Preparation And Antibacterial Activity Of Chitosan/Silver-Copper Composite Antibacterial Agent And Its Application On Silicone Rubber Natrix

In recent years, polymer antibacterial materials are used in a wide range ofmedical devices and textile and clothing field. People pay much more and moreattention to antibacterial, patients using catheters die mostly because ofinfection in the medical. With the development of science and technology andthe improvement of1iving standard, people are more conscious of their health.Therefore, antimicrobial polymer materials become one of the focuses of theclinical aspects and the textile sector. Chitosan (CS) is a polysaccharide whichexists widely and abundantly in the nature. Because of its biocompatibility andreactive functional groups, it is apt to react with other metal particles, Chitosan(CS) is non-toxic, safe and degradable, therefore, it can be widely used inmedical equipment, water purification and other fields. However, due to poor antibacterial properties when used alone, it can′t stand alone as an antimicrobialagent, when relatively high demand for antimicrobial activity is required. Silver(Ag) has higher broad-spectrum antimicrobial and antibacterial effect than othermetals, When the size of the silver particles is reduced to nano scale, theantimicrobial effect of silver will increase significantly, because nano materialspossess certain special surface effects and surface properties, so that changegreater antimicrobial effect. On the other hand, silver is expensive and in recentyears researchers have strengthened study to its toxicity when used extensively.In this paper, firstly, we choose to add copper (Cu) to improve the antibacterialeffect and reduce costs in order to prepare a green and facile compositeantibacterial agent. Secondly, the antimicrobial compound was grafted ontosilicone rubber substrate, in order to attain an antibacterial silicone rubberpolymer material for the medical applicability.In this thesis, a green composite antimicrobial agent (CS/Ag/Cu) wasfirstly synthesized by solid-liquid chemical reduction, and the influence ofreaction conditions on structure and properties of the antibacterial agent wasdiscussed in detail; then the morphology and chemical structure of the sampleswere analyzed using SEM, TEM, XRD, XPS and FTIR; the thermal propertieswere characterized by means of differential TGA; the antibacterial properties ofthe samples were investigated by minimum inhibitory concentration method(MIC), the survival percentage of the bacteria and shake flask (Flask shakingmethod). The main results are summarized as follows: (1) The organic-inorganic composite antibacterial agents CS/Ag/Cu wereprepared by a solid-liquid phase redox method, in which Cu(NO3)2was addedas an additional antibacterial agent, whereas chitosan acted as the reducingagent and the antimicrobial agent for the reduction of silver nitrate to obtainnanoscale silver particles. The optimal reaction conditions are: V(AgNO3):V(Cu(NO3)2)=1:3, the reaction temperature gradient T=40℃â†'50℃â†'60℃,reaction time t=2.5h.(2) Nano-silver particles of CAC antibacterial agent present as sphericalor nearly spherical. The particle size is about15-20nm and the distribution isquite even. Due to the synergistic antibacterial effect of Chitosan, nano-Silverand Copper, the antibacterial activity of CS/Ag/Cu composite antibacterialagents is superior to Chitosan and CS/Ag colloidal sol and its thermal stability ishigher that of Chitosan and CS/Ag colloidal sol.