The Construction Of The Hydrophobic And Hydrophobic Sites On The Surface Of Polypropylene Nonwoven Fabric And Its Adsorption Properties

In this research,a kind of amphiphilic polypropylene nonwoven with hydrophilic and hydrophobic site(PP-g-GMA-OA)was fabricated by grafting of glycidyl methacrylate(GMA)onto PP nonwoven through electron beam(EB)radiation induced graft polymerization and subsequent ring-opening reaction.The adsorption performance and adsorption behavior of endocrine disrupting chemicals(EDCs)such as DBP,DEHP and BPA,etc.were systematically investigated.The surface functional groups,element composition,surface morphology,surface energy and inner structure of PP-g-GMA-OA nonwoven were characterized by Fourier transform infrared spectrometer(FTIR),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),contact angle(CA),laser confocal scanning microscope(CLSM),etc.For comparasion,a comparative structure(PP-g-LMA)with hydrophobic site only was fabricated to elucidate the adsorption performance,adsorption kinetics,driving forces and adsorption activation energy and quantify the influences of hydrophilic and hydrophobic sites.Based on FTIR analysis,differential adsorption enthalpy,functional groups and driving forces between adsorbent and adsorbate,synergistic effect of hydrogen bonding and hydrophobic interaction was proposed.The participation coefficient and synergistic processes were described through comparative structure,changing adsorption solvebt system and modeling equations.The results indicated that hydrophobic interaction was the main driving force and hydrogen bonding assisted adsorption.In addition,adsorption priority was proposed according to adsorption energy,namely adsorbate occupied the hydrogen bonding site with higher energy preferentially and the hydrophobic interaction with lower eneygy was occupied afterwards.Polypropylene particle grafting experiment was designed and the paricle size was detected to indicate conncetions between grafting configuration and adsorption behaviors.The result revealed that the grafting configuration could be devided into extended and contracted configuration.Compared with contracted configuration,the extended configuration could offer more spaces and adsorption site,which would have beneficial influence on adsorption.The amphiphilic PP-g-GMA-OA nonwoven was futher utilized for oil-in-water(O/W)emulsion adsorption and two paradoxes in fabrication of oil sorbents were proposed.It was generally considered that excellent oil sorbents should have following characteristics:hydrophobicity and sufficient porosity.However both principles ignored the realities of application.Thus in this article,we proposed amphiphilic modification and fabrication of penetration channel,which was utilized for emulsion removal successfully.In the end,a cross-linking layer which performed as a unidirectional diffusion layer was fabricated onto polypropylene(PP)mat through UV radiation graft polymerization(PP-g-LA-co-EGDMA mat).The adsorption and retention capacity of common fibrous oil sorbent was enhanced.After saturation adsorption,the swelling of crosslinking layer of PP-g-LA-co-EGDMA mat could provide more spaces to accommodate more oil.On the other hand,the three-dimensional network structure could effectively prevent the leakage,which intensified the retention performance.In addition,the crosslinking layer could brace the inner fibrous structure and prevent the inner collapse.Consequently the reusability was enhanced.