18—A CONSIDERATION OF THE REAL MATURITY OF COTTON FIBRES

Maturity is an important fibre characteristic, which is related to the extent of development of the fibre wall Several methods exist to measure this characteristic, but all these methods are calibrated by starting from procedures that depend upon measurements made on swollen fibres, such as the ASTM or the BSI method. In this paper the results of an investigation are given in which maturity was measured directly on cross-sections of unswollen fibres. The results are compared with those obtained by measurements on swollen fibres as well as with estimations of maturity made by two indirect instrumental methods (the Arealometer and the IlC-Shirley Fineness/Maturity Tester (FMT)), both of which use the double-compression air-flow technique. It is concluded that microscopical measurements made on swollen fibres do not always adequately reflect the botanical maturity and that in any case the two instrumental methods are more reliable. Appropriate conversion formulae are given for estimating the true fibre maturity from both Arealometer and IlC-Shirley FMT readings.