Bioactive paper by eugenol grafting onto cellulose. Effect of reaction variables

In this work, eugenol grafting onto cellulose is proposed as a strategy for developing a biodegradable active packaging material. Grafting reaction were performed according to Doehlert experimental design with temperature range fixed to 120-180 °C, time range 15-60 min and eugenol amount from 2 to 8 wt%. Reaction advances increases with three variables analyzed as expected, while paper mechanical properties decrease due to both grafting and secondary reactions (crosslinking and degradation). Also, color changes respect to virgin paper increases with the increment of the three variables although paper appearance is good for the most samples. Desirability function was used to determine optimal reaction conditions, looking for a trade-off between the paper properties (color and elongation at break) and reaction advance. The optimal conditions determined were 160 °C, 15 min and 2 wt% eugenol amount. Modified paper showed antioxidant activity and repellent and insecticide activity against Tribolium castaneum and Rhyzopertha dominica, making it a good material for active packaging applications.