Synergistic Effects on Morphology and Properties of Polyurethane-Rubber foam Composite

Polyurethane (PU) foams are widely applied in cushioning, packaging, and construction, but their reliance on petroleum-based feedstocks and limited durability raises sustainability concerns. This study investigates the incorporation of ground tyre rubber (GTR) into flexible PU foams to enhance performance while promoting circular economy goals. Foams were synthesized via the free-rise method using polyethylene glycol (PEG 400) and isophorone diisocyanate (IPDI), with GTR fillers (≤0.4 mm) and silicone oil surfactant. Fourier-transform infrared spectroscopy confirmed successful urethane network formation, while scanning electron microscopy revealed that GTR disrupted cellular morphology, increasing porosity and heterogeneity. Mechanical analysis showed a substantial decline in compressive strength and modulus with increasing filler loading, attributed to poor filler matrix compatibility and uneven dispersion. Thermal analysis highlighted a dual effect where GTR suppressed the glass transition temperature, reflecting reduced microphase separation, yet improved thermal stability by delaying degradation onset and increasing residual char yield. Silicone oil partially mitigated structural collapse by refining cell morphology and enhancing compressive behavior. The results showed a trade-off between sustainability-driven waste rubber utilization and foam integrity. While GTR incorporation advances responsible resource recovery and contributes to Sustainable Development Goals (SDGs), unmodified fillers compromise mechanical reliability, limiting high-performance applications. Future work should emphasize interfacial engineering, including surface modification and compatibilizer integration, to reconcile environmental imperatives with performance requirements.

polyurethane foam, compressive test, glass transition temperature, degradation temperature, morphology, crumb rubber

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