Synthesis and characterization of boron and phosphorus-containing phenol formaldehyde resin-modified polyurethane composites

Composite films with polyurethane (PU), phenol formaldehyde resin (PFR) and boron, phosphorus-containing phenol formaldehyde resins (P-PFR and B, P-PFR), were synthesized using sol–gel and copolymerization techniques. These composite films were deposited via spin-coating onto an aluminum alloy (AA) for improve the corrosion protection. The effects of different types of PFR on the structural, thermal and mechanical properties and corrosion resistance of the composites were investigated. The structures and morphologies of the composites were investigated by the gel permeation chromatography (GPC), Fourier transform infrared (FTIR), scanning electronic microscopy (SEM) and atomic force microscopy (AFM). It was shown from the dynamic mechanical analysis (DMA) and thermal gravimetric analysis (TGA) that the mechanical and thermal properties of PU were improved by incorporation of PFR, P-PFR and B, P-PFR. In addition, the PU/PFR composites provided an excellent corrosion protection in comparison with PU according to potentio-dynamic and salt-spray analyses.