bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of polyamides from active diacyl derivatives of 3‐hydroxy‐1,2‐benzisoxazole and diamines under mild conditions
Authors: Ueda Mitsuru , Harada Toshiaki , Aoyama Shigeto , Imai Yoshio
Published: April 2003

New active diesters and diamides derived from 3‐hydroxy‐1,2‐benzisoxazole were prepared for use in polyamide synthesis. The active esters and amides reacted readily with amines to give quantitative yields of amides. The high reactivity to these active esters and amides was discussed in relation to the electon‐withdrawing effect of the leaving group and intramolecular general‐base catalysis. Solution polycondensation of new active diesters and diamides with aliphatic and aromatic diamines proceeded slowly under mild conditions to produce polyamides with inherent viscosities up to 1.5.
Photocrosslinking and thermal behavior of the polyesters containing conjugated diacetylenes
Authors: Patil A. O. , Deshpande D. D. , Talwar S. S. , Biswas A. B.
Published: April 2003

A series of polyesters containing conjugated diacetylenic groups in the polymer backbone were synthesized by interfacial condensation of 3,5‐hexadiyne‐1,6‐diol and diacid chlorides of succinic, glutaric, adipic, azealic, sebacic, terephthalic, and isophthalic acids. The polyesters were characterized by their infrared and ultraviolet absorption spectra, elemental analysis, and viscosity measurements. Powder x‐ray patterns indicated high degress of crystallinity. The polyesters were found to be highly photoreactive. The relative photoreactivities of the polyester films were determined by the adhesion method. Only small differences in the reactivity have been observed despite structural changes in the R group in the polymer backbone. Differential thermal analysis behavior of all polymers in the temperature range ambient to 300°C and isothermal behavior of HGI at two different temperatures have been studied.
Structure study of the furan–maleic anhydride copolymer
Authors: Ragab Yousif A. , Butler George B.
Published: April 2003

A structural study of furan–maleic anhydride copolymer (F–MAH) was undertaken to confirm its alternating nature and to determine its microstructure. The spectral properties of a model compound representing the alternating repeat unit, 2‐(2‐tetrahydrofuranyl)succinic anhydride, were compared with those of F–MAH. Their infrared (IR), 1H, and 13C nuclear magnetic resonance (NMR) spectra (after compensating for the absence of the olefinic double bond) were in good agreement with those of the copolymer. Furthermore, the observed splitting in the 1H‐ and 13C‐NMR spectra of F–MAH were assigned to cis–trans linkages on both the F and MAH units, with cis linkage being favored on both units, especially the former. The structure of 2,5‐dimethylfuran (DMeF)–MAH copolymer is similar to that of F–MAH copolymer, except that the preference of cis linkages is less pronounced. The structure of 2‐methylfuran (MF)–MAH copolymer is a complex structure with numerous 2,3‐furandiyl units. A mechanistic study was undertaken to elucidate the roles of F–MAH Diels–Alder adduct, and the charge‐transfer (CT) complex in the radical initiated copolymerization. The adduct reverted substantially to monomers under the reaction conditions; but, the amount of adduct remaining at equilibrium was quite appreciable; therefore, its participation could be ruled out on this basis alone. However, on polymerizing the adduct in the presence of F‐d4, the latter was incorporated into the copolymer to an extent indicative of free monomer exchange. Therefore, the adduct cannot be directly involved in the polymerization.
Use of 13C‐NMR in the study of reactions on crosslinked resins
Authors: Hodgkin J. H. , Willing R. I. , Eibl R.
Published: April 2003

Crosslinked poly(3,4‐pyrrolidinediylethylene)s with functional side chains that contain acid and ester groups were synthesized by a number of different methods and the structures of the various resins were compared by 13C‐NMR studies. The advantages and problems of this technique for structural determination of crosslinked polymers are compared with those methods normally used; for example, infrared (IR) and elemental analysis. Preliminary selective metal chelating abilities of the resins were determined.
13C‐NMR sequence analysis of polyesters from pentaerythritol and caprolactone
Authors: Newmark Richard A. , Runge Michael L. , Chermack Julie A.
Published: April 2003

Reaction of pentaerythritol (1) or dipentaerythritol with caprolactone yields prepolymers of the general structure

for i = 1, 2, 3, and 4 (2)‐(5). The 13C chemical shifts of the quaternary carbons in (1)‐(5) differ by more than 0.5 ppm. Conditions were determined to obtain quantitative intensity ratios of these carbons. The relative intensities give the distribution of the various branched structures and permit calculations of the average number of caprolactones per branch. Results are reported for caprolactone/polyol mole ratics of 3‐66.
Improved syntheses of benzils as polymer intermediates
Authors: Havens Stephen , Yu C. C. , Draney Dan , Marvel C. S.
Published: April 2003

Methods of synthesis of benzils were considered and some new combinations of old reactions were developed to make these materials more readily available as polymer intermediates.
Asymmetric selective polymerization of racemic methacrylates with the cyclohexylmagnesium bromide‐(−)‐sparteine system
Authors: Okamoto Yoshio , Urakawa Kazuhiko , Yuki Heimei
Published: April 2003

Asymmetric selective (or stereoelective) polymerization of various racemic methacrylates with cyclohexylmagnesium bromide (c‐HexMgBr)‐(‐)sparteine (1/1.2) catalyst was studied in toluene at −78°C. The methacrylates of α‐ethylbenzyl (EBMA), α‐isopropylbenzyl (i‐PBMA), α‐tert‐butylbenzyl (t‐BBMA), sec‐butyl (s‐BuMA), 1‐methylallyl (1‐MAMA), 2,3‐epoxypropyl (2,3‐EPMA), 2‐phenylpropyl (2‐PPMA), and menthyl (MentMA) alcohols were used as racemic monomers. In the polymerization of EBMA and i‐PBMA (S) enantiomers were consumed preferentially and the optical purity of initially polymerized i‐PBMA was as high as 97%. Optically pure (R) monomers were recovered at about 60% conversion for i‐PBMA and 80% for EBMA. In t‐BBMA, however, the (R) monomer was consumed preferentially over the (S) isomer. In the polymerization of s‐BuMA and 1‐MAMA (S) monomers were consumed in excess and the optical purity of the polymers formed in the early stage was about 30%. In 2,3‐EPMA and 2‐PPMA, which have asymmetric centers at the β position from the ester oxygen, (R) antipodes were more reactive. MentMA did not polymerize at −78°C. Enantiomer selectivity ratios rS and rR were determined in the polymerization of EBMA, i‐PBMA, and 1‐MAMA. All polymers except poly(t‐BBMA) were highly isotactic, but the tacticity of poly(t‐BBMA) could not be estimated. Circular dichroism spectra of optically active polymers of α‐substituted benzyl esters were measured.
Radical processes in polymer burning and its retardation. II. An ESR study of flame retardation of polypropylene
Authors: Tkáč A. , Špilda I.
Published: April 2003

Qualitative and quantitative free radical transformations between polypropylene alkyl radicals, oxygen, and brominated flame retardants in the molten and gaseous phases of thermally treated samples are described. By ESR technique it has been proved that, depending on the applied pressure during pyrolysis, highly reactive peroxy radicals or less reactive radicals of the retardant are formed. For flame‐retarded samples, compared with polypropylene without additives, the concentration of the primary alkyl radicals transferred from the molten to the gaseous phase is reduced by two orders of magnitude (from 7 × 1014 to 7 × 1012 spins/0.02 g), whereas the limiting oxygen index [LOI] is raised from 17–18% to 25–26%. The great variety of physical and chemical processes proceeding in molten polymer in the preflame zone and burning gaseous phase calls for use of different retardant types with a programmed release of Br and HBr with the temperature increase. The chain oxidation of the “fuel,” a product of the endothermic decomposition of polymer, determines the temperature of self‐ignition according to the number of initiating alkyl and allyl radicals formed per unit time; the [LOI] index depends more on the length of the kinetic chain of propagation reactions in the stationary process of oxidation at a given pressure.
Cationic copolymerization of β‐pinene and epichlorohydrin
Authors: Martínez F. , Gajardo I.
Published: April 2003

β‐Pinene and epichlorohydrin (ECH) have been copolymerized cationically using BF3(C2H5)2O and SnCl4 as catalysts. Polymerizations were carried out at −80°C in methylenechloride. Monomer reactivity ratios were determined in both catalysts which were r1(ECH) = 1.06 ± 0.15 and r2 (β‐pinene) = 0.32 ± 0.08 in BF3(C2H5)2O and r1(ECH) = 0.33 ± 0.11 and r2(β‐pinene) = 2.03 ± 0.44 in SnCl4. Copolymers of different composition were soluble in acetone and insoluble in methanol. This characteristic was taken to indicate that the polymeric products were real copolymers and not a mixture of two homopolymers of epichlorohydrin and β‐pinene.
Production of a poly(pyridinyl radical) by reduction with 1‐benzyl‐1,4‐dihydronicotinamide and N,N′‐dicyclohexylalloxan
Authors: Endo Takeshi , Okawara Makoto
Published: April 2003

It was found that 1‐ethyl‐4‐carbomethoxypyridinium iodide could be reduced by 1‐benzyl‐1,4‐dihydronicotinamide (BNAH) and N,N′‐dicyclohexylalloxan (DCA) to give 1‐ethyl‐4‐carbomethoxypyridinyl radical. The stable poly(pyridinyl radical) (P‐III) was obtained in a similar manner by the reduction of poly(pyridinyl salt) (P‐II).
Emulsion polymerization and copolymerization of vinyl benzoate
Authors: Plavljanić B. , Janović Z.
Published: April 2003

Emulsion polymerization of vinyl benzoate and its copolymerization with vinyl acetate or styrene are described. The effect of the potassium persulfate initiator, and the sodium lauryl sulfate emulsifier concentration on the rate of vinyl benzote homopolymerization and the molecular weight of the polymers was determined. In copolymerization with vinyl benzoate, both comonomers, vinyl acetate and styrene, decrease the initial polymerization rate. With increasing amounts of styrene in the comonomer mixture the polymerization rate increases but with vinyl acetate an opposite effect is observed. Reactivity ratios of copolymerizations were determined. For the vinyl benzoate [M1]‐styrene [M2] comonomer system a r1 = 0.03 and a r2 = 29.58 and for vinyl benzoate [M1]‐vinyl acetate [M2], a r1 = 1.93 and a r2 = 0.20 was obtained. From the vinyl benzoate‐styrene reactivity ratios the Qe parameters were calculated.
Sequence distributions of vinyl chloride‐vinyl acetate and vinyl chloride‐vinyl propionate copolymers
Authors: Okada Tadashi , Hashimoto Kazue , Ikushige Tetsuo
Published: April 2003

13C‐NMR spectroscopy was used in a detailed study of vinyl chloride‐vinyl acetate and vinyl chloride‐vinyl propionate copolymers. The NMR spectra of the methylene carbon region showed three split peaks whose intensities changed with composition of the copolymers. These peaks were assigned to diad sequences and the observed diad concentrations were in good agreement with the calculated concentrations in terms of the random copolymerization theory. For the methine carbon spectra of vinyl acetate or vinyl propionate units in the copolymers the degree of splitting of the signal was improved by the addition of tris(1,1,1,2,2,3,3‐heptafluro‐7,7‐diemthyl‐1,4,6‐octanedinata)‐praseodymium as a shift reagent. Four peaks assigned to the methine carbon were interpreted in terms of triad sequence distribution and tacticity.
Cationic oligomerization of anethole: Selective synthesis of dimers and trimers
Authors: Higashimura Toshinobu , Hiza Misao
Published: April 2003

A linear unsaturated dimer of anethole [II, (E)‐1,3‐bis(p‐methoxyphenyl)‐2‐methylpentene‐1], was prepared in 98% yield with an acetyl perchlorate (AcClO4) catalyst in a nonpolar solvent (C6H6) at a high temperature (70°C). At 0°C a linear unsaturated trimer was formed in high yield with dimer II. The geometric structure of the linear unsaturated dimers was determined by analysis of the nuclear Overhauser effect (NOE) on their 1H‐NMR spectra. NOE analysis showed that at 0°C with AcClO4, trans‐anethole gives the (E)‐form (II), whereas cis‐anethole yields the (Z)‐form. On the other hand, with a metal‐halide catalyst (BF3OEt2) a cyclic dimer and a cyclic trimer were produced in high yields in a polar solvent [(CH2Cl2)] at 70°C; higher oligomers (≥ tetramer) were scarcely formed. The effect of catalysts on the structure of oligomers was explained in terms of the interaction between a growing carbocation and a counterion.
Preparation of polystyrene with long chain branches via free radical polymerization
Authors: Tung L. H. , Hu A. T. , McKinley S. V. , Paul A. M.
Published: April 2003

Polystyrene with random long chain branches has been difficult to prepare. A new approach using small amounts of chain‐transferring monomers to copolymerize with styrene free radically was examined in this work. Of the several comonomers examined, vinylbenzylthiol yielded polystyrene with branched structure. But because of the high chain trnsfer constant, the branches occurred mainly in the low‐molecular‐weight end of the distribution. As a side interest, vinylbenzylthiol was found to be an effective agent for the broadening of molecular weight distribution.
Polymers with improved flammability characteristics. II. Phenolphthalein related copolycarbonates
Authors: Lin M. S. , Pearce E. M.
Published: April 2003

Analysis of phenolphthalein and bisphenol‐A copolycarbonates reveals a linear correlation between oxygen index (OI) and char yield (Y): OI = 0.34Y + 19.6, which can be compared with the empirical equation QI = 0.4Y + 17.5 proposed by D. W. Van Krevelen for other polymers. Analysis also suggests that no chemical interction occurs between the two comonomers during pyrolysis, which leads neither to enhanced char yield nor to enhanced oxygen index. Each copolymer component contributes to the char yield and oxygen index on an additive basis. Study of 4,5,6,7‐tetrabromophenolphthalein and phenolphthalein copolycarbonates shows that some enhancement of char yield does occur and that the lower the char yield, the higher the oxygen index, which is an indication of the predominance of a vapor‐phase bromine effect over that related to char. Study of 4,5,6,7‐tetrabromophenolphthalein and bis‐phenol‐A copolycarbonates is interpreted on the basis of two factors—the char effect that prevails over the vapor phase radical scavenging effect at lower bromine content and the reverse order at higher bromine content.
Preparation and properties of aromatic polypyrazoles from linear bis‐β‐diketones and aromatic dihydrazines
Authors: Imai Yoshio , Nakajima Toshio , Ueda Mitsuru
Published: April 2003

The cyclopolycondensation of linear bis‐β‐diketones with aromatic dihydrazines in dimethyl sulfoxide at 100–150°C produced a series of aromatic polypyrazoles with inherent viscosities up to 0.6 dL/g. All the polymers were highly soluble in a wide range of solvents, which included tetrahydrofuran and chloroform. The polypyrazoles showed excellent thermal stability with 10% weight loss at 410–490°C in air and nitrogen atmosphere.
Linear polythioesters. V. Products of interfacial polycondensation of 4,4′‐di(mercaptomethyl)‐benzophenone with some aliphatic acid dichlorides
Authors: Podkoscielny Wawrzyniec , Kultys Anna
Published: April 2003

New polythioesters by interfacial polycondensation of 4,4′‐di(mercaptomethyl) benzophenone with oxalyl, succinyl, adipoyl, suberoyl, and sebacoyl chlorides were obtained. To determine the optimal conditions for interfacial polycondensation the influence of the following factors on yield and value of reduced viscosity were studied: type of organic phase, the quantitative ratio of aqueous and organic phase, concentration of hydrogen chloride acceptor, molar ratio of reagents, temperature of reaction, rate of acid chloride addition, and contribution of catalyst and emulsifier. A thorough examination was carried out only for polycondensation of dithiol with adipoly and sebacoyl chlorides. The structure of all polythioesters obtained under the model conditions was determined by elementary analysis and infrared spectra. Initial decomposition and initial intensive decomposition temperature were defined from the curves of thermogravimetric analysis. Some mechanical and electrical properties of the polythioesters obtained from 4,4′‐di(mercaptomethyl)benzophenone and adipoyl and sebacoyl chlorides were determined. The molecular weight was not measured because of the low solubility of the obtained polythioesters.
15N‐NMR spectroscopy 32. Synthesis and characterization of polyelectrolytes based on polyaminamides
Authors: Kricheldorf Hans R.
Published: April 2003

The titrations of the polyammamides prepared from adipic acid and diethylenetriamine or di(3‐aminopropyl)methylamine were monitored by means of natural‐abundance 15N‐(NMR) nuclear magnetic resonance spectra. Opposite shift effects were found for amine and amide nitrogens upon protonation of the amino groups. These shift effects allow one to distinguish substitutions involving exchange of electric charges from other substitutions without isolation of the polymers. Reactions of the polyaminamides with β‐propiolactone, γ‐butyroslution, methyl‐methane sulfonate, prolyleneoxide, epichlorohydrine, maleic acid anhydride, succinic acid anhydride, carbon dioxide, ethylchloroformate, and methyne sulfonylchloride were carried out in water, and the resulting polyelectrolytes were characterized by means of 15N‐NMR spectra.
Formation and thermal‐induced decay of radical ions in polymer matrices
Authors: Torikai Ayako , Mishina Hitoshi
Published: April 2003

The formation of radical ions in γ‐irradiated polymethyl‐methacrylate (PMMA) matrices at 77°K and thermal‐induced reaction of these radical ions were of studied by optical absorption spectroscopic measurements. The radical ions of stilbene and pyrene were investigated. These radical ions decay according to second‐order kinetics, which means that the neutralization reaction of the cationic species and anionic species participates in the decay process. The kinetic plots consist of two straight lines; that is, fast and slow decay processes are concerned. The activation energies were estimated to be Efast = 2.4 kcal/mol and Eslow = 6.4 kcal/mol, respectively. The probability of recombination reaction depends on the distance between cationic and anionic species.
Spectral and thermodynamic studies of the interaction of binding site probes with poly(vinylpyrrolidone)
Authors: Reeves Richard L. , Harkaway Shelley A. , Sochor Alena R.
Published: April 2003

The binding of two ionic azo dyes (4‐phenylazo‐1‐naphthol mono‐and disulfonate) and a fluorescent probe (2‐p‐toluidinonaphthalene‐6‐sulfonic acid, TNS) to poly(vinylpyrrolidone) (PVP) was studied to obtain information on the nature of the interaction, binding isotherm, and binding site. Sorption of the dyes followed a Langmuir isotherm only at low polymer saturation. Apparent cooperativity in binding was seen at higher saturation. The polymer had a higher intrinsic binding constant but lower binding capacity for the doubly charged dye than for the structurally similar singly charged dye. Both dyes consisted of tautomeric mixtures of hydrazone and azonaphthol forms in equilibrium in the bound and unbound state. The preferential binding of the azonaphthol tautomer of the disulfonate was highly exothermic and accompanied by an entropy decrease. The binding of the hydrazone form was less favored by 1.8 kcal/mol, was weakly exothermic, and accompained by an entropy increase. Increased preference for the azonaphthol tautomer accompanied chain extension from charging the polymer. Chain extension had no effect on the emission frequency of bound TNS. Large differences in binding capacities for similarly charged dyes indicated the existence of specific dye‐site interactions. Arguments are presented against nonspecific hydrophobic interactions as predominant forces responsible for binding.
Photopolymerization initiated by charge‐transfer complex. I. Photopolymerization of methylmethacrylate with the use of quinaldine‐bromine and lutidine–bromine charge‐transfer complexes as photoinitiator
Authors: Mishra Munmaya K. , Lenka Subasini , Nayak Padma L.
Published: April 2003

Photopolymerization of MMA was carried out with quinaldine–bromine (QN–Br2) and lutidine–bromine (LU–Br2) charge‐transfer complexes as initiators. The rate of polymerization Rp increased with rising monomer concentration and the monomer exponent was computed as unity. At first the rate of polymerization accelerated and then reduced as the initiator concentration was increased. The initiator exponent was 0.5. The reaction was carried out at three different temperatures and overall activation energy was calculated at 4.0 kcal/mol. The kinetic data and other evidence indicate that the overall polymerization takes place in a radical mechanism. A suitable mechanism is suggested.
Thermomechanical trnasitions in polyphosphazenes
Authors: Choy I. C. , Magill J. H.
Published: April 2003

Unoriented and oriented samples of two phosphazene homopolymers with chemical structure [NPX2]n, where X = CF3CH2O and p‐CH3C6H4O, and three unfilled and filled alkoxy‐type polyphosphazene copolymers, plus one filled aryloxy‐type copolymer were examined with a Rheovibron viscoelastometer. Measurements were made from −120°C to temperatures above the T(1) transition of the respective polymers. The effects of orientation and repeated temperature cycling through the T(1) transition temperatures were studied. The overall physical behavior of these polyphosphazenes was dominated by changes that occurred in the primary softening dispersion and the mesomorphic or T(1) transition region. The enthalpy of the T(1) transition and the T(1) temperature were investigated by differential scanning calorimetry (DSC) as a function of temperature cycling in the T(1) region; for instance, the change in enthalpy in the T(1) region is about an order of magnitude larger than it is at Tm for the unfilled polyphosphazene homopolymers. The Tg's of the polyphosophazenes were also determined. Density measurements were made on oriented and unoriented specimens by the flotation method. Although an increase in density (and crystallinity) was observed when specimens were cycled through the T(1) transition, no significant difference in density was found between oriented and unoriented materials. Some discussion of the molecular origin of the T(1) transition is included.
Polymerization of cyclohexene oxide with Al(acac)3‐silanol catalyst supported by zeolite and porous silica
Authors: Hayase S. , Ito T. , Suzuki S. , Wada M.
Published: April 2003

The polymerization of cyclohexene oxide with Al(acac)3‐silanol catalyst supported by zeolite and porous silica has been investigated. Cyclohexene oxide was also polymerized to a lesser extent by a zeolite‐silanol catalyst and an Al(acac)3‐silica gel catalyst. The catalytic activity of the zeolite‐silanol system varied with the zeolite pore size. The catalytic activity of the Al(acac)3‐silanol system was enhanced by supporting the catalyst with porous silica or zeolite. The Al(acac)3‐silanol catalyst supported by zeolite was especially effective in increasing polymer conversion and molecular weight. Catalytic activity increased with increasing chemical interaction between silanol and porous silica. The molecular weight of the polymers with these catalysts increased in the order zeolite‐silanol> zeolite‐Al(acac)3‐silanol >Al(acac)3‐silanol ≈ Al(acac)3‐silanol supported by porous silica>Al(acac)3‐silica gel.
Thermal degradation of poly[(tetramethyl‐p‐silphenylene) siloxane]
Authors: Ikeda Masao , Nakamura Takashi , Nagase Yu , Ikeda Koji , Sekine Yoshiro
Published: April 2003

For the purpose of studying the mechanism of thermal degradation of poly[(tetramethyl‐p‐silphenylene) Siloxane] (poly TMPS) a series of polymers with silphenylene and siloxane bonds in the main chain were prepared and subjected to thermogravimetry (TG) and pyrolysis study. Analyses of products from poly TMPS degradation (in vacuum at a constant temperature) by gas chromatography (GC), infrared (IR), nuclear magnetic resonance (NMR) spectroscopy, and gas chromatography‐mass spectrometry (GC–MS) revealed that degradation occurs at the silphenylene bonds. The TG curves obtained in He for heating rates of 1,2,2.5,7.5, and 10°C/min were analyzed by the Ozawa method; activation energies of 39 ± 1 and 45 ± 2 kcal/mol were obtained respectively for the initial cleavage of the methyl side group and the later‐stage scission of the main‐chain silphenylene bond which leads to a major weight loss. The results agree with those obtained for other structurally similar polymers.
Dye‐sensitized photopolymerization. I. Photopolymerization of ethyl acrylate by sodium fluorescein‐ascorbic acid system in aqueous solution
Authors: Lenka Subasini , Nayak Padma L. , Mishra Munmaya K.
Published: April 2003

The kinetics of the polymerization of ethyl acrylate (EA) sensitized by dye‐reducing agent systems were investigated. The redox system sodium fluorescein‐ascorbic acid was used for the polymerization. The systems were buffered with phosphate buffer, and the effects of monomer, dye, temperature, etc., on the reaction system were investigated. The polymerization was followed by measurement of monomer disappearance (gravimetrically) and the chain length of the polymer formed (viscometrically). In the light of the experimental results a suitable kinetic scheme was proposed and the composite rate constants were evaluated.
Cationic polymerization by aromatic initiating systems. IV. Synthesis and characterization of α‐ω‐diphenylpolyisobutylene
Authors: Kennedy Joseph P. , Chung David Y. L.
Published: April 2003

The polymerization of isobutylene using ø3Al coinitiator and the tertiary chlorides tert.‐butyl chloride (t‐BuCl) and 2,6‐dichloro‐2,6‐dimethylheptane (Clt‐R‐Clt) initiators has been studied. Polymerization rates with the t‐BuCl/ø3Al and Clt‐R‐Clt/ø3Al initiating systems were high in the −20 to −70°C range. Yields and molecular weights increased with decreasing temperature. As predicted by model experiments the extent of phenylation increases with decreasing temperatures. According to spectroscopic evidence the polyisobutylenes carry phenyl end groups.
Cationic polymerizations by aromatic initiating systems. V. Oxidation and chlorination of α,ω‐diphenylpolyisobutylene and subsequent reaction with living polystyrene anions to form block copolymers
Authors: Kennedy Joseph P. , Chung David Y. L. , Guyot Alain
Published: April 2003

α,ω‐Diphenylpolyisobutylenes produced by the Clt‐R‐Clt/ø3Al initiating system have been derivatized. Model chloromethylation of t‐butylbenzene by CH3OCH2Cl in chloroform indicated that beyond ca. 35% yield significant alkylative side reactions occurred. Phenyl end groups (average 1.5 per chain) and unsaturated chain ends (from proton elimination) have been converted to carboxyl end groups by oxidation with RuO4 in chloroform. Subsequently the carboxyl end groups were converted to acyl chloride termini by reaction with SOCl2. The latter end groups were coupled with living polystyryl anions to form isobutylene‐styrene blcok copolymers.
Synthesis of polyphthalimidines with benzylidene group from aminophthalide monomers
Authors: Imai Yoshio , Takahashi Takeyoshi , Ueda Mitsuru
Published: April 2003

Two aminophthalide monomers, 6‐amino‐3‐benzylidenephthalide (I) and 3‐(p‐aminobenzylidene)phthalide (II), underwent self‐polycondensation in o‐phenylphenol at 250°C to yield polyphthalimidines with inherent viscosities up to 0.5 dL/g. These polymers were readily soluble in a variety of solvents such as dimethylformamide, dimethyl sulfoxide, m‐cresol, pyridine, and methylene chloride. The temperatures at which a 10% weight loss occurred by thermogravimetry in nitrogen were 460°C for the polymer derived from I and 490°C for the polymer from II. The glass transition temperature of the polymer from I was 332°C, determined by thermomechanical analysis.
Poly[trans‐1‐(3‐vinyl‐9‐carbazolyl)‐2‐(9‐carbazolyl)cyclobutane]. Synthesis and comparison with poly(9‐ethyl‐3‐vinylcarbazole)
Authors: Inoue Takashi , Tazuke Shigeo
Published: April 2003

Trans‐1‐(3‐vinyl‐9‐carbazolyl)‐2‐(9‐carbazolyl)cyclobutane(I) was synthesized. Homopolymerization of I and copolymerization with 9‐ethyl‐3‐vinylcarbazole(II) were conducted cationically. It was found that I polymerized to high molecular weight polymers (< 105) with good yields, although its polymerizability was lower than that of II. Copolymer composition was determined by gel permeation chromatology (GPC) analysis, based on the remaining monomer ratio. Fluorescence spectroscopy indicated that poly(I) did not form excimer. Excimer emission gradually appeared with increasing II content in poly(I‐co‐II) to the homopolymer of II. This difference between poly(I) and poly(II) was attributed to the crowded and sterically distorted chromophore assemblies in poly(I). 1H‐ and 13C‐NMR spectroscopy of cyclobutane groups in poly(I) compared with that in the monomer model compound supported the conclusion derived from fluorescence study.
Cationic polyelectrolytes. III. Nitrile‐group reaction of macromolecular compounds with N,N‐dialkylaminoalkylamines
Authors: Drăgan Stela , Bărboiu V. , Petrariu I. , Dima M.
Published: April 2003

The chemical reaction in aqueous medium of polyacrylonitrile and acrylonitrile–vinyl acetate co‐polymer using asymmetrical diamines of H2N(CH2)mNR2 (m = 2,3) structure was studied. It was found that the nitrile group is modified to an dialkylaminoalkylacrylamide group; also determined were the reaction conditions required to obtain the highest degree of chemical transformation of the nitrile groups. All modified compounds were characterized by analytical spectroscopy (IR and 1H NMR) and by rheological methods. It was also established that glutaronitrile can be used as a low‐molecular‐weight model to study the chemical transformation of nitrile groups in polyacrylonitrile and related polymers.
4‐Alkoxy‐2‐hydroxy‐4′‐vinylbenzophenones, ultraviolet‐absorbing monomers
Authors: Kamogawa Hiroyoshi , Takayanagi Yoko , Nanasawa Masato
Published: April 2003

2,4‐Dihydroxy‐4′‐vinylbenzophenone (I) and its 4‐alkyl ethers (II), Me, Et, n‐Bu, n‐Oct, and n‐dodecyl, were prepared in three steps by Hoesch synthesis, starting with p‐(2‐bromoethyl) benzonitrile and resorcinol and its monoalkyl ethers. I and its precursor 2,4‐dihydroxy‐4′‐(2‐bromoethyl) benzophenone were also converted into their 4‐alkyl ethers with alkyl halides in dimethylformamide (DMF) in the presence of sodium hydrogen carbonate. Copolymerizations of I and II with styrene took place smoothly with satisfactory conversions to yield copolymers with ε‐values around 104 L/mol cm−1 per benzophenone unit over the ultraviolet (UV) range of 235–340nm.
Polymerization of cyclohexene oxide with aluminum complex‐silanol catalysts. Part III. Dependence of catalytic activity on bulkiness of silanol and its intramolecular hydrogen bond
Authors: Hayase S. , Ito T. , Suzuki S. , Wada M.
Published: April 2003

Polymerization of cyclohexene oxide, especially the catalytic activity influenced by silanol structure, was examined by using an Al(acac)3–silanol compound catalyst. The catalytic activity increased as the acidity of silanol increased. It was prolonged by sterically hindered silanol compounds which prevented the silanol from self‐condensation and from joining with the epoxide. In addition, the greater catalytic activity produced by intramolecular hydrogen‐bonding silanol compounds is explained by the polymer effect.
Emulsifier‐free emulsion polymerization with cationic comonomer
Authors: Liu Li‐Jen , Krieger Irvin M.
Published: April 2003

An earlier article1 described the emulsion polymerization of styrene and various anionic comonomers, together with an anionic initiator, to give uniform latices at ca. 35% solids content. This article extends the work to cationic systems. Cationic comonomers 1,2‐dimethyl 5‐vinylpyridinium methylsulfate and 1‐ethyl 2‐methyl 5‐vinylpyridinium bromide were synthesized and used with azobis(isobutyramidine hydrocholoride) initiator in the emulsifier‐ free emulsion polymerization of styrene. Recipes and results were generally comparable to those of the anionic systems, excepts for the dependence of particle diameter on comonomers concentration. Here the initial decrease was followed by an increase in particle diameter at higher comonomer content. The surface charge increased sharply with comonomer content.
Surface reaction of particulate silica with polydimethylsiloxanes
Authors: Yu‐Fu Li , Yong‐Xia Xia , Dong‐Peng Xu , Guang‐Liang Li
Published: April 2003

The interaction of silica and oligomeric methylsiloxanes, methylsilicone oil as well as silicone gum at elevated temperature was studied. It was found that a reaction takes place between surface silanols and octamethylcyclotrasiloxane (D4) above 180°C. Part of the methylsiloxane replaces the surface silanols forming loops with the surface, while the other part is redistributed to its neighboring homologoues. The methylsiloxy surface groups thus formed can undergo further reaction with the other methylsiloxanes above 250°C. Methylsilicone oil behaves similarly. The reaction with silicone gum was demonstrated by the formation of “chemically bound rubber.” The mechanism of the reaction is discussed.
Diethylzinc/metal salt initiator systems. I. Stereospecific polymerization of N‐vinylcarbazole by ZnEt2/CoCl2‐quinoline
Authors: Biswas Mukul , Mishra Girish Chandra
Published: April 2003

In the presence of ZnEt2 the CoCl2‐quinoline complex polymerizes NVC with a rate increasing with ZnEt2 and CoCl2‐Q concentrations up to a certain concentration of ZnEt2 or CoCl2‐Q, thereafter becoming independent of either. At a fixed concentration of ZnEt2 and CoCl2‐Q the rate is second order with respect to NVC. The poly(NVC) obtained is freely soluble in benzene but leaves some insoluble fraction in methyl ethyl ketone, which has been characterized by 13C‐NMR to be a stereoblock polymer. X‐ray diffraction, IR, and thermal characteristics of the polymer have also been reported. [η] is virtually independent of monomer, in the concentration range 0.1–0.25 mol/L ZnEt2 and CoCl2‐Q concentrations. Oxygen as an additive inhibits the polymerization. A cationic coordination mechanism has been proposed and appropriate rate and degree of polymerization equations have been suggested.
Kinetics of polyesterification. I. Dibasic acid and glycol systems
Authors: Chen Show‐An , Hsiao Jui‐Chung
Published: April 2003

Polyesterification of diacid and diol in the absence of foreign acid is carried out under constant reaction temperatures from 140 to 180°C (rather than under constant oil bath temperature as is usually done) and molar ratios r of diol to diacid from 1 to 3.55. The experimental data obtained cannot fit conventional rate equations as they appear in the literature. Based on ion pair formation and considering additional proton transfer from acid to alcohol, we propose a reaction mechanism and rate equations. The rate equation is found to fit our experimental data very well except for r = 1. At r = 1, the kinetic plot shows two straight lines rather than one as predicted. This is attributed to unremoved water due to the higher molecular weight (and therefore higher viscosity) at r = 1 which causes a reverse reaction and slower apparent reaction rate.
Binding of methyl orange and its homologs by polyion complexes in aqueous solution
Authors: Takagishi Toru , Kozuka Hiroshi , Kuroki Nobuhiko
Published: April 2003

Polyion complexes of sodium poly(methacrylate) and piperidinium cationic polymers [I], which are insoluble in water and have an equal number of positive and negative charges, bind organic anions (methyl orange, ethyl orange, propyl orange, butyl orange, and pentyl orange) in aqueous solution. The strength of the binding is enhanced by an increase in the hydrophobicity of the polyion complex and the small cosolute. Moreover, strong cooperative interactions appear with increased uptake of the small molecule. Urea and an inorganic electrolyte (KCl) were examined for their effect on the binding, the amount of which is strongly suppressed by these additives. The significance of hydrophobic and electrostatic interactions which accompany the binding is described.
Synthesis and DSC study of model hard segments from diphenyl methane diisocyanate and butane diol
Authors: Camberlin Y. , Pascault J. P. , Letoffe J. M. , Claudy P.
Published: April 2003

Model hard segments having different chain length and chain terminating groups, such as methyl, ethyl, octyl, and octadecyl, have been synthesized from diphenyl‐methane diisocyanate (MDI) and butanediol and studied by DSC. In the case of short chain ends (i.e., methyl, ethyl, and octyl), hard segments having up to three MDI units show an increase of melting temperature Tm, while those with octadecyl chain end have Tm increase continuously with the number of MDI units. Enthalpy and entropy decrease with the augmentation of the hard‐segment length. Side groups on the chain ends have a great influence on the melting properties.
New processable polyaromatic keto‐sulfones with internal acetylene units
Authors: Lin See , Kriek George R. , Marvel C. S.
Published: April 2003

Polyaromatic ketone‐sulfones of high molecular weight have been obtained from bis‐(3‐carboxyphenyl) acetylene dichloride, isophthaloyl chloride, terephthaloyl chloride, and 4,4‐diphenoxydiphenyl sulfone in a Friedel‐Craft‐type polycondensation. The polymer products are white powders and form transparent, strong films. These polymers could be reacted by Diels–Alder cycloaddition with 1,4‐diphenyl‐1,3‐butadiene. These polymers showed only a very slight increase in viscosity over those that were not reacted with diphenylbutadiene.
Decomposition of polypropylene hydroperoxide by hindered amines
Authors: Carlsson D. J. , Chan K. H. , Durmis J. , Wiles D. M.
Published: April 2003

The hindered amine‐induced decomposition of polypropylene hydroperoxide was studied in the solid state and in the presence of a liquid solvent and the polymer was compared with model hydroperoxides. The high reactivity of the macrohydroperoxides appears to be related to the adjacent, hydrogen‐bonded hydroperoxide groups that occur in the polymer. The hindered amines are converted to nitroxides in the reaction via hydroxylamine intermediates. Amine‐induced decomposition of polypropylene hydroperoxide is faster in the absence of a liquid solvent for the amine than in the presence of the solvent, probably because of the strong amine‐hydroperoxide association that occurs in the solid state. The decomposition process in the solid state is sufficiently rapid for the reaction to contribute to the effectiveness of hindered amines in the light stabilization of polymers.
Coordination polymers. XIII. Synthesis and investigation of polymers obtained by the reaction of maleic acid with ZnO
Authors: Vancso‐Szmercsanyi I. , Kallo A.
Published: April 2003

In some cases metal dicarboxylates can be considered as polymers. Formation of crystalline or amorphous polymer depends on the type and ratio of the metal ion to the carboxylate ligand and on the preparation conditions. The “polymer salt” synthesized by the reaction of ZnO and maleic acid shows special feature due to the cis configuration of the dicarboxylic acid. The polymer prepared in a water medium has a fibrillar morphology with a helical structure which is changed by heat treatment: a molecular rearrangement takes place which leads finally to amorphous polymer. The reaction of ZnO and fumaric acid (trans configuration) results in monocrystals containing crystal water or, after heat treatment, in powderlike polymer.
Emulsion polymerization of styrene. I. Review of experimental data and digital simulation
Authors: Bataille P. , Van B. T. , Pham Q. B.
Published: April 2003

Isothermal emulsion polymerization at 60°C of styrene in a batch reactor were studied by using sodium lauryl sulfate as surfactant and potassium persulfate as initiator source. The concentrations of surfactant and initiator were varied during the runs. The polymerization evolution was followed as samples were taken at regular intervals. These emulsion samples were analyzed for monomer conversion, rate of polymerization, as well as for the size and the size distribution of the particles. The molecular weight and molecular weight distribution were obtained by gel permeation chromatography. Our study showed that fresh nucleation takes place even at high conversion, causing a continuous shifting toward broadening of particle size distribution. Contrary to the theory of Smith and Ewart, which assumes a constant number of particles during interval II of the polymerization reaction, our digital simulation of the reaction presents better experimental results with a variable number of particles, and indicates that the Hui–Hamielec model for termination constant kt as function of conversion is not applicable under our working conditions.
Emulsion polymerization of styrene. II. Effect of Ag(I) and Fe(II) on the polymerization of styrene initiated by potassium persulfate
Authors: Bataille P. , Van B. T. , Pham Q. B.
Published: April 2003

The emulsion polymerization of styrene initiated by potassium persulfate catalyzed by Ag(I) and/or ferrous ions Fe (II) was studied. It was found that silver ions in conjunction with potassium persulfate accelerate the polymerization of styrene. Ferrous ions reduce the polymerization rate by termination reaction with primary radicals. Both silver ions and ferrous ions act as transfer agents with the result of lowering of the average molecular weight of the polymer.
Sulfonation and subsequent rections of ethylidene norbornane and dihydrodicyclopentadiene. The chemistry of some small molecule models for EPDM rubbers
Authors: Thaler Warren A.
Published: April 2003

Ionomers prepared by the sulfonation of EPDM rubbers have been the subject of considerable investigation with regard to their remarkable bulk and solution properties; however, relatively little is known about the chemistry of the sulfonation and the structure and subsequent reactions of the sulfonated intermediates. This article reports an effort to enlarge our understanding of sulfonate ionomers by examining the chemistry of small molecule analogs of the olefinic sites which are present in low concentrations in EPDMs. Ethylidene norbornane (ENBH) and dihydrodicyclopentadiene (DCPDH) were synthesized as models for EPDMs which use ethylidene norbornene and dicyclopentadiene as their respective termonomers. The sulfonated products from the two models were quite different, a sultone with a rearranged carbon skeleton being formed in the former case and a remarkable regiospecific sulfonic acid in the latter. Conditions necessary for hydrolysis and ammonolysis were established, the former proceeding essentially by a substitution mechanism, the latter via a retro‐Wagner Meerwein elimination. Rate studies showed the importance of solvent effects in these sulfonation reactions which were attributed to a combination of site reactivity and acetylsulfate solubility. Mixed solvents were effective in improving reactivity while maintaining the solvency necessary for EPDM polymers. The results of this model study are being used as a guide in studies of EPDM polymers.
Radiation‐induced graft copolymerization of mixtures of styrene and acrylamide onto cellulose acetate. I. Effect of solvents
Authors: Bhattacharyya S. N. , Maldas D.
Published: April 2003

The grafting of styrene and acrylamide, from both their binary and unitary systems, on cellulose acetate film was studied by means of the cobalt‐60 postirradiation grafting technique. The extent of grafting was found to be dependent on preirradiation dose, reaction time, and temperature, and the optimum conditions were evaluated. The effect of solvents, e.g., water, methanol, ethanol, isopropanol, and t‐butanol were studied. The composition of the binary mixture as well as the nature of the alcohol used as the solvent were found to have a strong influence in modifying the course of grafting. Each component of the binary monomer mixture was found to sensitize the grafting of the other, when the former is present in relatively large concentration. The observed results are discussed in detail in terms of relative molecular reactivity and reactivity ratios.
Synthesis of a polycarbonate by reaction of carbon dioxide, dipotassium 4,4′‐isopropylidenediphenolate and α,ω‐dihalo compounds
Authors: Rokicki Gabriel , Kuran Witold , Kiełkiewicz Jȩdrzej
Published: April 2003

To study the possibility of obtaining aliphatic‐aromatic polycarbonates the reactions of CO2, dipotassium 4,4′‐isopropylidenediphenolate, and different α,ω‐dihalo compounds were studied in polar aprotic solvents in the presence of various catalysts. It was shown that in addition to the crown ethers already in use as catalysts in this type of polycondensation reaction cryptates and polyglyme exhibit similar catalytic activity. The influence of temperature, CO2 pressure, solvent, and structure of the α,ω‐dihalo compound on the yield of the polymer formed was established. A relationship between the type and amount of catalyst used, especially crown ether, on the reaction yield was revealed, and some physicochemical properties of the polymers obtained were determined. Studies of the model reaction between CO2, potassium phenolate, and different α,ω‐dihalo compounds under conditions analogous to those of the studied reaction were carried out. On the basis of the results obtained attempts were made to explain the reaction mechanism.
Polymerization of 1‐chloro‐2‐phenylacetylene induced by UV irradiation of Mo(CO)6
Authors: Masuda Toshio , Kuwane Yoshinori , Higashimura Toshinobu
Published: April 2003

Polymerization of 1‐chloro‐2‐phenylacetylene was effected by the catalyst formed by UV irradiation of Mo(CO)6 in carbon tetrachloride to provide in high yield a polymer whose weight‐average molecular weight reached 2 × 106. UV irradiation and an appropriate halogenated hydrocarbon were essential for the formation of active species. The formation of a metal carbene as active species was inferred. Poly(1‐chloro‐2‐phenylacetylene) was a light‐yellow solid having the structure $ \rlap{--} ({\rm CCl\dbondCPh\rlap{--} )}_n $. The polymer was soluble in aromatic and halogenated hydrocarbons, and a film could be formed from polymer solution.
Polyterephthalates of 2,3‐disubstituted butanediols‐1,4: Effect of aliphatic substituents on Tg and Tm of the polyesters
Authors: Florjanczyk Z. , Deopura B. , Stein R. S. , Vogl O.
Published: April 2003

Poly(2,3‐dialkylbutanediol‐1,4 terephthalates) with the alkyl substituents CH3, C2H5, n‐C3H7, iso‐C3H7, n‐C4H9, and n‐C10H21, andn‐C16H33 were synthesized from the corresponding 2,3‐dialkylbutanediols‐1,4 and dimethyl terephthalate or terephthaloyl chloride. The substituents of the butanediol‐1,4 portion of the polyterephthalates influence the 13C NMR chemical shifts of the carbon atoms near the branching site, the glass transition (Tg), and the crystallizability. Small alkyl substituents do not change the Tg of the polymers, whereas bulky substituents such as the isopropyl group increase the Tg and long normal alkyl groups as substituents decrease the Tg of the polymers. Crystallinity in these polyterephthalates was found only with CH3 and C16H33 as the 2,3‐dialkyl substituents in the butanediol‐1,4 portion of the polyester. This crystallinity of polyterephthalate of 2,3‐di‐C16H33 substituted butanediol‐1,4 could be assigned to side‐chain crystallization of the paraffinic groups.