The researchers explored a way to make sugarcane bagasse fibers better for making composites with polyester. They treated the fibers with steam and alkali washing to change their properties. Steam explosion reduced certain components in the fibers and increased others. Alkali washing further improved the fibers. Composites made with these treated fibers showed better density, thermal stability, water absorption, and strength compared to those made with untreated fibers. The changes in the fibers due to the treatments led to these improvements in the composites.