Font Size: a A A

Control Of Intermolecular Weak Interaction For The Fabrication And Performance Study Of Antifouling Ultrafiltration Membranes

Posted on:2016-04-11Degree:MasterType:Thesis
Country:ChinaCandidate:X C FanFull Text:PDF
GTID:2311330485955065Subject:Chemical engineering
Abstract/Summary:PDF Full Text Request
Fabrication of high performance ultrafiltration membranes(high flux, antifouling and strong stability) is the basic way to solve membrane fouling and high cost problem. Surface segregation is an in situ modification method for fabricating antifouling membranes. Generally, in this approach, amphiphilic block copolymers, consisted of hydrophobic segments and hydrophilic segments, play dual roles of surface modification and pore-forming agent. And functional surface, such as antifouling surface and thermo-responsive surface, can be constructed by altering the chemical composition of hydrophilic segments of amphiphilic block copolymers. However, low permeation flux and weak stability of surface functional groups limit the large-scale application of surface segregation.To solve the above problems, PVC/PVF, PES/PEG-MTB and PES/PVF ultrafiltration membranes were fabricated with Polyvinylchloride(PVC) and Polyethersulfone(PES) as membrane bulk materials, and polyvinylformal(PVF) and m-trihydroxybenzene(MTB) as membrane modified materials. The influence of intermolecular weak interaction between membrane bulk materials and membrane modified materials, involving hydrophobic interaction, hydrogen bond interaction and hydrophobic and hydrogen bond synergistic interaction, on the chain behavior of membrane bulk materials during phase inversion process, the segregation behavior of membrane modified materials during surface segregation process and the residence stability of membrane modifier materials on membrane surface was researched.During phase inversion process, the hydrophobic interaction between membrane bulk materials and membrane modified materials would disturb the rearrangement of membrane bulk materials and delay the solidification behavior via crystallization, gelation, or vitrification, increasing the permeation flux; Hydrogen bond interaction would rarely affect permeation flux due to short interaction range; When hydrophobic interaction and hydrogen bond interaction both existed, hydrophobic interaction would close the range between membrane bulk materials and membrane modified materials to intensify the disturbance of hydrogen bond interaction to the rearrangement of membrane bulk materials, remarkablely increasing the permeation flux. During surface segregation process, the interaction between membrane bulk materials and membrane modified materials would remarkablely affect the segregation behavior of membrane modified materials: when the interaction was too weak, membrane modified materials would excessively segregate to the coagulation bath and there would be no surface modified effect; When the interaction was too strong, membrane modified materials would insufficiently segregate and similar modification effect would consume more membrane modified materials, increasing membrane fabrication cost. Moreover, the stronger interaction between membrane bulk materials and membrane modified materials, the stronger residence stability of membrane modified materials would be obtained, avoiding the loss of surface functional groups and improving membrane life.In conclusion, high performance ultrafiltration membranes with high flux, antifouling and strong stability could be fabricated through the rational design of membrane modified materials, controlling the interaction between membrane bulk materials and membrane modified materials.
Keywords/Search Tags:Ultrafiltration, Surface segregation, Hydrophobic interaction, Hydrogen bond interaction, Antifouling, High permeation flux, Stability
PDF Full Text Request
Related items