摘要:

AbstractTen series of model filaments with increasing orientation and swelling degrees ranging between 16 and 1.2 were prepared from three viscoses containing 4, 6, and 10.5% cellulose. Their birefringence was measured and their x‐ray diagrams taken and quantitatively evaluated in order to determine the over‐all orientation of the iiber substance and that of the crystalline portion. It is shown that a general relation exists between the orientation of the crystallites and that of the entire fiber substance which is the same in all fibers stretched in the swollen state. Once the birefringence of a filament is known, the orientation factor of its crystallitee can be computed without taking an x‐ray photograph. From the data further evidence can be derived to the effect that the orientation of the crystallitm cannot be accounted for by the theory of affined deform

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030101

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY

摘要:

AbstractExpreiments have been carried out on the benzoyl‐peroxide catalyzed polymerization of methyl isopropenyl ketone at 25 and 40°C. in cyclohexane, a solvent which dissolves the monomer but causes the polymer to be precipitated. It is shown that in solutions of suitable concentration (40–80%) the effect of the cyclohexane is to increase both the rate of polymerization and the intrinsic viscosity of the resulting polymer. The significance of these observations and of other recent experimental work is discu

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030102

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY

摘要:

AbstractRecently published measurements of moisture sorption vs. relative humidity for a series of proteins have previously been analyzed in a way which permits calculation of the integral free energy of sorption for any final pressure of water vapor. The present paper is an extension of these calculations to additional proteins from the list reported by Bull; integral and differential free energies and integral and differential heats and entropies of sorption have been calculated as functions of the amounts of water sorbed onsilk, wool, egg albumin (unlyophilized and heat coagulated), salmine, collagen, gelatin and lactoglobulin (crystalline and lyophilized). All calculations are referred to saturated water vapor as the standard state. Some of the proteins show positive net differential entropies of sorption at low vapor pressures. It is postulated that the partial molal entropy of sorption is made up of two terms, a negative entropy of sorption proper and a positive entropy of solution. Partial rearrangements of the protein chains at the beginning of the sorption process would effectively be an incipient solution which would give rise to a positive partial molal entropy of sorption if the second term is greater than the first. This speculation has support in the fact that the differential entropy of salmine, which dissolves at a relative vapor pressure of about 0.7, begins to show positive values at a relative vapor pressure of 0.35.

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030103

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY

摘要:

AbstractA turbidimetric method has been developed for determining the styrene content in water and soap solution. The solubility of styrene in distilled water was 0.022% while in 2.0% potassium oleate solution it was 0.65 to 0.88%. The course of the polymerization of a saturated solution of styrene in 2% potassium oleate was followed by a colorimetric analysis based on reaction with dilute potassium permanganate. The rate of polymerization decreased rapidly after 50% conversion. The activation energy was estimated to be 17,000 kcal., somewhat less than in solution. The molecular weight of the polymer produced was 200,000. Occasional erratic results were ascribed to possible influence of various amounts of air sealed in the polymerization mixtures.

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030104

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY

摘要:

AbstractPhysical and mechanical properties of copolymers from dienes and acrylic nitrile have been studied. The gradual increase of density is an indication of the strong intermolecular forces exerted by nitrile groups. The mutual interaction of nitrile groups and methyl groups leads to a reduction of the mobility of flow units. This can be deduced from a relative comparison of hardness, elastic recovery, stress–strain properties, and brittle point of the three polymer‐homologous ser

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030105

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY

摘要:

AbstractFive twelve‐carbon mercaptans of definite structure are prepared and used to demonstrate that the rate of diffusion of mercaptan regulators in emulsion polymerization varies inversely with the length of the longest straight chain of the mercaptan structure (including the sulfur). In a given class of mercaptans (primary, secondary, or tertiary) the mercaptan consumption during polymerization varies directly with the diffusion rate. Solution viscosities of the resulting polymers are in accord with these finding

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030106

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY

摘要:

AbstractIt has been demonstrated that the homogeneity in respect to molecular weight of emulsion copolymers of butadiene and styrene can be increased by the use of certain derivatives ofn‐dodecyl mercaptan rather than the mercaptan itself. These derivatives decompose and relasen‐dodecyl mercaptan at an even rate during the polymerization reaction. Several new derivatives ofn‐dodecyl mercaptan are desc

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030107

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY

摘要:

AbstractBenzoyl, anisoyl, veratroyl,p‐bromobenzoyl,p‐phenylbenzoyl,p‐benzoylbenzoyl,p‐methylsulfonylbenzoyl,p(N,N‐dimethylsulfonamido)‐benzoyl and ‐naphthoyl disulfides are promoters of the emulsion copolymerization of butadiene and styrene, but exhibit little effect on the polymer properties. Furoyl, phenyl,p‐chlorophenyl andp‐bromophenyl disulfides are neither promot

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030108

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY

摘要:

AbstractPrecise analytical methods are developed using iodine monochloride for the determination of unsaturation in polybutadiene and polyisoprene and their copolymers with styrene. The complicating side reactions, splitting out and substitution, as well as the influence of the solvent employed are investigated in detail. It is concluded that GR‐S at various conversions has the theoretical unsaturation. Emulsion polybutadiene exhibits 97 to 98% of the theoretical unsaturation, emulsion polyisoprene 97% sodium polybutadiene 92%, and sodium polyisoprene 85%. The amount of unsaturation in these last two polymers as well as in the sodium copolymer of butadiene and styrene (75:25) is considerable less than theoretically expecte

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030109

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY

摘要:

AbstractMethods for the preparation of fiber‐forming polymeric amides from ω‐amino acids and The variation in melting points of the polymeric their amide‐forming derivatives are described. The variation in melting points of the polymeric amides with increasing chain length of the recurring unit is dis

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030110

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY