摘要:

AbstractWool has been modified to render it more hydrophobic by two methods. The first method involved treating the wool with benzoyl, lauroyl, stearoyl, and dodecenyl chlorides and with trifluoroacetic anhydride. Substantial degrees of reaction with the wool were achieved when the correct solvent media and reaction conditions were used. These varied with the particular reagent employed. Pyridine was particularly effective with the acid chlorides, whereas dimethyl sulfoxide was best with trifluoroacetic anhydride. Pyridine is believed to function both as a swelling agent and as an acid acceptor in these treatments. The second method of treatment was the grafting of vinyl and allyl monomers to wool by the use of high energy radiation. Both60Co γ‐rays at 0.3 Mrad/hr. and Van de Graaff γ‐radiation at 3 Mrad/min. were found to be highly effective. The presence of a swelling agent in the monomer solution was found to be essential even in the case of acrylonitrile in dimethyl formamide. Water and methanol in small amounts were found to be highly efficient swelling agents. Substantial quantities of monomer could be grafted in most cases without difficulty when the correct conditions were

ISSN:0021-8995    

DOI:10.1002/app.1966.070100901

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractThe wool–water relationships of the modified wools prepared as described in Part I of this series have been studied. The drained water content of fabric and the solution isotherms and diffusion constants of water vapor into untreated and modified wools have been measured. Most of the treated wool fabrics showed considerable decreases in the drained water contents compared with the untreated wool. However, the degree of improvement depended markedly on the conditions of modification, particularly with the styrene grafted materials. In some cases values close to those of a comparable polypropylene fabric were found. The sorption isotherms also showed that the modifications reduced, substantially in some cases, the regains even when calculated on the wool content only. The diffusion constants were difficult to measure because of the heats of sorption causing temperature changes during the sorption; however, at lower regains this effect could be corrected. It was found that both the direct chemical modification and the grafted wools showed a diffusion behavior which was more characteristic of hydrophobic materials in that the diffusion constants tended to decrease with increasing concentration. At low humidities the diffusion constants were larger than in the untreated wool, but at higher humidities lower diffusivities were found with the modified wool

ISSN:0021-8995    

DOI:10.1002/app.1966.070100902

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractThe study of factors influencing the adhesion properties of polyurethane coatings to aluminum has been continued. The data indicate that the addition of additives to polyurethanes can affect their peel strengths. The addition of epoxy resins, chlorinated paraffins, or sulfonamide–formaldehyde resins results in increased peel strengths; the use of a mixture of fatty acids resulted in reduced values. The isocyanate structure can also play an important role; those producing more flexible films (such asm‐xylylene di‐isocyanate) result in higher peel strength values. Other factors found to be of importance included the concentration of aromatic and aliphatic groups, the type of solvent used in casting the films, the crystallinity of the polyether glycols and the presence or absence of certain substituents, such as fluorine, in the polyurethane chain. Tracer studies have indicated that the mechanism of adhesion failure involves the breaking of the polymer‐polymer as well as polymer–substr

ISSN:0021-8995    

DOI:10.1002/app.1966.070100903

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractThe calculation scheme for correcting the broadening effect due to imperfect resolution on gel permeation chromatograms was compared with actual performances of a gel permeation chromatography (GPC) column. The experiment consisted of fractioanting a high‐density polyethylene on a GPC unit and then determining the chromatograms of the cuts collected. The chromatograms of the cuts were also computed from the starting chromatogram using experimentally determined resolution factors. The degree of agreement between the calculated and experimental chromatograms of the cuts shows convincingly that the previously proposed calculation scheme is satisfactory for the treatment of GPC dat

ISSN:0021-8995    

DOI:10.1002/app.1966.070100904

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractSix examples were used to illustrate the application of a previously reported method of calculating molecular weight distribution from gel permeation chromatograms. These examples show that the correction for the imperfect resolution of the GPC column is important when the distribution is narrow but minor when the distribution is broad. They show also that the variation of the resolution factorh, defined previously, with eluent volume can be neglected in the calculation. When the chromatograms are very narrow in distribution or when they are complex some difficulties are encountered. The two computer programs written to implement the previously described numerical calculations are shown to be adequate for these difficult cases but there are also limitations.

ISSN:0021-8995    

DOI:10.1002/app.1966.070100905

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractHigh quality packaging films from hydroxyethyl cellulose of low degree of substitution (DS) are being produced commercially in this country and abroad. Increasing demand for this and a variety of other applications requires a rapid and simple production control method for determining hydroxyethyl substitution of cellulose. None of the known analytical methods fulfills these requirements. The present paper describes a method which is based on the relationship between the solubility and the molar hydroxyethyl substitution of hydroxyethyl cellulose. A washed and dried sample of hydroxyethyl cellulose is dissolved in 7% aqueous sodium hydroxide. Methyl alcohol, a nonsolvent, is used to precipitate a fraction of the sample. The turbidity of the equilibrium system is determined and optical density readings are related to molar substitution. The method is most useful in low DS ranges of 2–8% EtO but is susceptile to broader application through adjustment of the composition of the solvent–nonsolvent mixture. Relatively large variations in DP can be tolerated. The molar substitution level of an hydroxyethyl cellulose sample can be obtained in 40 min. by this method, making it a practical production control techni

ISSN:0021-8995    

DOI:10.1002/app.1966.070100906

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractComparison of aging of a sulfur vulcanizate with a control having stable crosslinks, shows that oxygen affects reactions of the crosslink as well as of the hydrocarbon. Crosslink scission is inhibited. Results are in agreement with an earlier Suggestion that new crosslinking is enhanced by oxygen, although less than observed for natural rubber. This may be an effect of carbon black and amine antioxidants present in the vulcanizates.

ISSN:0021-8995    

DOI:10.1002/app.1966.070100907

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractPolyacetaldehyde has been prepared in the liquid and vapor phases without the addition of a catalyst by storing undiluted acetaldehyde in the dark at a temperature of −68°C. for 3–6 months. When acetaldehyde was stored in an untreated Pyrex flask, 20% high polymer, 55% paraldehyde, and less than 1% metaldehyde were obtained. The polymer was an elastomeric solid with a low to moderate degree of crystallinity and an intrinsic viscosity of 0.63 dl./g. When the sample was stored in a Pyrex flask which had been pretreated with alcoholic potassium hydroxide followed by a water wash, 16–17% high polymer and 6% paraldehyde were obtained. Some polymer formed on the unwetted glass above the liquid. It was slightly elastic, at least moderately crystalline, and had an intrinsic viscosity of 1.6 dl./g. It is suggested that the formation of this polymer was initiated by basic active sites on the Pyrex surface which acted by an anionic mechanism. Also some polymer was formed in the liquid phase. This material was an amorphous, highly viscous oil with an intrinsic viscosity of 0.28 dl./g. It was probably formed by a cationic mechanism. It is also suggested that a relatively small amount of paraldehyde was formed in the alkali‐treated flask in the liquid phase due to neutralization of the Brønsted acid sites and possibly some of the Lewis acid sites on the surface of

ISSN:0021-8995    

DOI:10.1002/app.1966.070100908

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractThe effects of a filler in an elastomer can be described by means of a theory based on a simple model in which the filler particles are assumed to be of uniform size, of cubic shape, and dispersed in such a manner as to occupy the points of a cubic space lattice. For the case of shear deformation, simple relations can be derived for the increase in the storage modulusG' and the loss modulus,G″ of the bulk material with an increase in filler content. Furthermore, the theory predicts the temperature shift of two points which can be easily determined experimentally: the inflection point ofG' and the maximum ofG

ISSN:0021-8995    

DOI:10.1002/app.1966.070100909

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractThe setting of textiles made from cellulosic materials can be done with swelling and deswelling processes. Standard cotton fibers, purified by extraction, have been set in sodium hydroxide solutions with and without additions of thiocyanate salts. Treatments have also been done in zinc chloride and calcium thiocyanate and in a solution of potassium hydroxide in a mixture of butanol and kerosene. After rinsing and drying of the cotton samples, KBr pellets for infrared investigations were produced. Deuteration of the fiber sample for investigation was made in a special apparatus. Single and differential infrared diagrams have been run with and without previous deuteration of the set cotton samples. The infrared maximum of absorption of the OH band changes as a result of the setting treatment. The infrared diagrams show that the setting treatment in alkaline solution gives a broadening of the OH band towards higher and lower wavelengths, which indicates a transfer of the hydrogen bonding energy both to higher and lower energies. The diagrams from the deuterated samples indicate that the strong hydrogen bonds resulting from the setting treatment are partly resistant to deuteration. The results are discussed on the basis of setting and setting reactions.

ISSN:0021-8995    

DOI:10.1002/app.1966.070100910

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY