Investigation of dynamic mechanical, fatigue, and creep behavior of squid fish–derived collagen and <i>Alpinia galanga</i> stalk fiber–reinforced vinyl resin composites

The present study examines the mechanical, viscoelastic, creep, fatigue, and tribological behavior of vinyl ester composites reinforced with alkali-treated Alpinia galanga stalk fiber and alkali-treated squid fish–derived collagen filler. The developed hybrid composites exhibit marked performance improvements compared with the neat vinyl ester matrix. Among all formulations, VFC2 demonstrated the most superior fatigue performance, achieving 25,947, 22,797, and 19,678 cycles at 25%, 50%, and 75% of Ultimate Tensile Stress (UTS), respectively, corresponding to an improvement of approximately 300–316% over specimen V. This enhanced fatigue resistance is attributed to the optimal combination of 40 vol.% treated fiber and 3 vol.% treated collagen, which forms a uniformly dispersed and strongly bonded hybrid reinforcement network that suppresses micro-crack initiation and efficiently dissipates cyclic stresses. For long-term and functional performance, VFC3 exhibited the best wear, creep, and dynamic mechanical analysis (DMA), recording the lowest specific wear rate of 0.020 mm 3 /Nm, minimum creep strains of 0.0062, 0.0071, and 0.0088, and the highest storage and loss moduli of 16.4 GPa and 0.17 GPa, respectively. These enhancements are attributed to the higher 5 vol.% treated collagen content, which promotes matrix densification, restricts molecular mobility, increases interfacial friction, and facilitates stable transfer layer formation during sliding. Scanning Electron microscopy (SEM) observations corroborate these findings, revealing voids in the neat matrix, strong fiber–matrix adhesion in VFC0, uniform filler dispersion in VFC2, and denser collagen network in VFC3.