SOIL BURIAL ASSESSMENT OF CROSSLINKED FUNGAL CHITOSAN COMPOSITE FILMS REINFORCED WITH CELLULOSE NANOCRYSTALS EXTRACTED FROM SUGARCANE BAGASSE

Madah Hussain; Sung Ting Sam; Noorulnajwa Diyana  Yaacob; Nur Mawaddah Majib; Lian See Tan; Wai Kian Tan

Madah Hussain Faculty of Chemical Engineering & Technology, Universiti Malaysia Perlis (UniMAP), Kompleks Pusat Pengajian Jejawi 3, 02600 Arau, Perlis, Malaysia
Sung Ting Sam Center of Excellence Geopolymer and Green Technology, Universiti Malaysia Perlis (UniMAP), 01000, P.O. Box 77, D/A Pejabat Pos Besar, Kangar, Perlis, Malaysia.
Noorulnajwa Diyana Yaacob Faculty of Chemical Engineering & Technology, Universiti Malaysia Perlis (UniMAP), Kompleks Pusat Pengajian Jejawi 3, 02600 Arau, Perlis, Malaysia.
Nur Mawaddah Majib Faculty of Chemical Engineering & Technology, Universiti Malaysia Perlis (UniMAP), Kompleks Pusat Pengajian Jejawi 3, 02600 Arau, Perlis, Malaysia.
Lian See Tan Department of Chemical Process Engineering, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, 54100 Kuala Lumpur, Malaysia.
Wai Kian Tan Institute for Research on Next Generation Semiconductor and Sensing Science, Toyohashi University of Technology, 1-1, Hibarigaoka, Tempaku-cho, Toyohashi, Aichi, 441-8580 Japan.

Keywords: Fungal chitosan, cellulose nanocrystals, soil burial test, biodegradable composite films

Abstract

An increase in non-biodegradable plastic waste has driven the hunt for sustainable packaging solutions. This study developed biodegradable composite films using fungal chitosan (FCH) reinforced with cellulose nanocrystals (CNC) from sugarcane bagasse (SCB) and crosslinked with glutaraldehyde (GA). The films were prepared by solution casting and characterised for biodegradability and structural changes. The formulations evaluated included non-crosslinked neat FCH (FCH0), non-crosslinked composites with 1, 3, 5, and 7 wt% CNC (FCH-CNC1 to FCH-CNC7), and glutaraldehyde-crosslinked variants (GA-FCH0 and GA-FCH-CNC1 to GA-FCH-CNC7). A 15-day soil burial test confirmed that all films were biodegradable, though they degraded at different rates. FCH0 exhibited the highest susceptibility to microbial attack, with approximately 72 % weight loss. Visual inspection further showed that FCH0 developed more voids and cavities compared to composite films, indicating weaker resistance to microbial activity. In contrast, the crosslinked FCH/CNC composite films exhibited a controlled, significantly slower degradation rate, attributed to the formation of a dense polymer network via covalent imine linkages that restricted microbial enzyme penetration. The incorporation of CNC and GA enhanced structural stability, resulting in fewer surface defects and reduced weight loss during soil burial. Field Emission Scanning Electron Microscopy (FESEM) analysis confirmed surface disintegration and void formation in degraded samples, while Fourier Transform Infrared (FTIR) spectroscopy evidenced the cleavage of glycosidic bonds. The results suggest that crosslinking effectively modulates the biodegradation rate without compromising the material's eco-friendliness. These findings establish crosslinked FCH/CNC composites as a promising, durable, and sustainable alternative to conventional plastics for food packaging applications.