Dick, Caroline M. and Liggat, John J. and Snape, Colin (2001) Solid state 13C NMR study of the char forming processes in polychloroprene. Polymer Degradation and Stability, 74 (3). pp. 397-405. ISSN 0141-3910Full text not available in this repository. (Request a copy from the Strathclyde author)
Polychloroprene, also known as neoprene, is an elastomer commonly utilised in the electrical and automobile industries. Its degradation is known to occur predominantly in a two stage process: HCl is lost in the initial step, whilst the second step involves the production of volatile hydrocarbons through chain scission. In this paper we describe the use of solid state 13C NMR as a probe for structural changes in the condensed phase during these degradative steps. Cross polarisation-magic angle spinning (CP-MAS) analysis of virgin polychloroprene and a series of samples degraded at temperatures between 275 and 550 °C reveals that as degradation becomes more advanced there is a steady loss of sp3 carbon with a commensurate growth in sp2 carbon. The bulk of the chlorine loss occurs by 350 °C with the aliphatic carbon lost by 550 °C, by which temperature the residue is essentially aromatic carbon. Dipolar dephasing experiments show that this residue is essentially a network of, on average, tri-substituted phenyl rings.
|Keywords:||Polychloroprene, Thermal degradation, Char formation, Solid state 13C NMR, DSC, TGA, Chemistry, Materials Chemistry, Polymers and Plastics, Mechanics of Materials, Condensed Matter Physics|
|Subjects:||Science > Chemistry|
|Department:||Faculty of Science > Pure and Applied Chemistry|
|Depositing user:||Mr Derek Boyle|
|Date Deposited:||08 Mar 2006|
|Last modified:||06 Jan 2017 03:05|