Mechanically robust carboxymethyl cellulose/graphene oxide composite cross-linked by polyetherimide for fruits...

Modulating the interactions between biopolymer matrix and nanofillers highly determined the mechanical performances of composite packaging materials. Herein, we innovatively proposed a sort of eco-friendly and mechanically robust carboxymethyl cellulose/graphene oxide/tannic acid/polyetherimide (CMC/GO/TA/PEI, CGTP) composite by employing PEI as cross-linker and TA as proton donor. The amidation reaction between -NH₂ and -COOH chemically connected the CMC/GO, CMC/CMC and GO/GO and the physical interaction (e.g. hydrogen bonds and molecular entanglements) was beneficial to form dense structures. The chemical/physical bonds among polymers and nanofillers contributed to dissipate the external energy. The toughness was effectively reinforced from 1.68 MJ/m³ for CGTP₀ to 4.63 MJ/m³ for CGTP_1.0. Furthermore, the CGTP_1.0 composite film also delivered improved gas (moisture and oxygen) barriers, UV protection and antimicrobial features. Originating from these merits, the shelf life of fresh fruits (e.g. strawberries, blueberries and cherry tomatoes) was prolonged at least 5 days under ambient conditions when the packaging box was covered by the fabricated CGTP_1.0 film. Our findings not only provided a facial strategy to reinforce the interactions between biopolymer matrix and nanofillers, but also boosted the development of eco-friendly packaging materials with robust structures in the area of food packaging.