Study on Novel Modified Phenolic Foams with Added Pine Wood Sawdust

The use of low-cost agricultural and forestry waste for the preparation of modified phenolic foam (MPF) has attracted widespread attention and has shown promising prospects. This study proposes a novel method for producing MPF using pine sawdust. The full components of pine wood powder and its liquefied products were used as raw materials, and the resin was modified with a silane coupling agent (KH560), triethylene glycol (TEG), and nylon 66 (PA66). Subsequently, three novel MPFs were successfully fabricated using a transplanted core foaming technique, and their material properties were subsequently investigated. The results showed that all three MPFs exhibited excellent compressive strength and flame retardancy, with compressive strength ranging from 5.93 MPa to 12.22 MPa and oxygen index values between 36.2% and 41.5%. In terms of water resistance, the MPFs significantly outperformed traditional phenolic foam (PF); in particular, the addition of 4% KH560 and PA66 reduced the water absorption rate to as low as 2.5%. Furthermore, the powdering rate and thermal conductivity of all MPFs were significantly reduced, with chalking rates decreasing by 28.57% to 50%. This research presents a novel method for preparing MPF using agroforestry waste as a partial replacement for phenol. This approach achieves high-value utilization of pine sawdust while maintaining the performance of the MPF, thus broadening the avenues for MPF production.