The effects of citric acid on thermal and mechanical properties of crosslinked starch film

• Main Authors: Chen, Wei Ci, Syed Mohd. Judah, Sharifah Nor Munirah, Ghazali, Siti Khairunisah, Munthoub, Dayangku Intan, Alias, Hajar, Mohamad, Zurina, Abd. Majid, Rohah
• Format: Article
• Published: Italian Association of Chemical Engineering - AIDIC 2021
• Subjects: TP Chemical technology
• Online Access: http://eprints.utm.my/id/eprint/94711/; http://dx.doi.org/10.3303/CET2183034

Plastic waste from film packaging is one of the major threats to environmental sustainability. The problem can be reduced by using a biodegradable raw material such as starch to replace the non-biodegradable petroleum-based plastic. However, starch is highly hydrophilic and brittle, which needs to be modified to improve these drawbacks. In this research, a mixture of tapioca starch (S) and glycerol (G) was crosslinked with citric acid (CA) at different ratios (0, 0.4, 0.6, 0.8, 1.0 wt% of dry basis). Effects of CA contents on the degree of crosslinking, thermal stability, and tensile properties were investigated. The sample that contained 0.6 wt% CA showed the highest degree of crosslinking (i.e. 56 %), good thermal stability, high modulus (10 MPa) and tensile strength (0.16 MPa), and low elongation at break (161 %) when compared with other samples. Samples that have higher CA contents (i.e. 0.8 wt% and 1.0 wt%) experienced the acid hydrolysis on the crosslinking site, reducing the degree of crosslinking, thermal stabilities, and tensile properties.