David D. McAlister

Enzyme-retting of flax and characterization of processed fibers

Enzyme-retting formulations consisting of Viscozyme L, a pectinase-rich commercial enzyme product, and ethylenediaminetetraacetic acid (EDTA) were tested on Ariane fiber flax and North Dakota seed flax straw residue. Flax stems that were crimped to disrupt the outer layers were soaked with various proportions of Viscozyme-EDTA solutions, retted, and then cleaned and cottonized with commercial processing equipment. Fiber properties were determined and crude test yarns were made of raw and Shirley cleaned flax fibers and cotton in various blend levels. Cleaned fibers were obtained from both seed and fiber flax types, but with variations due to treatment. Retting formulations produced fibers having different properties, with enzyme levels of 0.3% (v/v as supplied) giving finer but weaker fibers than 0.05% regardless of EDTA level. Experimental yarns of blended flax and cotton fibers varied in mass coefficient of variation, single end strength, and nep imperfections due to sample and formulation. With cost and fiber and yarn quality as criteria, results established a range in the amounts of components comprising retting formulations as a basis for further studies to optimize enzyme-retting formulations for flax. Under conditions examined herein, Viscozyme L at 0.3% (v/v) plus 25 mM EDTA produced the best test yarns and, therefore, established a base for future studies to develop commercial-grade, short staple flax fibers for use in textiles.

Single Cotton Fiber Properties of Low, Ideal, and High Micronaire Values

The Favimat, a single fiber testing machine, is used to quantify the affects of cotton crimp on fibers from three samples consisting of cottons containing low, high, and ideal micronaire values for textile processing. In order to get a better representation of all fibers within these samples, the cotton is further divided into the Suter-Webb array length groups. Following cotton crimp image capturing, fiber fineness is determined by the vibroscope method. The mean values for these samples indicate that cotton containing more crimp in the fibers leads to larger elongation, force to break, linear density, tenacity. and work to rupture. The seven length groups from these cottons indicate that longer cotton fibers appear to contain more crimps per cm. The results suggest that the Favimat is satisfactory for measuring current and future cotton properties.

Modifying Dew-Retted Flax Fibers and Yarns with a Secondary Enzymatic Treatment

Preliminary studies by atomization test the application of various kinds of enzymes as a means of tailoring dew-retted flax fibers in a low moisture atmosphere. A series of chemical and physical tests determines the effect of enzymes on fibers and blended yarns (50:50 flax : cotton). GLC analysis of post-treatment fiber washes shows that lipase and cellulase release the most sugars, likely due to structural disorganization of the fiber matrix. Glucose is the sugar most released by enzyme treatment. Mid-infrared spectros copy of fibers indicates the loss of carbohydrates and the presence of absorbed proteins following all enzyme treatments. All treatments reduce fiber strength and elongation compared to untreated fibers, with cellulase reducing fiber strength the most at 56% of the untreated control. Treatments reduce the occurrence of thick and thin places but reduce yarn strength as well. In general, lipase and arabinanase treatments influence yarn properties the most by increasing strength over the buffer-only treatment, increasing elongation over untreated and buffer-treated yams, and reducing neps and thick/thin places. These preliminary results suggest strategies to optimize enzyme treatments for improved textile properties.