied in connection with the hindered rotation about its amide CN bond. The propagating radical observed is only related to the methacryl group but not to the allyl group both in MAMA and its monofunctional counterparts. Polymerization at −78°C yielded a polymer with a lower degree of cyclization(88.8%) as compared with that of polymers formed at higher temperatures (93.5% above 0°C). A structural study revealed that the increment of the unsaturation in the poly‐MAMA obtained at −78°C is due to the allyl group and the content of pendant methacryl group is almost unchanged over the temperature range from −78 to 120°C. These results led to the conclusion that the polymerization of MAMA at −78°C proceeds mainly through the methacryl group, the rate‐determining step is the cyclization reaction, and, in addition, cyclization reaction scarcely occurs when it polymerizes through the allyl group. Since MAMA is frozen into a glassy state, the effect of glass transition temperature (Tg) has been studied and it was suggested that the polymerization of MAMA proceeds only above Tg.
Studies with model membranes. XXII. Evaluation of thermodynamic parameters and testing of theories of membrane and bi‐ionic potential based on nonequilibrium thermodynamics
Authors: Siddiqi Fasih A. , Nasim Beg M. , Prakash Poorna
Published: April 2003

Thermodynamically effective fixed‐charge density of mercuric phosphate and carbonate parchment‐supported membranes have been evaluated by the most recent method of Nagasawa et al., based on the thermodynamics of irreversible processes and compared with the values obtained by the Kobatake et al. and Teorell—Meyer—Sievers (TMS) methods. Bi‐ionic potential (BIP) has also been measured for these membranes with three pairs of electrolyte solutions: KClNaCl, KClLiCl, and NaClLiCl. Theoretical values of BIP have been calculated by using the membrane potential and BIP theories recently developed by Toyoshima et al., based on nonequilibrium thermodynamics. Various parameters have also been evaluated and it was found that the theoretical equation of BIP is applicable to these parchment‐supported membranes.
Copolymerization of acrylonitrile with 2‐hydroxyalkyl methacrylates
Authors: Bajaj P. , Jain P. C. , Gangopadhyay D.
Published: April 2003

The radical copolymerization of acrylonitrile with 2‐hydroxyethyl‐ (HEMA) and 2‐hydroxypropyl‐methacrylate (HPMA) has been studied in two media: dimethylformamide (DMF) and dimethylsulfoxide (DMSO), at 60°C. Copolymer composition was determined from the hydroxyl content and reactivity ratios were calculated by the Kelen‐Tüdös method. The values of r1 and r2 computed by the integrated and the Kelen‐Tüdös methods have been compared. A strong influence of the solvent on the reactivity ratios, particularly on r2 (HEMA or HPMA), has been observed. The copolymers prepared in DMSO are richer in hydroxyalkyl acrylates than those prepared in DMF. This effect may be attributed to preferential monomer solvation and the stability of the growing radicals. The influence of hydroxyalkyl acrylate comonomer on the properties of acrylonitrile copolymers (intrinsic viscosity and thermal behavior) are also discussed.
ESCA applied to polymers. XXII. An investigation of sample charging phenomena for polymeric films on gold
Authors: Clark D. T. , Dilks A. , Thomas H. R. , Shuttleworth D.
Published: April 2003

Sample charging phenomena arising in the ESCA experiment have been investigated for gold and polymer films of known thickness ranging from 5 Å to 20 μ deposited on gold either insulated from or in electrical contact with the spectrometer. Charging induced by a monochromatic x‐ray source is typically an order of magnitude greater than that induced by a nonmonochromatized source and exhibits a marked time dependence. A novel source of secondary electrons which employs a low‐power, low‐pressure mercury lamp external to the spectrometer source chamber as an alternative to an electron flood gun is described, and the charging and biasing characteristics of polymer films as a function of film thickness are discussed and demonstrated to provide an extra informational dimension for the study of polymeric materials.
Syntheses and reactions of functional polymers. XCVII. Chemical activation and functionalization of poly(γ‐methyl‐L‐glutamate)
Authors: Kudo Akira , Endo Takeshi , Tosabayashi Yoshihiro , Okawara Makoto
Published: April 2003

To enhance its solubility in common solvents poly(γ‐methyl‐L‐glutamate) (PMG) was transesterificated with ethylene chlorohydrin, ethylene cyanohydrin, and β,β,β‐trichloroethanol, respectively. The aminolyses of the resulting polymers proceeded easily in pendant ester groups to give the corresponding amides in reasonable yields without main chain fission. By these procedures the incorporation of functional groups such as azide, amino acid, and thiol into PMG is successfully performed.
Coordination reaction of cobaloxime with 4‐vinylpyridine‐styrene copolymer
Authors: Terada Ei‐Ichi , Nishikawa Hiroshi , Cho Jinshū , Tsuchida Eishun
Published: April 2003

The equilibrium constants of the coordination reaction of chlorodimethylformamide·cobaloxime with 4‐vinylpyridine–styrene copolymers (PPS) were determined. The constants for PPS, which contain 20–50% 4‐vinylpyridine (4VP) unit, measured about 1.3 × 105 liter/mole larger than those in the pyridine system (6.8 × 104 liter/mole). When the polymer ligand is 4VP homopolymer or contains less than 20% 4VP unit, K values are lower. The rate constants (kf) of the coordination reactions of the cobaloxime with polymer ligands were also measured in dimethylformamide (DMF) and benzene. In DMF kf decreased with an increase in 4VP unit content of the polymer ligand; in benzene it was increased by the 4VP fraction. These results can be explained by the variation in conformation of the polymer chain in each solvent. The effect of the polymer chain on complexation was discussed on the basis of the kinetic data.
Polymerization of coordinated monomers. XIV. Systematic deviations from alternating regulation in copolymerization of methyl methacrylate with styrene in the presence of metal halides
Authors: Hirai Hidefumi , Tanabe Tsuneaki , Koinuma Hideomi
Published: April 2003

Methyl methacrylate (MMA) and styrene (St) copolymerize in the presence of zinc chloride at 3°C under photoirradiation. The contents of methyl methacrylate in the copolymers obtained at a [ZnCl2]/[MMA] molar ratio of 0.4 are systematically larger than 53 mole %, which is the limiting value at a small feed ratio of methyl methacrylate. The resulting copolymers are confirmed as the sole products and not the mixtures by thin layer chromatography. The effect of dilution of the monomer feed mixture with toluene on copolymer composition suggests that it depends chiefly on the feed concentration of styrene and hardly at all on monomer feed ratios. Copolymerizations are also conducted in the presence of stannic chloride at −17°C under photoirradiation and in the presence of ethylaluminium sesquichloride at 0°C with spontaneous initiation. The contents of methyl methacrylate in both copolymers obtained at feed ratios lower than 60 mole % almost correspond to the 1:1 alternating copolymer and increase systematically with higher feed ratios. The systematic deviations of copolymer composition obtained in the presence of metal halides are reasonably interpreted by the participation of the binary molecular complex composed of metal halide and methyl methacrylate in the polymerization of the ternary molecular complex composed of metal halide, methyl methacrylate, and styrene.
Radical cyclocopolymerization of divinyl ether and maleic anhydride. A 13C‐NMR study of the polymer structure
Authors: Kunitake Toyoki , Tsukino Mitsuo
Published: April 2003

The structure of the 1:2 copolymer of divinyl ether and maleic anhydride was investigated by 13C‐NMR spectroscopy. The polymer contains the bicyclic unit composed of one molecule of each monomer and the maleic anhydride unit. The carbon chemical shift for these units was calculated on the basis of the chemical shift of many model compounds. The major peaks of the cyclopolymer prepared in chloroform were consistent with the presence of the symmetrical bicyclic unit with cis junction and the trans monocyclic anhydride unit. The carbonyl carbon spectrum for the copolymer obtained in a mixed solvent of acetone and CS2 suggested the predominant formation of the unsymmetrical bicyclic unit. The polymerization process was discussed on the basis of these results.
Dye‐sensitized photoinitiated cationic polymerization. The system: Perylene–triarylsulfonium salts
Authors: Crivello J. V. , Lam J. H. W.
Published: April 2003

Perylene has been found to photosensitize the photolysis of triarylsulfonium salts at wavelengths from 390 to 475 nm. Using perylene in combination with various triarylsulfonium salt photoinitiators, the photoinduced cationic polymerizations of cyclohexene oxide and 2‐chloroethyl vinyl ether have been demonstrated using light of these wavelengths.
Low‐temperature modification of dienic polymers via the “Ene” reaction with 4‐substituted‐1,2,4‐triazoline‐3,5‐diones
Authors: Butler George B. , Williams A. Grady
Published: April 2003

4‐Substituted‐1,2,4‐triazoline‐3,5‐diones have been used to synthesize a series of new polydienes by the “ene” reaction at ambient temperatures. The extent of chemical conversion can be varied widely and up to 93% of the diene‐repeating units of the parent polymer chain undergo reaction. Yields of the new polymers based on the reactant range from 90 to 95% at room temperature; their physical properties range from secondary crosslinking effects or elasticity at low degrees of conversion to rigid, amorphous polymers with high softening points at high degrees of conversion. The new polymers show a predictable correlation between the extent of conversion and the softening point. A similar correlation exists between the polarity of the new polymers and the extent of conversion. Polydienes with conversions to the extent of 45% or greater are soluble in aqueous solutions of sodium hydroxide and those with conversions of 60% or greater are soluble in aqueous sodium bicarbonate. Thus, in general, the new polymers (1) have higher Tg, (2) become increasingly polar, hence are soluble in polar solvents, and (3) possess a reasonably acidic proton, hence form salts. Bistriazolinediones result in room temperature crosslinking. A kinetic study with model compounds suggests that the rate of the reaction can be varied, depending on the electronic nature of the 4‐substituent.
Monomer‐isomerization polymerization. XVII. Monomer‐isomerizations copolymerizations of 2‐butene with 3‐heptenes and 4‐methyl‐2‐pentenes with Ziegler‐Natta catalyst
Authors: Otsu Takayuki , Endo Kiyoshi , Yousufzai A. H. K.
Published: April 2003

2‐Butene(2B) copolymerizes with 3‐heptene(3H) and 4‐methyl‐2‐pentene(4M2P) by a monomer‐isomerization copolymerization mechanism in the presence of TiCl3–(C2H5)3Al catalyst at 80°C to yield the copolymers of 1‐olefin units. By comparison, the copolymerization of 1‐butene(1B) with 4‐methyl‐1‐pentene(4M1P) was also carried out under similar conditions. The composition of the copolymers obtained from these copolymerizations was determined from the ratios of optical densities D723/D1380 and D1170/D1380 in their infrared (IR) spectra. The apparent monomer reactivity ratios for the monomer‐isomerization copolymerization of 2B with 3H and 4M2P, in which the concentration of olefin monomer in the feed was used as 2‐olefin, were determined as follows: cis‐2B(M1)/3H(M2); r1 = 4.00, r2 = 0.20: trans‐2B(M1)/3H; r1 = 3.50, r2 = 0.20; 4M2P(M1)‐trans‐2B(M2): r1 = 0.05, r2 = 9.0. These results indicate that the isomerization of 2‐olefins to 1‐olefins was important to monomer‐isomerization copolymerization.
Photolytic behavior of copolyamides from adipic and truxillic acids
Authors: Caccamese S. , Maravigna P. , Montaudo G. , Recca A. , Scamporrino E.
Published: April 2003

The synthesis of copolyamides from adipic and truxillic acids with piperazine was undertaken to include photoreactive units in aliphatic polyamides and to throw light on the factors that control the photolytic rates and photochromic behavior of these materials. The results indicate that the introduction of variable amounts of truxillic units (photodegradable) induces a measurable increment in the photolytic rate of the aliphatic polyamide. Moreover, it has been found that the addition of strong acids induces a higher photolytic cleavage of the polyamides, which may allow a further reduction in the amount of truxillic units in the copolyamides.
Stereochemistry in cationic polymerization of alkenyl ethers. II. Formation of poly(ß‐substituted vinyl ether)s with erythro‐meso structures
Authors: Hirokawa Yoshitsugu , Higashimura Toshinobu , Matsuzaki Kei , Uryu Toshiyuki
Published: April 2003

The formation of polymers with erythro‐meso structures, which could not be obtained from propenyl ethers with BF3O(C2H5)2, was studied by 13C‐NMR spectroscopy on poly(ß‐substituted vinyl ether)s obtained under a variety of conditions of polymerization. It was established that poly(cis‐ethyl propenyl ether) obtained with Al2(SO4)3–H2SO4 complex in toluene at 0°C was a highly stereoregular polymer with an erythro‐meso structure. Cis‐2‐chlorovinyl ethyl ether and cis‐methyl and ethyl butenyl ethers also yielded polymers with erythro‐meso structures under the same conditions. In addition, with BF3O(C2H5)2 at −78°C these three cis isomers produced amorphous polymers with threo‐meso, racemic, and, in a few cases, erythro‐meso structures, whereas cis‐ethyl propenyl ether produced polymers with only threo‐meso and racemic structures by the same catalyst. On the other hand, all trans isomers produced stereoregular polymers with threo‐meso structures with BF3O(C2H5)2 at −78°C, regardless of their ß‐substituents; no erythro‐meso structures were found in the polymers obtained.
Polymerization of t‐butyl thiirane. III. Temperature effect on the stereoelective polymerization
Authors: Dumas Philippe , Spassky Nicolas , Sigwalt Pierre
Published: April 2003

The effect of temperature on stereoelective polymerization of t‐butyl thiirane was studied. Although the overall kinetic scheme was not modified by a change of temperature, a strong effect on the stereoelectivity ratio was observed. Very high optical yields were obtained for polymerizations run below 0°C. On the other hand, at temperatures higher than 120°C, the stereoelection is inversed; i.e., the opposite enantiomer is chosen. The stereoselectivity ratio varies with temperature according to an Arrhenius relationship.
Thermotropic liquid crystalline polymers. II. Polymers with amino acid fragments in the side chains
Authors: Shibaev V. P. , Tal'roze R. V. , Karakhanova F. I. , Platé N. A.
Published: April 2003

The comblike polymers, poly(Nε‐methacryloyl‐Nα‐acyl) derivatives of L‐lysine, which contain amino acid fragments and long sequences of methylene groups in the side chain, were synthesized. This article, which is based on x‐ray data, differential thermal analysis, and optical microscopy, describes the structure of these polymers and their properties. It also shows that the combination of anisodiametric side groups with a “rigid” matrix of main chains leads to a liquid crystalline structure of examined polymers.
Ferrocene‐containing polymers. II. Radiation‐induced copolymerizations of ferrocenylmethyl methacrylate with styrene, methyl methacrylate, and ethyl acrylate
Authors: Tsubakiyama Kyoji , Matsuo Togoro , Sasaki Takashi , Yoshida Kenzo , Araki Kunio
Published: April 2003

Ferrocenylmethyl methacrylate (FMMA) was copolymerized with styrene (St), methyl methacrylate (MMA), and ethyl acrylate (EA) in benzene solution at 25°C by γ radiation. The reactions proceeded by a free radical mechanism, and monomer reactivity ratios were derived by the Tidwell–Mortimer method for St(M1)–FMMA(M2), r1 = 0.35 and r2 = 0.46; for MMA(M1–FMMA)(M2), r1 = 0.85 and r2 = 1.36; for EA(M1)–FMMA(M2), r1 = 0.36 and r2 = 3.03. The Q and e values of FMMA determined from copolymerization with St were 0.97 and 0.55, respectively. Terpolymerization of a MMA–FMMA–EA system based on the Alfrey–Goldfinger equations was studied. This is a typical terpolymerization system in which reactivities of the monomers obey the Q–e scheme. Comparing the results obtained here with those previously reported for other monomers, we concluded that FMMA is one of the most highly reactive monomers among alkyl methacrylates.
Polymerization of aromatic nuclei. XIX. Polymerization of thiophene by aluminum chloride
Authors: Kovacic Peter , McFarland Kathryn N.
Published: April 2003

Thiophene was polymerized in high yield on exposure to aluminum chloride in solvent under mild conditions. Experimental evidence [IR, NMR, UV, and mass spectra, elemental analyses, reductive desulfurization, and comparison with the literature trimer of thiophene (prepared with phosphoric acid)] suggests the following structure:
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From gel permeation chromatography an average weight of 1290 was obtained, which corresponded to the presence of 15 rings; the highest‐molecular‐weight chains contained about 192 rings. Mechanistically, participation of cationic intermediates is proposed. Apparently chain extension can occur by various routes, including participation of neutral oligomer molecules.
Synthesis of polyamides from active 2‐benzothiazolyl diesters and diamines under mild conditions
Authors: Ueda Mitsuru , Sato Akira , Imai Yoshio
Published: April 2003

2‐Benzothiazolyl benzoate as a model compound was successfully synthesized from the benzoylation of 2‐benzothiazolone under kinetically controlled conditions. The aminolysis of 2‐benzothiazolyl benzoate afforded excellent yields of N‐substituted benzamides at room temperature in a short reaction time. Solution polycondensations of new active diesters, di‐2‐benzothiazolyl isophthalate and di‐2‐benzothiazolyl terephthalate, with aliphatic and aromatic diamines, took place rapidly even at room temperature and yielded polyamides with high molecular weight. The high reactivity of 2‐benzothiazolyl benzoate was discussed in relation to intramolecular general base catalysis and the tautomeric effect of the benzothiazolone moiety.
Thermally reversible polymer systems by cyclopentadienylation. II. The synthesis of cyclopentadiene‐containing polymers
Authors: Kennedy Joseph P. , Castner Kenneth F.
Published: April 2003

The synthesis of polymers containing either terminal or pendant cyclopentadiene (CPD) groups has been studied. Using information obtained from model studies, the synthesis of polyisobutylenes containing a CPD terminus was accomplished by the use of the tert‐butylchloride–dimethylcyclopentadienylaluminum initiator system. Isobutylene polymerization by this system under carefully chosen conditions is essentially transfer free, and termination occurs by cyciopentadienylation. The presence of CPD end group has been established by UV spectroscopy and reaction with maleic anhydride. Selectivity toward termination by cyclopentadienylation increases with decreasing temperatures; at −41°C and low conversion (<10%) ca. 72% of the polymer chains terminate in this manner. The synthesis of polymers containing randomly distributed pendant CPD groups along the chain has been accomplished by cyclopentadienylating with dimethylcyclopentadienylaluminum chlorobutyl rubber and chlorinated poly(ethylene‐co‐propylene) (Cl‐EPM). Pendant CPD groups undergo Diels‐Alder/retro‐Diels‐Alder condensations yielding thermally reversible networks; e.g., a cyclopentadienylated Cl‐EPM was remolded three times to elastic sheets.
Factors affecting electrical conductivity of carbon black‐loaded rubber. II. Effect of concentration and type of carbon black on electrical conductivity of SBR
Authors: Abdel‐Bary E. M. , Amin M. , Hassan H. H.
Published: April 2003

Effect of the concentration of four types of carbon black, namely, HAF, FEF, ISAF and GPF, on the electrical conductivity of SBR (1502) was studied. The anomalous behavior of conductivity [σmin in σ(T) curves] becomes more pronounced as we approach a characteristic value of carbon concentration, F0, at which maximum anomaly occurs; F0 was found to depend on the type of carbon black. Moreover, the depth of the valley shape of the σ(T) curve increases with the particle size of carbon black used.
Statistical approach to the molecular weight distribution of condensation polymers
Authors: Orlova T. M. , Pavlova S.‐S. A. , Dubrovina L. V.
Published: April 2003

A mathematical linear polycondensation model in which the probability of bond formation depends on its index number and the limitation of molecular propagation were considered has been proposed. From this model a three‐parameter function of macromolecular weight distribution and degree of polymerization distribution of the macromolecules have been derived. Under certain conditions less common one‐ and two‐parameter functions can result. Two‐ and three‐parameter functions have been used in the description of experimental molecular weight distribution of polyarylate samples prepared under different conditions of synthesis. Theoretical functions conform to experimental data.
On the glass transition temperature of comblike polymers: Effects of side chain length and backbone chain structure
Authors: Reimschuessel H. K.
Published: April 2003

Polymers composed of monomer units that contain n‐alkyl side chains are characterized by a monotonical decrease in the glass transition temperatures toward a critical value (Tg)c as the number of C atoms in the side chain increases toward a corresponding critical value nc. Thus the glass transition temperatures of these comblike polymers are for a given backbone chain structure directly related to the molecular weight (M) of the monomer unit. This relationship can be represented by the differential equation dTg/dM = −k′M[Tg − (Tg)c], which on integration yields Tg = (ΔTg)0 exp−[k(M2 − M)] + (Tg)c, where (ΔTg) = (Tg)1 − (Tg)c, and the subscript 1 refers to n = 1. Values for Tg calculated according to this relationship are in good agreement with published data on polybutadienes, polystyrenes, poly(vinyl ether)s, polyacrylates, polymethacrylates, polyitaconates, poly(phenylene ether)s, and poly(N‐maleimide)s. For these polymers the critical quantities nc and (Tg)c can be estimated rather well by the simple relationships nc = 1 + 2.8 × 10−2 (Tg)1 and (Tg)c = (Tg)1 − nc(nc − 1). The Tg(M) relationship derived appears to be applicable also to copolymers that contain monomer units with alkyl side chains.
Criteria for diffusion limitation in coordination polymerization
Authors: Chien James C. W.
Published: April 2003

The following criteria are proposed to judge whether a coordination polymerization may be diffusion controlled or not: (1) If the number‐average molecular weight and polydispersity of the polymer calculated from kinetic rate constants as a function of time agree with the experimental values, the polymerization is not diffusion controlled. (2) The polymerization may be diffusion controlled if the Thiele modulus, the ratio of the characteristic diffusion time to the characteristic reaction time, is much greater than unity; if it is much smaller than unity, the polymerization is reaction controlled. (3) If an initial linear dependence of rate of polymerization on catalyst concentration changes over to a square‐root dependence, the polymerization may be diffusion limited. (4) The polymerization is likely to be diffusion limited if the instantaneous rate of polymerization is proportional to the rate of particle growth when the proportionality coefficient is the surface area of the particle. Criterion (1) is a necessary and sufficient condition as stated, as its converse is not true. All the other criteria are merely necessary but not sufficient conditions. The established Ziegler–Natta catalysts have activities too low to cause diffusion limitation; the Phillips catalyst system is likely to be diffusion limited. The polydispersity of polyolefins produced with Ziegler–Natta catalysts are not the consequence of diffusion control but are the characteristics of the catalysts in their kinetics of initiation, propagation, chain transfer, and termination.
Vibrational spectra and IR dichroism of poly(tetramethyl‐p‐silphenylene‐siloxane) and its chain structure
Authors: Dobos S. , Zelei B.
Published: April 2003

Raman spectra of poly(tetramethyl‐p‐silphenylene‐siloxane) were investigated in solution with depolarization ratios and in the solid state. Polarized infrared (IR) spectra were studied on oriented polymer samples. Assignments of the vibrational bands are given and IR dichroic and Raman data are in agreement with tetragonal P41 space group symmetry. These data provide information on the arrangement of the SiC6H4Si groups in the unit cell. On the basis of vibrational spectra the dynamic interaction between adjacent benzene rings is negligibly small and the rings preserve their local D2h Pseudosymmetry.
Polymerization of acrolein and methyl vinyl ketone induced by amine–water and pyridine–phenol systems
Authors: Yamashita Natsuki , Inoue Hiroshi , Maeshima Toshihisa
Published: April 2003

It was reported that acrolein (AL) in tetrahydrofuran (THF) polymerizes at temperatures below 0°C in the presence of pyridine (Py) and water. To clarify this polymerization mechanism the polymerization of AL and methyl vinyl ketone (MVK) by an initiation system such as Py–water, triethylamine (Et3N)–water, or Py–phenol(Ph) was carried out. The polymerization rate (Rp) of MVK in the Et3N–water system was expressed by the same equation, Rp = k [Et3N] [H2O] [MVK]2, used for AL in the Py–water system. Meanwhile, β‐hydroxypropionaldehyde, β‐phenoxypropionaldehyde, γ‐ketobutanol, and β‐phenoxy‐1‐methylpropionketone were obtained as the initial addition products. The polymer of AL obtained was composed of polymer units of vinyl and aldehyde polymerization, but the structure of MVK polymer obtained by the Py–water system was composed of only vinyl polymerization units. The polymerization of MVK by the Py–Ph system did not occur, however. These results were discussed in terms of the initiation and propagation mechanisms.
Anionic block copolymerization of ϵ‐caprolactam
Authors: Petit D. , Jerome R. , Teyssie Ph.
Published: April 2003

ϵ‐Caprolactam anionic homopolymerization was studied in the presence of different model activators. On the basis of the results ester‐ and isocyanate‐terminated polymers were used as macroactivators and nylon‐6–polyvinyl or polydiene block copolymers were synthesized in high yields. The physical properties and morphology of a nylon–polybutadiene triblock copolymer were characterized.
Syntheses of polymerizable viologens bearing a terminal vinyl group
Authors: Kamogawa Hiroyoshi , Mizuno Hideyuki , Todo Yasuto , Nanasawa Masato
Published: April 2003

Viologens that bore a terminal vinyl group were synthesized by four sequences of reactions: (1) N‐vinylbenzyl‐N′‐n‐propyl‐4,4′‐bipyridinium bromide chloride (V) was synthesized by the reaction of 4‐(4′‐pyrodyl)‐N‐n‐propyl pyridinium bromide (III) with vinylbenzyl chloride; (2) N‐β‐acrylamidoethyl‐N′‐n‐propyl‐4,4′‐bipyridinium dibromide (IX) was synthesized by the Menschutkin reaction of III with 2‐aminoethyl bromide hydrobromide and subsequent reaction with acryloyl chloride; (3) N‐β‐methacryloyloxyethyl‐N′‐n‐propyl‐4,4′‐bipyridinium dibromide and its analogs (XI) were synthesized by the reactions of III with the corresponding acyloxyalkyl bromides; and (4) N‐vinyloxycarbonylmethyl‐N′‐n‐propyl‐4,4′‐bipyridinium bromide chloride (XIII) was synthesized by the reaction of III with vinyl chloroacetate. With the exception of monomer XIII in which hydrolysis in large extent was observed during attempted polymerization, the synthesized monomers polymerized smoothly in aqueous solutions by a conventional radical procedure. Comparisons of the absorption peaks of the radical cations produced by reductions in aqueous solutions with those produced in films by ultraviolet (UV) irradiation indicate that the radical cations of polymers are associated intramolecularly in aqueous solutions.
Polymerizations of substituted cyclopropanes. II. Anionic polymerization of 1,1‐disubstituted 2‐vinylcyclopropanes
Authors: Cho Iwhan , Ahn Kwang‐Duk
Published: April 2003

Among the four 1,1‐disubstituted 2‐vinylcyclopropanes, diethyl 2‐vinylcyclopropane‐1,1‐dicarboxylate (Ia), 2‐vinylcyclopropane‐1,1‐dicarbonitrile (Ib), ethyl 1‐cyano‐2‐vinylcyclopropanecarboxylate (Ic), and 1,1‐diphenyl‐2‐vinylcyclopropane (Id), Ib and Ic polymerized well with sodium cyanide in N,N‐dimethylformamide. Ib was most reactive and a polymer (IIb) from Ib exhibited an inherent viscosity of 1.05 dl/g (concentration of 1.0 g in 100 ml of 95% H2SO4). All experimental results indicated that the polymerization proceeded by ring opening and that the structure of the polymers had pendant vinyl groups. The polymer IIc from Ic was soluble in common solvents like acetone, but IIb was soluble only in 95% H2SO4. Reactions of those compounds with benzenethiolate ion in ethanol yielded addition products that supported the ring‐opening polymerization of those monomers. In the postulated mechanism of polymerization cyanide ion attacks the carbon of a cyclopropane ring with electron‐releasing vinyl group and the resulting anion is thereby stabilized by two electron‐withdrawing substituents. The propagation takes place by the reaction of the anion with another monomer molecule.
Melamine–formaldehyde resins: Constitutional characterization by fourier transform 13C‐NMR spectroscopy
Authors: Tomita Bunichiro , Ono Hirokuni
Published: April 2003

The random chemical structures of melamine–formaldehyde resins, including methylated melamine–formaldehyde resins and urea–melamine formaldehyde resins, were investigated by 13C‐NMR spectroscopy (Fourier transform). All the combined formaldehydes, methylol and methyl ether groups, methylene structures, and dimethylene ether structures were assigned. A 13C chemical shift of methylene carbon occurred by substitution of other constituents of the methylene group for a proton of the adjacent monosubstituted nitrogen atom, as shown in a 13C‐NMR spectrum of urea–formaldehyde resins. It was found that the chemical shift of each corresponding carbon of both melamine resins and urea–melamine resins was almost superimposed with that of urea resins.
Copolymers of 2‐hydroxyethyl methacrylate and alkyl acrylates: Studies of molecular weight distribution and thermal behavior
Authors: Varma I. K. , Patnaik S.
Published: April 2003

Several copolymers of 2‐hydroxyethyl methacrylate (HEMA) with methyl acrylate (MA), ethyl acrylate (EA), n‐butyl acrylate (BA), and methyl methacrylate (MMA) were prepared at 70°C in nitrogen atmosphere using 0.2% (w/v) benzoyl peroxide as initiator. The copolymer composition was evaluated by estimation of hydroxyl group in the copolymers. Intrinsic viscosity of HEMA–EA, HEMA–BA, and HEMA–MMA copolymers was determined at 35°C in dimethyl formamide. Molecular weight distribution of copolymer samples was evaluated by gel permeation chromatography. Thermal behavior of the copolymers was investigated by dynamic thermogravimetry. Thermal stability decreased on increasing HEMA content in MA, EA, and BA copolymers. However, a reverse trend was observed in HEMA–MMA copolymers.