bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional polymers and sequential copolymers by phase transfer catalysis, 3. Syntheses and characterization of aromatic poly(ether sulfone)s and poly(oxy‐2,6‐dimethyl‐1,4‐phenylene) containing pendant vinyl groups
Authors: Percec Virgil , Auman Brian C.
Published: April 2003

A method for the syntheses of α,ω‐dibenzyl aromatic poly(ether sulfone)s (PSU) and poly(oxy‐2,6‐dimethyl‐1,4‐phenylene) (POP) containing pendant vinyl groups is presented. The first step of the synthetic procedure involves the chloromethylation of PSU and POP to provide polymers with chloromethyl groups. POP, containing bromomethyl groups, was obtained by radical bromination of the methyl groups. Both chloromethylated and bromomethylated starting materials were transformed into their phosphonium salts, and then subjected to a phase transfer catalyzed Witting reaction to provide polymers with pendant vinyl groups. A PSU, containing pendant ethynyl groups, was prepared by bromination of the PSU, containing pendant vinyl groups, followed by a phase transfer catalyzed dehydrobromination. Differential scanning calorimetry of the thermal curing of the polymers containing pendant vinyl and ethynyl groups showed that the curing reaction is much faster for the polymers containing vinyl groups. The resulting network polymers are flexible when the starting polymer contains pendant vinyl groups, and very rigid when it contains pendant ethynyl groups.
A new synthetic approach for the preparation of polymer supports based on beaded copolymers of styrene and 2,4,5‐trichlorophenyl acrylate: Synthesis and swelling behaviour of poly(styrene‐co‐acrylamide) resins
Authors: Arshady Reza
Published: April 2003

A new synthetic approach for the preparation of polymer supports/polymeric reagents is reported. The method is based on the chemistry of activated esters, and it is generally simpler than the methods conventionally employed for the preparation of funcationalized resins. Thus, the details of a series of beaded, and predominantly alternate, poly(styrene‐co‐2,4,5‐trichlorophenyl acrylate)s is given. These activated resins were readily converted into highly functionalized poly(styrene‐co‐acrylamide) resins by aminolysis with a functional groups carrying amine. Resins with low degrees of functionality were obtained by partial aminolysis of the activated resins with a simples amine, and subsequent reaction with a functional group carrying nucleophile, or vice versa. A number of the new resins were examined for their swelling behaviour in a wide range of solvents and were found to show a considerably more general solvent compatibility than either styrene‐ or N,N‐dimethylacrylamide‐based resins. The relatively general solvent compatibility of the new resins is briefly discussed in terms of their copolymer structure and its is suggested that the dual “hydrophobic‐hydrophilic”, character of these resins may be of important practical implications in, among others, solid phase peptide synthesis.
The role of CT monomer complexes in radical copolymerization
Authors: Rätzsch Manfred , Steinert Volker
Published: April 2003

The mechanism of the copolymerization of monomers forming a charge‐transfer complex in the reaction mixture was investigated. A condition for establishing a certain mechanism consists in the determination of the elementary rate constants of the copolymerization; the results are in good agreement with well‐known elementary rate constants for radical polymerization. We could prove the mechanism by the method of Giese producing radicals in high concentrations. The radicals react either with monomers or monomer pairs, and the initiating radicals obtained are subsequently transferred into the hydrogenated form. The initial reaction products were identified by gas chromatography. Only addition to the radicals of either maleic anhydride or styrene and not of the CT‐complex was established by the reaction products in the mixture of styrene with maleic anhydride.
The adsorption of divalent metallic ions by polyamides having oligo(oxyethylene) segments in the repeating unit
Authors: Iwabuchi Susumu , Nakahira Takayuki , Yoshikawa Masahiko , Sato Yukitoshi , Kojima Kuniharu
Published: April 2003

Polyamides 1a – d having 1 to 4 oxyethylene units in the repeating unit were prepared from α‐(2‐aminoethyl)‐ω‐aminooligo(oxyethylene)s (2a – d) and sebacoyl chloride. The adsorption of divalent metallic ions by the polyamides 1 was found to be in general in the order: Cu2+ > H ≫ Zn2+ ∼ Cd2+. Polyamides with longer oligo(oxyethylene) units exhibit better adsorption capacities. The adsorption of Hg2+ by a polyamide with four oxyethylene units in the repeating unit follows a Langmuir adsorption isotherm, with a binding constant of K = 146 1 per mol of repeating units and a maximum Hg2+ adsorption of ws = 0,36 mol per mol of repeating units.
Metathesis degradation of partially cyclopropanated 1,4‐polybutadiene: Consideration of side reactions in the calculation of block size distribution
Authors: Hummel Klaus , Martl Michael G. , Chemelli Ronald , Grießer Herbert , Wukovnig Siegfried , Zekoll Haimo
Published: April 2003

(Z)‐1,4‐Polybutadiene was partially cyclopropanated with bis(iodomethyl)zinc and the polymer was degraded with (E)‐4‐octene in the presence of WCl6/(CH3)4Sn as catalyst. The products were identified by gas chromatography/mass spectrometry and determined by gas chromatography. The block size distribution in the partially cyclopropanated polymer was calculated from these products. A method is described by which the decrease in yield of the modified degradation products, caused by side reactions during the olefin metathesis, can be taken into account in this calculation. It is concluded that under the given experimental conditions the block size distribution is random.
Phase transfer catalysed reaction between chloromethylated poly(styrene‐co‐divinylbenzene) and the superoxide radical anion
Authors: Kolarz Bozena N. , Rapak Andrzej
Published: April 2003

The reaction of chloromethylated poly(styrene‐co‐divinylbenzene) (1 wt.‐% of divinylbenzene) with potassium superoxide in the presence of phase‐transfer catalysts was studied. It was found that in dimethyl sulfoxide and in the presence of 18‐crown‐6, the hydroxymethylated polymer is the main product with a yield of 45%. In dimethylformamide the transformation of chloromethyl groups was found to be the highest, but only 60% of alcohol groups are present in the resulting product. In benzene the transformation reaches only 25%. With Bu4NI as catalyst in a mixture of solvents, the transformation of chloromethyl groups proceeds with 85% yield and the product contains 80% hydroxyl groups.
Systèmes réactifs polyuréthannes bloqués, 2. Cinétique de réaction en présence d'un allongeur de chaînes. Structure et propriétés des polyuréthannes‐urées obtenus
Authors: Viollaz François , Pascault Jean‐Pierre , Camberlin Yres
Published: April 2003

Poly(urethane‐urea)s, were prepared from α‐hydro‐ω‐hydroxypoly(oxytetramethylene) (4 or POTM), 2‐butanone oxime (9) as blocking agent and diamines (5, 6) as chain extenders. By DSC the kinetics of reactions of the blocked system with the two chain extenders 3‐aminomethyl‐3,5,5‐trimethylcyclohexylamine (5) and 4‐4′ methylenedicyclohexylamine (6) were studied. With the two chain extenders similar results were obtained. The enthalpy of the reaction was found to be about 40 J/g and the kinetic order is unity. Thermal analysis shows the amorphous character of the hard segments. The phase segregation degree is higher with 6 as chain extender. With 6, better mechanical properties at high temperature were obtained, but ultimate elongation and tensile strength are higher with chain extender 5.
Polymerisation of 1,3,5‐trioxane in presence of maleic anhydride, 2. An example of cationic living polymerisation
Authors: Atreyi Mahalakshmi , Vasudevan Balakrishnan Ashok , Kumar Surendra
Published: April 2003

Evidence is presented for the possible existence of ‘living’ ends in the cationic polymerisation using ZnCl2, BF3 · OEt2, and γ‐rays as initiators of 1,3,5‐trioxane to polyoxymethylene in presence of maleic anhydride (1 : 1 by mole), where this binary system exists as a melt.
Functional metal porphyrazine derivatives and their polymers, 14. Synthesis and properties of [bis‐ or tetrakis(decyloxycarbonyl)phthalocyaninanto]metal complexes
Authors: Shirai Hirofusa , Hanabusa Kenji , Kitamura Mitsutoshi , Masuda Etsuko , Hirabaru Okikazu , Hojo Nobumasa
Published: April 2003

A novel class of [bis‐ and tetrakis(decyloxycarbonyl)phthalocyaninato]metal complexes (metal = Fe(III), Co(II), Ni(II), or Cu(II)) (6a, b and 2a – d) was synthesized by condensation of the corresponding acid chloride derivatives (5 and 1) with 1‐decanol. The electrical conductivities of polystyrenes, containing these complexes as dispersions, were measured.
Intrinsic viscosity versus molecular weight relationship of polystyrene in cis‐decahydronaphthalene
Authors: Kulicke Werner‐Michael , Prescher Michael
Published: April 2003

Intrinsic viscosities [η] and mean‐square radii of gyration 〈R〉 of a polymer homologous series of commercially available narrow‐molecular‐weight‐distribution polystyrene (PS) samples in a molecular‐weight range of 800 up to 24 · 106 were determined in cis‐decahydronaphthalene at 25°C by light‐scattering and viscosity measurements. These dilute solution properties were compared with those for PS in the good solvent toluene, in the constitutional isomer trans‐decahydronaphthalene both at 25°C and in cyclohexane at 34,5°C as a theta‐system.
On the temperature dependence of the elasticity of agarose gels
Authors: Nishinari Katsuyoshi , Watase Mineo , Ogino Kazuyoshi
Published: April 2003

The elastic modulus E of agarose gels with different molecular weights are determined as a function of temperature. E increases slowly from 5°C up to a certain temperature Tmax, which depends on the molecular weight, and then decreases gradually at first and then rapidly. Tmax is shifted to higher temperatures with increasing molecular weight. E is discussed in terms of an entropic and an energetic contribution. The entropic part decreases while the energetic part increases with increasing temperature.
Polymeric sulfoxides as liquid‐liquid phase transfer catalysts
Authors: Kondo Shuji , Ohta Kunihiro , Ojika Ryoko , Yasui Haruhiko , Tsuda Kazuichi
Published: April 2003

Soluble polymeric sulfoxides were prepared by free‐radical polymerization of methyl 4‐vinylphenyl sulfoxide and methyl 4‐vinylbenzyl sulfoxide, and copolymerization of these monomers with styrene. These polymers serve as effective phase transfer catalysts for several reactions under liquid‐liquid biphase conditions. The catalytic activity of copolymers containing styrene units is generally higher than that of homopolymers. On the other hand, copolymers with acrylonitrile co‐units do not exhibit catalytic activity. It was found that polymeric sulfoxides extract all alkali metal cations examined here more efficiently than their monomeric analogs, and that the binding ability increases with increasing density of active sites, suggesting a cooperative effect of sulfoxide groups. It is reasonable therefore to assume that the catalytic activity is due to both cation binding on the polymers and activation of the anions caused by desolvation in the hydrophobic region of the polymers.
The kinetics of acid hydrolysis of polymeric ketone acetals
Authors: Hudeček Slavko , Otoupalová Jaroslava , Světlík Jan , Čefelín Pavel , Ryska Miroslav
Published: April 2003

The kinetics of acid hydrolysis of poly[(2,2‐dimethyl‐1,3‐dioxolane‐4‐yl)methyl methacrylate] and of its copolymers with methyl methacrylate in homogeneous phase was investigated by means of mass spectrometry using perdeuterated acetone as the internal standard. It was found that under conditions of a pseudomonomolecular reaction the homopolymer is capable of an acceleration process with respect to the splitting‐off of acetone according to the content of the syndiotactic dyads. The respective rate constants K0 and K1 were calculated. Characterization of the steric situation by means of models of polymeric ketonacetals and the absence of acceleration in the case of copolymers even containing only a small amount of methyl methacrylate units lead to the conclusion that the reported phenomenon is due to steric effects combined with a neighbouring group effect.
13C NMR investigation of crosslinked polyethylenes
Authors: Hortling Bo , Levon Kalle , Soljamo Kari , Pellinen Jukka , Lindberg J. Johan
Published: April 2003

Crosslinked polyethylenes (PEX) with different degrees of crosslinking were separated in sol and gel fractions by extractions with hot o‐dichlorobenzene. The distribution of branches was determined by 13C NMR‐spectroscopy, according to the method of Randall et al. The relative amounts of butyl branches decrease in the gel fraction and increase in the sol fraction with increasing degree of crosslinking. For the other branches the changes were small or not observable. In addition, the activation energies for a sol and a gel fraction were determined by measurements of the spin‐lattice relaxation times T1 at temperatures between 303 and 403 K. The activation energy was higher for the gel fraction, suggesting a restricted motion of the polymer segments in the gel.
The molecular structures of 1,1‐diphenylethyl methacrylate and triphenylmethyl methacrylate
Authors: Kageyama Hiroyuki , Hayashi Yoko , Harada Shigeharu , Kai Yasushi , Kasai Nobutami , Okamoto Yoshio , Hatada Koichi
Published: April 2003

The molecular structures of 1,1‐diphenylethyl methacrylate (1,1‐DPEMA) and triphenylmethyl methacrylate (TrMA) were determined by means of X‐ray diffraction. 1,1‐DPEMA: monoclinic, space group P21/a,a = 9,666(6), b = 19,94(2), c = 8,132(6) Å, β = 104,49(7)°, and Z = 4; TrMA: monoclinic, space group P21/n, a = 17,349(3), b = 9,487(2), c = 11,254(2) Å, β = 102,30(2)°, and Z = 4. Both structures were solved by the direct method and refined by the block‐diagonal least‐squares procedure to R = 0,175 and 0,056 for non‐zero reflections, respectively. In both molecules, conformations about the C(1)C(2) and C(1)O(1) bonds are all synperiplanar and one of the two or three phenyl groups attached to the C(5) atom is in trans to the O(2).
Reactive latex studies, 2. Kinetics and retention of enzymatic activity in the covalent protein bonding to a polymer latex
Authors: Suen Chih‐Her , Morawetz Herbert
Published: April 2003

Bovine serum albumin (BSA) was coupled to the reactive chloromethyl groups of poly(vinylbenzyl chloride) latex following the process both by the amount of BSA covalently bound and the chloride ion released. The primary bond formation is very insensitive to temperature with protein adsorption probably rate determining. Subsequent bond formation has an unusually high temperature coefficient and may depend on the deformability of the BSA molecule. On covalent bonding of ribonuclease 10% of the enzyme activity is retained.
Cationic degradation of poly(thio‐1,1‐dimethylethylene) [poly(isobutylene sulfide)]
Authors: Bhatti Saqlain A. , Goethals Eric J.
Published: April 2003

High molecular weight poly(thio‐1,1‐dimethylethylene) [poly(isobutylene sulfide)] obtained by anionic polymerization of 2,2‐dimethylthiirane (isobutylene sulfide) was degraded to a mixture of low molecular weight compounds when treated with a catalytic amount of methyl trifluoromethanesulfonate. The following degradation products were found: 2,2,5,5‐tetramethyl‐1,4‐dithiane (3), 2,2,6,6‐tetramethyl‐1,4‐dithiane (4), 2‐isopropyl‐4,4‐dimethyl‐1,3‐dithiolane (2), and an equimolar mixture of 3,3,6,6‐tetramethyl‐1,2,5‐trithiepane (5) and 2‐methylpropene (isobutylene). The formation of dithiolane 2 is explained by a hydride transfer to a transient carbenium ion.
Block copolymers by metathesis polymerisation
Authors: Amass Allan J. , Bas Suleyman , Gregory Denis , Mathew Mathew C.
Published: April 2003

A transformation reaction from anionic to metathesis was used to prepare block copolymers of styrene and cyclopentene. The composition of the products was established by elemental and UV analysis. A mechanism for the formation of the propagating centre in the olefin metathesis reaction was postulated that will account for the incorporation of the alkyl group of the cocatalyst in the first formed metal carbene.
Kinetic investigations of the free radical crosslinking copolymerization in the pre‐gel state, 2. Styrene/ethylene dimethacrylate and styrene/diisopropenylbenzene systems
Authors: Hild Gérard , Okasha Rouzi
Published: April 2003

A kinetic investigation of the free radical crosslinking copolymerization was carried out using the following monomer systems: styrene/ethylene dimethacrylate, styrene/m‐diisopropenyl‐benzene and styrene/p‐diisopropenylbenzene. The conversion curves of each individual monomer and the instantaneous composition of the copolymer formed were determined from vapor phase chromatography measurements. The rate of consumption of each monomer follows first order kinetics except for the system styrene/p‐diisopropenylbenzene in which strong deviations can be observed. The reactivity ratio of styrene, determined by VPC, is compared with the value obtained by the Kelen‐Tüdős linearization method. As for the system styrene/divinylbenzene, the fundamental role of the pendant bonds in the process has been established. Their ability to react with incoming radicals to form crosslinks determines the formation of interchain linkages and thus the gelation of the system.
Synthesis of water‐soluble branched polysaccharides and their antitumor activity, 1. Branched polysaccharides from cellulose acetate
Authors: Matsuzaki Kei , Yamamoto Iwao , Sato Takaya , Oshima Ryuichi
Published: April 2003

Branched polysaccharides of cellulose having β‐glycosidically linked D‐glucose branches were synthesized by condensation of 3,4,6‐tri‐O‐acetyl‐(1,2‐O‐ethylorthoacetyl)‐α‐D‐glucopyranose with activated cellulose acetates (DS ≈ 2) in boiling chlorobenzene in the presence of a catalytic amount of 2,6‐dimethylpyridinium perchlorate. The branched polysaccharides were converted into water‐soluble polysaccharides by saponification and then tested for their antitumor activity. Synthetic, branched polysaccharides with 30% or more branching were found to be completely soluble in water. The structure of branched polysaccharides was determined by methylation analysis, and it was found that branching occurred preferentially at the Cxyh6 positions by β‐glucosidic linkages. The antitumor activity for Sarcoma 180 transplanted to mice was high for polysaccharides with a high DP. Cellulose did not react with acetyl glucose orthoester even after activation.
Preparation of polyamides containing α‐diketone moieties and their transformation into 1,2,4‐triazine rings with amidrazones
Authors: Akutsu Fumihiko , Takeyama Hidekazu , Miura Masatoshi , Nagakubo Kuniharu
Published: April 2003

Polyamides 3–5 containing 1,2,4‐triazine rings in the main chain were prepared by condensation of amidrazones 2 with polyamides 1 containing α‐diketone moieties, with conversions between 10 and 87%. The thermal stabilities and the solubilities of the resulting polymers 3–5 were enhanced by the introduction of the 1,2,4‐triazine rings in the main chain.
Cation binding properties of poly(crown ether)s with photodimerizable groups. Enhanced cation binding ability via a photochemical template effect
Authors: Shirai Masamitsu , Ueda Akihiko , Tanaka Makoto
Published: April 2003

Polymers having both crown ether moieties as cation binding sites and cinnamic acid ester moieties as photodimerizable pendant groups were prepared. On irradiation with UV light the cinnamic acid ester groups of the polymers caused dimerization in dilute solution without formation of any insoluble material. Irradiation was carried out in THF and THF‐methanol (1 : 1 vol. ratio) in the absence and presence of cations as a template, respectively. The cation binding properties were investigated by means of the method of picrate salts extraction. The cation extractability of the photoreacted polymers was higher than that of the original polymers. Furthermore, the cation binding ability of the photoreacted polymers was less sensitive to temperature than that of the original polymers. The effect of the degree of photodimerization of the polymers, of the kind of cations used as a template during photodimerization of the polymers, and of the concentration of the template action on the extractability of polymers were investigated in detail.
Graph theory of configurational and viscoelastic properties of polymers
Authors: Yang Yuliang , Yu Tongyin
Published: April 2003

A simple method for calculating the moments of the radius of gyration of polymers is developed. It can be applied to any molecule which does or does not possess close circuits in its structure. In the Rouse theory of viscoelastic behaviour, various functions such as the zero‐shear‐rate viscosity, η0, and the steady‐state recoverable compliance, J, are directly related to the moments of the radius of gyration and hence the results obtained may prove useful for interpreting rheological data.
Polybutadiène hydroxytéléchélique, 7. Cinétique de polycondensation en solution et en masse du polybutadiène hydroxytéléchélique avec le méthylène‐4,4′ di(isocyanate de phényle) en l'absence de catalyseur. Etude par 1H NMR et 13C NMR
Authors: Ghafari Mahmoud El , Pham Quang Tho
Published: April 2003

Quantitative determinations by 13C NMR performed with insoluble polyurethanes allow to study the kinetics of the polymerization in bulk between hydroxytelechelic polybutadiene G 1000 and 4,4′‐methylene diphenylisocyanate (MDI). Comparisons have been made with (G 1000 + MDI) polymerization and (monoalcohol or G 1000 + phenyl isocyanate) model reactions in toluene. With [NCO]/[OH] = 1 and T ⩽ 60°C, in solution as well as in bulk, conversions are not complete. Because of the presence of gels, part of the reactive functions have been found to be trapped. For kinetic tests, only the first stage of the polymerization (conversion < 70%) may be taken into account. In bulk, the two alcohol functions are equally reactive, whereas in toluene, the hydroxylated 1,4 ends of the polybutadiene chains are more reactive. As evidenced for model reactions in the foregoing paper of this series, the kinetics fit better with the 3rd order than with the 2nd order equation. Nevertheless, at higher temperatures, the 2nd order may be used. The autocatalysis phenomenon found effective for model reactions is negligible in polymerization. All kinetic constants and activation parameters calculated must be considered to be apparent ones only.
Etude de nouvelles membranes asymétriques à base de copolymère à blocs styrène‐isoprène‐styrène, 1. Synthèse, modification chimique et caractérisation
Authors: Harjanto Fadjar , Mendjel Hocine , Sledz Joseph , Schué François , Meyer Guy
Published: April 2003

A styrene‐isoprene‐styrene block copolymer was selected for the preparation of new asymmetric membranes which have blood compatibility properties after chemical modification by addition of gazeous N‐chlorosulfonyl isocyanate to the double bonds of the polyisoprene sequences. The membranes were examined with a scanning electron microscope. The permeability of the membrane was studied as a function of time, pressure and viscosity.
Dégradation du poly(carbonate de bisphénol‐A) en phase liquide en présence de sels alcalins. Etude cinétique
Authors: Godard Pierre , Bailly Christian , Legras Roger , Mercier Jean‐Pierre
Published: April 2003

The degradation of poly(oxycarbonyloxy‐1,4‐phenyleneisopropylidene‐1,4‐phenylene) [poly‐(bisphenol‐A carbonate)] in cyclohexanone is shown to be efficiently catalyzed by organic salts and metal carbonates. The catalysis is of homogeneous type. More precisely, only the associated fraction of the dissolved salt is active. The apparent activation energy of the degradation ranges between 113 and 130 kJ · mol−1 (27 and 31 kcal · mol−1), being similar to energies usually observed for hydrolysis or alcoholysis of esters. A reaction mechanism based on the ketoenolic equilibirum in cyclohexanone is proposed to explain the fast degradation observed. The influence of the nature of ions is also assessed: the reactivity increases with decreasing cation diameter, whereas the nature of the anion is of no matter.
Equilibrium polymerization with a multifunctional initiator
Authors: Yan De‐yue , Cai Gang‐feng
Published: April 2003

The equilibrium polymerization with a multifunctional initiator is re‐treated theoretically. The expressions for the molecular weight distribution function, the number‐ and weight‐average degrees of polymerization, the distribution of the degree of branching and the average degree of branching of the polymer formed are rigorously derived. All the formulae given are much simpler than those reported by Baur and Eisenberg. A theoretical method is established by which all the molecular parameters of the polymer can be calculated from polymerization conditions, such as the equilibrium constants, the functionality of the initiator and the initial concentrations of initiator and monomer.
Graph theory of viscoelasticities for polymers with starshaped, multiple‐ring and cyclic multiple‐ring molecules
Authors: Yang Yuliang , Yu Tongyin
Published: April 2003

The graph method of linear viscoelasticities of polymers has been extended to calculate the relaxation spectra and shrinking factors of star‐shaped molecules, multiple‐ring molecules and cyclic multiple‐ring molecules. The results obtained are general solutions, by which the special case can be easily calculated and compared with literature if available. This shows that graph theory is very versatile in theoretically treating linear viscoelasticities.
Addition reactions of polymers containing pendant cyclic iminoethers with thiols, carboxylic, thiocarboxylic and sulfinic acids
Authors: Nishikubo Tadatomi , Tokairin Atsushi , Torikai Shigeru , Iizawa Takashi
Published: April 2003

Poly[1‐(2‐oxazoline‐2‐yl)ethylene] (2a), poly[1‐(5‐methyl‐2‐oxazoline‐2‐yl)ethylene] (2b), poly[1‐(4,4‐dimethyl‐2‐oxazoline‐2‐yl)ethylene] (2c), poly[1‐(4,4‐dimethyl‐5,6‐dihydro‐4H‐1,3‐oxazine‐2‐yl)ethylene] (2d), and poly[1‐(4,4,6‐trimethyl‐5,6‐dihydro‐4H‐1,3‐oxazine‐2‐yl)ethylene] (2e) were synthesized with high yields by radical polymerization, using AIBN as initiator. Polymer 2a was found to be soluble in water and in organic solvents such as methanol, acetone, chloroform and benzene, polymer 2b in hot water and in the same organic solvents, and polymers 2c and 2d are insoluble in cold and hot water. However, polymers 2d and 2e are soluble in diethyl ether and hexane. Addition reactions of polymers 2a–e with carboxylic acids and thiols were investigated. Reactions of polymer 2a with acetic acid, benzoic acid and cinnamic acid at 110°C for 10 h proceeded with 57–74 mol‐% conversion in DMF, NMP and DMSO, and reactions with benzenethiol and thiobenzoic acid quantitatively under the same reactions conditions. Reactions of polymers 2b and 2c with carboxylic acids proceeded with 4–36 mol‐% conversion, and with benzenethiol and thiobenzoic acid with 80–96 mol‐% conversion. From the results the following order of reactivities of these polymers may be suggested: 2a ≃ 2d > 2e > 2b > 2c. According to their higher nucleophilicity, the reactivities of benzenethiol and thiobenzoic acid towards the pendant 2‐oxazoline ring are much higher than those of carboxylic acids.
Synthesis of poly(vinyl alcohol)/poly(dimethylsiloxane) graft copolymer
Authors: Tezuka Yasuyuki , Fukushima Akira , Imai Kiyokazu
Published: April 2003

Poly(vinyl acetate)/poly(dimethylsiloxane) graft copolymer (4a), with a controlled poly(dimethylsiloxane) graft chain length, was synthesized by radical copolymerization of vinyl acetate with poly(dimethylsiloxane) (3) having a dimethylvinylsilyl end group. 3 was prepared by living anionic polymerization of hexamethylcyclotrisiloxane (1) with butyllithium and subsequent termination with chlorodimethylvinylsilane (2). Poly(vinyl alcohol)/poly(dimethylsiloxane) graft copolymer (4b) was then synthesized by selective saponification of the poly(vinyl acetate) segments in the graft copolymer 4a with K2CO3 in methanol.
The chemical dehydrochlorination of poly(vinyl chloride), 1. Studies on tetrahydrofuran solutions
Authors: Bowley Heather J. , Gerrard Donald L. , Maddams William F. , Paton Mark R.
Published: April 2003

The chemical dehydrochlorination of poly(vinyl chloride) was studied in solution in tetrahydrofuran. Two materials, a mass polymer of 55% syndiotacticity and a low temperature polymer of 63% syndiotacticity, were dehydrochlorinated with potassium hydroxide and with potassium tert‐butoxide. The dehydrochlorination products were characterised by their chlorine contents and by UV/visible, IR and Raman spectroscopy, as a function of reaction time. The course of the reaction was found to be substantially independent of tacticity and the dehydrochlorinating reagent. Initially, the reaction follows a similar path to that occurring during photo‐ and thermal degradation, but as the dehydrochlorination continues, longer conjugated polyenes are formed than by these two latter processes. Sequences of 60 double bonds occur at the dehydrochlorination levels of about 55% that are attained after reaction times of 24 h. These sequences are sterically protected from cross‐linking reactions by the presence of longish sequences of unreacted CHClCH2 units.
Micelle‐forming block copolymers: Pinocytosis by macrophages and interaction with model membranes
Authors: Pratten Margaret K. , Lloyd John B. , Hörpel Gerhard , Ringsdorf Helmut
Published: April 2003

A block copolymer (6) with both hydrophilic and hydrophobic regions was synthesized, in order to examine its interaction with model membranes and its uptake by living cells. The copolymer comprised poly(ethylene oxide) and poly(L‐lysine) with 50 mol‐% substitution of the ε‐amino groups with palmitoyl groups. To permit 125I‐labelling, p‐methoxyphenyl residues (1–4 mol‐%) were incorporated into the block copolymer and into a poly(ethylene oxide) used for comparison. Sudan Red 7 B solubilization studies indicated that the block copolymer, but not the homopolymer, forms micelles. Differential scanning calorimetry of dipalmitoyl‐phosphatidylcholine liposomes indicated that the block copolymer interacts with and probably penetrates lipid membranes. Both poly(ethylene oxide) and the block copolymer were captured by rat peritoneal macrophages in vitro, and inhibitor studies indicated that uptake of both polymers was by pinocytosis. Rates of uptake were indicative of adsorptive pinocytosis, and it is concluded that both poly(ethylene oxide) and the block copolymer present a largely hydrophilic aspect which interacts positively with the cell surface.
Continuous fractionation and solution properties of PVC, 3. Pressure dependence of the solubility in single solvents
Authors: Geerissen Heinz , Roos Jürgen , Wolf B. A.
Published: April 2003

From the break‐down in the viscosity and from the increase of the intensity of the scattered light, associated with the entrance into the two‐phase region, the pressure dependence of the demixing temperature of solutions of PVC 37 000, PVC 75 000 and PVC 100 000 in phenetole and PVC 75 000 in o‐xylene was measured up to 1 000 bar. (The numbers in the codes of the PVC specimens are their approximate molecular weights.) The application of pressure increases the demixing temperatures of PVC in both solvents by about 1 K/100 bar. For a qualitative forecast of the pressure effects, the solubility parameter theory in combination with the corresponding states principle, and an empirical correlation to the relative distance of the critical demixing temperature to the melting point of the pure solvent were used. The results of both concepts are in accord with the experimental findings.
Continuous fractionation and solution properties of PVC, 4. Pressure dependence of the solubility in a mixed solvent
Authors: Geerissen Heinz , Roos Jürgen , Wolf B. A.
Published: April 2003

Using a self‐constructed light scattering apparatus, the pressure dependence of the demixing temperature of solutions of PVC 20 000, PVC 37 000 and PVC 70 000 in THE/water was determined up to 1 000 bar for different compositions of the mixed solvent. (The numbers in the codes of the PVC specimens are their approximate molecular weights.) In contrast to the thetasolvents o‐xylene and phenetole, the solubility decreases with increasing pressure for all molecular weights and compositions under investigation typically by about 1 K/100 bar. The evaluation of the experimental findings demonstrates that the volume fraction of the nonsolvent in the mixed solvent, φ, is the variable that governs phase separation: For the present region of p and T, a given polymer solution demixes at a characteristic constant value of φ, no matter how it is reached. This fact allows the prediction of pressure influences from known pVT data of the pure components and measurements at atmospheric pressure. A qualitative theoretical understanding of the observed influences of p and T can be reached on the basis of the solubility parameter theory.
Continuous fractionation and solution properties of PVC, 5. Pressure dependence of the viscosity — influence of solvent
Authors: Geerissen Heinz , Roos Jürgen , Wolf B. A.
Published: April 2003

Viscosity measurements were carried out as a function of pressure and temperature with solutions of 8 wt.‐% PVC (Mw ≈ 75 000) in ten thermodynamically good solvents by means of a Searle‐type viscometer. A rollingxyhball viscometer was used for the investigation of the pure solvents. In all cases the viscosity increases in a more or less exponential manner when the pressure is raised. The viscosity ratio f1000 = η1000 bar/η1bar can be varied by the choice of the solvent from ca. 2 (tetrahydrofuran) to 3,0 (cyclohexanone) at 40°C. For a constant temperature of 40°C, the volumes of activation for the viscous flow of the solutions, V≠, or f1000 exceed that of the pure solvent, by typically 25%. The dependence of f1000 or V≠ upon temperature is not very pronounced. However, the greater the f1000‐values, the more marked are the temperature effects. The theoretical analysis of the data, including earlier measurements with PS, indicates that three terms contribute to f1000: the basic value (f1000)s stemming from the pure solvent, the value (f1000)p which the polymer would contribute under athermal conditions, and finally a thermodynamic term, (f1000)pa, considering the pull‐along effect (i.e. the specific forces a given segment exerts on other segments under variable thermodynamic conditions).
Extent of reaction, monomer conversion, and polymer yield in polycondensations
Authors: Elias Hans‐Georg
Published: April 2003

The extent of reaction of functional groups (pA), the extent of conversion of monomer molecules (qM), the true relative polymer yield (yp), the constitutional repeating unit‐based apparent relative polymer yield (y), and the monomer‐based apparent relative polymer yield (y) are defined and their interrelationships given. The use of y instead of yp overestimates the true yield, except in the limit of high degrees of polymerization. Use of y, on the other hand, always underestimates the true yield, especially at infinite degrees of polymerization. The correct expression for the calculation of the mass fraction of i‐mers in reactants with a Schulz‐Flory “most probable” distribution is given and shown to become identical with the usual approximation in the limit of vanishingly small mass of the leaving molecule.
Influence de la température de cristallisation sur la morphologie du polypropylène isotactique
Authors: Idrissi Mohamed Oulad Bouyahya , Chabert Bernard , Guillet Jacques
Published: April 2003

The isothermal crystallization of isotactic polypropene samples cooled from the melt is studied. Particular emphasis is given to the morphology which develops depending on the melting and crystallizing conditions. Thus, the evolution of birefringence for samples crystallized between −20°C and +150°C is explained in terms of a quadritic arrangement of lamellae. The evolution of the relative amounts of radial and tangential lamellae is followed by differential thermal analysis, small angle light scattering and optical polarization microscopy.
Poly(p‐hydroxycinnamic acid)
Authors: Elias Hans‐Georg , Tsao Jung‐Hsien (Louis) , Palacios Joaquin A.
Published: April 2003

Poly(p‐hydroxycinnamic acid) was synthesized by thionyl chloride activated polycondensation of p‐hydroxycinnamic acid at ambient temperatures and by polycondensation of its various monomeric esters at elevated temperatures. The thionyl chloride activated polycondensation proceeds as a 2‐stage process, yielding reduced viscosities of up to 102 mL/g. 360 MHz proton NMR spectra indicate an all‐trans structure and the absence of side reactions. The polymer with a melting temperature of 313°C can be pressed into films.
Polymerization by phase transfer catalysis, 2 Polythiocarbonates by polymerization of Bisphenol A with thiophosgene
Authors: Tagle Luis H. , Diaz Fernando R. , Vega Juan C. , Alquinta Pedro F.
Published: April 2003

Poly(oxythiocarbonyloxy‐1,4‐phenyleneisopropylidene‐1,4‐phenylene) (1) was obtained from 4,4′‐isopropylidenediphenol (Bisphenol A) and thiophosgene under phase transfer conditions, using quaternary ammonium and phosphonium salts and crown ethers as catalysts. The polymer was identified by IR and 1H NMR spectroscopy, and the molecular weights were estimated from inherent viscosity measurements. The influence of catalysts, solvent and thiophosgene addition was studied in order to find the best conditions. It was found that tetrabutylammonium bromide, dichloromethane and the addition of thiophosgene at once gives the highest yields and inherent viscosities. Other catalysts and solvents were less efficient or unefficient for this reaction.
Über die quantenausbeute der kettenspaltung von polystyrol in lösung bei bestrahlung mit wellenlängen λ ≧ 270 nm
Authors: Wolinski Leszek , Witkowski Konrad
Published: April 2003

Values of the mean number of chain scissions per macromolecule and the quantum efficiency of chain scission processes are presented for systems studied in our previous works, in which the photodegradation of polystyrene in solutions irradiated with mercury light (λ ≧ 270 nm) was investigated and changes of the weight‐average molecular weight M̄w were considered to be a measure for chain scission. The presented values of the number of scissions were obtained as follows: the molar mass distributions were determined for the investigated polystyrene samples by dynamic (quasielastic) light scattering experiments, before and after irradiation, the number‐average molecular weight values M̄n were calculated from these distributions and the mean number of scissions was obtained from the changes of the M̄n values.
A note on the intrinsic viscosity and huggins coefficient of low‐molecular‐weight polymers in mixed solvents
Authors: Caparros Ana Maria Rubio , Bohdanecký Miloslav
Published: April 2003

It is shown that in mixed solvents where preferential sorption takes place, the intrinsic viscosity and the Huggins coefficient contain contributions arising from the effect of preferential sorption on the viscosity of the mixed solvent surrounding the polymer molecules. These contributions become progressively more important as the polymer molecular weight decreases, and can be relevant at M ⪅ 104.
Chemical oxidation of a neutral electrochemically prepared polythiophene film
Authors: Cao Yong , Wang Ping , Qian Renyuan
Published: April 2003

Neutral polythiophene films obtained by NH4OH compensation of electrochemically polymerized samples were re‐oxidized chemically to the metallic state by a wide range of oxidants. The electrochemically and chemically oxidized polythiophene films were found to be quite stable in air. Results of IR, SEM and WAXS studies are described and discussed. The feasibility of chemical re‐oxidation of neutral electrochemically prepared polythiophene films offers a convenient means to produce flexible highly conductive polythiophene films.
Copolymerization of 9‐anthrylmethyl methacrylate with N‐phenylmaleimide
Authors: Simionescu Cristofor I. , Grigoras Mircea , Onofrei Geta
Published: April 2003

The radical copolymerization of 9‐anthrylmethyl methacrylate (1) with N‐phenylmaleimide (2), initiated by 2,2′‐azoisobutyronitrile at 60°C in 1,4‐dioxane, was investigated. Simultaneously with the copolymerization a Diels‐Alder cycloaddition of 2 to the anthracene nucleus takes place as side reaction. A charge transfer complex formation between the two monomers was evidenced by 1H NMR spectroscopy. The stability constant of the complex, which is an intermediate in the cycloaddition reaction, was found to be 0,05 1 · mol−1.
Copolymerization of propylene with 1‐butene in presence of the catalytic system TiCl4/Mg[(CH2)5CH3]2
Authors: Soga Kazuo , Ohtake Makoto , Ohnishi Rikuo , Doi Yoshiharu
Published: April 2003

The copolymerization of propylene with 1‐butene was carried out in presence of the catalytic system TiCl4/Mg[(CH2)5CH3]2 in heptane. A transparent copolymer with a random distribution (r1 · r2 = 1,0) was obtained. The catalyst shows a considerably high activity. The rate of monomer addition was found to be independent of the chemical structure of the growing polymer chain end, which is quite different for the copolymerization of ethylene with propylene.
Polymerization of monomers containing functional groups protected by trialkylsilyl groups, 4. Studies on anionic living polymerization of 4‐(tert‐butyldimethylsilyloxy)styrene
Authors: Hirao Akira , Takenaka Katsuhiko , Packirisamy S. , Yamaguchi Kazuo , Nakahama Seiichi
Published: April 2003

Anionic polymerization of 4‐(tert‐butyldimethylsilyloxy)styrene (2) was investigated under high vacuum conditions (≈ 10−6 mbar). 2 was readily polymerized by lithium naphthalide to form a “living polymer” at −78°C. By subsequent acid hydrolysis of the resulting polymer, a linear, nearly monodisperse polymer of 4‐vinylphenol of known molecular weight was obtained. Block copolymers of 2 with α‐methylstyrene were also prepared by means of this living system.
Organotin(IV) oxides and sulfides as modifiers of propene polymerization catalysts
Authors: Karayannis Nicholas M. , Lee Sam S.
Published: April 2003

Studies of a number of organotin(IV) oxides and sulfides as modifiers of Ziegler‐type propene polymerization catalysts are reported. The general trend observed is that organotin(IV) sulfides provide better catalyst activity‐stereospecificity combinations than the corresponding oxides. Among the various modifiers studied, μ‐thiobis[tri‐butyltin(IV)] was found to exhibit the best overall modifying effect. Combination of an organotin(IV) sulfide with a second modifier of the aromatic amine, N‐oxide, phosphite ester or cyclic ether type in a binary modifier package was shown to lead to catalyst systems with excellent stereospecificities and activities ranging from acceptable to outstanding. Possible interactions and reactions of the organotin modifiers with the components of the catalyst system are discussed.
Studies on chitosan‐induced metachromasy, 1. Metachromatic behaviour of sodium 2′‐hydroxy‐1,1′‐azonaphthalene‐4‐sulfonate in the presence of chitosan
Authors: Gummow Beryl D. , Roberts George A. F.
Published: April 2003

Solutions of chitosan in dilute acetic acid are shown to induce a metachromatic effect in the visible spectrum of the anionic dye sodium 2′‐hydroxy‐1,1′‐azonaphthalene‐4‐sulfonate (3) (C.I. Acid Red 88). The presence of chitosan reduces the intensity of λmax at 505 nm, whilst a new absorption band appears at 450 nm. This change may be observed visually as a change in colour from red to orange, suggesting that it may be of use in histological staining tests. A 1:1 stoichiometry is shown to exist between protonated amine groups on the polymer chain and negatively charged dye ions, at the point where the decrease in λmax reaches a minimum. Quantitative use of the metachromatic effect enables the determination of either the concentration in solution of a chitosan sample of known structure, or the amine group content of a chitosan sample of unknown structure.
Polymerization of propene in the presence of MgCl2‐supported Ziegler‐Natta catalysts, 1. The role of ethyl benzoate as “internal” and “external” base
Authors: Busico Vincenzo , Corradini Paolo , De Martino Luigi , Proto Antonio , Savino Vito , Albizzati Enrico
Published: April 2003

The effect of ethyl benzoate (EB) as a component of the solid catalyst (“internal” base) and/or of the co‐catalyst (“external” base) on propene polymerization in the presence of different MgCl2‐supported Ziegler‐Natta systems was investigated systematically. From the experimental results, it is suggested that internal EB mainly prevents TiCl4 from coordination on the MgCI2 crystal faces where mostly non‐stereospecific active sites would be formed, whereas external EB inhibits selectively the non‐stereospecific centres and decreases the reaction of the alkylaluminium with the internal base. A possible model of active sites for isotactic 1‐alkenes polymerization in the presence of MgCl2‐supported catalysts is presented, which is in good agreement with a large number of known experimental facts.
Moisture‐curable rubbers, 1. Moisture‐cure of halogenated butyl rubbers
Authors: Yamashita Shinzo , Yamada Akira , Ohata Masatoshi , Kohjiya Shinzo
Published: April 2003

Chlorinated and brominated butyl rubbers (CIIR and BIIR) were each compounded with 3‐aminopropyltriethoxysilane (APS) and dibutyltin dilaurate on a two‐roll mill, and were pressed at 150°C for 20 min. The resulting sheets were cured by soaking them in water. The progress of the moisture‐cure was followed by determining the network‐chain density (νs). The rate of the moisture‐cure was found to depend on the soaking temperature. The resulting maximum vs was, however, independent of the soaking temperature. The kinetic study of the reactions of CIIR and BIIR with APS in toluene revealed that the maximum replacement of the halogen atoms with APS (m) was ≈ 40% in CIIR and ≈ 70% in BIIR. Thus, the apparent cross‐linking efficiency of the moisture‐cure was evaluated from νs and m.
Kinetics and peculiarities of phase separation in the formation of semi‐interpenetrating polymer networks
Authors: Lipatov Yury S. , Grigor'yeva Olga P. , Kovernik Grigory P. , Shilov Valery V. , Sergeyeva Ludmila M.
Published: April 2003

The initial stages of phase separation in the formation of semi‐interpenetrating polymer networks (semi‐IPN's) based on copolymer from styrene with divinylbenzene (DVB)/poly(butyl methacrylate) (PBMA) were studied using an optical laser diffractometer. It was found that phase separation obeys the mechanism of spinodal decomposition. The peculiarity of phase separation in the system studied is due to the existence of a two‐stage process. Each stage exhibits different interdiffusion coefficients, sizes of microheterogeneity areas and activation energies.
Cinétiques de télomérisation, 4. Nouvelle méthode de détermination des constantes de transfert en catalyse radicalaire
Authors: Bauduin Gérard , Boutevin Bernard , Mistral Jean‐Pierre , Sarraf Léna
Published: April 2003

For the determination of transfer constants CT to the telogen in telomerization reactions started with free radicals we used three methods. The first one is the method of Mayo, the second one is based on the variation of the conversion degree of telogen to monomer and the last method requires the knowledge of the cumulated number‐average degree of polymerization DPn and monomer conversion αM of the samples during the reaction. Verifications of the proposed laws are made for methacrylic acid telomerization with CCl3Br and methyl methacrylate telomerization with benzenethiol as a telogen and 2,2′‐azoisobutyronitrile as the initiator at 70°C. The transfer constant to CCl3Br is ca. 0,03 and that to C6H5SH ca. 1,5.