Preparation,Functionalization And Separation Performance Of Nanofibrous Sterilization Film

The rapid development of biomedical industry has put forward higher requirements for the aseptic(degerming)treatment of biomedical products(such as proteins and nucleic acids).The traditional sterilization method of autoclave has great loss and damage to the activity and quality of products.At present,microfiltration degerming membrane materials on the market are mainly prepared by reverse rotation process,showing the defects of single product performance and structure,wide pore size distribution and the like.It is of great significance to develop a new type of membrane material with excellent filtration and sterilization.The diameter of fibers produced by traditional melt-blown spinning is difficult to reach less than 1?m,which leads to the difficulty in meeting the requirements of high-efficiency bacteria interception.Nanofibers prepared by electrospinning and other methods have fluffy membrane structure,large pore diameter,unsuitable for liquid separation,low preparation efficiency and difficulty in large-scale continuous production.Melt blending phase separation method can not only prepare nanofibers with controllable size in large quantities,but also is suitable for large-scale degerming application due to its compact fiber membrane structure and concentrated pore size distribution due to wet non-woven technology.Plasma treatment technology,as a new material modification method,has the advantages of simple operation,short preparation time and convenient realization of industrial production.In order to solve the above problems,different methods are adopted to functionalize thermoplastic polyethylene-vinyl alcohol copolymer(EVOH)nanofiber membranes,which realize high flux,high interception,high pollution resistance and sterilization capability of membrane materials.The simplicity and feasibility of functionalization methods also provide the possibility for industrial production of materials.The research content of this article is divided into three aspects in detail:Different sizes of EVOH nanofibers were prepared by melt blending phase separation method,and gradient structure nanofiber-based degerming membrane(NFM-GM)was prepared.NFM-GM combines the performance of nanofiber membranes with different sizes.The average pore diameter of the membrane is 120 nm,the stable water flux at 0.2 MPa is6240 L/(m~2·h),the flux decline rate is 4.6%,the interception efficiency is 98.40%for color paste scarlet with an average particle size of 107 nm,the interception efficiency is 99.1%for PS microspheres with an average particle size of 200 nm,and the interception ability of NFM-GM to bacteria reaches 100%for E.coli and S.aureus.The EVOH nanofiber membrane was soaked in 5-sulfosalicylic acid solution,and then 5-sulfosalicylic acid was grafted to the EVOH nanofiber membrane by surface plasma free radical polymerization to prepare sulfo-EVOH nanofiber-based degerming membrane(NFM-S).The results show that the optimal reaction time of surface plasma between 5-sulfosalicylic acid and EVOH nanofiber membrane is 60 s,which not only has a high grafting rate,but also greatly improves the hydrophilicity of the membrane surface.The flux of NFM-S was improved,the anti-fouling ability was increased,and the adsorption of bovine serum albumin(BSA)was decreased from 0.69%to 0.21%.NFM-S can achieve 100%degerming and filtering effect on E.coli and S.aureus.The EVOH nanofiber film(NFM)was prepared by coating the EVOH nanofiber suspension on PET nonwoven fabric substrate,and then the surface carboxylated EVOH nanofiber film(NFM-APT)was prepared by alkali solution activation and surface plasma treatment.The results showed that a composite structure sterilization film(NFM-APT)with ultra-thin active layer was prepared on PET nonwoven fabric substrate by EOVH nanofiber suspension coating,alkali solution activation and surface plasma carboxylation,and the thickness of the active layer was 4.7?m m.NFM-APT has a narrow pore size distribution,with a main distribution range of 120-150 nm and an average pore size of 134.7 nm.NFM-APT has high hydrophilicity with a contact angle of 24.7°.The stable water flux at 0.2 MPa is 7400.4L/(m~2·h)and the flux decline rate is 4.1%.Compared with commercial membrane PES,it has better rejection rate and permeability.The filtering and intercepting effect on E.coli,S.aureus and Brevundimonasdiminuta is 100%.NFM-APT showed good anti-pollution performance to bovine serum albumin(BSA)and yeast ribonucleic acid(RNA)in continuous filtration mode and static soaking mode.Compared with commercial PES,NFM-APT shows good reusability.