Gas Permeation Capabilities of PIM-Pyridine based Self-Standing Membranes

Abstract

High performance membrane materials, such as high free volume Polymers of Intrinsic Microporosity (PIMs), have been extensively examined for their potential gas separation performance. This research explores the possibility of PIM-Pyridine (PIM-Py), a less investigated PIM, as a potential material for CO2 separations. This work looks at standardising the synthesis of high molar mass PIM-Py polymers that could be cast into self-standing membranes. A low temperature and a high temperature method were investigated for this purpose and a range of reactions were conducted at different temperatures. Samples of PIM-1, the archetypal PIM, were also synthesised using these two methods and used as references for comparison. The polymers were characterised through various techniques and their topologies examined. The structures present in each polymer were related to their single and mixed gas permeation performance as self-standing membranes. Gas separation performance was evaluated using both single gas (CO2, N2 and CH4) and 50%:50% CO2:CH4 binary mixture at a feed pressure difference of 2 bar, at 25°C. Single gas CO2/N2 and CO2/CH4 selectivities of α = 49 and α = 24, respectively, were found for one PIM-Py sample having the highest network content, estimated from filtration experiments, which surpassed the newly defined 2019 McKeown-Jansen upper bound. Ageing studies on the PIM-Py polymer shows that the same sample held its single gas performance above the 2019 upper bound for over 140 days. Tetrazole modification to PIM-Pyridine were attempted to improve the gas permeation through adding CO2-philic groups to the polymer. The results show that self-standing membranes of PIM-Py having the right amount and kind of network, integrated appropriately, show promising gas permeation performance for CO2 capture and separation.

Date of Award	31 Dec 2020
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Peter Quayle (Supervisor) & Peter Budd (Supervisor)