摘要:

In order to ascertain the effect of a donor monomer, vinyl acetate (VAc), on the graft copolymerization of acceptor monomers, ethyl acrylate (EA) and butyl acrylate (BA), grafting of mixed vinyl monomers (EA + VAc) and (BA + VAc) was carried out on Himachali wool in aqueous medium using ceric ammonium nitrate (CAN) as a redox initiator. Graft copolymerization was carried out at different temperatures for various reaction periods. Percent grafting and percent efficiency were determined as functions of 1) concentration of mixed vinyl monomers, 2) concentration of CAN, 3) concentration of HNO34) temperature, and 5) reaction time. VAc, the donor monomer, was found to decrease percent grafting of EA and BA onto wool.

ISSN:0022-233X    

DOI:10.1080/00222338508056602

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The effect of polyanions on the formation of mixed dimers of methylene blue (MB) and trypaflavine (TF), MB and phenosafranine (PhS), and MB and pyronine G (PG) was investigated spectrophotometrically. The following polyanions were used: potassium poly(vinyl sulfate) (PVSK), potassium poly(styrenesulfonate) (PSSK), sodium poly(methacrylate) (PMANa), and sodium poly-(acrylate) (PAANa). The formation of mixed dimers was dependent on the kind of polyanion and polyanion-dye ratio. MB-photo-sensitized isomerization of cis-p-(phenylazo)-phenyltrimethyl-ammonium iodide (cis-PTA) to the trans-isomer was used advantageously to investigate the triplet excitation energy transfer between cationic dyes bound to polyanions. Although the efficiency of the excitation energy transfer between MB and cis-PTA was enhanced by the addition of polyanions, the formation of mixed dimer of MB with TF, PhS, or PG reduced the efficiency of the excitation energy transfer. Correlation with the formation of mixed dimer of MB with TF, PhS, or PG and the efficiency of the excitation energy transfer from MB to cis-PTA is discussed.

ISSN:0022-233X    

DOI:10.1080/00222338508056603

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This paper describes the evaluation of several polyethylene films that are suitable as liners for baby diapers. The chemical and physical characteristics of the films are discussed. Also discussed are polyblends as a route to films having unusual and superior mechanical properties.

ISSN:0022-233X    

DOI:10.1080/00222338508056604

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Solid-state13C-CP/MAS NMR has been used to obtain structural information on three Australian sapwoods (two hardwoods and one softwood), their residues after chemical treatment, and the frasses obtained after digestion by wood-eating termites and beetles. Whole wood spectra indicate substantial differences in both the lignin and hemicellulose components between the hardwoods and the softwood.

ISSN:0022-233X    

DOI:10.1080/00222338508056605

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Owing to their very large number, the composition of polymers is usually described by continuous distribution functions. A version of thermodynamics–called continuous thermodynamics–is established which is based directly on a continuous distribution function instead of the mole fractions, weight fractions, etc. of individual components or pseudocomponents. This continuous thermodynamics is applicable to all complex multicomponent systems such as petroleum, coal-derived liquids, tars, and polymers. Continuous thermodynamics is used in this paper for treating the influence of polymer polydispersity on the liquid-liquid equilibrium of polymer solutions. From a practical point of view, the main advantages of continuous thermodynamics in comparison with the pseudocomponent method are fewer convergence problems and a drastic reduction of computer time.

ISSN:0022-233X    

DOI:10.1080/00222338508056606

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Further properties of a Formula Periodic Table for Benzenoid PAH6s are presented. Whether the number of components of 1-factor and 2-factor subgraphs of benzenoid hydrocarbons are even or odd and the sign of the aNcoefficient of the characteristic polynomial is negative or positive are prescribed by this table. A method for computing the number of Dewar structures from the aacN-2coefficient of the acrylic polynomial is reviewed. It is shown that a stronger correlation of resonance energy and In aacN-2of In KNcexists than for In K where K = SC (structure count) aacN. It is conjectured that ethene is subspectral to all benzenoid PAH6 structures belonging to the Nc= 0(mod 4) row series of the formula periodic table for benzenoid PAH6s.

ISSN:0022-233X    

DOI:10.1080/00222338508056607

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The complex formation between cyclic urethane based on diethylene glycol and hexamethylene diisocyanate and ZnCl2has been investigated by the NMR method. It has been established that coordination proceeds only through oxygen atoms of cyclic urethane. Its ability to aggregate into ordered clusterlike complexes under the influence of ZnCl2has been proved, The effect of clusterlike complexes on styrene polymerization in the presence of such complexes and pure cyclourethane, leading to polyrotaxane formation, has also been investigated. X-ray diffractograms of extracted reaction products show the maxima typical for both polystyrene and cyclic urethane. The analogous investigation of products obtained in the presence of the linear analogue of cyclic urethane and its complexes with ZnCl2prove that polystyrene and urethane are not chemically bonded. The number of cyclic molecules corresponding to one polymer chain in the polyrotaxanes obtained has been calculated. It was established that this number is notably increased when cyclourethane is preliminarily bonded into clusterlike complexes with ZnCl2.

ISSN:0022-233X    

DOI:10.1080/00222338508056608

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Random copolyesters were prepared from dimethyl terephthalate, ethylene glycol (EG), and propane-1,3-diol (PrG) by melt-poly-condensation techniques, using varying amounts of EG and PrG. Compositions have been established by proton NMR spectroscopy. Intrinsic viscosity and number-average molecular weight were measured. Thermal properties have been studied by differential thermal analysis. Melting and degradation temperatures and thermodynamic parameters are discussed in terms of structural differences, particularly the effect of composition and chain flexibility.

ISSN:0022-233X    

DOI:10.1080/00222338508056609

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The copolymerization of N-vinylpyrrolidone (NVP) with chlorotrifluoroethylene (CTFE), initiated by gamma rays from a60Co source, has been studied at temperatures of 20 to −78°C in a dose rate range of 5 × 104to 3.8 × 105rd/h. The copolymerization rate was proportional to the 0.5 power of dose rate and showed a maximum at the equimolar concentration of both monomers. The apparent overall activation energy of copolymerization was determined to be 5.8 kcal/mol. 1, 1-Diphenyl-2-picrylhydrazil was found to be a strong inhibitor. The composition curve indicated a strong alternating copolymerization tendency. The monomer reactivity ratios were determined to be r(NVP) = 0.38 and r(CTFE) = 0.30, respectively, by the Fineman-Ross method. The copolymer obtained is a white powder. It is soluble in such solvents as acetone, dimethylformamide, and chloroform, but insoluble in water.

ISSN:0022-233X    

DOI:10.1080/00222338508056610

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:10.1080/00222338508056601

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor