Trewin A.,Center for Materials Discovery
CrystEngComm | Year: 2010
We present here structural models for three distinct crystalline polyamic acids which are potential precursors to polyimide networks. In each case, the two different isomeric forms are considered. © 2010 The Royal Society of Chemistry.
Martin C.F.,CSIC - National Coal Institute |
Stockel E.,University of Liverpool |
Clowes R.,Center for Materials Discovery |
Adams D.J.,University of Liverpool |
And 5 more authors.
Journal of Materials Chemistry | Year: 2011
Hypercrosslinked polymers (HCPs) synthesized by copolymerisation of p-dichloroxylene (p-DCX) and 4,4′-bis(chloromethyl)-1,1′-biphenyl (BCMBP) constitute a family of low density porous materials with excellent textural development. Such polymers show microporosity and mesoporosity and exhibit Brunauer-Emmett-Teller (BET) surface areas of up to 1970 m2 g-1. The CO2 adsorption capacity of these polymers was evaluated using a thermogravimetric analyser (atmospheric pressure tests) and a high-pressure magnetic suspension balance (high pressure tests). CO2 capture capacities were related to the textural properties of the HCPs. The performance of these materials to adsorb CO2 at atmospheric pressure was characterized by maximum CO2 uptakes of 1.7 mmol g-1 (7.4 wt%) at 298 K. At higher pressures (30 bar), the polymers show CO 2 uptakes of up to 13.4 mmol g-1 (59 wt%), superior to zeolite-based materials (zeolite 13X, zeolite NaX) and commercial activated carbons (BPL, Norit R). In addition, these polymers showed low isosteric heats of CO2 adsorption and good selectivity towards CO2. Hypercrosslinked polymers have potential to be applied as CO2 adsorbents in pre-combustion capture processes where high CO2 partial pressures are involved. © 2011 The Royal Society of Chemistry.
Jiang S.,Center for Materials Discovery |
Jones J.T.A.,Center for Materials Discovery |
Hasell T.,Center for Materials Discovery |
Blythe C.E.,Center for Materials Discovery |
And 3 more authors.
Nature Communications | Year: 2011
The main strategy for constructing porous solids from discrete organic molecules is crystal engineering, which involves forming regular crystalline arrays. Here, we present a chemical approach for desymmetrizing organic cages by dynamic covalent scrambling reactions. This leads to molecules with a distribution of shapes which cannot pack effectively and, hence, do not crystallize, creating porosity in the amorphous solid. The porous properties can be fine tuned by varying the ratio of reagents in the scrambling reaction, and this allows the preparation of materials with high gas selectivities. The molecular engineering of porous amorphous solids complements crystal engineering strategies and may have advantages in some applications, for example, in the compatibilization of functionalities that do not readily cocrystallize. © 2011 Macmillan Publishers Limited. All rights reserved.