Helen H. Epps

Color Measurement of Flax Retted by Various Means

Color measurements are made of various kinds of flax retted by dew, water, or enzymes. Two sets of samples are analyzed under different conditions using different spectropho tometers and by reflectance in the visible and near infrared spectral regions. Sample set one consists of 55 samples of various flax types retted by traditional dew and water methods and various experimental enzyme retted samples. Means and standard deviations of CIELAB color values for each of the classes are displayed as spheroid plots. The enzyme retted fiber flax class forms a separate group that is substantially lighter and slightly yellower than dew retted flax. Water retted flax is intermediate between dew and enzyme retted flax, but tends to be closer to dew retted flax. Near infrared spectra vary with different cleaning methods to remove shives from fibers. A second set of 16 samples consists of dew, water, and spray enzyme retted samples, the latter samples also analyzed with regard to subsequent cleaning processes. CIELAB and Hunter Lab methods provide similar comparisons, although CIELAB values are higher within treatments. Enzyme retted fibers tend (P > 0.05) to be lighter and yellower than water retted ones. None of the flax fibers are as light as the cotton samples included for comparison. The ΔE CIELAB values are 8.8 between dew and water retted fibers, 13.6 between dew and enzyme retted fibers, and 4.9 between water and enzyme retted fibers. Factors that affect the color of enzymatically retted flax fibers are prior microbial activity, shive content, and fiber fineness. These color methods could form the basis for developing a color standard for short staple flax fibers.

Thermal Transmittance and Air Permeability of Plain Weave Fabrics

The findings of earlier research on the influence of particular yarn and fabric structural variables on heat transfer and air flow through fabrics are used in explaining similarities and differences among measurements of air permeability and thermal transmittance of three medium-weight plain weave fabrics. Two fabrics constructed of staple polyester (PET) yarns exhibited higher air permeabilities and lower thermal transmittance values than the third fabric, which was composed of PET filament yarns. Bulk densities of the two staple yarn fabrics were approximately equal, but the fabrics differed in weight, thickness, fabric count, yarn tex, and yarn twist. The staple yarn fabric with the lowest fabric count, highest weight, and highest thickness exhibited the lowest thermal transmittance in both single and multiple layers; however, differences between its thermal transmittance values and those of the thinner, lighter weight staple yarn fabric were not statistically significant. There were significant differences in air permeability between each of the three fabrics. Measurements also were taken on multiple layers of the fabrics. Regression analysis revealed nonlinear declines in thermal transmittance and air permeability as fabric layers were increased. Differences in air permeability and thermal transmittance among the fabrics are explained on the basis of structural differences.

Color of Enzyme-Retted Flax Fibers Affected by Processing, Cleaning, and Cottonizing

Twenty-seven samples representing variations of retted flax fibers are analyzed using a color spectrophotometer and CIELAB models. Variables included enzyme or dew retting, fiber or seed flax, enzyme and chelator concentrations, and sequential cleaning steps. In addition to differences in color with enzyme or dew retting, the variables involved in enzyme retting also contribute to differences in the lightness, redness-greenness, and yellowness-blueness of the resulting fibers. Dew retted fiber flax, as well as seed flax that has weathered during storage prior to enzyme retting, is significantly darker than non-weathered, enzyme retted fiber flax. Pairwise comparisons show that lower enzyme concentrations (0.05% v/v as commercially supplied) produce redder and yellower fiber samples than those retted with higher (0.3% v/v) enzyme levels. Higher chelator levels, (i.e., 50 versus 25 mmol ethylenediaminetetraacetic acid) produce redder fibers. Fiber lightness significantly increases with additional cleaning steps. Results indicate that objective color measurements and color standards can define important fiber properties in order to tailor raw materials for specific industrial applications.

Insulation Characteristics of Fabric Assemblies

This research was conducted to assess thermal transmittance and air permeability of selected textile fabrics in single and multilayer configurations Fabric geometry was found to contribute significantly to both the thermal transmittance and the air permeability of the assemblies. Fabrics representing a range of fibers, yarn structures and fabric constructions were used to develop model textile assemblies which op timize thermal transmittance and air permeability. The findings of the study provide an understanding of the insulation performance of textile fabrics and fabric assem blies in a variety of applications, ranging from apparel to thermal insulation used in buildings.

Effect of scouring and enzyme treatment on moisture regain percentage of naturally colored cottons

The objective of this study was to determine whether enzymatic treatment can improve low moisture regain of three naturally colored cottons. There was an increase in weight of colored cottons after enzyme treatment. Moisture regain test was implemented to determine the cause of this increase. The result showed that moisture regain of three naturally colored cottons increased after scouring and increased further after enzyme treatment. Statistical results indicated that lipase was the least effective enzyme for brown cottons and the most effective enzyme for green cotton. For multiple enzyme treatment, treatments including amylase were most effective for brown cottons and for treatments including lipase were most effective for green cotton. Treatments with all four enzymes resulted in the lowest increase in moisture regain for all colored cottons.

Enzyme-Retted Flax Using Different Formulations and Processed Through the USDA Flax Fiber Pilot Plant

SUMMARY Mature Ariane flax was retted with various proportions of the commercial enzyme mixture Viscozyme L (0.05, 0.1, 0.2, and 0.3% of product as supplied) and ethylenediaminetetraacetic acid (4,7, and 18 mM) from Mayoquest 200. Retted material was then cleaned through the USDA Flax Fiber Pilot Plant (Flax-PP) consisting of the following: 9-roller crushing colander, top shaker, scutching wheel, and 5-roller grooved colander. To simulate cottonization of fiber for use in textiles, the Flax-PP-cleaned fiber was passed 1 × through a Shirley Analyzer. Fiber yields and properties (strength, elongation, fineness, and color), which were determined for the various processing stages, were influenced by various formulations and by processing stage. For this flax sample, 0.05% Viscozyme plus 18 mM EDTA produced the highest yield of Flax-PP and Shirley-cleaned fibers, strong fine fibers of light color, and the strongest coarse fibers from Shirley by-product material.

Degradation of Swimwear Fabrics: Effects of Light, Sea Water and Chlorine

Three knitted nylon/spandex swimwear fabrics dyed with acid dyes were subjected to xenon light, sea water, and chlorinated pool water. The effects of these treatments on color changes and tensile properties were compared. The three fabrics used in the study represented both light and dark colors. The greatest color change and the greatest loss in tensile strength was exhibited by the lightest colored fabric, while the darkest fabric exhibited the best colorfastness and retention of strength. Sea water and chlorinated pool water treatments were found to accelerate xenon light degradation of the fabrics.