Research on the effects of contents and types of water‐soluble chitosan on properties of antibacterial natural latex foam

Abstract This study used carboxymethyl chitosan (CMCS) and quaternized chitosan (QCS) as antibacterial agents to produce antibacterial natural rubber latex foam (NRLF) via the Dunlop method. The micro‐morphology, physical properties, tensile strength, compressive properties, and antibacterial activities were evaluated. The experimental results show that adding chitosan significantly reduces the pore size of the NRLF foam and makes its microstructure more compact. Specifically, at 0.4phr NRLF‐QCS, 42% of the foam pores are 0.2 mm in size. Both NRLF‐CMCS and NRLF‐QCS showed increased density, cross‐linking density, and water absorption with higher filler content. Compared to the control, both foams exhibited improved tensile properties: NRLF‐CMCS increased by 85% to 0.26 MPa, while NRLF‐QCS increased by 178% to 0.39 MPa. However, rebound properties after compression declined, with 0.8phr NRLF‐CMCS showing the lowest rebound rate at 48.56%. In terms of antibacterial properties, both NRLF‐CMCS and NRLF‐QCS show enhanced antibacterial activities against Escherichia coli , with NRLF‐CMCS demonstrating superior performance. The inhibition zone diameter increased from 10.6 to 13.24 mm, indicating significantly improved antibacterial efficacy. Highlights The antibacterial natural rubber latex foam (NRLF) was prepared by Dunlop method. Carboxymethyl chitosan (CMCS) and quaternized chitosan (QCS) were used as antibacterial agents to fabricate antibacterial NRLF. The physical properties of NRLF‐CMCS and NRLF‐QCS exhibit an increasing trend. Both NRLF‐CMCS and NRLF‐QCS exhibited enhanced efficacy against Escherichia coli .