Study On Preparation, Surface-modification And Antibacterial Application In Interior-wall Paint Of Nanometer MgO Powder

Since nano-MgO was prepared in the 1980s, nano-MgO has attracted manymaterial researchers because of its extensive application foreground. Its preparation,modification and application study hold a very important position in the presentresearch of nano-MgO. In this paper, we systematically study preparation andmodification of nano-MgO and application of nano-MgO powder composted withinterior wall paint. The funtional interior wall paint with antibacterial property wasobtained.In this paper, using MgCl₂·6H₂O and Na₂C₂O₄ as raw material, polymer (PEG)as protective agent, nano-MgO powder with good crystallinty and uniform particlesize distribution has been synthesized by solid-phase reaction at room temperature.The effects of calcination temperature, calcination time and the dosage of polymer(PEG) on the MgO powder particle size were studied in detail. Meantime, themechanism of the action of polymer (PEG) was also preliminarily studied. Themorphology and structure of nano-MgO powder were characterized by means ofX-ray powder diffraction (XRD), transmission electron microscope (TEM), FourierTransform Infrared Spectrophotometer (FT-IR) and laser sizer(LS). And thermaldecomposition temperature of the precursor of nano-MgO was analyzed bydifferential thermal analysis and the mogravimetry (DTA/TG). The results showedthat high purity nano-MgO powder whose average particle size was about 7.8 nm wasprepared by decomposing precursor at the temperature 500℃for 3 hours.The optimal modification agent which was selected was sodium laurate. Andnano-MgO has been surface-modified by sodium laurate, and the modification effecthas been studied by means of activation proportion, transmission electron microscope(TEM) and Fourier Transform Infrared Spectrophotometer (FTIR). The Single factorand orthogonal experiment results showed the surface modification effect ofnano-MgO was best at the conditions of modifier dosage of 15%, modification timeof 60min, modification temperature of 40℃and modification pH value of 6.Andunder the processing conditions, the activity index of the modified nano-MgO reached 90.5%. The modified nano-MgO particles exhibited hydrophobiccharacteristics and its dispersivity was good; The nano-MgO particle size before andafter modification was hardly changed. Both the physical absorption existed and thechemical bond was formed between nano-MgO particles and modification agent.Unmodified interior wall paint, interior wall paint modified by nano-MgO andinterior wall paint modified by modified nano-MgO were obtained by combiningchemistry dispersion method, physical method with ultrasonic dispersion method.The antibacterial property of the three types of paint was studied with theexperimental method of antibacterial circle. The result showed that the antibacterialcircle diameter of unmodified interior wall paint was only 0.5 cm smaller and itsantibacterial property was worse. And the antibacterial circle diameters of the interiorwall paint modified by nano-MgO and the interior wall paint modified by modifiednano-MgO were larger than that of the unmodified interior wall paint; Theantibacterial property of the interior wall paint modified by modified nano-MgO wasstronger than that of the interior wall paint modified by nano-MgO. When the weightamount of modified nano-MgO reached 3% (wt), the largest diameter of antibacterailcircle of the paint was 3.2 cm and its antibacterial property was best. Meantime, theantibacterial property of the paint was not afected by different soure conditions.Whether there was light or not in the process of the antibacterial experiment, the painthad antibacterial property. And antibacterial mechanism of nano-MgO waspreliminarily discussed.