Radiation Graft Modification Of Nylon 66 Fibers And Applications In Uranium Wastewater And Antimicrobial

Nylon 66(PA66)fibers,produced by the polycondensation of hexamethylene diamine and adipic acid,are the first commercial synthetic fibers,and have excellent wear resistance,fatigue resistance,heat resistance,and chemical resistance,which have wide application.In this study,vinyl monomers were grafted on the nylon 66 fibers by radiation induced graft polymerization,and then grafted fibers were further modified via a series of chemical reactions.The prepared functional nylon 66 fibers were tested in uranium wastewater treatment and antimicrobial evaluation.Amidoximated nylon 66 fibers,for the adsorption of uranyl ions,have been prepared successfully by the following process: polyglycidyl methacrylate(PGMA)was grafted on the nylon 66 fibers via simultaneous radiation induced graft polymerization,then,amidoximated groups were introduced on the PGMA graft chains via chemical modifications.The effects of monomer concentration on the degree of grafting were studied in detail as well as the effects of reaction time on the molar conversion of epoxy groups in the process of aminolyzation.The chemical structure,micromorphology,thermal properties,and mechanical properties of the pristine and modified nylon 66 fibers were carefully characterized by Fourier transform infrared spectroscopy,scanning electron microscopy,thermogravimetric analysis,and an electronic single fiber tensile strength tester.The effects of initial p H,sorption isotherms,adsorption kinetics,thermodynamic studies,adsorption selectivity,and application in stimulated nuclear industry effluents were studied.Results revealed that the amidoximated nylon 66 fibers showed a high adsorption efficiency and excellent selectivity for adsorption of low concentrations uranium(1-25 mg/L).In another work,antimicrobial nylon 66 fibers,possessing highly effective antimicrobial activity,have been prepared successfully by the following process: poly2-(dimethylamino)ethyl methacrylate(PDMAEMA)was grafted on the nylon 66 fibers via the simultaneous irradiation induced graft polymerization,then,Mn O4-anions were loaded on the PDMAEMA graft chains via chemical modifications.The effects of monomer concentration on degree of grafting were studied in detail.The chemical structure,micromorphology,thermal properties and elements forms of the pristine and modified fibers were carefully characterized by Fourier transform infrared spectroscopy,scanning electron microscopy,thermogravimetric analysis,and X-ray photoelectron spectroscopy,it was confirmed that Mn O4-anions were loaded successfully on the nylon 66 fibers.The antimicrobial activities of the modified nylon 66 fiber(PA66-Mn O4)were evaluated using Staphylococcus aureus(ATCC 6538)and Candida albicans(ATCC 10231),results indicated that PA66-Mn O4 fibers have high antimicrobial action(almost 100% reduction against S.aureus and C.albicans).Accelerated laundering durability tests were carried out following AATCC Test Method,the antimicrobial activity was maintained after 20 times of accelerated launderings.The mechanical properties of pristine,modified nylon 66 fibers,and PA66-Mn O4 fibers after 20 times accelerated laundering were measured using an electronic single silk strength tester.The preparation and laundering process did not change the mechanical properties of nylon fibers.