Study On The Synthesis Of ZnO/Ag Composite Nano-antibacterial Agent By Complex Precipitation Method And Their Application In Trans-1, 4-polyisorprene Rubber And Nature Latex

In this paper, ZnO/Ag composite nano-antibacterial agent was obtained viacomplex precipitation method. The influence of the process conditions on themorphology and productivity was mainly studied and the antibacterial performancewas evaluated. The antibacterial trans-1, 4-polyisorprene (TPI) rubber and theantibacterial nature latex (NL) was prepared by conventional twin-roll mixingmethod and impregnation method, respectively. Their antibacterial performance,mechanical properties and shape recovery rate were investigated.1. Firstly, the coordination compound solution was obtained with Zn(NO3)2,AgNO3 as the starting materials and NH3·H2O as the complexing agent. When thecoordination compound solution was heated to certain temperature, the flocculentprecipitate was obtained. After a little flocculation precipitation was generated,(NH4)2CO3 as precipitation was dropped in above mixture solution, then precursor ofZnO/Ag composite nano-antibacterial agent were obtained, which was consisted ofZn(OH)2 and Zn5(OH)8(NO3)2?2NH3 core and ZnCO3, Ag2CO3 and Zn5(OH)6(CO3)2shell. Finally, the precursor was calcined and ZnO/Ag composite nano-antibacterialagent was obtained. We mainly studied the influence of the process parameters suchas reaction temperature, reaction time, the calcined temperature, dosage of NH3·H2Oand (NH4)2CO3, etc on the productivity and morphology. BPANN was used to forecast and validate the results obtained in the different experiment conditions forvoting in the better preparation technics. The different morphologies ZnO/Agcomposite nano-antibacterial agent was obtained by adding different surfactants inthe coordination compound solution under above optimal process conditions.The results indicate that: the ZnO/Ag composite nano-antibacterial agent whichconsist of the hexagonal wurtzite-structured ZnO crystal and cubic structure Agcrystal can be obtained under the reaction temperature was about 60℃, the mol ratioof Zn(NO3)2:AgNO3:NH3·H2O: (NH4)2CO3 was 1:0.084:4.17:1.58, and the first stepreaction time was 45 min, the second step reaction time was 120 min, the precursorwas firstly calcined at 200℃in atmosphere for 90min, then raising the temperatureto 350℃, keeping for 240 min. The produce yield of ZnO/Ag compositenano-antibacterial agent with the diameter of about 5~15 nm was about 84.24 %.The forecast data of BPANN and the validate experiment data were highly tally,which indicates we can use BPANN to make forecast and optimizing the synthesisprocess of ZnO/Ag composite nano-antibacterial agent. Rod-like or sphericalZnO/Ag composite nano-antibacterial agents were obtained by adding certainamount various surfactants, such as PEG-6000, PEG-400 and CTAB/SDBS.2. The MIC values for the undispersed ZnO/Ag composite nano-antibacterialagent and ZnO/Ag composite nano-antibacterial agent dispersed by E80 on E. coliwas 250 mg/L and 50 mg/L and on S. aureus was 300 mg/L and 50 mg/L,respectively. The MIC values was much lower than that in the criterion of HG/T3794-2005, the criterion MIC value for the inorganic antibacterial agent was800mg/L.3. The crystalgrain growth kinetics results of ZnO/Ag compositenano-antibacterial agent show that the average particle size increased with increasingcalcined temperature. The crystalgrain growth exponent was 4.85, the kinetic rateconstant was 1.36×104 nm4.85/min, the activity energy was 172.29 kJ·mol-1, thecrystalgrain growth conforms to the diffusion growth mechanism.4. The antibacterial TPI rubber was prepared by adding undispersed anddispersed ZnO/Ag composite nano-antibacterial agent. The antibacterialperformance, mechanical properties and shape recovery rate of antibacterial TPIrubber were discussed and compared with common TPI rubber.The results indicate that:(1) Common TPI rubber had no antibacterial properties and the antibacterial TPI rubber had well antibacterial properties. Moreover, with the addition amount ofantibacterial agent increased the antibacterial rate of antibacterial TPI rubber onE.coli and S. aureus increase. When the addition amount of the antibacterial agent is5 g (3.58 %), the antibacterial rate of antibacterial TPI rubber is more than 99 %,which correspond with the strong antibacterial performance standards provided indisinfection technical specifications (2002) of Ministry of Health. The antibacterialrate of antibacterial TPI rubber on E. coli and S. aureus was 99.02 % and 97.44 %,99.34 % and 99.34 %, 99.67 % and 99.34 %, 99.34 % and 99.34 % when added theundispered antibacterial agent and the dispersed antibacterial agent by PVPK30, E80and 752W, respectively.(2) The tensile strength, tear strength, elongation at break and shape recoveryrate of the antibacterial TPI nano-composite material raised firstly and then declinedwith increasing dosage of the antibacterial agent. When addition amount of ZnO/Agcomposite nano-antibacterial agent was 5 g (3.58 %), the above mechanicalproperties of TPI rubber reached maximum, which was prior to commom TPI rubber.5. The antibacterial NL was prepared by adding undispersed and dispersedZnO/Ag composite nano-antibacterial agent. The antibacterial performance,mechanical properties of antibacterial NL were investigated and compared withcommon NL.The results indicate that:(1) Common NL had no antibacterial performance and the antibacterial NL hadwell antibacterial properties. Moreover, with the addition amount of antibacterialagent increased the antibacterial rate of antibacterial NL on E.coli and S. aureusincrease. When the addition amount of the antibacterial agent was 0.5 g (0.48 %), theantibacterial rate of the antibacterial NL was more than 99 %, which correspond withthe strong antibacterial performance standards provided in disinfection technicalspecifications (2002) of Ministry of Health. The antibacterial rate of the antibacterialNL on E. coli and S. aureus was 97.43 % and 98.11 %, 99.26 % and 99.24 %,99.26% and 99.62 % when added undispered antibacterial agent and the dispersedantibacterial agent by PVPK30, E80, respectively.(2) The tensile properties and tear properties of the antibacterial NL increasedfirstly and then decreased with the addition amount of ZnO/Ag compositenano-antibacterial agent increased. When addition amount of ZnO/Ag compositenano-antibacterial agent was 0.5 g (0.48 %), the tensile strength and tear strength of NL reached maximum, which was prior to commom NL.