Mechanical and Thermal Properties of Waterborne Polyurethane Coating Modified through One-Step Cellulose Nanocrystals/Graphene Materials Sols Method

Developing multifunctional coatings with excellent mechanical and thermal properties is highly desirable for wood-based composite application. The recent development of waterborne coatings for wood products suggests that a promising thermosetting material needs to also have properties like low volatile organic contents (VOCs), hardness, and fast curing. The cellulose nanocrystals/graphene materials (CNC/GM) sols were prepared through the one-step method as the thermally conductive and reinforced modifier for preparing waterborne polyurethane (WPU) coatings. The influence of this modifier on the thermal and mechanical properties such as thermal conductivity, abrasion resistance, and adhesion of WPU coatings was investigated. The results indicated that adding CNC/GM sols increased the hardness, abrasion resistance, and thermal conductivity of the WPU coatings, and meanwhile maintained the coating adhesion at the highest grade (level 1). The highest abrasion resistance value of 0.023 g/100 r was obtained for the modified WPU coating when the addition of GM was 3%.