Cellulose fiber drainage improvement via citric acid crosslinking

Wheat straw, as a non-wood fiber waste, is available worldwide and can be used in cellulosic matric production, promoting the application of sustainable materials. However, poor fiber properties and water drainage are the primary obstacles to its utilization. In this study, wheat straw pulp fibers were chemically crosslinked by citric acid (CA) in an environmentally friendly process. X-ray photoelectron spectroscopy and Fourier transform infrared spectra confirmed that the chemical treatment introduced carboxylic groups to cellulose fibers. Meanwhile, X-ray diffraction patterns showed that the crystallinity of cellulose was reduced. The average fiber length and water retention value of the pulp decreased with increasing CA dosage under the conditions of 3 mL/g CA₄ (4 wt% CA), and the drainage performance of the cellulose pulp improved by 21 %. Also, the crosslinking of fibers contributed to the mechanical properties of the cellulosic matrix, increasing the dry and wet strength by 21 % and 282 %, respectively. These results demonstrated that citric acid could be a sustainable method for improving the properties of wheat straw fibers, thereby promoting its application in fabricating sustainable materials.