| In recent years,disease-causing and harmful microorganisms represented by the new coronavirus have triggered many public health incidents worldwide,which seriously affect people’s normal life and threaten human health.In this paper,a new type of waterborne antimicrobial coating with green and antimicrobial properties was prepared by mixing the quaternary ammonium salt formed by triethylamine modified epoxy resin with waterborne acrylic resin coating as an antimicrobial agent,in order to be used in the interior walls of buildings,thus improving the health and safety level of people’s living and working environment.The main contents are as follows:（1）The synthesis of epoxy resin quaternary ammonium salt（QAC）was studied.The four QACs,E44-QAC,E51-QAC,E54-QAC and F51-QAC,were prepared by the ring-opening reaction between triethylamine hydrochloride and epoxy group in epoxy resin using epoxy resin（E44,E51,E54,F51）and triethylamine hydrochloride as the main raw materials.the effects of reaction temperature,reaction time and reactant ratios on the synthesis of E54-QAC and F51-QAC were investigated with emphasis.The optimal reaction conditions of the above two QACs were obtained as follows:reaction temperature of 80°C,reaction time of 5h,and the ratio of quaternary ammonium ion to epoxide group of 1:1.The structures of E54-QAC and F51-QAC were analyzed and characterized by infrared spectroscopy,nuclear magnetic spectroscopy and X-ray photoelectron spectroscopy.（2）The relevant properties of QAC were investigated.QAC has good water solubility and can miscible with water in large proportion and form clear,transparent and stable liquid;the quaternary ammonium ions in E54-QAC and F51-QAC have good thermal stability,and the decomposition temperature of quaternary ammonium ions ranges from 200℃to 272℃with mass loss of 25%and 23%,respectively;QAC has surface-active properties and can effectively reduce its surface tension in water-soluble systems,the surface tension of aqueous solution was reduced from 70 m N/m to 50 m N/m by 2 g/L E44-QAC;the above four QACs had good antibacterial effect on S.aureus and E.coli,and the antibacterial effect of E54-QAC was relatively good,and the lowest antibacterial concentration of E.coli and S.aureus was 4 mg/m L,respectively.E54-QAC can affect the respiratory metabolic process of S aureus and can also damage the cell membrane,which can lead to the death of bacteria.（3）An aqueous antibacterial coating was prepared using QAC,and the performance of the coating was studied.A waterborne antimicrobial coating containing QAC was obtained by adding QAC to a waterborne acrylic resin interior coating using a co-blending method.With the increase of E54-QAC addition,the content of quaternary ammonium ions on the surface of the coating increased continuously.When the concentration of E54-QAC was increased from 1%to 5%,the charge density of quaternary ammonium ions on the surface of the coating increased from 1.7318×1016/cm2 to 3.8449×1016/cm2,and the characteristic energy spectrum peak of C-N+in quaternary ammonium ions appeared at 402.18 e V;when the addition amount of E54-QAC is 5%,the comprehensive performance of the coating is the best,and its adhesion is grade 1,hardness is 5 H,flexibility is 2 mm,impact resistance is higher than 50 kg·cm,antibacterial rate against E.coli and S.aureus is 98.02%and 98.27%respectively,and the antibacterial performance of the coating is long-lasting,thermal stability and excellent resistance to water,acid and alkali. |
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