Preparation of Wheat Straw Hot-Pressed Board through Coupled Dilute Acid Pretreatment and Surface Modification

Abstract

The production of wheat straw waste board materials encounters challenges, including inadequate inherent adhesiveness and the utilization of environmentally harmful adhesives. Employing a hot-pressed method for converting wheat straw into board materials represents a positive stride towards the resourceful utilization of agricultural wastes. This study primarily focuses on examining the influence of hot-pressing process conditions on the mechanical properties of wheat straw board materials pretreated with dilute acid. Additionally, it assesses the necessity of dilute acid treatment and optimizes the hot-pressing conditions to achieve optimal results at 15 MPa, 2 h, and 160 °C. Furthermore, a comprehensive process is developed for preparing wheat straw hot-pressed board materials by combining dilute acid pretreatment with surface modification treatments, such as glutaraldehyde, citric acid, and rosin. Finally, a thorough characterization of the mechanical properties of the prepared board materials is conducted. The results indicate a substantial improvement in tensile strength across all modified wheat straw board materials compared to untreated ones. Notably, boards treated with glutaraldehyde exhibited the most significant enhancement, achieving a tensile strength of 463 kPa, bending strength of 833 kPa, and a water absorption rate of 14.14%. This study demonstrates that combining dilute acid pretreatment with surface modification treatments effectively enhances the performance of wheat straw board materials, offering a sustainable alternative to traditional wood-based board materials.