Preparation and properties of polybenzodioxane PIM-1 and its copolymers with poly(ethylene glycol)

摘要

This thesis describes the synthesis of soluble Polymer of Intrinsic Microporosity (PIM-1), fluoro-endcapped PIM-1 (F-PIM-1) and copolymers of F-PIM-1 with poly(ethylene glycol) monomethyl ether (MeOPEG). The main aim of the project was to alter the porosity of microporous PIM-1 in three ways: (a) synthesis of copolymers of F-PIM-1 with MeOPEG (b) blending of PIM-1 with MeOPEG in various proportions; and (c) adsorption of MeOPEG from aqueous solution byPIM-1. PIM-1 and F-PIM-1 were synthesized by step growth polymerization of tetrafluoroterephthalonitrile (TFTPN) with 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethyl-1,1'-spirobisindane (THSB), using the conventional method and a newly reported high shear mixing method. F-PIM-1 oligomers were then coupled to poly(ethylene glycol) monomethyl ether (MeOPEG). The products were analyzed by NMR, IR, MALDI ToF MSS, TGA and polystyrene based GPC as well as multidetector GPC techniques. The high shear technique generally produced high molar mass products and yields. This method was also more successful for copolymerization.Blending of PIM-1 and MeOPEG in different proportions resulted in macrophase separation. Copolymer products were used to facilitate mixing of blends (as compatibilizers), however only 5% of MeOPEG could be solubilised into a PIM-1 phase. The effect of compatibilizer was found to be affected by interaction between PIM-1 and copolymer. However, N2 adsorption studies showed that after thermal removal of MeOPEG, PIM-1 regained stable porosity with significant BET surface area.Fluorescence studies were aimed at applications of PIM-1 and copolymers in sensors. PIM-1 and copolymers, spin-coated on the polyester-based substrate Melinex, were studied with and without methanol treatment in an environment of different solvent vapours. The effect of time and volume on wavelength shift and change in intensity was studied. Polar solvents tended to cause a red shift with decrease in intensity while less polar solvents behaved otherwise. Based on fluorescence experiments, solvent profiles for PIM-1 and copolymers were established.