HYDROPHILIC MODIFICATION OF PPESK POROUS MEMBRANES VIA AQUEOUS SURFACE-INITIATED ATOM TRANSFER RADICAL POLYMERIZATION

Hydrophilic surface modification of poly(phthalazinone ether sulfone ketone)(PPESK) porous membranes was achieved via surface-initiated atom transfer radical polymerization(ATRP) in aqueous medium.Prior to ATRP.chloromethyl groups were introduced onto PPESK main chains by chloromethylation.Chloromethvlated PPESK(CMPPESK) was fabricated into porous membrane through phase inversion technique.Hydrophilic poly(poly(ethylene glycol) methyl ether methacrylate)(P(PEGMA)) brushes were grafted from CMPPESK membrane ...

A Comparative Study of Hydrophilic Modification of Polypropylene Membranes by Remote and Direct Ar Plasma

Surface modification of polypropylene membrane by argon （Ar） plasma-induced graft polymerization with hydrophilic monomer [acrylic acid （AA） in this work] was investigated. It was found that both the distance of the membrane from the Ar plasma center and the plasma power had a strong influence on the surface modification, hydrophilieity and graft yield （GY） of the treated membrane. Results suggest that remote plasma treatment with a proper sample position, plasma power and graft polymerization leads to a membrane surface with not only less damage, but also more permanent hydrophilicity, than direct plasma treatment does. By analyzing the morphology and the chemical composition of the membrane surface by scanning electron microscopy （SEM） and X-ray photoelectron spectroscopy （XPS）, as well as Fourier transform infrared attenuated total reflection spectroscopy （FTIR-ATR） respectively, a possible mechanism was tentatively revealed.

Hydrophilic Modification of Microporous Polysulfone Membrane via Surface-Initiated Atom Transfer Radical Polymerization and Hydrolysis of Poly（glycidylmethacrylate）

Poly（glycidylmethacrylate） （PGMA） brushes were grafted from chloromethylated polysulfone （CMPSF） mem- brane surface by surface-initiated atom transfer radical polymerization （S1-ATRP）, and the grafting was followed by hydrolysis of epoxy groups in the grafting chains to improve the membrane＇s hydrophilie property. Fourier trans- form infrared spectroscopy （FT-IR） and X-ray photoelectron spectroscopy （XPS） measurements confirmed the suc- cessful grafting and hydrolysis of PGMA. The grafting degree of the monomer, measured by periodic acid titration and gravimetric analysis, increased linearly with the polymerization time, while the static water contact angle of the membrane grafted with PGMA or hydrolyzed PGMA linearly decreased. In comparison with the PGMA-grafted membranes, the hydrolyzed PGMA-grafted membranes possess stronger hydrophilicity as indicated by their contact angle and hydration capacity, and as a result they have an improved antifouling property. Therefore, the control of the hydrophilicity of PSF membrane could be realized through adjusting the polymerization time and transforming the functional groups in the grafting chain.

Hydrophilic phytosterol derivatives: A short review on structural modifications, cholesterol-lowering activity and safety

Phytosterols have received extensive attention owing to their excellent cholesterol-lowering activity and the role in cardiovascular diseases prevention. However, poor solubility in both oil and water limited the application of free phytosterols in the food industry. Chemical or enzymatic modifications were effective to improve the physicochemical properties as well as the bioavailability and cholesterollowering activity of phytosterols. Higher oil solubility and lower melting point of phytosterols have been achieved by esterification and transesterification with fatty acids and triacylglycerols so as to enhance the bioavailability, reduce formation of precipitates, and improve the sensory quality of products.While the researches on the improvement on its water solubility is a hot topic. Hydrophilic phytosterol derivatives have promising applications in the food industry because most of foods belong to aqueous matrix. Hydrophilic modification is useful and meaningful for phytosterols in both industrial and commercial applications. This review mainly highlights the hydrophilic phytosterol derivatives in the following aspects:(i) hydrophilic modifications of phytosterols by coupling with various polar components;(ii) cholesterol-lowering activity and possible molecular mechanisms of hydrophilic phytosterol derivatives on reducing serum cholesterol level;and(iii) safety evaluation of hydrophilic phytosterol derivatives in cell-culture studies, animal models and clinical trials.

Amino-functionalized UiO-66-doped mixed matrix membranes with high permeation performance and fouling resistance

For the reduction of bovine serum proteins from wastewater,a novel mixed matrix membrane was prepared by functionalizing the substrate material polyaryletherketone(PAEK),followed by carboxyl groups(C-SPAEKS),and then adding amino-functionalized UiO-66-NH_(2)(Am-UiO-66-NH_(2)).Aminofunctionalization of UiO-66 was accomplished by melamine,followed by an amidation reaction to immobilize Am-UiO-66-NH_(2),which was immobilized on the surface of the membrane as well as in the pore channels,which enhanced the hydrophilicity of the membrane surface while increasing the negative potential of the membrane surface.This nanoparticle-loaded ultrafiltration membrane has good permeation performance,with a pure water flux of up to 482.3 L·m^(-2)·h^(-1) for C-SPAEKS/AmUiO-66-NH_(2) and a retention rate of up to 98.7%for bovine serum albumin(BSA)-contaminated solutions.Meanwhile,after several hydrophilic modifications,the flux recovery of BSA contaminants by this series of membranes increased from 56.2%to 80.55%of pure membranes.The results of ultra-filtration flux time tests performed at room temperature showed that the series of ultrafiltration membranes remained relatively stable over a test time of 300 min.Thus,the newly developed mixed matrix membrane showed potential for high efficiency and stability in wastewater treatment containing bovine serum proteins.

Amine-functionalized metal organic framework@graphene oxide as filler in PAEK-containing carboxyl group membrane for ultrafiltration with ultra-high permeability and strong fouling resistance

Achieving high fouling resistance and permeability using membrane separation technology in water treatment processes remains a challenge.In this work,a novel mixed-matrix membrane(MMM)(poly(arylene ether ketone)[PAEK]-containing carboxyl groups[PAEK-COOH]/UiO-66-NH_(2)@graphene oxide[GO])with superb fouling resistance and high permeability was prepared by the nonsolvent-induced phase separation method,by in-situ growth of UiO-66-NH_(2) on the GO layer,and by preparing hydrophilic PAEK-COOH.On the basis of the structure and performance analysis of the MMM,the maximum water flux reached 591.25 L·m^(-2)·h^(-1) for PAEK-COOH/UiO-66-NH_(2)@GO,whereas the retention rate for bovine serum albumin increased from 85.40%to 94.87%.As the loading gradually increased,the hydrophilicity of the MMMs increased,significantly enhancing their fouling resistance.The strongest anti-fouling ability observed was 94.74%,which was 2.02 times greater than that of the pure membrane.At the same time,the MMMs contained internal amide and hydrogen bonds during the preparation process,forming a cross-linked structure,which further enhanced the mechanical strength and chemical stability.In summary,the MMMs with high retention rate,strong permeability,and anti-fouling ability were successfully prepared.

Preparation of Hydrophilic and Shrink-Proofing Wool Fabrics Through Thiol-Ene Click Chemistry Reaction

To improve shrink-proofing performance and hydrophilicity of wool fabrics, the wool fibers were modified by poly(ethylene glycol) dimethacrylate(PEGDMA) through thiol-ene click chemistry reaction. Firstly, wool fabrics were reduced at room temperature with a high-efficiency disulfide bond reducing agent, tris(2-carbonxyethyl) phosphine hydrochloride(TCEP). Then the thiol-ene click chemistry reaction was initiated by dimethyl 2, 2’-azobis(2-methylpropionate)(AIBME) through the heating method. Fourier transform infrared(FTIR) spectroscopy, Raman spectroscopy, and scanning electron microscopy test results all showed that PEGDMA was successfully grafted onto wool fabric surface. Physical properties, hydrophilicity, and shrink-proofing performance were assessed. The wetting time of PEGDMA grafted wool fabrics decreased to about 3 s. After being grafted with PEGDMA, the felting shrinkage of wool fabrics rapidly decreased to about 8%. The anti-pilling properties of wool fabrics were also greatly improved to 5 class after 2 000 times of friction. Meanwhile, the load retention rate of fabrics could reach 90%. It provides a method of wool modification to improve hydrophilicity and anti-felting performance.

Improved blending strategy for membrane modification virtue of surface segregation using surface-tailored amphiphilic nanoparticles

Membrane modification is one of the most feasible and effective solutions to membrane fouling proble.m which tenaciousl.y hampers .the furher au .gmentation of me .rnbrane sep.aration technology.Blending modification with nanoparticles （NPs）, owing to the convenience of being incorporated in established membrane.p.rodu. ction lines, possesses an advantag, eous viability in practical applications.However, the existing blending strategy suffers from a low utilization efficiency due to NP encasement by membrane matrix. The current study proposed an improved blending modification approach with amphiphilic NPs （aNPs）, which were prepared through silanization using 3-（Trimethoxysilyl）propyl methacrylate （TMSPMA） as coupling agents and ZnO or SiO2 as pristine NPs （pNPs）, respectively.The Fourier transform infrared and X-ray photoelectron spectroscopy analyses revealed thepresence of appropriate organic components in both the ZnO and SiO2 aNPs, which verified the success of the silanization process. As compared with the pristine and conventional pNP-blended membranes, both the ZnO aNP-blended and SiO2 aNP-blended membranes with proper silanization （100% and 200% w/w） achieved a significantly increased blending efficiency with more NPs scattenng on the internal and external membrane surfaces under scanning electron microscope observation. This improvement contributed to the increase of membrane hydrophilicity. Nevertheless, an extra dosage of the TMSPMA led to an encasement of NPs, thereby adversely affecting the properties of the resultant membranes. On the basis of all the tests, 100% （w/w） was selected as the optimum TMSPMA dosage for blending modification for both the ZnO and SiO2 types.