Antimicrobial Waterborne Polyurethanes Based on Quaternary Ammonium Compounds

Preparation and Properties of a Novel Cross-Linked Network Waterborne Polyurethane for Wood Lacquer

Waterborne polyurethane (WPU) is a waterborne coating with excellent physicochemical properties. Its deficiencies of water resistance, chemical resistance, staining, and hardness have limited the wide application of polyurethane in the wood lacquer market. In this study, polycarbonate diols (PCDL) were used as soft segments and WPCU was modified by cross-linking using Trimethylolpropane (TMP) to prepare polycarbonate type WPU (WPCU) with cross-linked network structure. The new wood lacquer was prepared by adding various additives and tested by applying it on wood board. The successful synthesis of WPCU was determined by FTIR testing, and the cross-linking degree of WPCU was probed by low-field NMR. The viscosity of the cross-linked WPCU emulsion showed a decreasing trend compared to the uncross-linked WPCU emulsion, and WPCU-2 had the smallest particle size. Compared with the uncrosslinked WPCU film, the crosslinked WPCU film had lower water absorption (2.2%), higher water contact angle (72.7°), excellent tensile strength (44.02 MPa), higher thermomechanical, and better water and alcohol resistance. The effect of crosslinker content on the microphase separation of WPCU chain segments on the surface roughness of the film was investigated by SEM. The wood paint prepared by WPCU emulsion has good dry heat resistance, chemical resistance, and adhesion, and the hardness of the wood paint when the TMP content is 3% reaches H. It also has good resistance to sticky stains, which can be used to develop new wood lacquer.

Surface activation of medical grade polyurethane for the covalent immobilization of an anti-adhesive biopolymeric coating

Hospital-acquired infections are still a major concern worldwide, being frequently related to bacterial biofilm formation on medical devices, and thus difficult to eradicate with conventional antimicrobial treatments. Therefore, infection-preventive solutions based on natural polymers are being investigated. Recently, a marine cyanobacterium-derived polymeric coating (CyanoCoating) has demonstrated great anti-adhesive potential when immobilized onto gold model substrates. In this work, we took this technology a step closer to an industrial application by covalently immobilizing CyanoCoating onto medical grade polyurethane (PU). This immobilization was developed through the introduction of linkable moieties onto a PU inert surface using different pre-treatments. Besides the application of the polydopamine (pDA) linker layer, other processes frequently found in industrial settings, such as atmospheric plasma (using O2 or N2 as reactive gases) and ozone surface activations, were evaluated. From all the pre-treatments tested, the ozone activation was the most promising since the obtained coating not only revealed a homogeneous distribution, but also significantly reduced the adhesion of two relevant etiological bacteria in static conditions (the Gram-positive Staphylococcus aureus and the Gram-negative Escherichia coli). Moreover, it also impaired E. coli biofilm formation under simulated urinary tract dynamic conditions, reinforcing the potential of CyanoCoating as an antibiotic-free alternative to mitigate medical device-associated infections, particularly in the urinary tract.

Quaternary tannic acid with improved leachability and biocompatibility for antibacterial medical thermoplastic polyurethane catheters

The surfaces of indwelling catheters offer sites for the adherence of bacteria to form biofilms, leading to various infections. Therefore, the development of antibacterial materials for catheters is imperative. In this study, combining the strong antibacterial effect of a quaternary ammonium salt (QAS) and the high biocompatibility of tannic acid (TA), we prepared a quaternary tannic acid (QTA) by grafting a synthesized quaternary ammonium salt, dimethyl dodecyl 6-bromohexyl ammonium bromide, onto TA. To prepare antibacterial catheters, QTA was blended with thermoplastic polyurethane (TPU) via melt extrusion, which is a convenient and easy-to-control process. Characterization of the TPU blends showed that compared with those of the QAS, dissolution rate and biocompatibility of QTA were significantly improved. On the premise that the introduction of QTA had only a slight effect on the original mechanical properties of pristine TPU, the prepared TPU/QTA maintained satisfactory antibacterial activities in vitro, under a flow state, as well as in vivo. The results verified that the TPU/QTA blend with a QTA content of 4% is effective, durable, stable, and non-toxic, and exhibits significant potential as a raw material for catheters.

Waterborne Polyurethane Dispersions and Thin Films: Biodegradation and Antimicrobial Behaviors

Biodegradable and antimicrobial waterborne polyurethane dispersions (PUDs) and their casted solid films have recently emerged as important alternatives to their solvent-based and non-biodegradable counterparts for various applications due to their versatility, health, and environmental friendliness. The nanoscale morphology of the PUDs, dispersion stability, and the thermomechanical properties of the solid films obtained from the solvent cast process are strongly dependent on several important parameters, such as the preparation method, polyols, diisocyanates, solid content, chain extension, and temperature. The biodegradability, biocompatibility, antimicrobial properties and biomedical applications can be tailored based on the nature of the polyols, polarity, as well as structure and concentration of the internal surfactants (anionic or cationic). This review article provides an important quantitative experimental basis and structure evolution for the development and synthesis of biodegradable waterborne PUDs and their solid films, with prescribed macromolecular properties and new functions, with the aim of understanding the relationships between polymer structure, properties, and performance. The review article will also summarize the important variables that control the thermomechanical properties and biodegradation kinetics, as well as antimicrobial and biocompatibility behaviors of aqueous PUDs and their films, for certain industrial and biomedical applications.

Synthesis and antibacterial investigation of cationic waterborne polyurethane containing siloxane

Cationic waterborne polyurethane containing siloxane and quaternary ammonium salt in the side chain was synthesized, which showed an enhanced antibacterial property and hydrophobicity.