Preparation and Characterization of Room Temperature Vulcanized Silicone Rubber/Quaternized Chitosan–Betaine Hydrochloride Composite

Abstract

ABSTRACT To develop highly efficient antibacterial silicone rubber, this study employed a two‐step grafting method to graft glycidyltrimethylammonium chloride (GTMAC) and betaine hydrochloride (BHC) onto chitosan (CS), synthesizing a novel antibacterial agent, quaternized chitosan–betaine hydrochloride (HTCC‐BHC). This dual grafting process significantly enhanced the cationic degree of CS by introducing a higher density of N + (CH 3 ) 3 groups. Subsequently, HTCC‐BHC was incorporated into room temperature–vulcanized silicone rubber (RTV) via a solution blending approach, yielding HTCC‐BHC/RTV composites (HB‐RTV). To investigate its structure and properties, the composites were characterized by SEM, XRD, FTIR, 13 C NMR, DSC, rotational rheological analysis, and mechanical testing. The results indicated that increasing HTCC‐BHC content significantly improved the surface roughness, amorphous characteristics, crosslinking density, and mechanical properties of HB‐RTV. Molecular dynamics (MD) simulations and mean square displacement (MSD) calculations confirmed strong intermolecular interactions between HTCC‐BHC and RTV, reducing polymer chain mobility. Antibacterial assays revealed that HB‐RTV exhibited an inhibition rate of up to 99.99% against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ), with superior efficacy against E. coli . This was attributed to strong electrostatic interactions between the N + (CH 3 ) 3 groups in HTCC‐BHC and bacterial cell wall components, such as lipopolysaccharides and peptidoglycans. SEM and molecular docking further revealed that HB‐RTV exerted its bactericidal effect by disrupting bacterial cell membrane integrity and inducing cytoplasmic leakage. Thereby, the enhanced antibacterial efficacy contributes to improved preservation of fresh meat. This study provides a novel strategy for developing non‐toxic, highly antibacterial silicone rubber, establishing a theoretical and practical foundation for its applications in biomedical and packaging fields.