Crosslinking treatments for a commercially available aromatic polyamide reverse osmosis membrane were carried out to improve its chlorine resistance.The crosslinking agents including 1,6-hexanediol diglycidyl ether,ad...Crosslinking treatments for a commercially available aromatic polyamide reverse osmosis membrane were carried out to improve its chlorine resistance.The crosslinking agents including 1,6-hexanediol diglycidyl ether,adipoyl dichloride and hexamethylene diisocyanate ester with long flexible aliphatic chains and high reactivity with N-H groups were used in the experiments.Attenuated total reflective Fourier transform infrared spectra verified the successful preparation of highly crosslinked membranes by crosslinking treatments.It was suggested that the crosslinking agents were connected to membrane surface through the reactions with amine and amide Ⅱ groups,which is confirmed by surface charge measurements.Based on contact angle measurements,crosslinking treatments decreased membrane hydrophilicity by introducing methylene groups to membrane surface.With increasing amount of crosslinking agent molecules connected to membrane surface,the hydrolysis of unconnected functional groups of crosslinking agent produced polar groups and increased membrane hydrophilicity.The highly crosslinked membranes showed higher salt rejections and lower water fluxes as compared with the raw membrane.Since the active sites(N-H groups) vulnerable to free chlorine on membrane surface were eliminated by crosslinking treatments,the chlorine resistances of the highly crosslinked membranes were significantly improved by slighter changes in both water fluxes and salt rejections after chlorination.展开更多
Adopting Poly（ethylene glycol） adipate Dilpoly- （ethylene glycol）] adipate polydiglycol adipate glycol （PDAG）, 1,4-butanediol （BDO）, hydroxy silicone oil, methylene diphenyl diisocyanate （MDI） as the raw mat...Adopting Poly（ethylene glycol） adipate Dilpoly- （ethylene glycol）] adipate polydiglycol adipate glycol （PDAG）, 1,4-butanediol （BDO）, hydroxy silicone oil, methylene diphenyl diisocyanate （MDI） as the raw material, a new polyurethane elastic body can be made through prepolymerization. After measurement of the moisture permeability, adsorption quantity and mechanical properties of the membrane made with the elastic body, we also proofed its formula by infrared spectroscopy. The result showed that the moisture permeability of the membrane, with a certain intelligent thermotropic quality, will increase by 3 to 4 times when the temperature is between 25℃-45℃.展开更多
基金Supported by the National Natural Science Foundation of China （20676095）the Program of Introducing Talents of Discipline to Universities （B06006）
文摘Crosslinking treatments for a commercially available aromatic polyamide reverse osmosis membrane were carried out to improve its chlorine resistance.The crosslinking agents including 1,6-hexanediol diglycidyl ether,adipoyl dichloride and hexamethylene diisocyanate ester with long flexible aliphatic chains and high reactivity with N-H groups were used in the experiments.Attenuated total reflective Fourier transform infrared spectra verified the successful preparation of highly crosslinked membranes by crosslinking treatments.It was suggested that the crosslinking agents were connected to membrane surface through the reactions with amine and amide Ⅱ groups,which is confirmed by surface charge measurements.Based on contact angle measurements,crosslinking treatments decreased membrane hydrophilicity by introducing methylene groups to membrane surface.With increasing amount of crosslinking agent molecules connected to membrane surface,the hydrolysis of unconnected functional groups of crosslinking agent produced polar groups and increased membrane hydrophilicity.The highly crosslinked membranes showed higher salt rejections and lower water fluxes as compared with the raw membrane.Since the active sites(N-H groups) vulnerable to free chlorine on membrane surface were eliminated by crosslinking treatments,the chlorine resistances of the highly crosslinked membranes were significantly improved by slighter changes in both water fluxes and salt rejections after chlorination.
基金Acknowledgments： This work was supported in part by the National Natural Science Foundation of China （No. 20504023）.
文摘Adopting Poly（ethylene glycol） adipate Dilpoly- （ethylene glycol）] adipate polydiglycol adipate glycol （PDAG）, 1,4-butanediol （BDO）, hydroxy silicone oil, methylene diphenyl diisocyanate （MDI） as the raw material, a new polyurethane elastic body can be made through prepolymerization. After measurement of the moisture permeability, adsorption quantity and mechanical properties of the membrane made with the elastic body, we also proofed its formula by infrared spectroscopy. The result showed that the moisture permeability of the membrane, with a certain intelligent thermotropic quality, will increase by 3 to 4 times when the temperature is between 25℃-45℃.
