摘要:

The anomalous properties of the supercritical region require that, when the pressure-coefficient of the rate constant is expressed according to transition-state theory, the meaning of the term “volume of activation” be analyzed with care. Applications to the polymerization of ethylene are shown.

ISSN:0022-233X    

DOI:10.1080/00222337108061105

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Various kinds of the complexes of 2-phenyl-2-oxazoline with various Bronsted acids were prepared. From the elementary analysis and spectroscopic analysis of the complex, it was identified to be an equimolar oxazolinium salt. The monomer could be polymerized with the oxazolinium salt to give N-benzoyl-polyethylenimine. The polymer yield in bulk polymerization was linearly proportional to the reaction time, and the number-average degree of polymerization of the polymer obtained at the complete conversion was proportional to the initial molar ratio of the monomer to the complex. The catalytic activities of the oxazolinium salts increased with a decrease in the pKavalue of Bronsted acid in water. The results of the infrared spectroscopy and nuclear magnetic resonance spectroscopy of the oxazolinium salt at room temperature and elevated temperature indicated that the change of the double bond character of the imino and ether linkages is brought about by the complexation. On the basis of these results, the mechanism of the polymerization was proposed.

ISSN:0022-233X    

DOI:10.1080/00222337108061106

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

cis- and trans-Propylene oxide-1-d were synthesized from the corresponding propenyl halides via propenyllithium and propylene bromohydrin. Their NMR spectra (about 3% in benzene) were analyzed in terms of ABX3spin system and the assignment was carried out. The chemical shift of the methylene proton in cis position to the methyl group was found to be Δ = 1.86 ppm and that of the methylene proton in trans position Δ = 2.18 ppm (downfield from HMDS). The H-D couplings were observed in the methine-methylene part spectra decoupled from methyl protons. The observed JHD's agree with the theoretical relation: JHH= 6.5 14 X JHD.

ISSN:0022-233X    

DOI:10.1080/00222337108061107

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Except for a first-order dissociation, complete conversion is not possible in an equilibrium process no matter how efficient the removal of a byproduct may be. In a first-order dissociation process, complete reaction is only possible when the ratio of the rate constants of the forward to the backward reaction is greater than unity.

ISSN:0022-233X    

DOI:10.1080/00222337108061108

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

The excluded volume in macromolecules has been discussed in an elementary way, and has been compared with that of the real gases. The excluded volume has been classified into two categories, namely, inter-and intramolecular excluded volumes, and have been discussed in greater length in terms of their origin and their influence on configurational and hydrodynamic properties. It is concluded that the calculation of inter-molecular excluded volume is not difficult, while the intramolecular excluded volume requires detailed knowledge about the nature and the various interactions between the polymer segments.

ISSN:0022-233X    

DOI:10.1080/00222337108061109

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

The validity of the current statistical theory of rubber elasticity is verified by demonstrating the importance of intra- rather than intermolecular forces in the energy contribution to the elastic stress of polyacrylates.

ISSN:0022-233X    

DOI:10.1080/00222337108061110

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Melt index and melt viscosity measurements have been made on a series of ethylene-acrylic acid-acrylamide terpolymers. The terpolymers were prepared from a 2000 melt index ethylene-methyl acrylate copolymer and synthesis conditions were adjusted such that the polar groups varied from pure acid to pure amide to pure salt. Results of these measurements indicated the following order of melt viscosities at 190°C: 50% acid-50% amide < 100% amide < 100% acid < 33 1/3% acid amide-salt < 50% salt-50% amide < 50% salt-50% acid ≪ 100% salt. This order apparently arises because of the complex inter- and intramolecular hydrogen bonding and ionic bonding forces that exist in these systems.

ISSN:0022-233X    

DOI:10.1080/00222337108061111

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Anabsoluteanalytical procedure is found for obtaining the parameters of the differential, binary, copolymer composition equation, setting up a least-squares condition that places equal weight on all experimental lines of the Mayo-Lewis plot. The values of monomer reactivity ratios for the system ethyl methacrylate (M1-vinylidene chloride (M2), studied by Agron et al., are r1= 2.052 ± 0.043 and r2= 0.346 ± 0.052. These values, especially r1, differ from the estimates by Agron et al. The new solution, however, appears to yield the estimate of maximum likelihood for the reactivity ratios based on the given experimental data.

ISSN:0022-233X    

DOI:10.1080/00222337108061112

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Alternating copolymers of maleic anhydride and 5-ethylidene-, 5-methylene-, and 5-vinylbicyclo(2.2.1)-2-heptene were synthesized and found to contain the comonomers in a 1:1 ratio. Evidence is presented which supports a bicyclic structure which incorporates maleic anhydride as part of a six- or seven-membered ring in the repeat unit.

ISSN:0022-233X    

DOI:10.1080/00222337108061113

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

The binary system of tetramethyl tetrazene (TMT) and Co(II) chloride was used as initiator of acrylonitrile (AN) in dimethylformamide. The initial rate of polymerization (Rp) was found to be expressed by Rp = k[TMT]0.62[Co(II) chloride]0.57[AN]2.00

ISSN:0022-233X    

DOI:10.1080/00222337108061114

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor