磺基甜菜碱接枝共聚物共混改性聚砜超滤膜的研究

Study on Polysulfone-g-Sulfobetaine Methacrylate/-Polysulfone Blended Ultrafiltration Membranes

两性离子具有超强的亲水性和抗污染能力,通常用于易污染疏水材料表面的接枝改性,提高其亲水性和抗污染性,但该接枝改性反应一般发生在固液反应体系中,导致反应效率低和难以工业化放大等缺陷。今以聚砜(PSU)接枝磺基甜菜碱甲基丙烯酸酯(SBMA)为研究对象,以二甲亚砜(DMSO)为溶剂,使该接枝反应在均相体系下发生。该反应以PSU上预先接枝的氯甲基为原子转移自由基聚合反应(ATRP)引发基团,在氯化亚铜(Cu Cl)的催化下合成PSU-g-SBMA共聚物。元素分析和红外检测的结果表明,随着SBMA添加量的提高,共聚物接枝率呈上升趋势,且在SBMA:PSU摩尔比为5:1时,接枝率达到最高值61.9%。随后,将制得的PSU-g-SBMA与PSU共混,经由相转化法制备超滤膜,通过表征发现该膜呈典型的指状大孔结构,且牛血清白蛋白(BSA)截留率大于90%,纤维蛋白截留率大于99%。共混膜的接触角和静态蛋白吸附量均比纯聚砜膜有极大下降,且通量恢复率有很大提升,表明PSU-g-SBMA共混改性可有效提高PSU膜的亲水性和抗污染能力。综上,本研究阐述了一种两性离子接枝共聚物共混改性超滤膜的新方法,克服了两性离子固液接枝反应体系的缺陷,有助于将来实现两性离子改性超滤膜的工业化生产。

Zwitterionic molecules, as a sort of molecules with super hydrophilicity and antifouling property, have been usually grafted onto the hydrophobic surfaces to improve the hydrophilicity. Such grafting reactions were conducted in a solid-liquid system, which has disadvantages such as low reaction efficiency and difficulty in scale-up. In this study, dimethyl sulfoxide （DMSO） was used to be the solvent for both sulfobetaine methacrylate （SBMA） and polysulfone （PSU）. In such homogeneous system, SBMA was grafted onto PSU with chloromethyl group as initiator. According to Fourier transform infrared spectroscopy （ATR-FTIR） and elemental analysis, a high grafting yield of 61.9 % was obtained at the molar ratio of SBMA：PSU=5：1. Then, the PSU-g-SBMA was blended with PSU to prepare the ultrafiltration membranes via immersion precipitation method. It was found that the membranes showed finger-like pores in the section surface and had a BSA（bovine serum albumi） rejection of 〉90 %. And most importantly, the blended membranes showed greatly improved hydrophilicity and antifouling property as indicated by contact angle and static BSA adsorption. In conclusion, this study overcame the disadvantages of grafting reaction in solid-liquid system and facilitated the application of zwitterionic molecules for membrane modification.