Exploring the potential of chitin and chitosan extracted from shrimp shell waste in enhancing urea-formaldehyde wood adhesives

This work aims to investigate the properties of both chitin (CT), and chitosan (CS) extracted from shrimp shell waste (SSW) and its potential use for the improvement of urea-formaldehyde (UF) based adhesives in particleboards manufacturing. For this purpose, characterization techniques (SEM, ATR-FTIR, XRD, and TGA/DTG) were used to confirm the successful extraction of CT and CS. The effect of different ratios of 4, 6, 8, and 10 wt% of CT and CS, on the ultimate particleboard's mechanical properties (dry internal bond (IB), modulus of rupture (MOR), modulus of elasticity (MOE) and surface soundness (SS)) was investigated, and compared to the European Standards. It was evidenced that the optimal formulation of adhesives is (92:8; w:w) for both UF:CT and UF:CS leading to higher mechanical performance. For instance, MOE was uplifted to 3478 and 3568 MPa, and MOR was uplifted to 21 and 22 MPa, with the loading of CT and CS respectively, compared to MOE = 2579 MPa and MOR = 16 MPa for the particleboard glued with only UF adhesive. Moreover, when 8 wt% of CT and CS are formulated with UF adhesive, the formaldehyde emission from particleboard was reduced significantly about 36.11 and 37.18%, respectively. The addition of 8 wt% CT and CS exhibited a decrease in the values Thickness Swelling (TS) and Water Adsorption (WA) of the particleboards, highlighting the improvement of the physical properties of the final products. This study aims to promote the use of shrimp shell waste in the development of high added value products in wood urea-formaldehyde based adhesives.