摘要:

2,2,3,3-Tetramethyl-1,4-dibromobutane, when used as monomer for polymerization by Wurtz-type polycondensation, gave head-to-head polyisobutylene which is branched. Under similar conditions, 2, 5-dimethyl-2, 5-dibromohexane gave no polymer. Copolymerization of ethylene with tetramethylethylene under various conditions gave polyethylene of modest molecular weight with about 5% tetramethylene units in the polymer. 1,1,4, 4-Tetramethyl-1,3-butadiene (2,5-dimethylhexadiene-2,4) polymerized with BF3initiator to high molecular weight trans- 1,4-poly-(1,1,4,4-tetrarnethylbutadiene-1,3). The polymer could not be hydrogenated with soluble hydrogenation catalysts and only partially by chemical reduction with diimide. Under forcing conditions, incorporation of portions of the decomposition products of the precursor of the diimide was observed.

ISSN:0022-233X    

DOI:10.1080/00222338508063361

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The rate of emulsion polymerization of N-butyl acrylate and glycidyl methacrylate is influenced by the irradiation dose rate and the emulsifier type. With regard to the rate of polymerization and the stability of polymer emulsion, sodium dodecyl benzene sulfonate (SDBS) is found to be a better emulsifier than Tween 20. Irradiation dose, in order to obtain 90% conversion, is about 50 krd using SDBS emulsifier, compared to about 160 krd using Tween 20 emulsifier, both with an irradiation dose rate of about 80 krd/h. Irradiation dose, in order to obtain the same conversion, decreases with a decrease in irradiation dose rate. Thermal analysis showed that the glycidyl methacrylate content greatly influences the thermal stability of the polymer film.

ISSN:0022-233X    

DOI:10.1080/00222338508063362

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

We have defined electrochemical reactions (oxidation, reduction, coupling, etc.) and processes for potentially obtaining useful fuels, chemicals, and/or polymer intermediates from biomass-derived raw materials. Advantages of electrochemical processing include room temperature reactions, high driving forces, energy efficiency, and operability in relatively dilute solutions. Additional potential advantages are higher yield of desired products, easier separations, higher concentrations of final products (in process solutions), and the ability to “tailor the reaction to produce more of a specific product and/or different products.”

ISSN:0022-233X    

DOI:10.1080/00222338508063363

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A study of the copolymerization of α-pinene and styrene has been carried out at 10°C using anhydrous AlCl3as the initiator. It is found that styrene forms copolymer with α-pinene at all mono-meric ratios. A copolymer of 2320–3080 molecular weight is obtained. The softening range of the copolymer is 82 to 85°C. The copolymers are of commercial value.

ISSN:0022-233X    

DOI:10.1080/00222338508063364

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

In addition to the usual polydispersity with respect to molar mass, copolymers show chemical polydispersity. Thus, the species present may not be adequately characterized by a single variable, and a divariate distribution function has to be applied for describing the composition of the copolymer. In continuous thermodynamics, such continuous distribution functions are used directly (without splitting into pseudocomponents) for describing the composition of complex multicomponent systems. Whereas until now usually only one distribution variable has been used in continuous thermodynamics, consideration of copolymers requires an extension to divariate distribution functions. Continuous thermodynamics is generalized to divariate distribution functions in this paper. The liquid-liquid equilibrium of copolymer solutions is considered as a specific example.

ISSN:0022-233X    

DOI:10.1080/00222338508063365

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The kinetics of the polymerization of arylonitrile with ceric ammonium sulfate in the presence of 2-propanethiol as the redox initiator system in aqueous solution has been investigated. The rate of polymerization was found to be proportional to the square root of both ceric ion and thiol concentrations, and the monomer exponent was close to 1.5. Spectral studies indicated that there is a complex formation between ceric ion and the monomer acrylonitrile. A kinetic scheme, based on initial formation of this complex and its subsequent reaction with the thiol to produce the free radicals (RS.) responsible for initiation has been postulated to account for the observed results. The activation energy and different kinetic and transfer constants for the system have also been evaluated.

ISSN:0022-233X    

DOI:10.1080/00222338508063366

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A screening procedure has been developed to predict the average sequence distribution in vinyl copolymers from monomer13C-NMR data. The13C-NMR absorption frequencies of the carbon atoms of the polymerizable double bond are used to calculate the Alfrey-Price Q and e values as previously described by Borchardt and Dalrymple. These, in turn, are used to calculate the monomer reactivity ratios. Reactivity ratios for 54 copolymerizations were calculated by this procedure and compared to literature values. The copolymer sequence distribution may then be determined by means of a computer program written by Harwood. The sequence distribution in copolymers of methacrylic acid and dimethyl-aminoethyl methacrylate, acrylonitrile and methyl methacrylate, 1,1-dichloroethylene and methacrylonitrile, ethyl acrylate and n-butyl methacrylate, and acrylamide and sodium 2-acrylamido-2-methylpropane sulfonate were calculated from reactivity ratios derived from13C-NMR data and compared to literature values. This procedure may be used to calculate the reactivity ratios from13C-NMR spectra of monomers for which no Q and e values are known. By this method the average sequence distribution of such monomers in copolymers may be predicted, significantly reducing the number of copolymers to be synthesized and tested for use in various applications.

ISSN:0022-233X    

DOI:10.1080/00222338508063367

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Kanamycin, a broad-spectrum antituberculosis antibiotic, was coupled to three different collagen substrates using l-ethyl-3-(3-dimethylaminopropyl)carbodiirnide, glutaraldehyde, and periodiate-oxidized kanamycin possessing aldehyde functional groups. Kanamycin-treated collagen fibers have exhibited marked differences in their chemical contraction and relaxation, swelling, and shrinkage-temperature behavior compared to untreated collagen fibers. In an in vitro study, a release of 26% of the bound kanamycin from collagen-kanamycin complex was noticed.

ISSN:0022-233X    

DOI:10.1080/00222338508063368

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A group of six semiaromatic polyamides of 2,2′-[isopropylidenebis-(p-phenyleneoxy)]diacetic acid (Bisacid A2) were synthesized by low-temperature solution polycondensation techniques. Six different diamines were condensed independently with Bisacid A2chloride in a mixture of N-methylpyrrolidone (NMP and hexamethylhosphoramide (HMPA). The polymers were obtained in 82–95% yield and possessed inherent viscosities in the range from 0.32 to 0.63 dL/g. The polyamides were characterized by IR and 'H-NMR spectra. The molecular weight and molecular weight distribution of the polyamides were determined by gel-permeation chromatography. The thermal stability, thermal degradation kinetics, crystallinity, density, and solubility were also determined. A model diamide (MDA) was synthesized from aniline and Bisacid A2chloride to confirm the formation of polyamides from diamines.

ISSN:0022-233X    

DOI:10.1080/00222338508063369

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0022-233X    

DOI:10.1080/00222338508063360

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor