engleski

The influence of coarse wool cleanliness and quality on bulk properties

Fibre bulkiness is an extremely complex notion, defined as a relation between the volume of air and volume of fibre in a unit volume. The expression is highly subjective and is often used by estheticians and fashion designers, while the volume of the specific mass of fibres, specific volume ([cm3g-1] = quantitative expression of bulkiness), describing the usability of the fibres, is used both in professional and scientific literature, as well as in internal regulations of certain research and production institutions. Since the early investigations done by Van Wyk, specific volume has been defined on various apparatuses and employing different methods. The researchers vary the diameter and volume of the testing chamber, the amount (mass) of the sample, the manner of arranging the samples and pre-load used. All these factors strongly influence the reproducibility of the results, and is one of the reasons why there is no (besides the Australian, AS 3535, and a preliminary draft of the New Zealand standard for wool bulkiness) worldwide accepted standard (equipment and methods) for determining the bulk characteristics of textile fibres. Original equipment for investigating bulkiness properties of textile fibres has been constructed at the Faculty of Textile-technology in Zagreb, employing the basic idea of E.Sebastyen and T.S. Hickie. On the basis of numerous preliminary investigations of various textile fibres and wool of different origin, a method for testing bulk properties of the fibres has been developed. Characteristic properties for estimating fibre bulkiness, regarding their usage, have been defined. These are: - specific volume [cm3g-1], compressibility [%], relaxation or volume recovery Vo in [%] ; Employing the above terms and the methodology, we have tried to investigate the impact of wool quality (especially its fineness and medullation) and its general condition - cleanliness (dirty, raw wool - cleaned, scoured wool), together with the scouring conditions, or type of treatment (traditionally scoured wool - wool treated with enzymes), upon the bulkiness of coarse wool grown in Croatia. Investigations indicate there is no significant dependence of either of the three bulkiness properties of wool fibres (specific volume, compressibility and relaxation) upon its mean diameter - fineness, medullation and the content of dead fibre. Two bulkiness properties (specific volume and relaxation) are strongly influenced by the origin of the wool, as well as the sort and breed of the sheep, while the origin of the wool has no influence on the compressibility of the wool (specific volume of samples under high pressure).

textile testing; textile fibers; bulk properties; wool

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