Publication: Biodegradable polyvinyl alcohol (pva) /carboxymethyl cellulose (cmc) halochromic film using natural dye from red cabbage
No Thumbnail Available
Date
2024-08-01
Authors
Khor Wan Hui
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The conventional pH indicator film is often synthetic and non-biodegradable, which can contribute to pollution and environmental degradation. In this research, a biodegradable halochromic film was fabricated using natural dye (anthocyanin) from red cabbage, PVA, and CMC and formed into film through the solution casting method. Solid-liquid extraction method was used to extract anthocyanin from red cabbage, and the optimum parameters, such as type of solvent, temperature, and time to extract a higher amount of anthocyanin, were determined. Responsiveness of halochromic film with different amounts of PVA/CMC (100/0, 80/20, 60/40, 40/60, 20/80, 0/100) was determined by using air exposure from different pH buffer solutions (pH 2–pH 12) by observing the colour change within 120 seconds and analysing the total colour difference (ΔE) by using colour analysis software. Characterization of the film was done through FTIR, swelling test, tensile test and reusability test. The finding shows the optimum parameters to extract higher amounts of anthocyanin were a 1:1 ratio of ethanol to distilled water, 70°C of heating, and an extracted duration of 30 minutes. The halochromic film with higher CMC content undergoes a faster and more obvious colour change when air exposure to different pH buffer solutions. The tensile strength and Young’s modulus increase, while elongation at break decreases as CMC content increases. Anthocyanin halochromic film shows a good sensor at pH 2, 11, and 12 as it changes to red at pH 2, green at pH 11 and greenish yellow at pH 12. Halochromic film made from 60% PVA and 40% CMC shows a balance in both colour response time and mechanical properties.