Preparation Of Copper-Loaded Silica Nanoparticles And Their Antibacterial Performance In Polymers

Polymeric materials such as polypropylene and silicone rubber are widely used in various aspects of human life due to their good chemical inertness,easy processing,and low cost.However,bacterial adhesion and growth on polymer surfaces severely limit their applications.Therefore,the development of antibacterial materials that confer polymer antibacterial properties has received much attention from researchers and the market.Copper-based nanomaterials,as a new type of antibacterial agent,have broadspectrum antibacterial properties.However,the antibacterial properties of nanoscale copper-based materials are reduced due to problems such as high surface energy and easy agglomeration.Based on this,this paper uses silica as a carrier to load copper-based nanomaterials(nano copper,nano copper oxide)on the surface of silica,and conducts research on the preparation and properties of silica-loaded antibacterial powders and antibacterial polymers,systematically investigating the antibacterial properties,mechanical properties,and thermal stability of the materials.The main content and results are as follows.1.Preparation of amino-functionalized silica-supported copper and their application in polypropyleneIn this chapter,silica-supported copper nanopowders were prepared by liquid-phase in situ deposition technique using amino-functionalized silica as the carrier,copper sulfate as the copper precursor,and hydrazine hydrate as the reducing agent to form copper-ammonia complexes using amino and copper ions.The effects of Cu2+ concentration,molar ratio of N2H4·H2O to Cu2+,p H and temperature on the morphology and deposition amount of the powder materials were investigated;the effects of nanopowder addition in silica-loaded copper/polypropylene composites on the antibacterial properties,mechanical properties and thermal stability performance of the composites were studied.The results showed that a series of samples with copper loadings of 3.33 wt%,2.55 wt% and 1.79 wt% could be prepared at 70 °C,p H 10 and a molar ratio of N2H4·H2O to Cu2+ of 1:1 when the copper ions were added in varying amounts.Antibacterial tests of silica-supported copper nanoparticles show that the germicidal rate is 99.99% at a copper concentration of 0.895 μg/m L,and the corresponding minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of the antibacterial agent copper were 0.042 mg/m L and 0.666 mg/m L,respectively.The antimicrobial properties of the composites gradually increased with the addition of antimicrobial nanopowders and the germicidal rate was 96.99% and 99.00% at 6 wt% and 8 wt% additions,respectively,which meet the criteria of plastic type II and type I(germicidal rate ≥ 90% and ≥ 99%);the tensile strength gradually decreased and the elongation at break first increased and then decreased,and the elongation at break was 336% at 6 wt% addition;the thermal decomposition temperature of the composites increased by 10 °C at 8 wt% addition The thermal decomposition temperature of the composite increased by 10 °C at 8 wt% addition.2.Preparation of amino-functionalized silica-supported copper oxide and their application in polypropyleneCompared with copper nanopowders,copper oxide has high stability and low production cost.To further investigate the antimicrobial differences between copper oxide and copper,this chapter successfully prepared high-loading silica-supported copper oxide nanoparticles by high-temperature calcination.The effect of calcination temperature on Cu O crystallization and distribution was investigated,and the effect of the addition amount of silica-supported copper oxide nanopowders on the antibacterial properties,mechanical properties and thermal stability performance of the composites was examined.The results showed that the silica-supported Cu O nanoparticles could be obtained by calcination at 800 °C for 2 h.The antimicrobial test of the silica-supported copper oxide nanopowders showed that the germicidal rate was 98.01% at a copper oxide concentration of 1.665 μg/m L,and the MIC and MBC corresponding to 0.083 mg/m L and 2.664 mg/m L,respectively.The antimicrobial properties of the composites gradually improved with the addition of silica-supported copper oxide samples,and the germicidal rate could reach 97.41% at 8 wt% addition.Overall,the antimicrobial properties of the silica-supported copper oxide powder and its composites were slightly lower than those of the silica-supported copper powder and its composites.3.Preparation of double bond and amino co-modified silica supported copper and their application in silicone rubberThe antibacterial silicone rubber also has a good market prospect.Considering that the doublebond modified silica is beneficial to improve the mechanical properties of silicone rubber,in this chapter,based on the previous work,silica-supported copper nanopowder samples were prepared using amino and double-bond co-modified silica as carriers.The effects of the molar ratio of N2H4·H2O to Cu2+ and reaction time on the crystalline shape and distribution of the silica-loaded copper nanopowders were investigated,and the powder inhibition properties,antibacterial properties,mechanical properties and thermal stability properties of the composites were tested.The results showed that the silica-supported copper nanopowders could be prepared with a molar ratio of hydrazine hydrate to copper ions of 3,a reaction time of 0.5 h,a temperature of 70 °C and p H=10.The antimicrobial test of silica-supported copper powder showed 99.99% germicidal rate at a copper concentration of 0.895 μg/m L,and the corresponding copper concentrations for the minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)were 0.042mg/m L and 0.666 mg/m L,respectively.The antimicrobial properties of the composites increased gradually with the addition of silica-supported copper nanopowders,and the germicidal rate was 99.99% at 15 phr.The thermal stability,tensile strength and elongation at break of the composites with addition of ≤15 phr silicasupported copper nanopowders did not differ much from those of the blank composites,but the properties gradually decreased when the addition exceeded 15 phr.Overall,the composite material had the best antibacterial properties,mechanical properties,and thermal stability when the addition of copper-loaded nanosilic was 15 phr.