THEORETICAL METHOD FOR CHARACTERIZING TEXTILE FAILURE MECHANICS IN MECHANICAL RECYCLING WITH CARDED DRUMS

Due to the increasing speed of production, sale, and discard of home and apparel products, recycling of textiles is important for supporting the UN’s Sustainable Development Goal of Responsible Consumption and Production. In 2020, textile production was estimated to be responsible for 35% of primary microplastics released into the environment, 20% of global clean water pollution, and 10% of global greenhouse gas emissions. In 2018 the US generated around 17 million tons of textile waste and only 14.7% was recycled. Drum-operated textile shredding, a commonly utilized mechanical textile recycling technique, is not yet fully characterized. Even though there are many shredding machines that perform this process, the parameters that influence high-quality fiber output have not been researched; discovering ways to improve reusable fiber output is still a challenge. This research investigates the theory behind carded (toothed) drum textile shredding including how to improve the process outcome in order to obtain more reusable fiber and fewer textile pieces and dust. The mechanics of the textiles and fibers under tensile and shear stresses from the drums and drum teeth respectively were described to relate the textile material failure behavior to shredding process fiber outputs. Focusing on the interactions of the feeding drums and shredding drum, the drum-textile and tooth-yarn failure mechanics were characterized. By decreasing the teeth size and increasing the relative speed between drums, it is expected to increase the shear failure ratio, thus improving the shredding system. With this, it is expected that manufacturing new and better materials from recycled fibers becomes a possibility.