Surface Modification of Cellulose Microfibrils with Silane Agent for Eco-Friendly Hydrophobic Coatings

In this study, an optimized method for surface modification of cellulose microfibrils (CMF) with (3-Aminopropyl) trimethoxysilane (APTMS) for eco-friendly hydrophobic coating on kraft paper was achieved using Box-Behnken Design (BBD) through response surface methodology (RSM). Three parameters, including APTMS concentration, hydrolysis-condensation reaction time of APTMS and curing temperature of APTMS, were optimized to obtain the highest water contact angle (θH2O) of the coated kraft paper. The optimal coating conditions extracted by Design Expert Software for the highest value of water contact angle θH2O were APTMS concentration of 8.02% (v/v), APTMS hydrolysis-condensation reaction time of 68.2 min and APTMS curing temperature of 105.3°C. Under these conditions the water contact angle θH2O of 123.3° was obtained. The water contact angle θH2O obtained at these optimal coating conditions experimentally was 124.5°. Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), energy dispersive X-Ray (EDX) analysis and scanning electron microscopy (SEM) provided evidence of successful surface silylated of CMF with APTMS.