Abstract Fabricating large-scale fused filament fabrication (FFF) components is constrained by build volume, necessitating robust, low-cost bonding solutions. This study evaluates a sustainable solvent-based adhesive derived from upcycled waste acrylonitrile butadiene styrene (ABS) dissolved in acetone for bonding polylactic acid (PLA) structures. To assess bonding performance, modified single-lap joints were tested following ASTM D3163 tensile and ASTM D790 three-point bending standards. The experimental design investigated the influence of ABS concentration (16, 20, and 24 g per 50 mL acetone), three-year adhesive aging, and concentric versus zigzag surface architectures. Statistical analyses, including Taguchi, ANOVA, and Principal Component Analysis (PCA), were employed to quantify multivariate interactions. Tensile testing demonstrated that fresh adhesive with 16 g ABS applied to concentric patterns achieved a maximum lap-shear strength of 8.69 MPa, outperforming commercial cyanoacrylates. Remarkably, aged formulations retained approximately 86% of their original shear strength and 82.7% of flexural capacity, despite a 46% reduction in ductility due to solvent loss. ANOVA revealed that adhesive aging predominantly governs tensile strength and elongation, whereas surface pattern and adhesive concentration primarily dictate stiffness. PCA resolved a fundamental stiffness–ductility trade-off, indicating that concentric patterns maximize load capacity while zigzag architectures favor rigidity. Macroscopic and microscopic imaging confirmed predominantly cohesive fracture in fresh tensile specimens due to strong mechanical interlocking, whereas aged samples transitioned to adhesive debonding due to embrittlement and solvent loss. In flexural tests, fresh adhesives displayed cohesive-dominant mixed-mode failure, while aged samples exhibited adhesive-dominant mixed-mode fracture, confirming that aging weakens interfacial bonding while maintaining overall structural stability.
Emir Avcioglu (Thu,) studied this question.