title: Preparation and Characterization of Hydrophilically Modified PVDF Membranes by a Novel Nonsolvent Thermally Induced Phase Separation Method.
abstract: In this study, a nonsolvent thermally-induced phase separation (NTIPS) method was first proposed to fabricate hydrophilically-modified poly(vinylidene fluoride) (PVDF) membranes to overcome the drawbacks of conventional thermally-induced phase separation (TIPS) and nonsolvent-induced phase separation (NIPS) methods. Hydrophilically-modified PVDF membranes were successfully prepared by blending in hydrophilic polymer polyvinyl alcohol (PVA) at 140 °C. A series of PVDF/PVA blend membranes was prepared at different total polymer concentrations and blend ratios. The morphological analysis via SEM indicated that the formation mechanism of these hydrophilically-modified membranes was a combined NIPS and TIPS process. As the total polymer concentration increased, the tensile strength of the membranes increased; meanwhile, the membrane pore size, porosity and water flux decreased. With the PVDF/PVA blend ratio increased from 10:0 to 8:2, the membrane pore size and water flux increased. The dynamic water contact angle of these membranes showed that the hydrophilic properties of PVDF/PVA blend membranes were prominently improved. The higher hydrophilicity of the membranes resulted in reduced membrane resistance and, hence, higher permeability. The total resistanceRtof the modified PVDF membranes decreased significantly as the hydrophilicity increased. The irreversible fouling related to pore blocking and adsorption fouling onto the membrane surface was minimal, indicating good antifouling properties.
authors.affiliation: Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, China. huningen@163.com.
authors.forename: Ningen
authors.initials: N
authors.lastname: Hu
authors.affiliation: Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, China. xiaotonghu@nbu.edu.cn.
authors.forename: Tonghu
authors.initials: T
authors.lastname: Xiao
authors.affiliation: Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, China. caixinhai@ytu.edu.cn.
authors.forename: Xinhai
authors.initials: X
authors.lastname: Cai
authors.affiliation: Tri-Tech Chemical Co. Pty Ltd, 5-11 Normanby Ave, Sunshine VIC 3020, Australia. lining@ttcc.com.au.
authors.forename: Lining
authors.initials: L
authors.lastname: Ding
authors.affiliation: Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, China. fuyuhuafyh@163.com.
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Fu
authors.affiliation: Institute for Sustainability and Innovation, College of Engineering and Science, Victoria University, P.O. Box 14428, Melbourne 8001, Australia. xing.yang@vu.edu.au.
authors.forename: Xing
authors.initials: X
authors.lastname: Yang
keywords: PVDF/PVA blend membrane; antifouling property; hydrophilic modification; membrane resistance; nonsolvent thermally-induced phase separation (NTIPS)