Influence of polyaniline and cellulose nanocrystals on starch biopolymer film for intelligent food packaging

Abstract

The development of bioplastics is important to reduce the environmental impact of petroleum-based plastic, while intelligent food packaging is essential in reducing food wastage through the accurate indication of food spoilage. In this research, a biopolymer film that is able to detect food spoilage has been fabricated. Starch is the main matrix of the polymer film, while polyaniline (PANI) acts as the sensor component. The biopolymer film is reinforced with cellulose nanocrystal (CNC) extracted from oil palm empty fruit bunches (OPEFB) to enhance the sensor performance. CNC was successfully extracted from OPEFB with a yield and crystallinity index as high as 41% and 83%, respectively. Various characterization methods were employed to characterize the samples, including FT-IR and UV–vis, while TEM was used to scrutinize the morphology of the CNC. The thermal stability of the bio-nanocomposite films was studied through TGA and DSC. The XRD analysis indicates that CNC improves the crystallinity of the film from 18% to 41%. The performance of the bio-nanocomposite films as an ammonia sensor was studied through an ammonia sensitivity test, where the optimum starch/PANI/CNC 6% film has a limit of detection (LOD) and limit of quantification (LOQ) of 52 ppm and 156 ppm, respectively (R2 = 0.9909, RSD = 3.98%). Also, it shows selectivity to ammonia gas only. Therefore, the starch/PANI/CNC biopolymer film has great potential for its application as intelligent food packaging.