Abstract:
Polymers of intrinsic microporosity (PIM-1) synthesised by Budd and McKeown is well known for its application as gas separation membrane due to its excellent performance with high permeability and moderate selectivity. Therefore, modifications of this type of polymer has been developed as a means for improving performance. Specifically, there is a lot of attention on the nitrile group in PIM-1 as it is the most convenient reaction site to modify to various functional groups. Among these, the most highly desirable functional group is carboxylic acid due to its ability to undergo decarboxylation for crosslinking, polymer alloying and ionomer formation. The desired carboxylated PIM-1 (C-PIM) has been reported as the product of extensively base-catalysed hydrolysis of PIM-1. Furthermore, an important finding from a recent update on synthesis of C-PIM has proved that the peaks rise from the COOH in 1H NMR from the paper was mislabelled. Herein, monomer modification synthesis route and postsynthesis modification route were performed to obtain C-PIM. In the monomer modification route, TTSBI is polymerised with the different functionalised tertrafluoro monomer such as acid, methyl ester, t-butyl ester and bromine. The formed intermediate polymer is then further synthesis to obtain C-PIM. In the post-synthesis modification route, an acid hydrolysis of PIM- 1 was studied. A novel fast two-step post-synthesis modification to obtain C-PIM was performed. PIM-1 is first converted to PIM-CONH2 via hydrogen peroxide and PIM-CONH2 to C-PIM-NO via nitrous acid reaction. A combination of FTIR, 1H, 13C NMR, elemental analysis, UV-Vis, GPC, TGA, and TGA-MS were used to characterise the synthesised products.
