Nanocellulose/natural latex composite film with high barrier and preservation properties

Nanocellulose films have been extensively studied for their excellent oxygen barrier properties. However, in the presence of moisture and higher humidity, the oxygen barrier performance decreases rapidly. In this work, natural rubber latex (NRL) was used as a compounding material to improve the hydrophobic properties of 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) oxidized nanocellulose fibers (TOCNF) due to the ability of its naturally occurring phospholipid-protein surface to avoid the interfacial compatibility problems that exist in most hydrophobic polymers when mixed in aqueous solutions. The exposure of the internal hydrophobic isoprene molecular chains of NRL during the drying process allows the composite film to have greatly improved water resistance and excellent water vapor and oxygen barrier properties. The water vapor permeability (WVP) and oxygen permeability (OP) of the films were as low as 6.07×10 − 10 g·mm/m 2 ·s·pa and 3.11×10 − 15 cm 3 ·cm/cm 2 ·s·Pa, respectively. And the good water resistance of the composite film makes the wet tensile strength of the film up to 15.87 MPa, which reaches 71.69% of the dry tensile strength. In addition, the high ductility of NRL makes the laminate film good toughness, and its elongation at break can reach about three times that of most nanocellulose-based films. Experiments on strawberry preservation with composite films have shown that it can effectively slow down the deterioration of strawberries and extend their shelf life from two days to seven days. This study highlights the exceptional promise of these innovative films for use in food packaging applications.