A Novel Alkyd-Based Composite Modification System for Achieving High-Performance Acrylic Coatings on Bamboo

Acrylic resins are widely favored for bamboo protective coatings due to their superior weather resistance; however, their widespread application is limited by their inherent drawbacks, including brittleness, inadequate adhesion, and poor water resistance. In this study, an innovative composite modification strategy, pre-blending alkyd resin with selected modifiers, was developed to enhance the adhesion, water resistance, and toughness of acrylic resin paint films. Compared to unmodified acrylic resin, the optimal group exhibited enhanced adhesion strengths of 4.21 MPa on tinplate and 7.36 MPa on bamboo, representing improvements of 31.56% and 29.35%, respectively. This was accompanied by a 205 g increase in scratch resistance and a 44% decrease in water absorption, indicating a concurrent enhancement in toughness, strength, and water resistance within the composite system. As revealed by X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR) analyses, this enhancement was attributed to the formation of a multidimensional network structure arising from synergistic interactions among the modifier, the alkyd resin, and the acrylic resin. This study provides a theoretical basis for developing high-performance coatings for bamboo protection.