Steam explosion of flax - A superior technique for upgrading fibre value

As a result of the high cost of Farm operations in Europe, there is a considerable demand for agricultural products which have a high added value. One of these potential products is linen fibre for use in both fabrics in which fine but long fibres with high moisture resorption are preferred, and in composites to produce engineered materials, for which high purity and a high Young's modulus is preferred. The production of linen from flax by traditional methods involves retting, a biochemical process which serves to remove pectins and nonstructural carbohydrates. This process, carried out in the field or in the factory, is not very easy to control and the products are of variable quality. Steam explosion treatment (STEX) of flax following dew retting can be controlled to give a well defined severity of treatment (in the range log(10)2.9-log(10)4.1) which leads to good fibre quality with minimum loss in fibre yield. Due to limitations on the rate of steam penetration into the fibre bundles, a minimum treatment of 2 min seems to be necessary. Through the use of NaOH pretreatments and STEX the effect of low degrees of fibre retting can be compensated for and a high yield of useful fibre obtained. The high potential of steam exploded short staple flax fibres for use in textile and technical composites has been demonstrated. (C) 1998 Elsevier Science Ltd. All rights reserved.