摘要:

Alternating copolymers of cis-butene-2 and maleic anhydride were esterfied to the methylester which corresponds to head to head (H-H) poly(methyl crotonate).

ISSN:0022-233X    

DOI:10.1080/00222337408068633

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The anionic polymerization of ethylene oxide by alkali metal naphthalenes and anthracenes was studied in DMSO and THF to determine the effects of solvent and of polycyclic hydrocarbon, and to obtain information on the mode of initiation. No propagation occurred with lithium naphthalene, and this made it possible to isolate mono- and dihydroxyethyl naphthalene, the species formed on initiation.

ISSN:0022-233X    

DOI:10.1080/00222337408068634

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Perfluoro- 2,5-diazahexane- 2,5-dioxyl and a polymeric product resulting from its reaction with trifluoronitrosomethane have been used to cross-link elastomeric copolymers prepared from trifluoronitrosomethane, tetrafluoroethylene, and hexafluorobuta- 1,3-diene. The dioxyl, a diradical, is an effective vulcanizing agent at room temperature, and its polymeric derivative is similarly useful at elevated temperatures, presumably via in situ formation of diradicals which effect cross-linking. The thermal stabilities of the vulcanizates obtained are very similar to those of the raw elastomers.

ISSN:0022-233X    

DOI:10.1080/00222337408068635

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Vinyl chloride, vinyl fluoride, and tetrafluoroethylene were polymerized in a radio frequency electric glow discharge. It was found that when compared with the unhalogenated simple hydrocarbons, the rates of polymer deposition are in the order vinyl chloride, acetylene, tetrafluoroethylene, vinyl fluoride, ethylene. This observation can be rationalized by considering the ease with which free radical and unsaturated species can be formed in the plasma. IR spectra show that the structures of plasma-polymerized vinyl chloride and vinyl fluoride are in many respects similar to the plasma-polymerized hydrocarbon. The spectrum of plasma-polymerized tetrafluoroethylene, however, does not resemble that of conventional polytetrafluoroethylene. Addition of dichlorodifluoromethane to the monomer stream dramatically increased the polymer deposition rate; the effect is more subdued for chloromethane and is negligible for tetrafluoromethane. Elemental analysis indicates that little of the added halogens is present in the resultant polymers. Thus the halogenated compounds appear to act as a gas phase catalyst for the plasma polymerization of hydrocarbons.

ISSN:0022-233X    

DOI:10.1080/00222337408068636

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The radiation-induced cationic polymerization of isobutyl vinyl ether in solutions of diethyl ether and methylene chloride was investigated under conditions where the monomer and solvents were dried with molecular sieves to high levels of dryness. The investigation covered the temperature range from -16 to 90° C, the dose-rate range from 1015to 1020eV/ (g)(sec) (using both gamma rays and electrons), and the influence of diethyl ether and methylene chloride as solvents for the monomer.

ISSN:0022-233X    

DOI:10.1080/00222337408068637

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The γ-ray initiated polymerization of 4-methyl-1-pentene, 2-methyl-1-butene, and 2,3-dimethyl-1-butene has been studied under conditions of extreme dryness. Only low yields of oily low molecular weight polymers were obtained. It is suggested that the low propagation rate constants are responsible for the results obtained.

ISSN:0022-233X    

DOI:10.1080/00222337408068638

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

From Raman spectral data, no decrease in the double-bond content of polyisoprene popcorn polymer was detected following various periods of oxidation. No conclusion could be made concerning the fate of the 1,2 or 3,4 vinyl-group attachments.

ISSN:0022-233X    

DOI:10.1080/00222337408068639

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The primary products produced during the early stages of polyisoprene popcorn polymer autoxidation appear to be water, 2, 5-hexanedione, acetaldehyde, and two unknown compounds. Quantitative data are presented for the production of 2, 5-hexanedione and acetic acid. The scission mechanism undoubtedly involves the formation of acetonyl radicals which recombine to form 2, 5-hexanedione. A scission yield of one mole of scissions per 53 moles of oxygen was calculated for the room-temperature oxidation.

ISSN:0022-233X    

DOI:10.1080/00222337408068640

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Poly[3,3-bis(chloromethyl)] oxetane in vacuo, after λ-irradiation at 77°K and room temperature, showed ESR spectra consisting of a triplet (hfs of 22.0G) and a doublet (hfs of 17.8G), respectively. The triplet ESR spectrum is attributed to the -CH2-C(CH2Cl)-CH2-O- radical and the doublet ESR spectrum is attributed to the -CH2-C(CH2Cl)2-CH-O- radical. The G values for formation of radicals are estimated to be 0.3 and 0.5 at 298 and 77°K, respectively.

ISSN:0022-233X    

DOI:10.1080/00222337408068641

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

A relationship between intrinsic viscosity and molecular weight for fractionated cellulose is established. The exponent a of the Mark-Houwink equation is 0.80. The unperturbed dimensions of cellulose are discussed on the basis of the Stockmayer-Fixman and Kurata-Stockmayer viscometric theories, and it is determined that cellulose is not a very rigid macromolecule in nature. This conclusion disagrees with the results obtained by statistical mechanics procedures in which the restriction of β-glucose residues to the C1 conformation was kept. The steric hindrance factor, σ is about 2, and it seems to be independent of the substituents in cellulose if it is evaluated in both cellulose and cellulose derivatives from viscometric data. From statistical mechanics data reported in the literature, σ is estimated as 4.4 for cellulose and cellulose derivatives, such as cellulose nitrate, and this means that the steric hindrances of the substituents have little influence on the rigidity of cellulose derivatives. This view disagrees with the results obtained from the non-Newtonian behavior of cellulose and cellulose nitrate in dilute solutions. By applying the Noda-Hearst theory, the conclusion is reached that cellulose nitrate is a more extended macromolecule than cellulose.

ISSN:0022-233X    

DOI:10.1080/00222337408068642

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor