Cotton textile recycling is often accomplished with toxic chemicals. Here we show that mild physical and chemical treatments can deweave cotton fabric into fibers. We identified three solutions that deweave cotton fabric at 50 °C and a moderate stirring speed: 0.5 M citric acid, 0.5 M sodium nitrate, and a 3:1 by volume mixture of the two aforementioned solutions. The extent of deweaving is shown by scanning electron microscopy (SEM) in Fig. 1. The interior of a fiber bundle was imaged using X-ray computed tomography (CT) and shown in Fig. 2. Both tests confirmed that chemical deweaving increased spacing between fibers. SEM showed minimal differences in the curvature of fibers after deweaving, indicating no significant weakening occurred. Comparing DSC and zeta potential measurements of the fibers before and after treatments showed that a starchy material coated the fibers prior to deweaving. This coating provided charge neutrality and had a melting point of T~140C. The deweaving treatment resulted in a negative zeta potential with the largest increase occurring when the 3:1 formulation was applied. This indicates the negative charges applied on fibers increase interfiber repulsion, facilitating separation of fibers and deweaving. Furthermore, the charge increases surface functionality, which enables modification of surface chemistry and production of fibers that can be rewoven in fabric or repurposed for other valuable materials.

SEM of untreated cloth and two types of deweaved fibers

Micro CT of fabric before and after deweaving

Michael Cuiffo

Appearances