| The paper adds chitosan in TiO2nanoparticles in order to improve the sterilization rate of composite antibacterial agents, and then get optimum antibacterial properties of composite antibacterial agent. This paper will improve the sterilization rate of composite antibacterial agents from two ways such as how to disperse nano-TiO2and how to reduce the degradation of chitosan.In improving the dispersion of nano-TiO2experiments, the main judgments are based on centrifugal stability and particle size, zeta potential. Centrifugal stability measured by orthogonal experiment to determine the optimal dispersion process of nano-TiO2, experimental results show that centrifugal stability of the9th reaching69.8%is the highest of the sample, it means that the ethanol content was10%and sodium hexametaphosphate was1.5%(relative to the nano-TiO2), and then ultrasonic time is15min, also pH of the solution is10. by measuring the particle size and Zeta potential measurement results also show that the optimum dispersion conditions are the above, then the average particle size of9samples are270.1dnm and the absolute value of the average potential is37.8mv. In the same time the particle size of the9th sample is194dnm, and while the absolute value of potential is52.3mv. Two dispersants will be compounded if they can improve the stability of the dispersion, the results show that after compounding two different types of dispersant the dispersion is significantly increased. When the proportion between sodium hexametaphosphate and the polyethylene glycol1000is1:2,65.4%centrifugal stability,180dnm particle size,46.5mv the absolute value of the potential, indicating that it is the best dispersion. In dissolving chitosan experiments, the main judgment is based on the viscosity, because the larger the relative molecular mass of chitosan is, the viscosity greater is. Experimental results indicate that the viscosity of solution is375.2mPa.s when1.2%the concentrations of acetic acid,40%the amount of ethanol,2%the concentration of chitosan solution. In experiments of determining the coating formulations, we mainly from the pigment ratio, the ratio of adhesive, CMC dosage three aspects to consider. Changing the ratio of pigment and determining the viscosity, stability and solid content of coating, the results show that the viscosity is1158mPa.s and the stability is2ml when60parts GCC and40parts PCC. Thereby determining the ratio of the pigment is the top. The coating applied on the copy paper, the physical properties of the sheet was measured, the results show, the break index13.17KPa.m2/g, tear index7.3mN.m2/g and tensile index4.917N.m/g are all reaching the biggest when60parts GCC and40parts PCC. Changing the ratio of adhesive and determining the viscosity of paint, the results show that the viscosity of the paint is1158mPa.s when the ratio of the styrene-butadiene latex, PVA and chitosan is9:7:2. Changing the amount of CMC(with respect to the pigment) and measuring the viscosity of paint, the results show that the best amount of CMC is0.4%,This paper respectively antimicrobial experiments for the proportion of nano-TiO2/chitosan, pH and amount of paint by measuring the inhibition zone to determine the best antimicrobial conditions. The inhibition zone is18mm when the ratio of nano-TiO2/chitosan is2:1. The inhibition zone is17mm when pH is8. The inhibition zone is18mm when amount of paint is10g/m2. By considering the final decision is nano-TiO2/chitosan ratio of2:1,8Ph and paint amount of10g/m2.We use antibacterial paper packaging South pear, through testing the physiological indicators and sensory index of South pear to determine whether this paper has the function of antibacterial. The results show that the antibacterial paper packaging is smaller than paper packaging on the weight loss. When in storage18d South pear with paper packaging slightly shriveled, while that with antibacterial paper packaging always kept moderate humidity. Paper packaging and antibacterial paper packaging are all completely turned yellow when30days. But in contrast, antibacterial paper packaging can reduce the fruits’ yellow index. The colonies of antibacterial paper packaging is3.5log (cfu/g), and compared with the paper packaging antibacterial paper packaging has more antibacterial effect. The titratable acid of South pear with antibacterial paper packaging is overall higher than the control group. This can be seen, antibacterial paper packaging can reduce the titratable acid of South pear, and also can effectively keep the taste of South pear fruit. |
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