Innovative Nonwoven Fireproof Composite Felt from Recycled Waste Polyester Fibers

The booming global textile industry generates vast amounts of waste textiles, while traditional landfill and incineration strategies trigger serious environmental pollution and massive resource loss. To address this hurdle, we employed a cost-effective integrated technique of continuous opening–carding–needle punching coupled with hot pressing, which enabled the recycling of waste poly(ethylene terephthalate) fibers into 3D nonwoven composite felts by blending with alginate and low-melting-point fibers. The effects of the fiber mass ratio, needle punching frequency, and density on the mechanical performance of the composite were systematically investigated. The resultant composite achieved a UL-94 V-0 rating in the vertical burning test, accompanied by decreased total heat release, suppressed smoke production, and limited toxic gas release upon combustion. In-depth analysis of pyrolysis volatile components, combustion residues, and their phase compositions further clarified the flame-retardant mechanism of gas dilution coupled with dense char layer encapsulation. This work offers a simple and sustainable route to recycle waste textiles, and the obtained composite possessed high-value performance, showing promising prospects as an advanced flame-retardant material for thermal protection scenarios like automotive interiors and household decorations.