Enhancing Paper's Mechanical Strength and Antibacterial Properties through a Biopolymer-Based Coating

Area of Science:

• Materials Science
• Biotechnology
• Food Science

Background:

• Paper products require enhanced mechanical and antimicrobial properties for diverse applications.
• Sustainable and biodegradable materials are increasingly sought after for paper coatings.
• Soybean flour and carboxymethyl cellulose offer potential as bio-based coating components.

Purpose of the Study:

• To develop and optimize a novel biopolymer coating using citric acid-modified soybean flour (SBFC) and carboxymethyl cellulose (CMC).
• To evaluate the impact of the SBFC/CMC coating on the mechanical properties of paper.
• To assess the antibacterial efficacy of the coating against Gram-negative bacteria.

Main Methods:

• Citric acid-modified soybean flour (SBFC) synthesized via thermal cross-linking with Na2HPO4 catalyst.
• Fourier-transform infrared (FTIR) spectroscopy used to confirm bond formation.
• SBFC and CMC blended at various ratios, with a 50:50 formulation optimized.
• Tensile strength testing and antibacterial assays (CFU counts) performed on coated paper.

Main Results:

• The optimized 50:50 SBFC/CMC coating significantly improved paper tensile strength by 61.8%.
• The coating demonstrated notable antibacterial activity against Escherichia coli, achieving an 84-89% reduction in viable colonies (log10 reduction of 1.2-1.7).
• The formulation showed good dispersion stability and coating performance.

Conclusions:

• Citric acid-modified soybean flour and CMC form a promising sustainable biopolymer coating for paper.
• The coating effectively enhances both mechanical strength and antibacterial properties of paper substrates.
• This approach offers a multifunctional solution for improving paper hygiene, particularly for packaging applications.