摘要:

A nonlinear method (OPT) for the estimation of the reactivity ratios in copolymerization processes is proposed. This method makes use of all experimental data (the conversion values included) and may also use the composition equations determined according to either the simple terminal kinetic model or the penultimate model. It can be extended to ternary copolymerization processes, too. Application of OPT to ternary copolymerization data lead to reactivity ratios that are different from those obtained for the respective binary copolymerizations. The former give a better fit to the experimental results than the latter.

ISSN:0022-233X    

DOI:10.1080/00222338908052056

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

An analysis of experimental data for ternary copolymerizations has been performed by an optimizing calculation method, resulting in the estimation of therijcopolymerization constants. The azeotrope calculation results have been compared to those based on therijconstants found for binary copolymerization. For each set ofrijconstants, the possibility of the ternary azeotropy was studied. The formation of quasihomogeneous ternary copolymers was studied subsequent to the determination of the ternary pseudoazeotropy domains occurring at the intersection of the partial pseudoazeotropy domains.

ISSN:0022-233X    

DOI:10.1080/00222338908052057

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Long-alkyl-chain phenyl esters of β-alanine, glycine, andL-valine were prepared, and their monolayer properties were correlated with their molecular structures. These compounds formed stable monolayers on acidic subphases. In particular, thep-hexadecylphenyl esters of β-alanine and glycine were remarkably stable, and their monolayers could be deposited on calcium fluoride plates as Y-type film by Blodgett's technique. The polycondensation of multilayers under an atmosphere saturated with triethylamine was investigated by changes in the IR spectra. It was determined that the polycondensation proceeded by a first-order reaction mechanism in the initial stage and that the rate in multilayers was faster than that in the bulk crystalline powder. These results suggest that the polycondensation is accelerated by a regular arrangement of the monomer in the multilayers, where the active sites are concentrated and located better for the polycondensation. In the case of the polycondensation in multilayers of the glycine ester, two kinds of condensation proceeded to afford poly(glycine) and 2,5-piperazinedione.

ISSN:0022-233X    

DOI:10.1080/00222338908052058

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Chelate polymers derived from bis(2,4-dihydroxybenzaldehyde)propyl-enediimine M and bis(2,4-dihydroxyacetophenone)propylenediimine M (M = Fe2+, Co2+, Ni2+, Cu2+, Zn2+) with aromatic acid chlorides were prepared by interfacial polycondensation. Also, chelate polysiloxanes were obtained from the same monomers and α,ω-dichloropolydimethyl-siloxane. The spectral, thermal, magnetic, and electrical properties of the polychelates were studied.

ISSN:0022-233X    

DOI:10.1080/00222338908052059

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Polymeric analogs of tetramethylurea were prepared by free-radical polymerization ofN,N,N'-trimethyl-N'-p-vinylbenzylurea and copolym-erization of this monomer with styrene. These polymers are soluble in toluene and have the ability to extract alkali metal ions such as lithium, sodium, and potassium. Moreover, these polymers act as phase-transfer catalysts for typicalSN2 reactions, although the monomeric analogs tetramethylurea andN,N,N'-trimethyl-N'-benzylurea do not. A plausible mechanism for these catalytic reactions is proposed.

ISSN:0022-233X    

DOI:10.1080/00222338908052060

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A study of the solid-state ultraviolet photoreaction of polymer-bound pyridine andp-nitrophenoxy groups has shown that pyridinium nitrite crosslinks result from the photoquaternization process. The generation of ionic groups in the crosslinking effectively inhibits the solubility of the irradiated polymer matrix in nonpolar solvents.

ISSN:0022-233X    

DOI:10.1080/00222338908052061

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The solubilities and viscosities of four novel symmetric tri-n-alkyltin fluorides in various organic solvents were studied. It is shown that these compounds do behave as transient polymers. Increasing the length of then-alkyl chain beyondn-butyl imparts considerable solubility to this class of associative polymers and offers no steric hindrance to polymer chain formation. The effects of concentration, solvent type, temperature, and brine on the solution viscosities were also studied. These associative polymers effectively viscosify compressed gases (having liquid-like densities), such as propane andn-butane. They can therefore be used in enhanced oil recovery operations as well as in fracturing of oil wells.

ISSN:0022-233X    

DOI:10.1080/00222338908052062

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A great number of studies of polyelectrolyte complexes have been carried out by various investigators; most of them concentrated on the reaction between oppositely charged polyelectrolytes [1-3]. The structure and properties of the resultant complexes have been investigated to a lesser extent, and the understanding of this new class of polymer materials is still insufficient. Thus, we have been investigating the sorption of water vapor by the complexes and the morphological changes caused by this sorption [4,5].

ISSN:0022-233X    

DOI:10.1080/00222338908052063

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

In spite of the low reactivity of allyl monomers, attempts have been made to prepare polymers by polyrecombination of allyl aromatic compounds. We were encouraged by the stability of allyl radicals [1-8]. The literature on the Claisen rearrangement of polyfunctional allyl aryl ethers contains some observations of the formation of tarry masses and resinification of polyfunctional aryl ethers. Details of the polymerization and the possible structures were not studied. We felt it interesting to synthesize this new monomer, 2-methyallyl-p-cresol, by the rearrangement, and to study in detail the polymerization and characterization of the polymer.

ISSN:0022-233X    

DOI:10.1080/00222338908052064

出版商:Taylor & Francis Group    

年代:1989

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:10.1080/00222338908052055

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor