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Title: Polymer materials for the encapsulation and degradation of chemical warfare agents
Author: Wright, Alexander Joseph
Awarding Body: University of Kent
Current Institution: University of Kent
Date of Award: 2018
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Superabsorbent polymer hydrogel networks are found in everyday life, such as in nappies and spill kits. This research would focus on the development of a highly absorbent, catalytically active polymer system, for the encapsulation and degradation of organic materials and chemical warfare agents (CWAs) such as VX and sulfur mustard (HD). The superabsorbent nature of a series of styrene based polyelectrolyte networks, crosslinked with divinylbenzene, were examined. The electrolytic nature of the networks was established through the introduction of a quaternary ammonium ionic monomer at increasing mol% weighting. The resulting net-poly(styrene-co-4-vinylbenzyl trihexylammonium chloride-co-divinylbenzene) systems were studied for their ability to absorb common solvents. The swelling performance was then correlated with various physical properties including dielectric and solubility parameters. The predicted swelling degrees of additional solvents were calculated and showed good similarity to experimental results. The swelling behaviour of CWAs in this system was examined and a suitable simulant for HD and VX was determined from these results. In an attempt to increase the swelling of the CWAs, alternative low polarity monomers were screened using predictions from solubility parameter data. Alternative anions to the chloride were also screened in an attempt to increase the swelling performance in the electrolytic polymers. A poly(styrene-co-vinylbenzyl chloride-co-divinylbenzene) lightly crosslinked poly high internal phase emulsion (pHIPE) was also developed. The record breaking absorption capacities of a variety of CWAs, including sulfur mustard (HD) (Q = 40) and V-series (VM, VX, i-Bu-VX, n-Bu-VX) of nerve agents (Q ≥ 45) and a simulant, methyl benzoate (Q = 55) were observed in this polymer. The polymer showed fast swelling, (< 5 min to total absorption) and the ability to swell both from a monolithic state and from a compressed state. The polymer was then produced on increased scale (10 kg). The absorbent pHIPEs were further adapted to include a catalytically active MOF inside the pores at 25 wt%, in addition to internal buffer as part of the polymer matrix. This combination of changes led to a polymer sorbent which was able to swell and degrade a VX simulant (methyl paraoxon) and VX in situ without the need for external buffering. Modification of the styrene based pHIPE to include increasing amounts of myrcene was also investigated briefly as an approach to creating an elastomeric oil/CWA absorption capability, using a greener feedstock. To facilitate this, an alternative crosslinking monomer was synthesised and found to be an effective linker unit.
Supervisor: Holder, Simon Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available