a Department of Mechanical Engineering, Hindusthan College of Engineering and Technology, Coimbatore, 641032, Tamilnadu, India

b Department of Mechanical Engineering, SACS MAVMM Engineering College,

Madurai-625301

c Department of Mechanical Engineering, Pollachi Institute of Engineering and

Technology, Pollachi, Coimbatore, 642205, Tamil Nadu, India

d School of Mechanical Engineering, REVA University,

Rukmini Knowledge Park, Kattigenahalli, Yelahanka, Bengaluru-560064, India.

The present study examines how waste cotton microfiber-vinyl ester composites' flammability, thermal stability, and antibacterial qualities are affected by annealed-silane modified biosilica. Specimens were carefully manufactured using the solution casting method and thoroughly characterized in accordance with ASTM guidelines. Positive results from the flammability evaluation showed that adding annealed-silane modified biosilica could improve fire resistance. Notably, the VCB3 composite achieved a V-0 rating by showing decreased flammability, enhanced fire retardancy, and a decreased velocity of propagation or propagation speed of 9.77 mm/min. Moreover, it exhibited no cotton lightens and falling drops. These results hold significant promise for applications where fire safety is of utmost importance. In terms of thermal stability, the modified composites displayed heightened resistance to elevated temperatures. Specifically, the VCB3 composite showcased remarkable thermal stability, featuring a notably high initial decomposition temperature of 388°C.Furthermore, the investigation into the antimicrobial properties of these composites unveiled their potential as materials inherently resistant to microbial growth. Similar to the improvements seen in flammability and thermal stability, VCB3 demonstrated enhanced antimicrobial characteristics, with increased inhibitory diameters of 14.36mm and 14.72mm against S. Aureus and E. Coli, respectively. This quality holds substantial promise for various industries, particularly those emphasizing hygiene and microbial control.These results present promising opportunities for the use of these advanced composites in a variety of fields where fire safety, resilience to high temperatures, and antibacterial properties are desirable, such as healthcare, transportation, and construction.