Radiation-induced solid-state polymerization in binary systems. II. Relationship between polymerization rate and physical structure of binary systems

The radiation-induced solid-state polymerization of binary systems consisting of acrylic monomer (acrylamide, acrylic acid) and organic compounds was investigated. In the previous paper on binary systems the authors reported that the rate of polymerization increased in the solid state (eutectic mixture systems). The mechanism of rate increase has been investigated by examination of phase diagrams, viscosities, and surface tension of the binary systems. Viscosity and surface tension are the measure of the molecular interaction of the two-component systems. In addition, the effect of linear crystal growth rate and half maximum width of the x-ray diffraction diagram of the crystallization process were determined. The larger the molecular interaction between the two components, the slower the linear crystal growth rate of monomer. The size of the monomer crystal decreases and the dislocation density of the monomer crystals increases in systems with large molecular interaction. Consequently it can be concluded that the physical structure of a binary solid system is the most important parameter determining the rate increase of solid-state polymerization. Dislocation on the grain boundary is more important than defects inside of the crystal lattice. It was found that the acceleration of polymerization rate is large in binary systems with larger molecular interaction. In some systems such as organic acid—amide systems with strong hydrogen bonds, glassy phases may be formed in which monomer may readily polymerize at very low temperatures.     

Preparation and polymerization of some vinyl monomers containing the 1,3-dioxolane group

The synthesis and structure determinations of (2,2-dimethyl-1,3-dioxolan-4-yl)-methyl acrylate, 4-(2,2-dimethyl-1,3-dioxolan-4-yl)methyl itaconate, and [(2,2-dimethyl-1,3-dioxolan-4-yl)methyl] methyl fumarate are described. Reactivity ratios in the copolymerization of these monomers with other comonomers are reported and the Alfrey-Price Q and e values calculated. The post-polymerization study of the effects of ultraviolet light and heat on these polymers and copolymers is presented. The 1,3-dioxolane group when appended to the polymer chain performs as an internal ultraviolet sensitizer. A mechanism is offered to explain the crosslinking behavior of these polymers when treated with ultraviolet light.     

Homogeneous binary zirconocenium catalysts for propylene polymerization. II. Mixtures of isospecific and syndiospecific zirconocene systems

Isotactic polypropylene (i-PP) and syndiotactic polypropylene (s-PP) obtained with single-site C₂- and C_s-symmetric zirconocenes, respectively, activated with triphenyl carbenium tetrakis(pentafluorophenyl)borate (3) are immiscible with one another. Physical mixture of the two PPs is macrophase separated and crystallizes very slowly as is characteristic of s-PP. A solution of C₂- and C_s-symmetric zirconocenes with 3 also produces an incompatible mixture of i-PP and s-PP. However, in the presence of an excess of a crossover agent such as triisobutylaluminum (TIBA), a new polymeric material is obtained that exhibits lower T_m and ΔH_f than either of the two homosteric polymers and a much faster rate of crystallization than that of s-PP or its physical mixture with i-PP. Thermal annealing of this product markedly reduces the relative amount of crystalline phase compared to the amorphous phase and atomic force microscopy finds only microphase separation but not macroscopic phase separation. Fractionation and ¹³C-NMR showed the material to contain not only the homosteric i-PP and s-PP but also a stereoblock PP (i-PP-b-s-PP). The stereoblock fraction acts as a compatibilizing agent; it probably is produced by the exchange of propagating polymer chains between the syndiospecific and the isospecific sites assisted by the crossover agent. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2439–2445, 1999     

The phase equilibria in some binary systems containing stearic alcohol

The liquid — liquid and liquid — solid equilibrium temperatures are taken for the binary systems octadecanol + A (A=dicarboxylic acids, biphenyl or (K, Na) stearate). The results are discussed and a relation connecting the composition of the eutectics with the thermodynamic properties of fusion of the components is derived from the ideal equation and compared with the experimental one.

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Zusammenfassung Die Flüssig-Flüssig- und Flüssig-Fest-Gleichgewichtstemperaturen der binÄren Systeme Octadecanol + A (A=DicarboxylsÄuren, Diphenyl oder (K, Na/ Stearat) wurden ermittelt. Die Ergebnisse werden diskutiert und ein Zusammenhang zwischen der Zusammensetzung der Eutektika und den Thermodynamischen Eigenschaften der Schmelze der Komponenten wird aus dem Vergleich der idealen und der auf dem Versuchswege erhaltenen Gleichungen abgeleitet.

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Résumé On a mesuré les températures des équilibres liquide-liquide et liquide-solide des systèmes binaires octadécanol + A (A=acides dicarboxyliques, diphényle ou stéarate de potassium, sodium). On discute les résultats et l'on établit une relation entre la composition des eutectiques et les propriétés thermodynamiques de fusion des constituants, dérivée de l'équation initiale et comparée avec la relation expérimentale.

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- - + A (A = , (K, Na) ). , .

     

Radiation-induced polymerization of glass-forming systems. V. Initial polymerization rate in binary glass-forming systems

The radiation-induced polymerization of binary systems consisting of glass-forming monomer and glass-forming solvent in supercooled phase was studied. The initial polymerization rates were markedly affected by T_g (glass transition temperature) and T_v of the system (30–50°C higher than T_g), which turned to be functions of the composition. The composition and temperature dependence of initial polymerization rate in binary glass-forming systems were much affected by homogeneity of the polymerization system and the T_g of the glass-forming solvent. The composition and temperature dependences in the glycidyl methacrylate–triacetin system as a typical homogeneous polymerization system were studied in detail, and the polymerizations of hydroxyethyl methacrylate–triacetin and hydroxyethyl methacrylate–isoamyl acetate systems were studied for the heterogeneous polymerization systems; the former illustrates the combination of lower T_g monomer and higher T_g solvent and the latter typifies a system consisting of higher T_g monomer and lower T_g solvent. All experimental results for the composition and temperature dependence of initial polymerization rate in binary glass-forming systems could be explained by considering the product of the effect of the physical effect relating to T_v and T_g of the system and the effect of composition in normal solution polymerization at higher temperature, which was also the product of a dilution effect and a chemical or physical acceleration effect.     

Preparation and polymerization of some vinyl monomers containing the 2-oxo-1,3-dioxolane group

The syntheses and polymerizations of (2-oxo-1,3-dioxolan-4-yl)methyl acrylate, 4-(2-oxo-1,3-dioxolan-4-yl)methyl itaconate, and (2-oxo-1,3-dioxolan-4-yl)methyl maleate are described. Reactivity ratios in the copolymerization of these monomers with other comonomers are reported and the Alfrey-Price Q and e values calculated. The post-polymerization effects of ultraviolet light and heat on these polymers and copolymers are presented and compared to those for similar polymers containing the 2,2-dimethyl-1,3-dixolane groups, which performs as an internal ultraviolet sensitizer. The 2-oxo derivatives are crosslinked thermally but not by ultraviolet light. The crosslinking reaction can be catalyzed by acids, bases, and salts.     

Thermodynamics of binary mixtures containing alkynes. II

Molar excess enthalpiesH ^E of 1-hexyne + carbon tetrachloride, + dipropyl ether, + triethylamine, and of 3-hexyne + carbon tetrachloride, + dipropyl ether, + triethylamine at 298.15 K and atmospheric pressure were measured with aPicker-type flow microcalorimeter over the whole concentration range. At equimolar concentration,H ^E of 3-hexyne + carbon tetrachloride is stronglyexothermic (–499 J mol^–1), in contrast toH ^E =+14 J mol^–1 for the 1-hexyne system. As expected, for the ether and amine systems inverse behavior is observed: because of the active hydrogen of terminal alkynes the enthalpy of mixing at equimolar concentration is more exothermic with 1-hexyne (–185 J mol^–1, dipropyl ether; –300 J mol^–1, triethylamine) than with 3-hexyne (–25 J mol^–1, dipropyl ether; –92 J mol^–1, triethylamine). The curveH ^E vs. mole fraction is considerably skewed for 3-hexyne (x ₁) + triethylamine, the minimum being ca. –197 J mol^–1 atx ₁0.9.

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Thermodynamik binärer Mischungen mit Alkinen als eine Komponente. II. Zusatzenthalpien binärer Mischungen von 1-Hexin und 3-Hexin mit Tetrachlorkohlenstoff, Dipropyläther und Triäthylamin bei 298,15 K

Zusammenfassung Die molaren ZusatzenthalpienH ^E der sechs binären Systeme 1-Hexin + CCl₄, + Dipropyläther, + Triäthylamin, und 3-Hexin + CCl₄, + Dipropyläther, + Triäthylamin wurden bei 298,15 K und Atmosphärendruck über den gesamten Konzentrationsbereich mit einem dynamischen Strömungsmikrokalorimeter nachPicker gemessen.H ^E des Systems 3-Hexin + CCl₄ ist starkexotherm (–499 J mol^–1 fürx=0,5),H ^E des Systems 1-Hexin + CCl₄ endotherm (+14 J mol^–1,x=0,5). Hingegen verhalten sich die Mischungen Hexin + Dipropyläther bzw. + Triäthylamin den Erwartungen entsprechend. Wegen des aktiven Wasserstoffs endständiger Alkine ist die Zusatzenthalpie mit 1-Hexin stärker exotherm (–185 J mol^–1 mit Dipropyläther und –300 J mol^–1 mit Triäthylamin,x=0,5) als mit 3-Hexin (–25 J mol^–1 bzw. –92 J mol^–1). Die molare Zusatzenthalpie des Systems 3-Hexin (x ₁) + Triäthylamin ist ausgeprägt asymmetrisch mit einem Minimum von etwa –197 J mol^–1 beix ₁0,9.

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Communicated in part at the 2. Ulmer Kalorimetrietage, March 24–25, 1977, Ulm, Federal Republic of Germany.     

Radiation-induced solid-state polymerization in binary systems. IV. Solid-state polymerization in the glassy phase

The radiation-induced polymerization of glass-forming systems containing monomers has been investigated. It was found that irradiation below the second-order transition temperature T_g of the systems causes no in-source polymerization but causes a rapid postpolymerization on warming above the T_g after initial irradiation below the T_g. The post-polymerization was followed by differential thermal analysis and ESR spectra. It is caused above the T_g by the release of peroxy radicals trapped below the T_g, and its rate is proportional to the irradiation dose to some extent, often is explosively high, and brings about a remarkably large temperature rise by accumulation of polymerization heat. Irradiation above the T_g causes rapid in-source polymerization which is accelerated by the high viscosity of the monomeric system between T_g and T_s (WLF temperature) compared to crystal or ordinary solution polymerization. The temperature dependence of the in-source polymerization of glassy systems shows a peak between the T_g and T_s which may be the result of competing effects of the rate increase by the decreased termination near T_s and the rate decrease by the decreased propagation caused by the diffusion prevented near the T_g. The degree of polymerization was also investigated. The temperature dependence of the degree of polymerization of the polymers obtained by in-source polymerization shows a peak similar to that of the temperature dependence of conversion. Unusually large values of the Huggins constant k' are noted between T_g and T_s. The degree of polymerization of the polymer obtained by post-polymerized increases with the increase of irradiation dose and the polymerization rate; this may be the result of decreased chain transfer to nonpolymerizable components.     

The liquid-liquid and liquid-solid equilibria in some binary systems containing alkali metal stearates

The characteristics are submitted of the crystallization curves of binary systems composed of sodium or potassium stearate as one component and succinic, glutaric, adipic, pimelic, suberic or azelaic acid as the other.We are grateful to the CNR (Rome) for financial aid (CT-74-00676-03).     

Thermodynamic studies of some binary mixtures containing a self-associated component. II. Excess volumes of some mixtures of tetrahydrofuran with alcohols

Excess volumes of mixing, V^E, for binary mixtures of tetrahydrofuran (THF) with methanol, ethanol, n-butanol, tert-butanol, 2-bromoethanol and ethylene glycol have been determined from the experimental density measurements at 298.15 K over the entire composition range. The V^E data follow the order: ethylene glycol < 2-bromoethanol < methanol < ethanol < n-butanol < tert-butanol. The results have been explained in terms of self-association and the hydrogen bond-donating abilities of alcohols.     

有机硅活性中间体的研究 II. 一些含环丙基的有机硅化合物的合成及其结构

用锂有机物的方法合成了四种含有环丙基有机硅化合物,对上述每种化合物中可能存在着的立体异构进行了分离和和构型测定。     

Vapor–liquid equilibria in the binary system (−)-beta-pinene + (+)-fenchone: Analysis in terms of group contributions models of some binary systems containing terpenoids

Isobaric vapor–liquid equilibrium measurements are reported for the binary system (−)-beta-pinene + (+)-fenchone at the constant pressure of 13.33 kPa in the temperature range from 341.60 K to 393.25 K. The boiling temperatures of the mixtures were also measured at seven constant compositions in the pressure range from 2.56 kPa to 20.80 kPa. The experimental data were found to be thermodynamically consistent. Reduction of the vapor–liquid equilibrium data was carried out by means of the Wilson, NRTL and UNIQUAC equations. Our data on vapor–liquid equilibria for mixtures containing terpenoids are examined in terms of the DISQUAC and modified UNIFAC (Dortmund) group contributions models. Interaction parameters of the DISQUAC model are reported.     

Anionic polymerization initiators containing protected functional groups. II

An organolithium reagent substituted with a primary amine-protecting group [i.e.,? N(TMS)₂] has been prepared and used to polymerize 1,3-butadiene and isoprene. A method is described for converting the resulting? N(TMS)₂-containing polydienes into? NH₂-containing polymers. Both ? N(TMS)₂- and ? NH₂-terminated polydienes have been characterized with regard to microstructure, M _n, and M _w/M _n data, as well as qualitative and quantitative end-group analyses. The described preparative procedures represent a convenient route to the elusive primary amine-terminated polydienes.     

Studies in some new initiator systems for vinyl polymerization. II. Ammonia–halogen system as the redox initiator

The ammonia–halogen redox system has proved a promising initiator for polymerizing a number of vinyl monomers in aqueous media. Chlorine and bromine are most efficient, whereas iodine fails to initiate polymerization, probably due to its inhibitive tendency. Endgroups are halogen and amine and total about 0.5 per chain. On the basis of results of endgroup analysis, a mechanism of initiation through halogen and amine radicals, mainly through hydrogen atoms, is suggested. Consistent with the proposed mechanism the endgroup profile changes significantly with changes in pH.     

Synthesis and in vitro cytotoxic evaluation of some novel hexahydroquinoline derivatives containing benzofuran moiety

A series of new ethyl 4-(2-(benzofuran-2-yl)-4-substituted-1,4,5,6,7,8-hexahydroquinolin-1-yl)-benzoate 3a–c was synthesized by Michael condensation of benzofuran chalcones 1a–c and cyclohexanone to give 2-(2-benzofuranyl)-4-substituted-5,6,7,8-tetrahydro-4-H -chromene 2a–c, followed by reaction of the latter with ethyl 4-aminobenzoate. Condensation of 3a–c with different amines afforded the corresponding amides 4a–e. On the other hand, upon treatment compounds 3a–c with hydrazine hydrate gave the benzohydrazide derivatives 5a–c. The reaction of compounds 5a–c with different thio/isocyanate gave the corresponding thiosemicarbazide and semicarbazide derivatives 6a–c. Meanwhile compounds 5a–c were reacted with ethyl cyanoacetate and different β-dicarbonyl compounds such as acetyl acetone, ethyl acetoacetate, and diethyl malonate to afford pyrazolyl derivatives 7a, b; 8a, b; 9a, b; and 10a–c, respectively. Moreover, 5a–c were reacted with carbon disulfide to synthesize the corresponding oxadiazolyl derivatives 11a–c, while their condensation with different aromatic aldehydes gave the corresponding Schiff bases 12a–d. Cytotoxic evaluation of some of the newly synthesized compounds against human hepatocellular carcinoma cell lines (HepG-2) revealed that the tested compounds produce promising inhibitory effect against the growth of HepG-2 cells with IC₅₀ values ranged from 11.9 to 19.3 µg/mL.     

Thermodynamics of polymerization. Part IV. Free energy changes of binary copolymerization systems

Using a statistical thermodynamic method we discuss the general shape of a free energy change versus composition curve for a binary copolymerization system. This simple theoretical approach gives reasonable agreement with the experimental results.     

Radiation-induced polymerization of glass forming systems. VI. Polymerization rate at higher conversion in binary systems

The effect of temperature and composition on the inflection point in the time–conversion curve and the saturated conversion was investigated in the radiation-induced radical polymerization of binary systems consisting of a glass-forming monomer and a solvent. In the polymerization of completely homogeneous systems such as glycidyl methacrylate (GMA)–triacetin and hydroxyethyl methacrylate (HEMA)–propylene glycol systems, the time–conversion curve has an inflection point at polymerization temperatures between T_vm (T_v of monomer system) and T_vp (T_v of polymer system). Such conversions at the inflection point changed monotonically between 0 and 100% in this temperature range. T_v was found to be 30–50°C higher than T_g (glass transition temperature) and a monotonic function of composition (monomer–polymer–solvent). The acceleration effect continued to 100% conversion above T_vp, and no acceleration effect was observed below T_vm. The saturated conversion in homogeneous systems changed monotonically between 0 and 100% for polymerization temperatures between T_gm (T_g of monomer system) and T_gp (T_g of polymer system). T_g was also a monotonic function of composition. No saturation in conversion was observed above T_gp, and no polymerization occurred below T_gm. In the polymerization of completely heterogeneous systems such as HEMA–dioctyl phthalate, no acceleration effect was observed at any temperature and composition. The saturated conversion was 100% above T_g of pure HEMA, and no polymerization occurred below this temperature in this system.     

Solid-state polymerization of acrylamide and its derivatives complexed with some lewis acids. II. Radiation-induced in-source polymerization

Radiation-induced solid-state polymerizations of complexes of N-tert-butylacrylamide, N-tert-amylacrylamide, and N-tert-hexylacrylamide with zinc chloride and zinc bromide have been studied. An accelerating effect of temperature and an inhibiting effect of oxygen on the polymerization process were observed. The activation energies have been established. The influence of monomer structure as well as the halide used on the polymerization rate have been discussed and some regularities have been pointed out. The polymers obtained show good solubilities in common solvents, which proves that they are not crosslinked.