34—THE CONTROL OF THE SHAPE AND DIMENSIONS OF KNITTED WOOL FABRICS

An account is given of an investigation of the use of steam treatments as a means of controlling the shape and dimensions of plain-knitted wool fabrics, firstly by allowing the fabric to relax towards its dimensionally stable state during steaming and secondly by steam-setting the fabric while it is held at a predetermined width. This steam-setting procedure is compared with two permanent-setting treatments for wool—a chemical-setting treatment and setting in boiling water.

Of the two methods of producing a dimensionally stable fabric, namely, by relaxation and by setting, the relaxation method is by far the more effective. The most important result of this work is that knitted wool fabrics—whether unset, steam-set, or permanently set—will always approach their completely relaxed shape and dimensions after only a couple of minutes' gentle agitation in water. It is concluded that conventional methods of shaping knitted wool fabrics and garments, which rely principally on steam-setting the fabric or garment to a size and shape different from its relaxed size and shape, are not likely to produce garments that have good dimensional stability and good shape-retention properties.

The ineffectiveness of permanent-setting agents in producing dimensionally stable knitted garments is contrasted with the relative effectiveness of these agents in producing pleats and permanent creases in wool cloths. This difference in behaviour is explained in terms of the different levels of individual fibre strains involved.     

31—INTERACTIONS BETWEEN ALKYLSULPHATES AND CATIONIC SHRINK-RESIST RESINS FOR WOOL PART II: THE INFLUENCE OF VARIOUS ALKYLSULPHATES ON THE SHRINKAGE OF KNITTED WOOL FABRICS

A study of the effect of the aggregates formed between Hercosett and alkylsulphates (C₈–C₁₄) in preventing the shrinkage of wool samples pre-treated with methylamine and hydrogen peroxide is reported. The amount of surfactant adsorbed on each pre-treated wool sample was estimated, and a mechanism by which the aggregate exhausts on the fibre is suggested.     

56—THE WRINKLING BEHAVIOUR OF WOOL FABRICS: THE EFFECT OF THE STRUCTURE OF FORMALDEHYDE CONDENSATION POLYMERS ON THE STABILIZATION OF ANNEALED WOOL

An investigation is reported of the use of formaldehyde condensation polymers of aromatic amines, heterocyclic amines, and phenols to stabilize the improved wrinkle-recovery of annealed wool. These polymers were formed in situ during the annealing process.

The most effective polymer networks were those obtained from the reaction of formaldehyde with multifunctional compounds such as (i) 2,4,6-triaminopyrimidine, (ii) 2,6-diaminopyridine, (iii) 3,5-diamino-1,2,4-triazole, (iv) 1,3,5-trihydroxybenzene, (v) 1,3-dihydroxybenzene, and (vi) 2,4,6-triamino-s-triazine.     

10—THE WRINKLING BEHAVIOUR OF WOOL FABRICS: THE EFFECT OF ANNEALING AND CROSS-LINKING

An investigation is described in which various polyfunctional compounds were applied to wool in attempts to stabilize the temporary improvements in wrinkle-recovery brought about by ‘annealing’. Several reactive systems involving formaldehyde were found to produce the desired permanently improved wrinkle-recovery.     

42—THE EFFECT OF DEAGEING ON SOME MECHANICAL PROPERTIES OF WOOL OUTERWEAR FABRICS

This paper describes an experimental investigation of fabric-wrinkling behaviour as measured on a Thermobench, fabric stress-relaxation measured under both constant and varying ambient conditions, and inter-fibre friction of a series of three wool fabrics tested in both their ‘aged’ and ‘deaged’ states. Deaging of these fabrics was achieved by four different methods. It is shown that simply soaking in water at room temperature is an effective and practical deageing procedure for wool fabrics.     

42—THE ESTIMATION OF CROSS-LINKS IN WOOL FROM THE EXTENT OF SWELLING IN FORMIC ACID

An account is given of the application of a gravimetric method for measuring the extent of swelling of wool in formic acid to a series of wool samples containing decreasing amounts of randomly distributed disulphide bonds. In accordance with the Flory-Rehner equation, a linear relation was observed between disulphide content and V 5/3, where V is the volume of dry wool expressed as a fraction of the volume of swollen wool. This calibration curve was then used in conjunction with swelling data to assess the number of cross-links introduced on the treatment of wool with formaldehyde and other bifunctional reagents. The method is particularly useful for ranking in order relatively high levels of cross-linking.     

25—THE WRINKLING OF WOOL WORSTED FABRICS. PART I: FIBRE AND YARN DEFORMATION IN BENDING

Experiments are described in which the extensional, bending, and twisting strains of seven fibres were measured in a wool worsted fabric deformed in a multiple-pleat tester. The only significant strain appeared to be the bending strain.     

24—THE EFFECT OF FIBRE PROPERTIES AND WEAVE CRIMP ON THE HYGRAL EXPANSION OF WOVEN WOOL FABRICS

A study is reported in which 53 plain-weave and 55 twill-weave fabrics were produced under nominally identical conditions from different wool lots ranging greatly in fibre properties. The hygral expansion of these fabrics was measured and related to the various fibre properties and weave crimp.

It was found that fabric geometry, as reflected in weave crimp, was the most important factor contributing to hygral expansion, higher weave crimp leading to higher hygral expansion. Weave crimp also increased with an increase in staple crimp, as did hygial expansion, the effect of staple crimp being largely due to its effect on weave crimp.

Results obtained on the 108 all-wool fabrics and on six mohair fabrics produced under identical conditions to the all-wool fabrics indicated that weave crimp rather than fibre properties per se plays the main rôle in determining hygral expansion.     

14—REVERSIBLE AND IRREVERSIBLE DIMENSIONAL CHANGES IN WOOL FABRICS

An account is given of experiments made with an apparatus constructed for recording, simultaneously and continuously, weight and length changes during the drying and steaming of fabrics. Hot air at a temperature of 100 or 115°C was used in the drying experiments. Steaming was done under the same conditions. The maximum level to which the moisture regain could be increased with steam varied with the fabric construction. Below this maximum level, absorption and desorption experiments with relaxed fabrics gave reproducible and identical hygral-expansion curves. Moisture-regain changes below saturation caused by steaming and drying did not completely release the strain in fabrics cohesively set. The difference resulting from the use of saturated and superheated steam was negligible. The lower the temperature during cohesive setting, the less resistant was the set towards moisture-regain changes.     

31—SOME ASPECTS OF THE MECHANISM OF SEAM SLIPPAGE IN WOVEN FABRICS

A theoretical analysis (subject to some assumptions) of the principles of seam slippage in woven fabrics is presented. It is shown that the amount of seam slippage, or fabric resistance to seam slippage, depends on such factors as yarn-to-yarn friction, yarn-to-sewing-thread friction, yarn flexural rigidity, and stitch and fabric geometry.     

9—THE VALIDITY OF PRESSURE-CORING FOR ESTIMATION OF THE CONTENT OF BURR MEDIC IN WOOL BALES

Miniature wool bales of about normal packing density (approximately 16 lb/ft³ on a greasy-wool basis) were constructed from burr-free greasy wool with burr added in such a way that the true over-all burr content was known. These were sampled with a range of pressure-coring tools differing in size. Except when small coring tools were used in bales of high burr content, there was no significant difference between the mean burr content of several core samples from a miniature bale and the true over-all value for that bale. It is concluded that the act of pressure-coring does not distort the burr content of a sample and that the sample is therefore suitable for determination of clean-wool content. The between-core variance of burr content decreases as the size of coring tool increases.     

10—THE VALIDITY OF PRESSURE-CORING FOR ESTIMATION OF THE CONTENT OF NOOGOORA BURR IN WOOL BALES

Experiments are described to establish the validity of samples, for Noogoora-burr determination, taken from wool bales with pressure-coring tools. Coring tools of ¾-in. and larger diameters give unbiassed samples for the determination of both Noogoora burr and burr medic. The ½-in.-diameter tool, although previously shown to give unbiassed samples for the determination of burr medic, is subject to some bias in the sampling of bales containing Noogoora burr.     

35—THE ACTION OF SODIUM LAURYLSULPHATE IN THE BLEACHING OF WOOL WITH HYDROGEN PEROXIDE IN AN ACIDIC MEDIUM

A study is reported of the influence of a sodium laurylsulphate treatment, at different pH values, on the properties of wools bleached with hydrogen peroxide in an acidic medium with Prestogen W used as stabilizer. It is shown that the pretreatment at different pH values gives whiter wools but a lower content of cysteic acid and greater alkali-solubility than untreated wool under the same conditions. Bleaching wool m a hydrogen peroxide bath containing sodium laurylsulphate in an acidic medium and using Prestogen W gives rather similar variations, although these are more perceptible than those derived from the application of a pretreatment with sodium laurylsulphate and a post-bleaching treatment.     

49—THE EFFECT OF THE RELATIVE BEHAVIOUR OF BLEND COMPONENTS IN DETERMINING THE STRUCTURE OF WOOL CARPET YARNS

An account is given of the use of a tracer-fibre technique to investigate the configuration, the mean radial position, and the contribution to hairiness of various typical blend components in purewool carpet yarns produced on three different spinning systems. Tracer fibres selected to represent the components of an ‘unimproved’ fleece were found to behave differently during spinning, both from each other, and from tracer fibres selected from ‘improved’ fleeces. The choice of spinning method (woollen, open-end, or semi-worsted) was found to have most effect on the arrangement of fibres near the surface of the yarns.     

14—COMPARISON OF THE FELTING PROPERTIES OF LOOSE WOOL FIBRES,WORSTED-SPUN YARN,AND KNITTED FABRIC

When the felting properties of loose wool, yarn, and fabric are compared, before and after chemical modification, only a poor relationship is found between the felting rates of all three assemblies. It is therefore impossible to predict the effect of a particular treatment on a fabric by applying the same conditions of treatment to the loose wool. A very detailed study of a particular treatment is necessary before loose-wool felting can be used for prediction purposes.     

17—THE PREDICTION OF THE COMMERCIAL CARBONIZING YIELD OF WOOL

An investigation is reported in which the core-test yield was compared with the achieved mill yield for 90 commercial batches of Australian wool. Eight Australian mills participated in the trial. It was found that the wool base of the greasy wool (B _g%) was directly proportional to the achieved mill yield. The carbonizing loss, which was on the average 3.05% (on an oven-dry basis), was negatively correlated with the vegetable-matter base of the greasy wool (VMB _g%. The most precise prediction of the achieved mill yield was given by the equation:

ECCY% = 1.1972 B _g% + 0.1616 VMB _g% ? 5.12,

where ECCY% is the estimated commercial carbonizing yield. For the 90 batches in the trial, the standard error of the prediction was 1.95%.     

23—STUDIES OF THE SULPHTTOLYSIS OF WOOL FIBRES PREVIOUSLY TREATED WITH IONIC SURFACTANTS

A study is reported in which wool fibres were pre-treated with ionic surfactants and subsequently subjected to sulphitolysis at different pH values in order to follow the chemical behaviour of cystine disulphide bonds in relation to that of bisulphite ions when surfactant molecules had previously been fixed on the protein. The influence of several parameters, such as the pH, concentration, temperature, and time of treatment of wool fibres with ionic surfactants, on the cystine reactivity was studied. Investigations of how treatment with alkylsulphates in the chain-length range C₆–C₁₆ modifies the reactivity of the native protein to sodium bisulphite are also reported.     

9—THE CONSISTENCY OF THE VALUATIONS OF GREASY WOOL BY SIX APPRAISERS IN A WOOL-BUYING FIRM

A study is made of the consistency of six woolbuyers' estimations of type, yield, and valuation of greasy wool. Parameters for consistency and accuracy are estimated and intra-class correlation coefficients used to rank the buyers within the firm. The results indicate that changes in greasy-price limits are influenced more by changes in type appraisal than by changes in yield estimation. The method is discussed as a means of regularly checking the standard and improvement of buyers in a firm.     

29—THE MEASUREMENT OF THE LENGTH-TO-DIAMETER RATIO OF SHORT SNIPPETS OF WOOL

An expression relating the length-to-diameter ratio of circular cylinders to the over-all volume that a random assembly of a given quantity of cylinders takes up is derived for variable length and variable diameter of a snippet. The results of experimental determinations are shown to correlate well with these theoretical considerations. The formula was checked for wool fibres with diameters in the range 20–30 μm and for snippet lengths from 0.2 to 2 mm.