Synergic flame-retardant effect of cellulose nanocrystals and magnesium hydroxide in polyurethane wood coating

In this paper, a wood coating based on waterborne polyurethane (WPU)/nano-cellulose crystalline (CNC)/Magnesium hydroxide (MH) was prepared. Efficient dispersion of MH in WPU presence 5 wt% CNCs observed by biological microscope leading to material with improved esthetic, thermal and fire-retardant properties mechanical performance. By thermogravimetric analysis (TG/DTG) comparison WPU, the maximum weight loss rate (RTmax) WPU/CNC/MH decreased dramatically from 13.2 6.63, residue increased sharply 4.69% 40.55%. The results pyrolysis combustion flow calorimeter (PCFC) showed that flame-retardant performance composite is also greatly improved, peak heat release (pHRR) being reduced 350 w/g 121 w/g. When applied panels, according Limiting oxygen index (LOI) experiment, for < 40 wt%, combustibility grade B2 level (combustible material), whereas > B1 (flame retardant material).