Effect of polyethylene terephthalate fiber reinforced with non-hydrophilic nano-silica on the mechanical,thermic, and chemical shielding characteristics of saturated polyurethane composite

The research investigates the reinforcing effect of scrap polyethylene terephthalate (PET) fiber, non-hydrophilic nano-SiO₂(NS-972) and heat suppressing agents in saturated polyurethane (SPU) composites. PET fiber was obtained through industrial mechanical processing from scraped PET. Thermic and surface morphology of synthesized SPU composites was characterized by using scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Thermic characteristics of filled PU,NS-PET fiber (1.5%)-APM (1:1) (PU-NF1.5A) composite with (1:1) proportion of additive NS-PET fiber (0.5–2%) and halogen free fire-extinguishing additives APM (0–3%) were determined utilizing UL-94, TGA, critical oxygen index, and smoke density. The tensile properties of the composite improved to 42.27% (4.14 MPa) when the filler content was increased to 1.5%. The WCA, moisture permeability and chemical resistance analysis indicated that fabricated composite films with variable additive content had excellent hydrophobicity and improved resistance to water, humidity, and chemical resistance. TGA data shows the increased thermal resistance of reinforced PU composite is attributed to the increased thermal deterioration temperature, resulted to the higher thermic degradation temperature of the terephthalic and sebacic acids used in the synthesis of PU. Smoke producing capacity of composite PU-NF1.5A (0–3%) reduced from 82% to 52%. The LOI improved from 19 to 23 (?vol.%) at 3% APM additives.