Soil biodegradation of cotton fabrics treated with common finishes

Cotton is one of the most widely used natural fibers available. However, to overcome some of its shortcomings, manufacturers have placed various finishes on cotton fabrics to improve wrinkle recovery, flame retardancy, anti-microbial behavior, water repellency, etc. This study measures the impact of common finishes on the biodegradability of 100% cotton fabrics in a soil laboratory environment. Under a controlled laboratory environment, cotton fabrics treated with 9 different finishing chemicals or chemical combinations were tested according to the standard test method, ASTM D5988-12, for up to 154 days. Results indicate crosslinked fibers show better protection from biodegradation when compared to the control fabric and non-crosslinked fabrics. The production of carbon dioxide (CO₂) as a function of time was measured to determine the degree of biodegradation. Untreated cotton samples produced 2500 mg of CO₂ after 154 days, approximately 40% more than that of the crosslinked treated fabric. Weightless studies showed the untreated fabrics and non-crosslinked finished having 40–60% weight loss after 154 days, while the crosslinked fabrics had unless than 20% weight loss over the same time period. Scanning electron microscope (SEM) images were used to observe the visual degradation level for each sample showed certain treated fabrics showed a less evidence of cracking on the fiber surface along with less microorganism growth. Fourier-transform infrared spectroscopy (FTIR) analysis showed that in general, treated fabrics with higher CO₂ production and higher weight loss showed greater evidence of microorganism growth when analyzing peak bands typically associated with microorganism growth irreversibly bonded to the fibers.