摘要:

AbstractThree important characteristics of loose wool bulks; compression, felting, and handle score are shown to be dependent upon the decrimping properties of the fibers. The relationship between decrimping energy and compressional load is very strong and it is suggested that rapid measurement of compressional properties may be of use in commerece and manufacture.

ISSN:0021-8995    

DOI:10.1002/app.1974.070181201

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

年代:1974

数据来源: WILEY

摘要:

AbstractMelt spinning of poly(ethylene terephthalate) was studied by measuring the filament tension at the take‐up roll and by measuring filament diameterD(X) at various distancesXbelow the spinnerette. A new method is developed to calculate temperature distribution both along and perpendicular to the fiber axis. Results of these calculations are compared with experimental values. The attenuation of filament diameter depends primarily on the take‐up speed and the output rate. Spinning temperature and molecular weight have relatively small effects. Mass flow rate and take‐up speed are the major factors controlling the cooling rate, while other spinning parameters such as polymer molecular weight and spinnerette orifice size have a small effect. The Trouton viscosity β is both temperature and molecular weight dependent. Values of β derived from these experiments can be expressed mathematically as follows:\documentclass{article}\pagestyle{empty}\begin{document}$ \begin{array}{l} \log \beta = \frac{{1900}}{T} - 1.77{\rm for }0.56{\rm IV PET} \\ \log \beta = \frac{{1900}}{T} - 1.50{\rm for }0.84{\rm IV PET.} \\ \end{array} $\end{d

ISSN:0021-8995    

DOI:10.1002/app.1974.070181202

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

年代:1974

数据来源: WILEY

摘要:

AbstractA generalized form of the equations of linear viscoelasticity is presented which enables theoretical treatment of situations where a material is not at equilibrium with its environment and/or is subjected to a changing environment. These generalized equations are used successfully to predict the recovery behavior of wool and nylon fibers from bending deformations in experiments involving conditions of changing temperature and relative humidity.

ISSN:0021-8995    

DOI:10.1002/app.1974.070181203

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe usefulness of an oligomer as an internal standard in gel permeation chromatography (GPC) has been investigated under deliberately varied experimental conditions—temperatures of the oven and the siphon, and flow rate. It was demonstrated that the effects of variations in the flow rate and temperature of the siphon on the elution volumes can be significantly minimized, even if not completely eliminated. Use of an oligomer, possibly having a chemical composition similar to that of the samples, is recommended as an internal standard in GPC experiments for better reproducibility and precisio

ISSN:0021-8995    

DOI:10.1002/app.1974.070181204

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

年代:1974

数据来源: WILEY

摘要:

AbstractAn analytical procedure for determining the antioxidant (i.e., Akroflex CD) content in neoprene rubber has been developed. The method is based on the infrared absorption analyses of chloroform extractables from the cured rubber at 1600 cm−1and 1300 cm−1. Good agreement is found between these two independent sets of measurements. In an attempt to elucidate the antioxidant loss mechanism found with neoprene, thermal aging studies were carried out over the temperature range of 80°–200°C. Using the infrared analytical procedure, antioxidant loss rates at the different temperatures were established. The activation energy value (5.1 kcal/mole) for the loss rate as well as other aging data suggest that the antioxidant is lost by a diffusion me

ISSN:0021-8995    

DOI:10.1002/app.1974.070181205

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

年代:1974

数据来源: WILEY

摘要:

AbstractA simple computer simulation of linear temperature‐programmed thermal volatilization analysis (TVA) provides useful insights into the effects of the order of reactionn, the Arrhenius preexponential factorA, the overall activation energy δE, and the linear rate of heating β on the position and shape of TVA thermograms. Analysis of the numerical results of simulation experiments leads to a method for evaluating ΔE,A, andnfrom TVA data. The computer‐simulation approach can easily incorporte mechanistic complexity. The latter possibility is applied to cases wherenand ΔEare changing during the course of reaction, and it is shown that the proposed method gives good recovery of ΔEfor such r

ISSN:0021-8995    

DOI:10.1002/app.1974.070181206

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

年代:1974

数据来源: WILEY

摘要:

AbstractPolycaprolactone is degraded by the moldP. pullulansin the presence of other nutrients. The weight loss from solid polymer films covered by a nutrient agar gel on which colonies are growing is used to establish comparative rates of degradation. There is substantial loss (16 mg/cm2surface area) from a whole polymer of low (2,000) molecular weight in three weeks at 30°C. A high (30,000) molecular weight whole polymer degrades about 0.15 as much in the same time period. A fraction in the same range (38,000) but with a narrower molecular weight distribution shows no significant loss. This indicates that whole polymers of high molecular weight may lose only a portion of their distribution by microbial degradation in short‐term tests. This hypothesis is tested by making mixtures of high (61,000) molecular weight with low (2,000) molecular weight polymer. Degradation is directly proportional to the low molecular weight content in these short‐term tests with a single species of mold. Other workers have shown previously that in long‐term, soil‐burial tests, even a high (40,000) molecular weight polycaprolactone is essentially completely degraded after

ISSN:0021-8995    

DOI:10.1002/app.1974.070181207

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

年代:1974

数据来源: WILEY

摘要:

AbstractAn experimental study has been carried out to better understand the phenomenon of stress buildup during the mold‐filling process in the injection molding operation. For the study, a rectangular mold with two glass windows was constructed, so that stress birefringence patterns of molten polymers flowing into the mold could be photographed with the aid of a polariscope. As a feeding system, a 1‐in. extruder was used attached to the mold with a 2‐ft length of stainless steel tubing having a relief valve. In this way, the injection pressure (and injection velocity) was carefully controlled to ensure that the glass windows would not be damaged. The development of stress birefringence patterns during the mold‐filling process was recorded on a movie film. It was observed that, in isothermal operation, when flow stopped after the mold was filled, stresses relaxed immediately because of the very slow cooling of the mold by ambient air. However, it was observed that, as cooling proceeded, stresses were gradually built up again in the mold. It was possible, therefore, to determine the residual stress in the mold, which originates from the cooling proces

ISSN:0021-8995    

DOI:10.1002/app.1974.070181208

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

年代:1974

数据来源: WILEY

摘要:

AbstractPolar and steric effects together govern the reverse osmosis separation of amino acids in single‐solute aqueous solution systems. The solute transport parameter for the completely ionized aliphatic amino acids (with no additional polar groups other than one NH2and one COOH) in the pK1range of 4.03 to 1.71 can be represented as a function of pK1and the steric parameter ΣEs. The latter parameter has a relatively greater influence with respect to the separation of zwitter ions. The effect of the polar parameter pK1on solute separation increases with increase in the concentration of the ionic species R+(or decrease in the concentration of the ionic species R−) in the feed solution. The effect of the presence of additional polar groups in the amino acid molecule is to increase its basicity. Experiments withp‐aminobenzoic acid solutions indicate that the undissociated acid is preferentially sorbed at the membrane–solution interface. With respect to both aliphatic and aromatic amino acid ions, solute separation is in the order R−>R±>R+for the cellulose acetate membrane m

ISSN:0021-8995    

DOI:10.1002/app.1974.070181209

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe physical properties, morphologies, and fracture characteristics of samples injection molded from blends of polypropylene and a low‐viscosity hydrocarbon oil are described. Unexpectedly large improvements in mechanical and optical properties are found to occur on the addition of a nucleating agent (copper phthalocyanine). Both the ultimate tensile strength and the elongation of unnucleated samples are doubled by incorporation of as little as 0.01% of the nucleant. Similar increases in the properties of unnucleated blends are observed when the barrel temperature of the molding machine is reduced. In both cases, marked improvements in visual uniformity occur. It is shown that these gains can be correlated with improved dispersion of the oil as spherulite size is reduce

ISSN:0021-8995    

DOI:10.1002/app.1974.070181210

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

年代:1974

数据来源: WILEY