Preparation and properties of boron-modified phenolic foams composites

In order to improve high temperature resistance of phenolic foams, B₂O₃ was incorporated in it to synthesize boron-modified composites by mold forming and curing. Microstructure of resultant phenolic foams were studied. Effects of boron content on compressive properties and high temperature resistance of phenolic foams are investigated. The results showed that compressive fracture characteristics of boron modified phenolic foams was pseudoplastic. Toughness of resin matrix and compressive strength of phenolic foams could be improved by proper amount of B₂O₃. The compressive strength of PF-4 is best, 10.14 MPa, 5.18% higher than PF-0. Boron was beneficial to improving high temperature stability of phenolic foams. Thermal decomposition temperature and carbon yield are enhanced with increase of B₂O₃. PF-7 showed better high temperature stability than others, whose thermal decomposition temperature with 10% weight loss is 447°C, 76.68% higher than that of PF-0, and carbon yield is 66.37% at 800°C, 16.05% higher than that of PF-0.