Preparation And Application Of Nano-copper Methanol Complex/Barium Sulfate Modified PA6 Composites

Polyamide 6(PA6)is widely used in the fields of clothing fabrics,packaging films,electronic components,aerospace and so on because of its prominence in comprehensive performance.However,bacteria can germinate easily in pure PA6 due to its strong hygroscopicity.Therefore,the research and development of PA6 with antibacterial function has very important academic significance and commercial value.At present,most of the antibacterial PA6 materials are silver antibacterial agents,but as for them,the problems such as high cost,poor safety,color pollution and so on generally exist.At present,functional modification is a common way to modify materials.By adding one or more functions to PA6,the application value and properties of the composite can be greatly improved.The purpose of this study is to prepare PA6 composite with low cost,high safety and good antibacterial function by composite modification,while maintaining or improving the mechanical properties of the composite.To this end,a new black coprecipitation with similar functions to copper oxide@barium sulfate(Cu O@BaSO₄)co-precipitation was prepared by reacting copper sulfate solution with barium hydroxide solution,and then the enhanced antibacterial PA6 composite was prepared by blending and extruding with PA6.The correlation calculation and analysis show that black matter is a new complex of copper ion and methanol.Therefore,this study analyzed the valence state of the new complex,simulated and calculated its possible chemical structure,and found that it was a copper-methanol complex(MeCu).The structural properties of copper methanol complex@barium sulfate(MeCu@BaSO₄)co-precipitation were further studied.The results show that the melt blending of MeCu@BaSO₄ coprecipitation and PA6 chips by twin-screw extruder can not only endow PA6 with excellent antibacterial properties,but also keep the mechanical properties of PA6 unchanged.The PA6-MeCu@BaSO₄composite has good spinnability.The specific research results are as follows:(1)By designing a series of experiments of different reactant concentration and reaction temperature gradient,the best reaction conditions for preparing MeCu@BaSO₄ coprecipitation are obtained as follows:at 25?normal temperature and 0.5mol/L reactant concentration,the prepared MeCu@BaSO₄ coprecipitation has the smallest particle size and the best dispersion.The co-precipitation of MeCu@BaSO₄nanoparticles prepared under the optimum conditions was analyzed by Infrared spectrometer(FTIR).The characteristic absorption peaks of methyl,hydroxy,copper oxygen bond(Cu-O)and barium sulfate were clearly observed by FTIR.After being burned under high temperature,the methyl peak did not disappear completely,which indicated that the chemical binding force of methanol and copper ion was very strong and had high thermal stability.The results of transmission electron microscopy(TEM)show that the average particle size of the coprecipitation of nano MeCu@BaSO₄ is between 20-80nm,and the morphology of single nano particle is clear.However,in most cases,TEM cannot distinguish the two because of the coexistence of barium sulfate and copper methanol complexes.The measurement of the interplanar spacing of the high-resolution transmission electron microscope(HTEM)revealed only the interfacial plane of barium sulfate(JCPDS file:01-1229).(2)At room temperature,MeCu was prepared by the reaction of0.5mol/L copper sulfate aqueous solution and sodium hydroxide methanol solution.FTIR analysis further confirmed that the ligand in MeCu@BaSO₄ co-precipitation was methanol.TEM shows that MeCu particles are well distributed and the average size is below 10nm.In addition,its HTEM showed that the crystal surface spacing of MeCu was0.272nm,which was consistent with the crystal surface of(110)of copper oxide(JCPDS file:89-5896),indicating that MeCu had a crystal structure similar to that of copper oxide.Preliminary theoretical calculations have obtained a series of copper ion coordination units with different valence states and possible coordination compound structures.According to the quality of the product and the content of copper element,we can infer that the molecular weight of MeCu is between 226.15-226.95.The structure of MeCu can be determined as[Cu(II)(CH₃OH)₄](OH)₂ by theoretical calculation,parallel experiment and X-ray photoelectron spectroscopy(XPS).(3)A PA6-MeCu@BaSO₄ composite was prepared by melt extrusion using a twin-screw extruder.Scanning Electron Scattering(SEM)results showed that MeCu@BaSO₄ particles were well dispersed in the PA6matrix,and the particle sizes were all below 100nm.After the MeCu@BaSO₄composite modification,the tensile strength,flexural strength and impact strength of PA6 composites increased simultaneously.When the content of MeCu@BaSO₄ was 2.5%,the tensile strength,flexural strength,and impact strength of the composites increased by9.0%,20.7%,and 5.4%,respectively.Thermogravimetric analysis(TG)shows that the addition of nano-MeCu@BaSO₄ changes the thermal stability of pure PA6 composites.The thermal decomposition temperature increased with the increase of co-precipitation content within a certain range;the results of differential thermal analysis(DSC)showed Within a certain range of addition,the addition of nano-MeCu@BaSO₄ increased the crystallinity of PA6.The antibacterial properties of PA6 composites also increased significantly with the increase in the amount of MeCu@BaSO₄ added.When theCu²⁺content was 0.12%,PA6composites had the same antibacterial performance as pure PA6;when theCu²⁺content was increased to 1.5%,PA6-MeCu@BaSO₄ composites had a high sterilization rate against E.coli and S.aureus 99.9%.(4)PA6-MeCu@BaSO₄ fiber was prepared by melt spinning.The experimental results showed that the MeCu@BaSO₄ particles are well dispersed on the surface of the antibacterial PA6 fiber without obvious agglomeration.PA6 fiber has a smooth surface and a uniform diameter,which shows good spinnability.The addition of nano-MeCu@BaSO₄ had no obvious effect on the crystalline form of PA6 fibers,but it had a slight increase in the thermal decomposition temperature and crystallization temperature of the fibers,and in a certain addition range,it helped to increase the crystallinity of PA6 fibers.The antibacterial properties of PA6 fiber were significantly enhanced with the addition of MeCu@BaSO₄:when the content of Cu²⁺was 0.12%,PA6-MeCu@BaSO₄ fiber had the same antibacterial properties as pure PA6.When the content of Cu²⁺increased to 0.6%,the bactericidal rate of PA6-MeCu@BaSO₄ fiber against E.coli reached 95%,the bactericidal rate against S.aureus reached 91%.