摘要:

The polyelectrolyte chain configuration of low molecular weight sodium amylose xanthate (NaAX) in aqueous and salt solutions has been studied by viscometry and light scattering. The viscometric results in aqueous solution have been found to be in accordance with the Fuoss's modified equation. The intrinsic viscosities of NaAX in salt solutions from 0.00125 to 0.25 M NaCl have been determined and the expansion factoraat each ionic strength has been determined. The dependence of a on ionic strength has been studied according to the theories of Hermans and Overbeek, Flory, etc. But though qualitative agreement between experimental and theoretical results has been found, quantitative agreement was far from expectations. The frictional coefficient per monomer unit | has been calculated from the relationship of Kirkwood and Riseman. The NaAX macromolecule has been found to have the polydispersed random coil chain configuration in 0.25 M NaCl. Some macromolecular configurational parameters such as effective bond length b, Kuhn-Kuhn equivalent chain length Am, and steric factor α has been determined.

ISSN:0022-233X    

DOI:10.1080/00222337108061097

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Because of the intriguing Theological behavior of alginates and unanswered questions concerning the solution conformation of these biopolymers, some of the physicochemical properties of alginates were investigated by means of light-scattering, rheology, optical rotation, nuclear magnetic resonance, and near infrared spectroscopy studies.

ISSN:0022-233X    

DOI:10.1080/00222337108061098

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

It is shown that macromolecules with polyconjugated systems are capable of forming strong 7r-complex associates. The paramagnetic centers cause intercombinative transitions in auto- or α-complexes with other molecules and increase their reactivity (“effect of local activation”).

ISSN:0022-233X    

DOI:10.1080/00222337108061099

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

The thermal degradation mechanism of tetrabrominated epoxy resin was investigated in order to explain its flame retardant mechanism. From the results obtained it was concluded that the flame retardant mechanisms are 1) a lowering of temperature through degradation and 2) the formation of hydrogen bromide and its role in catalysis in the condensation reaction of the resin.

ISSN:0022-233X    

DOI:10.1080/00222337108061100

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Chloromaleic anhydride was found to copolymerize with divinyl ether to form soluble copolymers of 1:1 composition, devoid of residual unsaturation. A bicyclic structure is proposed in which the polymer backbone consists only of divinyl ether units. The ease with which the copolymers underwent dehydrohalogenation suggests that the hydrogen and chlorine atoms on the anhydride unit are in a trans configuration as a result of a stepwise cycli-zation process.

ISSN:0022-233X    

DOI:10.1080/00222337108061101

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

A simple Huckel treatment of the transition states for the monomer-radical reactions in free radical copolymerization is developed. The resulting equations for the reactivity ratios are compared with those from the Q-e treatment of Alfrey and Price. It is concluded that the Q-e scheme can be regarded as a version of a molecular orbital approach.

ISSN:0022-233X    

DOI:10.1080/00222337108061102

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

The copolymerization of styrene with methyl methacrylate (S/MMA = 4/1) or acrylonitrile (S/AN = 1/1) in the presence of ethylaluminum sesquichloride (EASC) yields 1/1 copolymer in toluene or chlorobenzene. In chloroform the S-MMA-EASC polymerization yields 60/40 copolymer while the S-AN-EASC polymerization yields 1/1 copolymer. In the presence of EASC, styrene-α-chloroacrylonitrile yields 1/1 copolymer (DMF or DMSO), S-AN yields 1/1 copolymer (DMSO) or radical copolymer (DMF), S-MMA yields radical copolymer (DMF or DMSO), α-methylstyrene-AN yields radical copolymer (DMSO) or traces of copolymer (DMF), and α-MS-methacrylo-nitrile yields traces of copolymer (DMSO) or no copolymer (DMF). When zinc chloride is used as complexing agent in DMF or DMSO, none of the monomer pairs undergoes polymerization. However, radical catalyzed polymerization of isoprene-AN-ZnCl2in DMF yields 1/1 alternating copolymer. The copolymerization of S/MMA in the presence of EASC yields 1/1 alternating copolymer up to 100°C, while the copolymerization of S/AN deviates from 1/1 alternating copolymer above 50°C. The copolymerization of S/MMA deviates from 1/1 copolymer at MMA/EASC mole ratios above 20 while the copolymerization of S/AN deviates from 1/1 copolymer at MMA/EASC ratios above 50.

ISSN:0022-233X    

DOI:10.1080/00222337108061103

出版商:Taylor & Francis Group    

年代:1971

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:10.1080/00222337108061096

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor