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ARS Home » Research » Publications at this Location » Publication #116147
Title: DEFINING FLAX QUALITY

Author
item MORRISON III, WILEY

Submitted to: Agro-Food Industry Hi-Tech
Publication Type: Review Article
Publication Acceptance Date: 7/24/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: Expert graders have always graded flax, the source of linen, using eye/hand evaluations much the same as in done for tobacco. There is a need for universal test methids that can be used to grade flax to improve international trade. The current work has shown that fibers and yarns that are low in residual wax and cuticle are graded high. In addition, studies have shown that the method of retting, a controlled rotting that releases fibers from the stem, influences the ease of removal of these components during further processing. Currently the Association of Testing and Materials (ASTM) has a subcommittee in place to develop needed test methods for flax.

Technical Abstract: Expert graders using subjective, eye/hand evaluations have always defined flax fiber and yarn quality. Samples of graded flax fiber and yarn were characterized using wet chemicals and instrument analyses. Samples that were graded as being of high quality generally had less wax, aromatics, and cuticle associated with the fibers. In addition, Raman, 13C NMR, and pyrolysis mass spectrometric analysis provided information that supported the findings of the chemical analyses. Since the removal of cuticle appears to be critical to high quality fibers, the retting process, a controlled rotting of the plant, is of importance. Samples of water and dew-retted flax were analyzed chemically and with pyrolysis mass spectrometry (PyMS) and the results related to fiber fineness and strength. Dew-retting removed greater amounts of waxes, phenolics and cutin as compared to water-retted samples. Water-retted samples are stronger and finer. Principle component analysis of the PyMS data grouped water and dew-retted samples separately based on differences in strength, fineness, wax, and cuticle markers. Factors that could be included in standards for trade of flax such as color, non-fiber (trash) content and length, strength, and fineness are currently being developed.