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The application of the expanded polystyrene (EPS) waste to the functional material is still a challenge. The hydrophobic property of polystyrene has a potential to create a superhydrophobic surface. Here, we use expanded polystyrene waste to coat surfaces in two different ways—spray coating and dip coating—to produce superhydrophobic surfaces for food packaging. The ZnO was employed to make the surface rougher. However, the combination of ZnO and EPS waste produces only a hydrophobic surface. For spray coating and dip coating, the maximum water contact angle is 119° and 125° respectively. The scanning electron microscope (SEM) picture reveals many holes that increase the surface's roughness. The hydrophobic surface significantly cuts down on cleaning time. According to the food packaging parameter test mandated by the Indonesian Food and Drug Administration (BPOM) (BPOM regulation No. 20, 2019), the coating complies with heavy metals and ethanol stimulant migration testing requirements for food packaging. However, the migration condition in acetic acid stimulant surpasses the maximum standard. The total migration in 3% acetic acid stimulant (40°C for 10 days) is 22.95 mg/dm2 while the maximum value is 10 mg/dm2.

Self-cooling material usually uses synthetic or employ harmfull chemicals. Nanocellulose from bacterial culture composited with CaCO3 and ZnO is proposed to overcome the limitation. Bacterial nanocellulose was prepared via kombucha fermentation. Obtained bacterial nanocellulose was bleached using H2O2 to remove impurities. The bleached bacterial nanocellulose exhibited a nanofiber shape and a cellulose I crystalline structure with a crystallinity of 44.3 %. The fiber diameter was approximately 92.51 ± 21.46 nm. Bleached bacterial nanocellulose had a higher nanocellulose content than unbleached bacterial nanocellulose. The bleached bacterial cellulose was composited with CaCO3 and ZnO particles to form randomly distributed particles. The composite decreases sample temperature as high as 3.8 °C and 3.7 °C for CaCO3 and ZnO composites, respectively.

Ramie is one of the long natural fiber has strong mechanical properties. To improve the quality of ramie fiber, this study developed a bio degumming method from superior isolates of pectinolytic fungi Rhizopus sp. and optimization of raw fiber based on harvesting time. The results of the pectinolytic fungi selection were used as a bio degumming bio starter under optimum conditions of pH and temperature. Also, fiber material harvested at 50-day and 60- day to obtain an increase in the physical quality. The bio degummed fiber was analysed to determine the tenacity and fineness, the functional groups contained, thermal analysis, moisture regain and content, material polymers, and degree of crystallinity. Based on the results, the finest ramie properties with 50-day harvested fiber are as follows: strength 24.54 ± 0, 02 g/tex, elongation 12.04 ± 2,90%, fineness 1.33 ± 0,17 tex, moisture regain 8.23 ± 0,18 %, and moisture content 8.96 ± 0,21 %. Ramie fibers at initial conditions and after bio degumming at 50 and 60-day harvested had the same pattern of thermal stability. The dyeability test showed that the degummed 60-day harvested fibers has the greatest dye fixing ability. The bio degumming process with this method can improve the quality and dyeability of the rami fiber which can be used for future applications.