Research on Gypsum-Based Composites for Optical Media in Projection Applications Based on Sustainable Development Principles

To improve the optical efficiency and environmental adaptability of projection materials in public exhibition scenarios, gypsum-based composites were obtained with TiO2 and pretreated corn straw powder, strategically embedding circular economy principles into material design through the valorization of agricultural waste. This composite features outstanding low-carbon, realizing agricultural straw recycling of exhibition projection projects. The phase composition, microstructure, mechanical behavior, water resistance, and optical properties of the composites were systematically investigated using XRD, SEM, TGA, FTIR, UV-Vis, XPS, refractive index, and whiteness measurements. The results showed that the incorporation of straw powder enhanced the structural integrity of the gypsum matrix, while the subsequent addition of TiO2 reduced water absorption and improved both the refractive index and whiteness. At a TiO2 content of 20 wt.%, both the refractive index and whiteness increased substantially relative to pure gypsum. These results demonstrate that the synergistic modification of gypsum with pretreated straw powder and TiO2 effectively improves both structural stability and optical performance. This work provides a feasible strategy for transforming low-value waste into high-value optical applications, contributing to the sustainable development goals of green building and waste recycling.