多壁碳纳米管(MWNT)/聚丙烯腈(PAN)共混复合膜的制备及性能研究

Fabrication and characterization of raw multi-walled carbon nanotube(MWNT)/polyacrylonitrile(PAN) blending membrane

为了提高PAN膜的性能,首先用超声分散将MWNT溶解在N,N-二甲基甲酰胺(DMF)中,之后加入PAN,通过相转化法制备MWNT/PAN共混复合膜.研究表明,随着MWNT添加量的增加,共混膜的拉伸强度呈先增加后减少的趋势,从2.2 MPa上升到2.4MPa后拉伸强度开始下降.这是由于适量的MWNT起到物理交联的作用,而添加过多,导致MWNT团聚,降低共混膜的拉伸强度.断裂伸长率随着添加量的增加缓慢下降,从20%下降到18.6%;水通量随着MWNT添加量的增加呈先增加后减少的趋势,在添加量为质量分数1%时较纯PAN膜增加了近60%,后水通量呈下降趋势,但是仍然高于PAN膜.这一变化趋势是由膜孔结构的变化和MWNT堵孔共同作用的结果.共混膜的截留率也呈先增加后减少的趋势.当MWNT添加量为4%时,截留率达到最大值96%.抗污染性能测试结果显示膜的水通量恢复率随着添加量的增加呈先增后减少的趋势,在添加量为7%时,达到70%.抗污染性能提高的原因是膜的润湿性得到改善.

MWNT was dissolved in DMF by ultrasonication,then the PAN was blended and mixed by mechanical stirring to improve the properties of the PAN membrane,The MWNT/PAN blending membrane was fabricated by phase inversion method.It was found that the tensile strength of the blending membranes was increased then decreased with the increasing content of MWNT,Tensile strength reached maximum of 2.4 MPa at the 7%of MWNT loading.The MWNT serves as the physical linking at the small amount,while MWNT tends to agglomerate at the excessive amount.Elongation decreased slightly with the increased MWNT,from 20%to 18.6%.The water permeability increased by 60%at 1%loading of MWNT,but decreased with the content of the MWNT,which attributed to the combined efforts by delaying solvent and non-solvent exchange and pore blocking.Rejection reached the maximum at 96% when 4%MWNT was added.From the anti-fouling test,due to the enhanced wettability,the flux recovery ratio increased and then decreased with the content of MWNT.When the MWNT content was 7%,the flux recovery ratio attained maximum of 70%.