Research On Functionalized Polypropylene Non-woven Fabrics Imitating Mussels

Mussel biomimetic precipitation technology is a new and potential surface engineering method,which has been widely used in material surfac e hydrophilic modification and introduction of functional groups.However,the traditional mussel-like modified material,dopamine,has limited its further application and development in material surface modification due to its expensive price and unsatisfactory hydrophilic effect.A novel biomimetic sedimentation technology of mussel based on cross-linking and co-deposition of catechol and polyethyleneimine was studied in this paper.A kind of Janus polypropylene nonwovens with asymmetric wettability structure and an effective adsorbent for adsorbing heavy metals in water were prepared.The specific research in this paper is as follows:The mechanism of coprecipitation modification of catechol and polyethyleneimine was studied.The mechanism of coprecipitation was revealed as follows:catechol and polyethyleneimine were crosslinked by Michael addition reaction or Schiff base reaction to form a network polymer,and the non-covalent bond force mainly consisted of hydrogen bond was adhered to the surface of polypropylene nonwovens;the quality of catechol and polyethyleneimine in the reaction solution was studied.The optimum mass ratio of catechol to polyethyleneimine was 2:1,reaction time was 12 h and solution pH was 8.5.For the preparation of Janus polypropylene nonwovens with asymmetric wettability,this study made full use of the hydrophobicity and low density of polypropylene nonwovens,and immersed polypropylene nonwovens unilaterally in the mixed solution of catechol and polyvinylimide,so that catechol and polyvinylimide were co-deposited on the surface of polypropylene nonwovens unilaterally,thus achieving unilateral parent.For the purpose of hydration modification,polypropylene nonwovens with asymmetric wettability Janus structure were prepared.The material can realize the directional and spontaneous infiltration of water droplets from hydrophobic side to hydrophilic side,and has a good effect on the reduction of water evaporation rate.For the preparation of heavy metal adsorbents,polypropylene nonwovens were immersed in the mixed solution of catechol and polyethyleneimine by full immersion.A heavy metal adsorbent for adsorbing Cd(Ⅱ)in water was prepared by co-deposition of catechol and polyethyleneimine onto the surface of polypropylene nonwovens.The effects of reaction time,initial concentration and pH on the adsorption properties of cadmium ions were discussed.The adsorption kinetics,adsorption isotherm and adsorption thermodynamics were simulated.The results showed that the maximum fitting adsorption capacity of the material was 57 mg/g.After six times of desorption-adsorption,the modified polypropylene nonwovens still had a good adsorption effect on cadmium ion.In the discussion of its adsorption mechanism,it is found that the adsorption of Cd(Ⅱ)mainly depends on the chelation of-NH2 with Cd(Ⅱ).