Plasticizing effects from citric acid/palm oil combinations for sorbitol-crosslinked starch foams

The purpose of this research is to explore the possibility of citric acid crosslinking starch-based foam in the presence of palm oil as well as plasticized with sorbitol. Starch compounds were foamed using a thermocompression technique after being prepared simply with a cooking mixer. The flexural strength of the foams was found to be dependent upon the citric acid loading. The FTIR analysis results through calculating the intensity ratio of absorption peaks at 3300 and 1149 (I-3300/I-1149) indicated that a lower amount of free hydroxyl group was left from the citric acid added specimens. The TGA curves displayed lowering thermal stability that implied the occurrence of crosslinking reaction via esterification of the citric acid modified sorbitol/starch compounds. The results of the citric acid incorporation were also suggested by the physical properties investigation, which included SEM images, density, degree of swelling and water solubility. For the citric acid-filled foams, cell wall thickness and density both increased as water solubility decreased. All of the observed results confirmed that the citric acid crosslinking sorbitol/starch-based foam was prepared and characterized for use as alternative biodegradable trays and plates foam application.

Automated summary

This research investigated the possibility of citric acid crosslinking starch-based foam in the presence of palm oil and sorbitol plasticizer. The results showed that citric acid loading affected the flexural strength of the foams and led to improved thermal stability and reduced water solubility. The new foam material, prepared by citric acid incorporation, displayed potential for biodegradable trays and plates as alternative environmentally friendly options.