Application of Eco-Friendly Waterborne Polyurethane Composite Coating Incorporated with Nano Cellulose Crystalline and Silver Nano Particles on Wood Antibacterial Board

Abstract

To endow wood plate with antimicrobial properties, waterborne polyurethane (WPU) coatings incorporated with nano cellulose crystalline (NCC) and silver nanoparticles (AgNPs) were prepared. AgNPs were obtained by the chemical reactions of silver nitrate solution and sodium borohydride solution. The scribe testing results showed that the adhesion of the NCC-WPU composites was improved with the addition of NCC. The adhesion reached its peak when the amount of NCC added was 1%. Scanning electron microscopy (SEM) observation displayed that the NCC dispersed into the WPU without aggregation. NCC was well able to bind WPU and wood cell walls tightly together. Atomic force microscopy (AFM) and ultraviolet-visible (UV-vis) results revealed that WPU/NCC/AgNPs composites were homogeneous. This compatibility was also confirmed by transmission electron microscopy (TEM) analysis. The antibacterial property was improved too. When the adding amount of NCC was 0.5%, and the proportion of silver elements added was 5%, the antibacterial effect was at its best. As a comparison, the antibacterial effect of hybrid colloid without the addition of NCC was far less than that of including NCC. The WPU/NCC/AgNPs composite could be applied as an antibacterial coating in wood materials.Polymers 2020, 12, 407 2 of 11The board with surface antibacterial function not only retains all of the characteristics of traditional wood board, but also has the function of inhibiting and killing most harmful bacteria and inhibiting their growth and reproduction. In the future, antibacterial board will have a huge potential demand and broad development prospects [9].Applying antibacterial coating on the surface of the material is the simplest and most efficient way to make them have antibacterial properties. Among wood coatings, waterborne polyurethane (WPU) is a kind of widely used one because of its environmental protection characteristics and easy construction, but the antimicrobial properties are very poor [10][11][12].In order to improve the antimicrobial properties, many inorganic nanoparticles were introduced. Nano metal particles are a kind of important inorganic fillers, which have been successfully applied to the functionalization of polymer materials, bringing new functions to polymer materials [13][14][15]. However, the formation of aggregates will greatly reduce the applicability of inorganic nanoparticles. It is a great challenge to avoid agglomeration in the binding process of inorganic nanoparticles and host polymers.Silver nanoparticles (AgNPs) are a widely recognized antimicrobial material because of their nontoxicity. The silver nanoparticle has numerous applications in many places such as food and other industrial products. Although there are many ways to prepare AgNPs, most of them are easier to form aggregates, which will greatly reduce the number of non-aggregates and the applicability of nanoparticles [16]. In order to minimize the aggregation of nanoparticles, the addition of a reducing agent in the presence of nanocellulose is the ...

Application of Nanotechnology in Wood-Based Products Industry: A Review

“…Waterborne polyurethane [ 144 ] coatings (WPU) incorporated with nanocrystalline cellulose (NCC) and silver nanoparticles (AgNPs) were used to improve antibacterial property of wood board [ 145 ]. The AgNPs were known for their antimicrobial material but aggregated easily during the preparation process.…”

A Superhydrophobic, Antibacterial, and Durable Surface of Poplar Wood

“…When the temperature and humidity and other environmental conditions are appropriate, these microorganisms will attach to the wood for a large number of growth and reproduction, resulting in wood decay, discoloration, and moldy, which influence the strength, toughness, and permeability of wood [ 6 , 33 , 34 , 35 ]. It also poses a threat to the life and health of the users [ 36 , 37 , 38 ]. Therefore, antibacterial treatment of wood is needed to maintain the properties of wood and prevent the spread of disease [ 39 ].…”

Preparation of Silver Antibacterial Agents with Different Forms and Their Effects on the Properties of Water-Based Primer on Tilia europaea Surface

“…The antibacterial rate against Escherichia coli was 99.99%, and the antibacterial rate of Staphylococcus aureus was 87.5%. Cheng et al [19] prepared a waterborne polyurethane coating of nano-cellulose crystal and nano-silver composite suitable for wood, which has compatibility and antibacterial properties. According to relevant literature reports, although nano-silver has excellent antibacterial properties, it has high requirements for equipment and operation, and the small particle size is easy to agglomerate when added into aqueous coatings, resulting in the decline in coating properties [20,21].…”