In this excerpt from his book Manufacturing Processes for Textile and Fashion Design Professionals, Rob Thompson describes the properties of plant fibers.
Plant fibers, whether harvested from the seed pod, stem, or leaf, are made up of the same ingredients. Cellulose is a strong linear polymer made up of repeating glucose units. It forms very fine strands, called microfibrils, in the plant cell walls. These are bonded together with a matrix of hemicellulose, lignin and pectin. As the plant grows, new layers of cell wall are formed around the outside.
The proportion of diverse polymeric substances and structure of the fiber is determined by its role in nature. Whereas flax (structural bast fiber) has a high proportion of hemicellulose, cotton (seed hair) is virtually pure cellulose. Their contrasting properties‹strength, handle, and colorability‹are the result of these differences.
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Thanks to fiber structure, they have a high level of absorbency and so are often utilized in pile fabrics to make towels, and woven into warm-weather clothing that remains dry. Water absorption causes the fibers to swell and so closes up the gaps in tight weaves. This means that some cotton fabrics are naturally water-repellent (without the need for coating or laminating).
One of the downsides of plant fibers is that they tend to have low resiliency, resulting in wrinkles and fiber breakage. A good example of this is linen woven with flax and used to make summer suits. Coatings help to reduce wrinkling, but they may also affect the natural quality of the material and are considered a health hazard if formaldehyde-based resins are used.
As a natural material, the fibers are susceptible to ultraviolet light, mold and insect attack. However, certain types exhibit very high resistance to one or more of these factors. For example, hemp is naturally antibacterial, which means it is resistant to mold and mildew. Combined with the fact that hemp is strong and resistent to heat, ultraviolet light and salt water, this is a very desirable material for a wide range of decorative and technical applications.
Many of these fibers are suitable for dyeing‹cotton is produced in the widest range of bright and pastel colors‹although the necessary bleaching and chemical treatments can affect the strength and resilience of the fiber. Therefore, many plant fibers are used primarily in their natural colors. Omitting bleaching and dyeing greatly reduces the environmental impacts of producing plant fiber textiles.
Excerpt from “Manufacturing Processes for Textile and Fashion Design Professionals.” Copyright © 2014 and reprinted by permission of Thames & Hudson Inc.