Biodegradable Poly(butylene succinate) Laminate with Nanocellulose Interphase Layer for High-Barrier Packaging Film Application

In response to rising concerns over the environmental and human health ramifications of polymers derived from petroleum, particularly in the food packaging industry, research has pivoted towards more sustainable materials. Poly(butylene succinate) (PBS), selected as the polymer matrix, stands out as one of the most promising bio-based and biodegradable polymers suitable for film blowing and lamination. A layered spray-coating technique was employed to apply 1, 5, 10, and 20 layers of nanofibrillated cellulose (NFC) between blown PBS films, creating a three-layer laminate structure. NFC sourced from minimally processed hemp stalk waste highlights the potential for minimizing environmental impact. The water vapor transmission rate (WVTR) of these films, a critical parameter for food packaging, was assessed in a controlled environment at 38 °C and 90% relative humidity over a period of two months. The integration of a single NFC layer, constituting 0.35% of the composite's weight, was observed to significantly reduce the WVTR by up to 5.5-fold. It was noted that higher NFC layer counts above 10 reduced the adhesion within the laminate layers. Morphological assessments showed that the number of structural defects increased with a higher count of NFC layers. As the count of NFC layers increased, the optical transparency of the laminates dropped from approximately 65% to 25% in the visible light spectrum. Notably, by weight percent, NFC proved to be an effective barrier even without chemical modification. The developed laminates stand out as a viable, green option for food packaging, offering a sustainable and renewable solution.