Could hemp improve the performance of denim blends? Researchers in Turkey seem to think so.
A new study conducted by researchers in the department of textile engineering at Istanbul Technical University and published last month in the Research Journal of Textile and Apparel, looked at the effects of incorporating hemp fiber into single- and dual-core stretch yarns using cotton/elastane blends and cotton/T400/elastane blends. The researchers looked at how the hemp fibers affected moisture management, thermal comfort and tactile properties in both untreated and rinsed denim fabrics.
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Researchers evaluated seven different types of denim fabric compositions for moisture management properties, which included air permeability, water absorbency, vertical and transfer wicking ability, drying time and rate, and relative water vapor permeability. The study also tested for thermal properties of conductivity, absorptivity and resistance, as well as tactile properties of compressibility, shear rigidity, bending rigidity and formability.
The analysis found that adding hemp fibers to stretch denim improved moisture management, air permeability, water absorption, wicking, relative water vapor permeability and drying efficiency, particularly in single-core yarn blends.
Researchers also discovered that hemp increased thermal absorptivity, providing a cooler feel, especially in dual-core yarns. And the fiber also improved tactile comfort by reducing shear and bending stiffness, which produced softer, more easily shaped fabrics that enabled smoother sewing and a better look.
The researchers said they wanted to explore the use of hemp in denim blends since a study of its type had not been previously conducted, even though there’s growing interest in incorporating natural fibers with cotton in denim blends to improve the sustainability of the material.
Hemp has been on the rise for several years now in the denim industry, with brands such as Levi’s, Lucky Brand and Naked & Famous incorporating the fiber in jeans over the past decade.
Two years ago, Fashion for Good launched its “Beyond50 Denim: Combining Cottonized Hemp and Green Chemistry” project, which aimed to increase hemp content in denim to 50 percent or more by applying new technologies. That tech—SEFF’s Nano-Pulse, which transforms raw hemp into more cotton-like fiber, and FIBRE52’s chemistry that gives cellulosic fiber-based fabrics a softer feel—was used to help make coarse hemp fibers more useable for apparel applications. Most denim blends using hemp only include 20 or 30 percent of the fiber due to its coarseness.
Hemp usage has become more appealing to brands looking for more sustainable fiber alternatives. The fast-growing crop typically requires less water and fewer chemicals than other fibers such as cotton, and it also absorbs more carbon dioxide than many other natural fibers.
