摘要:

High molecular weight polyphenyl-as-triazines were prepared at ambient temperature by the cyclopolycondensation of perfluoroglutaramidrazone and perfluoroadipamidrazone with various bis(1,2-dicarbonyl) monomers. The effect which the perfluoroalkylene group had upon certain chemical and physical properties of the polymers was determined. Thermal evaluation involved TGA, DSC, TMA, and isothermal weight loss studies of films at 232 °C in air. The polymers exhibited excellent hydrolytic stability as evidenced by retention ofninhafter boiling in water (24 hr) and 10% sodium hydroxide solution (8 hr). A stable uncyclized intermediate was isolated from the reaction of perfluoroadipamidrazone and benzil which was cyclized to the phenyl-as-triazine model compound [3,3′ -perfluorotetramethylenedi (5,6-diphenyl-as-triazine)].

ISSN:0022-233X    

DOI:10.1080/10601327508056939

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The new generalized bond energy scheme has been extended to organic oxygen compounds. About 50 different types of bonds have been identified and their ΔHf°(g) contributions and atomization energies evaluated by a procedure similar to multilinear regression analysis. Recent thermochemical data (1969-1973) on 145 oxygen compounds and about 80 ring compounds have been employed to test the efficiency of the scheme in predicting the gas phase heats of formation. This was found to be about ±0. 8 kcal/mole, which is quite comparable to the group contribution method of Benson and co-workers involving a much larger number of parameters.

ISSN:0022-233X    

DOI:10.1080/10601327508056940

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Deviations from the “ideal” behavior have been observed in the polymerization of styrene in acetone. Both monomer and initiator exponents differ from the expected values. The poor thermodynamic properties of acetone as a solvent for the polystyrene chain seem responsible for the decrease of the initiation rate exponent, owing to the presence of a noticeable primary termination reaction. The strong effect of the reaction medium on monomer exponent can be related to the electron-donating tendency of acetone. The sharp decrease of the fractional rate of polymerization as a function of dilution has been interpreted in terms of lowering of the propagation rate constant, presumably due to solvent complexation of the growing chains.

ISSN:0022-233X    

DOI:10.1080/10601327508056941

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The polymerization of acrylonitrile and methyl methacrylate initiated by copper(II) chelates of polyvinylamine and 1,3-diaminopropane was studied kinetically in dimethylsulfoxide solution in the presence and absence of carbon tetrachloride. Time-course changes in visible as well as ESR spectra were measured for different systems containing the copper(II) chelates. The initiation mechanism is discussed from the speetrophotometric and kinetic data results.

ISSN:0022-233X    

DOI:10.1080/10601327508056942

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The tertiary amine catalyzed polymerization of 2-hydroxy-4-(2,3-epoxypropoxy)benzophenone (HEPBP) in melt and o-xylene solution was studied. UV, IR, and NMR spectra of the polymer thus obtained were evaluated and its molecular weight was determined. In order to elucidate the polymerization of HEPBP, the model reaction of 2-hydroxybenzophenone with 4-(2,3-epoxypropoxy)benzophenone at an equimolar ratio as well as the reaction of HEPBP with 2,4-dihydroxybenzophenone at a molar ratio of 2:1 was investigated. A reaction mechanism was suggested for the polymerization of HEPBP on the basis of the results obtained. According to this mechanism, a catalytic center originates during initiation, and that center affords phenoxyl anion by reacting with HEPBP. In the following step phenoxyl anion opens the epoxide ring and an alkoxide anion arises. The basic alkoxide anion is stabilized by a proton transfer of a phenolic group. The successive recurrence of these reactions results in the growth of the polymer chain.

ISSN:0022-233X    

DOI:10.1080/10601327508056943

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Polymerizations of two N-vinylpyridazinones, 3-(2-vinyl)-6-methylpyridazinone (I) and 3-(2-vinyl)-6-methyl-4,5-dihydropyridazinone (II), were carried out in the presence of several acids. The cationic polymerization of II was found to take place in the presence of acids, but not of I. Radical copolymerization of the I-BF3OEt2 complex with styrene gave an alternating copolymer.

ISSN:0022-233X    

DOI:10.1080/10601327508056944

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

2-Vinyl-4,6-diamino-s-triazine (VDAT) was polymerized in aprotic solvents with the basic initiators potassium tert-butoxide (tert-BuOK), sodium methoxide, and n-butyllithium. It was confirmed by IR and NMR that the polymerization progressed by hydrogen transfer. The catalytic activity decreased in the order cited. In the case of tert-BuOK, the mechanism of initiation was investigated by NMR of the polymer obtained at the initial stage and gas chromatographic determination of tert-butanol in the reaction mixture, and the mechanism of propagation was investigated by viscosity measurements, copolymerizations with divinyl compounds, and fractionation of the copolymers. The results showed that the initiation started with hydrogen abstraction by the initiator anion, and that propagation proceeded by inter-molecular hydrogen transfer.

ISSN:0022-233X    

DOI:10.1080/10601327508056945

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

A computer program is described which enables the azeotropic composition of ternary systems to be calculated from known reactivity ratios. Supplementary to this, triangular diagrams showing the dependence of polymer composition on monomer composition may be drawn by a plotter program and give a rapid synopsis of the polymerizing system.

ISSN:0022-233X    

DOI:10.1080/10601327508056946

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

In order to prepare full-cured resin by room temperature curing, the effect of the peak exotherm temperature on the degree of cure was investigated by using three types of unsaturated polyester resins including bisphenol-type, iso-type, and G-type resins. The degree of cure was examined by Barcol hardness, the conversion of styrene, and the conversion of fumarate double bond.

ISSN:0022-233X    

DOI:10.1080/10601327508056947

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The effects of different reaction parameters, such as catalyst, cocatalyst, and temperature, on reactivity ratios have been studied for the case of the copolymerization of propylene oxide (M1) with tetrahydrofuran (M2). The reactivity ratios were found to vary with the type of catalyst and cocatalyst used; however, the product of their values, r1r2, remained essentially constant. For the three catalysts studied, viz., 1) triphenylmethyl cations, (C6H5)3C+, in combination with three different gegenions (hexafluorophosphate, PF6−; hexafluoroarsenate, AsF6−; and hexafluoroantimonate, SbF6−; 2) antimony pentachloride, SbCl5; and 3) borontrifluoride etherate, BF3:(C2H5)2O, the values of r1, calculated on the basis of constant reactivity ratio products, were found to increase with temperature in the range −10 to 20°C. However, for BF3:(C2H5)2O initiated copolymerizations, the values of ri decreased between −30 and −10°C. The magnitude of this increase or decrease depends on the concentration of the diol cocatalyst used. The energetics of the propagation reactions studied, as obtained from plots of In r1and In r2vs 1/T, showed that the concentration of diol had practically no effect on the thermodynamic parameters, ΔH and ΔS. Based on activation enthalpy (ΔH11- ΔH12) and entropy (ΔS11- ΔS12) differences for increasing reactivity of PO, the catalysts were found to lie in the following order with respect to their relative reactivities: (C6H5)3C+SbF6−> (C6H5)3C+AsF6−> SbCl5> (C6H5)3C+PF6−> BF3:(C2H5)2O. The different activation enthalpy and entropy values obtained in the two temperature ranges mentioned above are attributed to the presence of different ion-pairs.

ISSN:0022-233X    

DOI:10.1080/10601327508056948

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor