Enhancing water resistance of regenerated cellulose films with organosilanes and cellulose nanocrystals for food packaging

Abstract

Cellulose has been explored as potential alternative to traditional petroleum-based packaging materials, but its hygroscopic features lead to fast penetration of water and reduced mechanical properties of cellulose-based materials under humid and wet conditions. Chemical vapor deposition of organosilanes can incorporate hydrophobic moieties to overcome water sensitivity, but also decrease the strength of cellulose films. Herein, two commonly used organosilanes were selected to improve the water resistance of cellulose films, and cellulose nanocrystals were incorporated to compensate for the loss in mechanical strength. The results revealed that the films with dual modifications showed the unchanged tensile strength of around 57MPa when the environmental relative humidity increased from 0 to 60% and the highest wet strength of about 12MPa compared to the original and singly modified cellulose films. The water vapor permeability significantly decreased from 4.07 × 10−7 to about 3.3 × 10−7g·m−1·h−1·Pa−1 after the modification, and all the films could completely disintegrate within 14 days. Moreover, the cookies preserved by the modified cellulose films for 100 days showed similar weight gain (∼1.2%) and lower peroxide value (∼5.6meq/kg) than the ones covered by commercial plastic wrap. Therefore, this study presents a promising approach to develop cellulose films with enhanced water resistance for food packaging applications.