Antibacterial/Antiviral Cellulose Fibers And Paper Products

Paper products are necessary in our daily life, and a lot of paper products are required toposses antibacterial and antiviral abilities. However, the paper products with antibacterialproperties currently have the defects of high cost or short-lasting, restricting their industrialapplications. Therefore, it is important to prepare antibacterial and antiviral paper productsusing the new methods.In this thesis, β-cyclodextrin grafted cellulose (β-CD-Cel) and β-cyclodextrin graftedcationic starch (β-CD-CS) were prepared by grafting β-CD onto cellulose fiber and cationicstarch using citric acid (CA) and epichlorohydrin (ECH) as crossliking agents, respectively.β-CD-Cel and β-CD-CS were loaded with an antibacterial agent (CipHCl) to form inclusioncomplexes, and the release properties of CipHCl from inclusion complexes were also studied.Then the inclusion complexes were added to the pulp to prepare antibacterial paper. Theantimicrobial activities and physical properties of the paper were investigated. Furthermore,β-CD-CS was loaded with an antivirus agent (ACV) to form inclusion complexes,β-CD-CS-ACV, and the release properties of ACV from inclusion complexes were studied.β-CD-CS-ACV was added to the pulp to prepare antiviral paper. The effect of adding amoutof β-CD-CS-ACV on the antivirus ability of paper products was also investigated. Thefollowing main conclusions were obtained through these studies:(1) The optimal conditions for the synthesis of CA-β-CD:n(SHP):n(CA):n(β-CD)=1:2:1, raction time1.5h at100℃, liquid to solid ration2:5, at which, the carboxylgroup content of CA-β-CD was0.97mmol/g CA-β-CD, and β-CD content of CA-β-CD was72.5%based on the weight of β-CD. The ESI-MS spectra of CA-β-CD indicate that one β-CDmolecule reacts with two or three CA molecules, respectively. The optimal reaction conditionsof CA-β-CD reacting with cellulose: reaction time15min, reaction temperature160℃,[CA-β-CD]=300g/l, pH3.4, at which the grafting ratio was9.7%. About3.6mg of CipHClabsorbed onto1g of oven-dried cellulose fibers when the absorption reached equilibrium.The loading amout of CipHCl to β-CD-grafted cellulose fibers increased remarkablycompared to that to virgin cellulose fibers, and the equilibrium loading amount to graftedcellulose fibers was about13.6mg/g. The cumulative release of CipHCl from the virgin fiberswas90%in the first30min, while that from the β-CD grafted fibers reached the same levelafter240min.(2) The optimal conditions for the synthesis of β-CD-CS: n(ECH):n(β-CD)=5, reactiontemperature40℃, m(β-CD):m(CS)=2:1,[NaOH]=300g/l, at which β-CD content of CA-β-CD was14.3%based on the weight of β-CD, and the degree of substitution ofβ-CD-CS was0.027. Grinding method was used for the formation of inclusion complexesbetween β-CD-CS and CipHCl. The optimal grinding conditions of inclusion complexes:n(CipHCl):n(β-CD)=2:1, m(H2O):m(β-CD-CS)=2:1, grinding time40min, at which, theloading amount of CipHCl in inclusion complexes was25.1mg/g β-CD-CS. The release rateof CipHCl from inclusion complexes increased almost linearly in the first95min, then therelease rate tended to be slow and reached equilibrium after350min, at which the cumulativerelease was about90%.(3) β-CD-Cel-CipHCl and β-CD-Cel-CipHCl were added to the pulp to prepareantibacterial paper. With increased content of two kinds of inclusion complexes, theantibacterial effect of paper sheets increased significantly. When the adding amount ofβ-CD-Cel-CipHCl and β-CD-CS-CipHCl were50%and10%respectively, the inhibition rateof paper sheets against E.coli and S.aureus were both higher than99%. The antibacterialactivity of the paper with β-CD-CS-CipHCl was higher than that of the paper withβ-CD-Cel-CipHCl at the same adding amounts of CipHCl. Furthermore, with increasedcontent of β-CD-Cel-CipHCl, the tensile strength, tear strength and brightness of paper sheetsdropped dramatically, while those of β-CD-CS-CipHCl firstly increased and then dropped.(4) Grinding method was used for the formation of inclusion complexes betweenβ-CD-CS and ACV. The optimal grinding conditions of inclusion complexes:n(ACV):n(β-CD)=2:1, m(H2O):m(β-CD-CS)=2:1, grinding time40min, at which, the loadingamount of CipHCl in inclusion complexes was14.8mg/g β-CD-CS. The release rate ofCipHCl from inclusion complexes increased almost linearly in the first60min, then therelease rate tended to be slow and reached equilibrium after275min, at which the cumulativerelease was about94%. With increased content of β-CD-CS-ACV, the antiviral activity ofpaper sheets increased. When the adding amount of β-CD-CS-ACV was15%, the virucidalactivity of paper sheets was90%.