Performance of Fire Retarded Waste Mixed Plastics and Waste Glass Fibres for Sustainable Engineering Solutions

The fire performance of virgin low-density polyethylene (vLDPE), waste mixed plastics (wMP), and waste glass fibre (wGF) reinforced waste mixed plastics was investigated with and without the addition of fire retardant (Aluminium Trihydroxide, ATH). The fire performance was quantified through commonly reported metrics including the time to ignition, mass loss rate (MLR), heat release rate (HRR), and effective heat of combustion (EHC) at three different heat flux conditions (20, 40, and 60 kW/m2). The addition of wGF changed the general HRR behaviour and promoted a steadier state process. Compared to the vLDPE, the addition of wGF is shown to decrease the peak heat release rate, although it extended the burning duration. This result suggests that the wGF helps reduce the rate of heat transfer into the composite material compared to the pure wMP and virgin PE samples. FR treatment was found to reduce the peak heat release rate by 30-40% on average, which corresponds well to previous studies. However, this decrease in heat release rate is also accompanied by an increase in CO production–a key indicator of incomplete combustion and toxic emissions. This shows the importance of optimizing multiple fire safety metrics in the design of composite systems.