ISSN:0449-2951    

DOI:10.1002/pol.1964.100020401

出版商:John Wiley&Sons, Inc.    

年代:1964

数据来源: WILEY

摘要:

AbstractAcrylamide polymerizes at 25°C. in aqueous solution by photosensitization with eosin, in absence of any reducing agent and of oxygen; a strong photoreduction of the dyestuff proceeds simultaneously. The photopolymerization has been followed gravimetrically, while the rate of photoreduction was followed colorimetrically. The rate of photoreduction is proportional to the absorbed light intensity. The rate constants are proportional to the monomer concentration when this concentration is lower than 0.42 mole/l.; above this value they are independent from it. The rate of photopolymerization is proportional to the square root of the eosin concentration when this concentration is ≤ 10−6mole/l.; above this value, the rate becomes independent of the eosin concentration. With respect to the monomer the order of reaction varies from 1.5 to 1.85 when the eosin concentration is 0.4 × 10−6and 6 × 10−6moles/l., respectively. With respect to the light intensity, the order of reaction is 0.35 when the monomer and eosin concentrations are respectively, 2.8 moles/l. and 0.4 × 10−6moles/l. The kinetics of photoreduction are interpreted on the basis of a reaction between the excited triplet state of the dye and the monomer, and a kinetic scheme is presented. The kinetics of photopolymerization are explained by a termination process between a growing chain and a primary radical, besides the usual termination process between two g

ISSN:0449-2951    

DOI:10.1002/pol.1964.100020402

出版商:John Wiley&Sons, Inc.    

年代:1964

数据来源: WILEY

摘要:

Abstract1,5‐Hexadiene has been polymerized with a number of modified alkyl metal coordination catalysts to crystalline polymers having an unusual combination of properties. These polymers are crystalline, have high tensile strengths, high melting points, high densities, and yet are very flexible. Poly‐1,5‐hexadiene has a chain identity period of 4.80 A., and is best difined as consisting primarily of 1‐methylene‐3‐cyclopentyl units in which the substituents arecisand the cyclopentane ring is in an envelope conformation. Since not all the monomer units incorporated into the chain are cyclized, the polymer more closely resembles an interpolymer than a

ISSN:0449-2951    

DOI:10.1002/pol.1964.100020403

出版商:John Wiley&Sons, Inc.    

年代:1964

数据来源: WILEY

摘要:

AbstractThe heat coloration and alkali coloration of PAN was investigated with model compounds by measuring infrared absorption spectra and ultraviolet absorption spectra. Some of the information obtained from this work supported the opinion of Grassie et al., who proposed the formation of partly hydrogenated naphthyridine‐type structure to explain the alkali coloration of PAN. The intramolecular ring closure mechanism of the initiation to propagate to the partly hydrogenated naphthyridine‐type structure of heat‐treated PAN proposed by Grassie et al., which, however, may involve the dehydrogenated structure somewhere, was supported, too. On the other hand, the formation of intermolecular azomethine‐type crosslinking structure proposed by Schurz et al. was not supported by any results of the experiments with model co

ISSN:0449-2951    

DOI:10.1002/pol.1964.100020404

出版商:John Wiley&Sons, Inc.    

年代:1964

数据来源: WILEY

摘要:

AbstractThree unsaturated polyesters were crosslinked with different amounts of styrene, and for the resulting polymers the 10‐sec. shear modulus was measured as a function of temperature. It was observed that the polymers have well defined glassy, transition, and rubbery regions. The equation for the shear modulus from the theory of rubber elasticity was applied for the plateau regions of the polymer

ISSN:0449-2951    

DOI:10.1002/pol.1964.100020405

出版商:John Wiley&Sons, Inc.    

年代:1964

数据来源: WILEY

摘要:

AbstractCopolymers of ethyl acrylate with three different dimethacrylates were prepared over the complete range of copolymer composition. Modulus temperature curves of these polymers were constructed and contrasted with the modulus temperature curves of phenol–formaldehyde type polymers. The ethyl acrylate–dimethacrylate polymers appeared to have rubbery plateau regions at high temperatures, even for very high mole percentages of dimethacrylate. This was especially true if the dimethacrylate molecule had a long flexible chain within it, as in tetraethylene glycol dimethacrylate. On the other hand the phenol–formaldehyde type polymers and polyethylene glycol dimethacrylate did not appear to have rubbery plateau regions. Up to 12 mole‐% of dimethacrylate the shear moduli of the ethyl acrylate copolymers in the rubbery plateau region were independent of the structure of the dimethacrylate at equivalent crosslink concentrations. Furthermore these polymers appear to obey the laws of ideal rubber elasticity with a front factor o

ISSN:0449-2951    

DOI:10.1002/pol.1964.100020406

出版商:John Wiley&Sons, Inc.    

年代:1964

数据来源: WILEY

摘要:

AbstractPoly‐(trans‐CHDCHD) and poly‐(cis‐CHDCHD) have been obtained with [Al(Et)3+ TiCl4] and with [Al(i‐Bu)3+ TiCl4]. Poly‐(trans‐CHDCHD) and poly‐(cis‐CHDCHD) obtained with [Al(Et)3+ TiCl4] give mutually different infrared spectra. The characteristic absorption bands of the former are found at 1335, 1288, and 594, and 586 cm.−1, and those of the latter at 1306, 597, and 590 cm.−1. In order to interpret these spectra, the normal vibration frequencies of the model structures, namely, erythro‐diisotactic and threo‐diisotactic structures, have been calculated. From the comparison of the observed and calculated frequencies, it has been concluded that poly‐(trans‐CHDCHD) obtained with [Al(Et)3+ TiCl4] consists mainly of the threo‐diisotactic and disyndiotactic portions and poly‐(cis‐CHDCHD) obtained with the same catalyst consists mainly of the erythro‐diisotactic and disyndiotactic portions. The relation between the type of double bond opening and the structure of the resultant polymer has been discussed, and it has been concluded that thecis‐opening of the double bond occurs in the polymerization reaction with [Al(Et)3+ TiCl4]. The spectra of poly‐(trans‐CHDCHD) and poly‐(cis‐CHDCHD) obtained with [Al(i‐Bu)3+ TiCl4] are not so different from each other, but they are different from the spectra of the polymers obtained with [Al(Et)3+ TiCl4]. The polymers obtained with [Al(i‐Bu)3+ TiCl4] show characteristic bands at 2919, 2850, 2176, 2095, 1453, 660, 623, 600, 593, 581, 566, and 545 cm.−1. These bands give evidence of the presence of isolated CH2and CD2groups. This fact indicates that the hydrogen–deuterium exchange reaction in m

ISSN:0449-2951    

DOI:10.1002/pol.1964.100020407

出版商:John Wiley&Sons, Inc.    

年代:1964

数据来源: WILEY

摘要:

AbstractA simple centrifugation method for the clean separation of chemically heterogeneous latex particles is described in some detail. It exploits density differences among particles that could be due to differences in composition, degree of crosslinking, crystallinity or other structural features. Particles differing in density by as little as 0.005 g./ml. have been cleanly separated. The fractionation of particles differing in density by less than the above should be feasible with this method which is applicable to concentrated as well as dilute latices.

ISSN:0449-2951    

DOI:10.1002/pol.1964.100020408

出版商:John Wiley&Sons, Inc.    

年代:1964

数据来源: WILEY

摘要:

Abstractα‐Trifluoromethyl vinyl acetate has been synthesized. Although the homopolymer has not been obtained, this new monomer readily copolymerizes with a variety of vinyl monomers including styrene. Alcoholysis of vinyl acetate/α‐trifluoromethyl vinyl acetate copolymers leads to trifluoromethyl‐substituted polyvinyl alcohols having new and unusual properties. These polyvinyl alcohol derivatives, containing about 30 wt.‐% of fluorine, are completely insoluble in water but dissolve in the lower alcohols. Because of the increased acidity of fluorosubstituted alcohols, they are also soluble in dilute aqueous alkalies to yield polyalkoxide‐typ

ISSN:0449-2951    

DOI:10.1002/pol.1964.100020409

出版商:John Wiley&Sons, Inc.    

年代:1964

数据来源: WILEY

摘要:

AbstractNitrogen adsorption isotherms were determined for a number of polyolefinic compounds. B.E.T. calculations showed that most of the samples possess surface areas averaging about 0.5 m.2/g., although a few very high molecular weight polyolefins precipitated during polymerization have areas of about 8 m.2/g. On most of the polyolefins, theCvalues from the B.E.T. equation are unusually small, indicating a relatively low heat of nitrogen adsorption. Adsorption isotherms were determined with krypton on two of the high polymers and were found to yield areas in satisfactory agreement with those obtained from the nitrogen adsorption experiments.

ISSN:0449-2951    

DOI:10.1002/pol.1964.100020410

出版商:John Wiley&Sons, Inc.    

年代:1964

数据来源: WILEY