Sustainable, Biobased Silicone with Layered Double Hydroxide Hybrid and Their Application in Natural-Fiber Reinforced Phenolic Composites with Enhanced Performance

With wide application of natural fibers in polymer composites, improvements in their flame retardancy, water absorption, and electrical resistance become an urgent need. To this end, 4.5 wt % of layered double hydroxide (LDH) is introduced into sisal fiber reinforced biobased silicone modified phenolic composites. The modified composites optimally shows 60% reduction in total heat release (20.2 MJ/m²) compared to the composites without LDH. In addition, the biobased silicone modifier TDS is incorporated into phenolic resins (SPF), to further reduce water absorption rate to 6 wt %, and increase volume electrical resistance up to 4.6 × 10¹⁶ Ω m. The SPF-SF-SDBSLDH exhibits a high impact strength of 4.2 kJ/m², over 50% higher than the unmodified PF-SF composites. The SEM observations show that the SPF composites exhibit better interfacial interaction with sisal fiber than normal phenolic (PF) composites. All these flame retardant, impact strength and electrical resistance properties are compatible with the requirement for applications as molding compounds. Our research provides a cost-effective method to improve the performance of this sustainable natural-fiber reinforced composites with novel and low cost biobased silicone modifier and LDHs. These high performance composites are promising for applications in high technology areas such as the microelectric industry and lightweight automotives.