Development of Moulding using Sweet Sorghum Bagasse and Citric Acid: Effects of Application Method and Citric Acid Content

摘要

The effective use of agricultural residues is desirable. In this study, the manufacturing of mouldings using sweet sorghum bagasse powder and citric acid as an adhesive was attempted. The effects of the application method and citric acid content on the bending properties and water resistance of the mouldings were investigated. Powder and liquid applications were used. The citric acid solid content based on the total weight of the mouldings was adjusted to 0, 15, 20, 25, and 30 weight percent. The dumbbell-shaped moulding was manufactured at 200 degrees C and 4 MPa for 10 minutes. The relationship between the bending properties and citric acid content differed depending on the application method; the powder application was effective for obtaining high bending properties with a lower citric acid content. The water resistance of the moulding was greatly affected by the application method when a low citric acid content was used, and it was affected by the citric acid content when a high citric acid content was used. According to the data measured from Fourier-transform infrared spectroscopy, it was easy to contain unreacted citric acid in the moulding with the powder application, and an ester linkage formed easily when the liquid application was used. It was suggested that the citric acid tends to work as an adhesive in the powder application, and it tends to modify the bagasse powder in the liquid application.