二次界面聚合法制备聚酰胺-脲-酰亚胺反渗透复合膜

Novel polyamide-urea-imide composite reverse osmosis membrane prepared via two-step interfacial polymerization

采用二次界面聚合法制备得到一种新型的聚酰胺-脲-酰亚胺反渗透复合膜。首先将关键功能单体5-异氰酸酯-异酞酰氯(ICIC)与4-甲基-间苯二胺(MMPD)经单面界面聚合形成初生态的基膜,之后将关键功能单体N,N′-二甲基间苯二胺(DMMPD)与初生态基膜上残留的ICIC及未反应完的酰氯基团(—COCl)进行二次界面聚合,再经热处理、水漂洗制得一种新型的聚酰胺-脲-酰亚胺(MMPD-ICIC-DMMPD)反渗透复合膜。采用傅里叶衰减全反射红外光谱(ATR-FTIR)和X射线光电子能谱分析了膜活性分离层的化学结构,利用扫描电镜(SEM)和原子力显微镜(AFM)观察了所成膜的表面形态,同时测试了膜的耐氯性能,并与单次聚合聚酰胺-脲(MMPD-ICIC)膜作对比。结果表明,采用二次界面聚合法在功能化基膜MMPD-ICIC上引入一超薄ICIC-DMMPD层,使得所成二次聚合膜MMPD-ICIC-DMMPD的活性分离层相对稍厚,表面更光滑,且亲水性和耐氯性能更好。

A novel polyamide-urea-imide composite reverse osmosis（RO）membrane was prepared via two-step interfacial polymerization.5-Isocyanato-isophthaloyl chloride（ICIC）as a key functional monomer first reacted with 4-methyl-m-phenylenediamine（MMPD）to prepare the initial RO membrane by the single-step interfacial polymerization technology,then the other key functional monomer N,N′-dimethyl-m-phenylenediamine（DMMPD）was polymerized with the remaining ICIC and acyl chlorine group（—COCl）of the initial RO membrane to obtain the new polyamide-urea-imide（MMPD-ICIC-DMMPD）composite RO membrane after heat curing and water rinse.The surface chemical structure of membrane active layer was analyzed by a combination of attenuated total reflectance infrared（ATR-IR）and X-ray photoelectronic spectroscopy（XPS）,the surface morphology of membrane was observed via scanning electronic microscopy（SEM）and atomic force microscope（AFM）,and the contact angle and chlorine resistance performance of membrane were also measured.The polyamide-urea（MMPD-ICIC）membrane via single-step polymerization was contrasted in all measurements.The result showed that due to the grafting of a super thin ICIC-DMMPD layer on the initial MMPD-ICIC membrane surface,the MMPD-ICIC-DMMPD membrane via two-step interfacial polymerization had smoother surface,slight thicker active separation layer,better hydrophilicity and resistance performance than the MMPD-ICIC membrane via singe-step interfacial polymerization.