Preparation,Structure And Properties Of Graphene/Rubber Latex Composites

Natural rubber(NR)is widely used in medical and health field,sealing protection,transportation and other fields due to their wide sources,low cost,and good elasticity.Especially in the recent outbreak of the COVID-19,latex gloves are one of the important materials to fight the epidemic,leading to that latex gloves have been receiving more and more attention.The property requirement for the gloves also become strict.The gloves should not only protect the skins from direct hurt,but also block viruses,bacteria and other substances.However,rubber composites contain many micropores with diameters ranging from hundreds to thousands of nanometers.Bacterium are generally 0.5 micrometers in diameter,and some viruses have even smaller diameters of hundreds or even tens of nanometers.These bacterium and viruses may penetrate the micropores of rubber gloves to contact the skins.Therefore,it is of great significance to further improve the barrier and antibacterial properties of natural rubber latex products.In this thesis,graphene oxide(GO)was used as a reinforced filler and carrier.Polydopamine(PDA)was used as double-sided adhesives,and silver was attached on the surface of graphene oxide.The effect of different dosages of filler on the mechanical properties,gas barrier properties and antibacterial properties of natural rubber latex was studied.The contents of this thesis are as follows:First,based on the excellent self-polymerization and adhesion properties of dopamine(DA),polydopamine(PDA)was formed on the surface of GO sheets.Ag particles were further adhered on the PDA-GO sheets.Finally,the impregnation method was used to prepare graphene/rubber latex composite film,and its mechanical properties,gas barrier properties and antibacterial properties were analyzed.The results showed that the hydrogen bond interaction between NR macromolecules and Ag-PDA-GO filler resulted in the formation of an isolated network structure during the mixing process of NR latex.When the Ag-PDA-GO was 0.2 phr,the Ag-PDA-GO fillers were uniformly dispersed in the NR latex.The filler network composed of Ag-PDA-GO sheets extend the gas diffusion path,leading to the improved gas barrier properties Ag-PDAGO/NR composites.In addition,the different contents of Ag led to different release concentrations of silver ions.When the content of AgPDA-GO was 0.1 phr,The Ag-PDA-GO/NR composites exhibited excellent antibacterial properties.The minimum inhibitory concentration(MIC)values of Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)were 16 ?g/mL and 32 ?g/mL,respectively.On the basis of the above research,natural soluble chitosan(CS)was used as stabilizer,reducing agent for GO and antimicrobial agent.Graphene oxide was used as a carrier.A novel GO-Ag-CS antimicrobial composite was prepared using impregnation method,and its mechanical properties,gas barrier properties and antibacterial properties were analyzed.The results showed that the addition of GO-Ag-CS effectively improved the tensile strength and tear strength of natural latex composites.The filler network of the composite was more complicated.Especially,the barrier performance of the composite was highest when the mass ratio of GO-AgCS was 0.2 phr.In terms of antibacterial,GO-Ag-CS solution with the GOAg-CS mass ratio of 1:0.5 showed all excellent antibacterial performance against E.coli and S.aureus.