Applications Of Macromolecular Assembly In Spherical Polyelectrolyte Brush Film And Oil-flow Modifier

Macromolecular assembly is regarded as a new way of approaching ordered-packing macromolecular by non-covalent bonds. And it has great potential in application area owing to controllable advantage. This thesis aims to prepare nano-sized spherical polyelectrolyte brush (SPB) film and poly (maleic acid alkylamide-co-α-olefin)(MAC) comb-type copolymers to expand the research and development of macromolecular assembly. Nano-sized SPB film preparation is based on assembly of polyelectrolyte chains on the core and SPBs on the porous, while MAC comb-type copolymers preparation is based on assembly of MAC with paraffin and asphaltene.SPB is first synthesized by photo-emulsion polymerization. And then SPB films are prepared by packing, phase-inversion and spin-coating respectively. PS (polystyrene)-PAA (polyacrylic acid) brushes are assembled onto microporous polyethersulfone (PES) membrane successfully with filter device. The SPB arrays have a narrow size distribution and serve as channels for size sieving. Meanwhile, MAC comb-type copolymers are synthesized by copolymerization of α-olefins and maleic anhydride followed by amidation with alkylamine. Non-polar side chains assemble with long chain n-paraffins and co-crystallize, while polar carboxyl and amide groups interact with asphaltenes to prevent their aggregation upon cooling. The main work is described as follows:Characterization methods such as SEM, pure water flux are employed on SPB film. SPB packing film is easy to modify and PS-PAA brushes serve as nano-sized screening channels, which lead to narrower pore size distribution. The maximum pore size decreases as mean diameter of SPB decreases. This is due to the cubic closest packing occupying the space.The properties of SPB films prepared by phase-inversion method are related to glass transition temperature of the cores and chains of SPB. PS-PAA brush film is easy to crack while PB-PAA brush film not. The mixed film shows higher tensile strength and lower water absorption as content of PS increases or AA decreases. This is because lower glass transition temperature allows easier movement of polymer chains. The SPB film prepared by spin-coating is able to form monolayer and close packing when spin-coating speed is more than3000r/min. The film thickness decreases as spin-coating speed increases. Rheology and optical microscopy measurement show MAC copolymers can improve the cold flow ability by reducing yield stress and crystals size. MAC with longer side chain showed better result. MACs can either assemble with long chain n-paraffins or co-crystallize by the non-polar side chains. The carboxyl and amide groups interact with polar aromatic asphaltenes to prevent their aggregation upon cooling.