Controlled curing of resole phenol formaldehyde/unsaturated polyester blends and applying for steel–steel adhesive

Polymer blending technique is a promising solution for solving some critical industrial problems by gaining new desired properties for the newly formed materials. Blending various ratios of resole phenol formaldehyde (RPF)/unsaturated polyester (USPE), 10, 20, 30, to 90 wt %, were processed to optimize the mixing conditions by controlling time, temperature, and ratio of blending. In addition, the curing conditions of touch dry, full curing, shelf life, hardness and the steel–steel adhesive were investigated. The blend ratio RPF/USPE (70:30) was selected as an optimized sample at 150°C for 50 min. It was characterized by Fourier transform infrared spectroscopy, dynamic mechanical analysis, scanning electron microscopy, X‐ray diffraction, thermogravimetric analysis, and differential scanning calorimeter. The curing process and the interactions between RPF and USPE were studied. Durability with artificial weather aging was evaluated visually and by measuring hardness which confirmed the prepared material is fit for outdoor uses. This work introduces a strategy to control the curing process, enhance the shelf life and adhesion properties for steel–steel adhesives based on RPF/USPE blends.