Mechanical, wear, fatigue, water absorption and flammability of silane-treated Indian squid chitin powder-dispersed pineapple fiber-polyester composite

The purpose of this research is to investigate the creation and properties of a composite material that is based on polyester and reinforced with pineapple fibers and silane-treated chitin that was obtained from the endoskeleton of an Indian squid. The curing hardener was cobalt naphthenate, and the accelerator was methyl-ethyl-ketone peroxide. The chitin extraction process involved washing, drying, and grinding the fish pen into a powder. The silane treatment of chitin was performed, which involves the hydrolysis of a silane coupling agent in an aqueous solution of ethanol and water at a 2 wt% concentration. Composite specimens were fabricated using the hand layup technique. Among the various composites, specimen PC3, containing 2.0% chitin, exhibited superior mechanical, physical, and durability properties. PC3 showed the highest tensile strength of 151.8 MPa and a tensile modulus of 5.37 GPa. It also demonstrated excellent flexural strength of 192.5 MPa and a flexural modulus of 6.33 GPa. The compression strength of PC3 was recorded at 174.9 MPa. The izod impact toughness reached 5.3 kJ/m², and the hardness was measured at 89.1 Shore-D. Wear resistance tests indicated a wear rate of 0.0024 mm³/Nm. The flammability test showed a limiting oxygen index (LOI) of 28.2%, indicating good flame resistance. For fatigue properties, PC3 demonstrated the highest endurance, with fatigue life counts of 39,741, 36,746, and 33,412 cycles at 25, 50, and 75% of UTS, respectively. Water absorption tests showed a water uptake of 1.2% after 24 h of immersion. The silane treatment of chitin enhances the chemical interaction between the fiber and the polymeric matrix by creating a Si–O–Si linkage, which improves surface hydrophobicity and compatibility with organic molecules. This treatment facilitates better bonding within the composite material, leading to enhanced mechanical and durability properties. SEM analysis revealed enhanced adhesion between the fibers and chitin fillers, leading to improved load transfer efficiency and reduced fiber pull-out. The morphology and distribution of chitin particles within the matrix further highlighted their role in reinforcing the composite, contributing to the observed improvements in mechanical, physical, and durability properties. Overall, the incorporation of silane-treated chitin from Indian squid significantly enhances the performance characteristics of polyester-based composites, presenting a viable approach for advanced material applications.