摘要:

AbstractA method for studying the thickness of adsorbed polymer films, based on the reduction in effective cross section for liquid flow caused by the deposition of such a film on the interior of a capillary, is described. A sintered disk is used instead of a single capillary to raise the flow rate to an easily measured level, to avoid the difficulties of obtaining or fabricating the extremely fine capillaries which would be required, and to eliminate the extreme precautions needed to prevent plugging of a single capillary. Techniques for characterizing the sintered disks are presented. When applied to benzene solutions of stearic acid and of polystyrene, film thicknesses of 30 and 312 A., respectively, were obtained. This is in good agreement with present knowledge of fatty acid adsorption, and suggests that the polymer is adsorbed in a highly extended configuration. The application of this method to solutions of poly(vinyl acetate), poly(methyl methacrylate), and polystyrene in several solvents at various temperatures is described in a following paper.

ISSN:0449-296X    

DOI:10.1002/pol.1966.150040901

出版商:John Wiley&Sons, Inc.    

年代:1966

数据来源: WILEY

摘要:

AbstractThe kinetics of bulk polymerization of acrylonitrile, leading to a transparent polymer, was studied. The reaction was followed by a dilatometer specially designed for high degrees of conversion and for continuous supply of monomer during the reaction. The last stages of polymerization were followed by density determinations. It was found that the kinetic scheme did not show any irregularities, and that the major condition for obtaining a transparent polymer is a continuous supply of monomer to fill up the gaps formed by the contraction during the polymerization process.

ISSN:0449-296X    

DOI:10.1002/pol.1966.150040902

出版商:John Wiley&Sons, Inc.    

年代:1966

数据来源: WILEY

摘要:

AbstractA radiochemical technique involving the use of36Cl has been described previously for the measurement of butyl rubber unsaturations. This method has now been applied to the estimation of the much lower concentration of double bonds present in polyisobutene prepared by the cationic polymerization of isobutene at a low temperature. The nature of the reaction of polyisobutene with radiochlorine in the absence of air is examined, and the experimental results are discussed in relation to present theories of the mechanisms of chain termination in cationic polymerization.

ISSN:0449-296X    

DOI:10.1002/pol.1966.150040903

出版商:John Wiley&Sons, Inc.    

年代:1966

数据来源: WILEY

摘要:

AbstractThe radiation‐induced copolymerization of styrene with liquid formaldehyde in bulk and in solution has been studied at low temperatures. In bulk and in methylene chloride solution copolymerization took place, whereas in diethyl ether solution only homopolymerization of the formaldehyde was found. At −78°C., in bulk and in methylene chloride solution, no evidence of polystyrene blocks could be found, whereas at −30°C. in bulk about 30% of the styrene content of the copolymer was in the form of high molecular weight blocks. The rate of copolymerization in methylene chloride solution was found to be first‐order with respect to dose rate and third‐order with respect to formaldehyde concentration similar to results reported for formaldehyde in toluene solution. The thermal stabilities of the copolymers were found to be intermediate between those of pure polyoxymethylene and commercially stabilized polymers. Since the latter were of higher molecular weight and contain added stabilizers, the increased thermal stabilities of the copolymers were considered to be particularly

ISSN:0449-296X    

DOI:10.1002/pol.1966.150040904

出版商:John Wiley&Sons, Inc.    

年代:1966

数据来源: WILEY

摘要:

AbstractThe copolymerization of aziridines and cyclic imides was studied. Aziridines copolymerized alternately with cyclic imides to give crystalline polyamides. Ethylenimine and succinimide copolymerized to nylon 2,4, melting near 300°C., without any catalyst. Similarly, the corresponding crystalline polyamides were obtained from the systems of 1,2‐propylenimine–succinimide, ethylenimine–glutarimide, and ethylenimine–phthalimide. The copolymerization of aziridines and cyclic imides in the presence of BF3OEt2gave a copolymer which was rich in aziridine units, whereas, the addition of triethylamine had no influence on the copolymer composition. A mechanism of copolymerization was proposed based on the facts thatN‐tetramethylenesuccinamide was obtained by the reaction of pyrrolidine and succinimide,N‐acetylethylenimine reacted with acetamide to yieldN,N′‐diacetylethylenediamine and that the rate of this copolymerization was dependent on the electroph

ISSN:0449-296X    

DOI:10.1002/pol.1966.150040905

出版商:John Wiley&Sons, Inc.    

年代:1966

数据来源: WILEY

摘要:

AbstractSymmetrical diamines, containing preformed carbonamide linkages, were prepared by reacting nitrobenzoyl chlorides with aromatic diamines and reducing the dinitro intermediates. The diamines were polymerized with aromatic diacid chlorides to give wholly aromatic ordered copolyamides of exceptionally high thermal stability. Ordered diamines were prepared containing only phenylene units as the aromatic portion, and others containing phenylene and naphthylene or biphenylene groups. Low‐temperature solution polymerization of these diamines with isophthaloyl chloride, 4,4′‐bibenzoyl chloride, or 2,6‐naphthalenedicarbonyl chloride, gave thirteen ordered copolyamides, each containing a naphthylene and/or biphenylene group in its repeating unit. Differential thermal analyses and thermogravimetric analyses showed these polymers to have melting points or decomposition temperatures of from 420 to over 500°C. Films of one of the polymers had a breakdown voltage of 3000 v./mil at 180°C. Fibers of the same composition had tenacities of up to 8 g/den.; a 5.5 g/den. sample retained 85% of its tenacity after 17 hr. at 300°C. and 21% af

ISSN:0449-296X    

DOI:10.1002/pol.1966.150040906

出版商:John Wiley&Sons, Inc.    

年代:1966

数据来源: WILEY

摘要:

AbstractThe ultraviolet (λ = 2537 A.) photolysis of a degassed mixed phenyl and methyl polysiloxane liquid is examined in terms of gas and crosslinking yields. Results are compared to the published values obtained by ionizing irradiation of this type of molecule. It is shown that ultraviolet radiation is less efficient by two orders of magnitude in producing decomposition (i.e., gaseous products) than is ionizing radiation. The comparisons for crosslinking efficiencies are less certain, but the yields seem to have much more similar values in this case based on a spectroscopic estimation of crosslinking (i.e., analysis for substituted phenylcyclohexadiene formation). The gas quantum yields were ϕH2= 2.6 × 10−5, ϕCH4= 0.63 × 10−5, ϕC2H6≈ 0.12 × 10−5, and ϕC2

ISSN:0449-296X    

DOI:10.1002/pol.1966.150040907

出版商:John Wiley&Sons, Inc.    

年代:1966

数据来源: WILEY

摘要:

AbstractCarefully determined cationic copolymerization parameters of cyclic ethers, formals, and esters are collected. Relative reactivity correlates with basicity and free energy. Further correlations of the copolymerization parameters for styrene, the effect of promoters, and the known mechanism of hydrolysis permitted a decision between the carbonium ion (including acylium ion) or the oxonium ion as the active intermediate of the propagation. Structural features which promote depropagation are identified. Equations describing these possibilities were derived and briefly discussed. Catalyst and solvent effects limited the correlation possibilities.

ISSN:0449-296X    

DOI:10.1002/pol.1966.150040908

出版商:John Wiley&Sons, Inc.    

年代:1966

数据来源: WILEY

摘要:

AbstractSeveral new initiating systems involving a molecular halogen, halates, or perhalate as one of the components and a reducing metal salt, ammonia, an amine or an organic compound as the other component, have been introduced for the aqueous (and in a few cases the non‐aqueous) polymerization of methyl methacrylate. Some of the resulting polymers have been subjected to endgroup analysis by the application of the ultrasensitive dye techniques recently developed in our laboratory. Reducing metal salt—halogen‐initiated polymers are found to incorporate hydroxyl and halogen endgroups, while polymers initiated by amine—halogen systems incorporate hydroxyl and halogen as well as amino endgroups. However, in the ammonia—halogen system polymers incorporate only halogen endgroups. On the basis of the results of the endgroup analysis of the polymers an attempt has been made to explain the probable initiation mechanism with regard to the nature and identity of the initiating species involved in such

ISSN:0449-296X    

DOI:10.1002/pol.1966.150040909

出版商:John Wiley&Sons, Inc.    

年代:1966

数据来源: WILEY

摘要:

AbstractAs an extension of earlier work on the condensation of ferrocene with aldehydes, the polycondensation of ferrocene withp‐ ando‐carboxybenzaldehyde is described. While, in the former case, regular polycondensation occurs giving rise to a polymer composed of ferrocenylene and 4‐carboxybenzal units, a deviation from this route is observed in theo‐carboxybenzaldehyde case, where a polymer containing both carboxybenzal and 3,3‐phthalide bridging units between the ferrocenylene groups is formed instead. This unexpected behavior can be accounted for by a hydride abstraction mechanism. In support of the polymer structure proposed, 3‐ferrocenylphthalide and 3,3‐diferrocenylphthalide are isolated as intermediates or by‐products. In both polymer series, number‐average molecular weights up to 3000 (unsubfractionated) are measured. The polymers are soluble in a number of organic solvents and can be cu

ISSN:0449-296X    

DOI:10.1002/pol.1966.150040910

出版商:John Wiley&Sons, Inc.    

年代:1966

数据来源: WILEY