Roles and evidence of wood flour as an antibacterial promoter for triclosan-filled poly(lactic acid)

• Published in: Composites. Part B, Engineering Engineering, 2012-10, Vol.43 (7), p.2730-2737
• Main Authors: Prapruddivongs, C., Sombatsompop, N.
• Format: Article
• Language: English
• Subjects: A. Polymer-matrix composites (PMCs); Applied sciences; B. Mechanical properties; Composites; D. Thermal analysis; E. Extrusion; Exact sciences and technology; Forms of application and semi-finished materials; Laminates; Physicochemistry of polymers; Polymer industry, paints, wood; Technology of polymers
• ISSN: 1359-8368; 1879-1069
• DOI: 10.1016/j.compositesb.2012.04.032

► The wood flour was found to change the hydrophilicity of the PLA. ► Addition of triclosan did not had an effect on the mechanical properties of PLA. ► The wood flour could act as “antibacterial promoter” in triclosan/PLA blends. Mechanical and antibacterial performances of poly(lactic acid) (PLA) were assessed as a function of triclosan and wood fillers under a wide range of contact times using Gram-negative Escherichia coli (E. coli, ATCC 25922) as testing bacteria. Water contact angle (WCA) measurement, Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) were performed to characterize the PLA, its blend with triclosan, and its composite with wood filler, and used to substantiate the antibacterial performance results. The experimental results suggested that introduction of wood flour changed the mechanical properties of PLA, whereas triclosan had no definite effect on the mechanical properties. E. coli growth appeared to increase with contact time for PLA, but to decrease with contact time for the wood/PLA composites. Based on the results and quantitative evidence, it was proposed that the wood flour acted as an “antibacterial promoter” for triclosan blended wood/PLA composites, which facilitated triclosan migration onto the wood/PLA composite surfaces to kill the bacteria. The molecular interactions between PLA, triclosan and wood were quantitatively characterized experimentally by CAM, DSC and FTIR. The change in hydrophilicity by the presence of wood filler was found to be the main reason for the improved antibacterial activity of triclosan in the wood/PLA composites.