Catalytic thermal decomposition of polyamides and polyurethanes mixed with acidic zeolites

János Bozi, Marianne Blazsó

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The purpose of this work was to examine the pyrolysis products derived from zeolite-polyamide and zeolite-polyurethane mixtures prepared in different ratios in order to elucidate the chemical reactions taking place under pyrolysis of these polymers in the presence of acidic Y zeolites (ultra stabilized HY (HUSY) and NH4NaY). Therefore 5:1, 3:1, and 1:1 ratios of zeolite and nitrogen-containing polymer (polyamides and polyurethanes) mixtures were pyrolysed at 500°C in a micro-pyrolyser on-line coupled with GC/MS. The products and product distribution of zeolite-polymer mixtures indicate that the amount of catalysts significantly affects the pyrolysis product distribution. In case of zeolite-PA-6,6 1:1 mixtures hexanedinitrile is the main pyrolysis product indicating that the thermal decomposition of PA-6,6 via cis-elimination is enhanced. Main pyrolysis products of zeolite-PA-6 mixtures of 1:1 ratio are dihydro-azepine isomers that are the dehydrated derivatives of ε-caprolactam. Pyrolysis of 1:1 zeolite-PA-12 mixtures leads to the promoted formation of dehydrated cyclic monomer isomers (azacyclotrideca-dienes) . For zeolite-PUR 1:1 mixtures it was concluded that MDI decomposition to N-containing aromatics is enhanced, while the polyester and polyether segments degrade to monomer type products and to aromatics. For all zeolite-polymer mixtures increasing ratio of catalysts leads to increased amount of aromatics (benzene and naphthalene compounds) and light unsaturated hydrocarbons, while the amount of main products of 1:1 mixtures decreases.

Original languageEnglish
Pages (from-to)189-197
Number of pages9
JournalJournal of Analytical and Applied Pyrolysis
Volume97
DOIs
Publication statusPublished - Sep 2012

Keywords

  • Catalytic pyrolysis
  • Polyamide
  • Polyurethane
  • Pyrolysis-GC/MS
  • Y zeolite

ASJC Scopus subject areas

  • Analytical Chemistry
  • Fuel Technology

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