Renewable, Biodegradable Polylactic Acid-Cellulose Nanocrystal Composites for Packaging Applications
The demand for bioderived and biodegradable packaging is rising because of increasing concerns about the impacts of nonrenewable raw materials and plastic waste streams; however, many of the polymers commonly derived from renewable materials have drawbacks, including inferior barrier properties and poor processing characteristics. Cellulose nanomaterials, along with other sustainable approaches, have the potential to improve the properties and processing of biobased polymers such as polylactic acid (PLA). With this in mind, Forest Service scientists developed fully biobased, transparent composite films based on cellulose nanocrystals (CNCs) and PLA for packaging applications. The research results show that adding only 1 percent CNCs to PLA decreased water vapor transmission rate by 33 percent and oxygen transmission rate by 62 percent, which can be important parameters in maintaining food quality. They also also successfully demonstrated environmentally friendly, fully renewable modification techniques for modifying CNCs, and preliminary evidence suggests that these modifications may aid processing and potentially replace expensive processing aids. The films were produced using blown-film extrusion, which supports the suitability of these films for commercial production of packaging films.