Fabrication Of Chitosan/Titanium Dioxide Nanocomposite Material And Its Application In Antibacterial Cellulosic Paper

Among these antibacterial materials,antibacterial cellulosic paper is generally considered to be one of the most promising candidates largely because of its inherent advantages of cellulosic paper,particularly environmental benefits.In general,antibacterial paper holds great promise for many applications,e.g.,food wrappers,hospital paper,indoor environmental protection paper,and sanitary paper.Due to the increasing awareness of infectious diseases caused by different microorganisms,the development and application of functional antibacterial paper will received increasing attention.In this context,it is thus of great practical interest to develop an efficient process for imparting antibacterial properties to conventional cellulosic paper.In general,cellulose-based antibacterial paper can be produced via direct wet end addition of antibacterial agents,surface coating and impregnation(a material with antibacterial property is made to permeate the fiber structure,rather than merely coat on the surface).Nevertheless,the properties of antibacterial cellulosic paper were highly dependent upon the used chemicals.As a matter of fact,chitosan,known to have high antimicrobial activity,has been widely used as antibacterial components for a wide range of application because of its biodegradable,non-toxic and non-allergenic natures.In particular,the application of chitosan-based nanocomposite in cellulosic paper has gained increasing attention because it is capable of imparting the cellulosic paper with reinforced mechanical properties in addition to antimicrobial activity.More importantly,TiO2 nanoparticles,one of the most potential ultraviolet(UV)light-sensitive inorganic bactericide with intrinsic photoelectric properties,have shown great promise in the antimicrobial related application.As a consequence,the integration of chitosan/titanium dioxide will produce synergistic effect on the improvement of the overall properties of cellulosic paper.For the above reason,in the present work,the feasibility and possibility of the applicaiotn of chitosan/titanium dioxide in the production of cellulosic paper via either surface coating or wet-end formation process was discussed.Here,an environmentally friendly chitosan/titanium dioxide nanocomposite coating was designed/prepared and subsequently employed for imparting antibacterium and improved mechanical properties to cellulosic paper via surface coating.Initially,surface modification of titanium dioxide was conducted by using sodium laurate via chemical reaction,which was found to be able to exert a significantly positive effect on the dispersion stability in chitosan based system.Furthermore,effect of titanium dioxide nanoparticle loadings on the rheological behavior of nanocomposite coatings was investigated.Surface application of chitosan/titanium dioxide nanocomposite coatings to cellulosic paper was performed,and the antibacterial activity and mechanical properties of surface-coated cellulosic paper were examined.Results showed that the increased titanium dioxide nanoparticle loadings decreased the viscosity and dynamic viscoelasticity of the as-prepared coatings,and improved the antibacterial activity and mechanical properties of surface-coated cellulosic paper.The optimum loading of titanium dioxide nanoparticles was identified at 10%.This work suggested that chitosan/titanium dioxide nanocomposite coatings may have the potential to be used as a promising antibacterial protective coating for paper packaging.In addition to the surface coating application of chitosan/titanium dioxide nocomposites to cellulosic paper,the feasibility and possibility of the application of chitosan/titanium dioxide nocomposites in the wet-end formation process of cellulosic paper was identified.The results showed that the obtained cellulosic paper via wet-end formation process had desired mechanical properties.However,the antibacterial activity of cellulosic paper here against E.coli is relatively limited in comparison to that of the obtained cellulosic paper via surface coating process.