Solid state 13C NMR study of the char forming processes in polychloroprene

Caroline M. Dick, John J. Liggat, Colin Snape

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

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.
LanguageEnglish
Pages397-405
Number of pages8
JournalPolymer Degradation and Stability
Volume74
Issue number3
DOIs
Publication statusPublished - 2001

Fingerprint

Neoprene
Carbon
Nuclear magnetic resonance
solid state
nuclear magnetic resonance
carbon
Elastomers
degradation
Degradation
Magic angle spinning
cross polarization
Chlorine
automobiles
elastomers
Hydrocarbons
Automotive industry
metal spinning
chlorine
cleavage
hydrocarbons

Keywords

  • Polychloroprene
  • Thermal degradation
  • Char formation
  • Solid state 13C NMR
  • DSC
  • TGA

Cite this

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abstract = "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.",
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Solid state 13C NMR study of the char forming processes in polychloroprene. / Dick, Caroline M.; Liggat, John J.; Snape, Colin.

In: Polymer Degradation and Stability, Vol. 74, No. 3, 2001, p. 397-405.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Solid state 13C NMR study of the char forming processes in polychloroprene

AU - Dick, Caroline M.

AU - Liggat, John J.

AU - Snape, Colin

PY - 2001

Y1 - 2001

N2 - 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.

AB - 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.

KW - Polychloroprene

KW - Thermal degradation

KW - Char formation

KW - Solid state 13C NMR

KW - DSC

KW - TGA

UR - http://dx.doi.org/10.1016/S0141-3910(01)00174-4

U2 - 10.1016/S0141-3910(01)00174-4

DO - 10.1016/S0141-3910(01)00174-4

M3 - Article

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EP - 405

JO - Polymer Degradation and Stability

T2 - Polymer Degradation and Stability

JF - Polymer Degradation and Stability

SN - 0141-3910

IS - 3

ER -