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West Bromwich, United Kingdom

Pullan N.,Aston University | Liu M.,Robinson Brothers Ltd. | Topham P.D.,Aston University
Polymer Chemistry | Year: 2013

Controlled polymerization of 2-chloro-1,3-butadiene using reversible addition-fragmentation chain transfer (RAFT) polymerization has been demonstrated for the first time. 2-Chloro-1,3-butadiene, more commonly known as chloroprene, has significant industrial relevance as a crosslinked rubber, with uses ranging from adhesives to integral automotive components. However, problems surrounding the inherent toxicity of the lifecycle of the thiourea-vulcanized rubber have led to the need for control over the synthesis of poly(2-chloro-1,3-butadiene). To this end, four chain transfer agents in two different solvents have been trialed and the kinetics are discussed. 2-Cyano-2-propylbenzodithioate (CPD) is shown to polymerize 2-chloro-1,3- butadiene in THF, using AIBN as an initiator, with complete control over the target molecular weight, producing polymers with low polydispersities (M w/Mn < 1.25 in all cases). © 2013 The Royal Society of Chemistry. Source

Shen Y.,Queens University of Belfast | Maamor A.,Queens University of Belfast | Abu-Dharieh J.,Queens University of Belfast | Thompson J.M.,Queens University of Belfast | And 5 more authors.
Organic Process Research and Development | Year: 2014

Despite the numerous advantages of continuous processing, high-value chemical production is still dominated by batch techniques. In this paper, we investigate options for the continuous dehydrogenation of 1,2,3,4- tetrahydrocarbazole using a trickle bed reactor operating under realistic liquid velocities with and without the addition of a hydrogen acceptor. Here, a commercial 5 wt % Pd/Al2O3 catalyst was observed to slowly deactivate, hence proving unsuitable for continuous use. This deactivation was attributed to the strong adsorption of a byproduct on the surface of the support. Application of a base washing technique resolved this issue and a stable continuous reaction has been demonstrated. As was previously shown for the batch reaction, the addition of a hydrogen acceptor gas (propene) can increase the overall catalytic activity of the system. © 2014 American Chemical Society. Source

Berry K.,Aston University | Berry K.,Robinson Brothers Ltd. | Liu M.,Robinson Brothers Ltd. | Chakraborty K.,Robinson Brothers Ltd. | And 4 more authors.
Rubber Chemistry and Technology | Year: 2015

An investigation into the mechanism by which ethylene thiourea (ETU) cross-links polychloroprene (CR) in combination with zinc oxide (ZnO) was undertaken. This was achieved through an examination of the mechanisms of crosslinking CR with ETU and ZnO separately and in unison. Spectroscopic and physical characterization techniques were employed to probe the cross-linking mechanisms of CRusing other standard rubber accelerators and model compounds with analogous structures and functionalities to ETU. These investigations have resulted in the proposal of a new mechanism by which ETU and ZnO can synergistically cross-link CR, in addition to providing new evidence to support concomitant mechanisms already published for cross-linking CR. Source

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