Colour stability of oil-heat treated black locust and poplar wood during short-term UV radiation

Robert Nemeth, Laszlo Tolvaj, Miklos Bak, Tibor Alpar

Research output: Contribution to journalArticle

7 Citations (Scopus)


Black locust (Robinia pseudoacacia L) samples with high extractive content and poplar (Populus × euramericana cv. Pannónia) samples with low extractive content were chosen for the test. The specimens were thermally treated at 160 and 200 °C in sunflower oil for 2, 4, and 6 h then irradiated by a strong UV emitter mercury lamp up to 36 h. The effects of thermal treatment and UV radiation were monitored by colour measurement. The results indicated that the extractives play an important role in the photodegradation of oil-heat treated wood. Thermal treatments reduced the lightness change effect of photodegradation. The oil-heat treated black locust samples showed similar photodegradation properties independently on the thermal pre-treatment time and temperature. The redness of oil-heat treated black locust samples hardly changed during UV radiation proving the photostability of the thermally modified extractives. The redness change of poplar samples caused by UV radiation was partly determined by the temperature of thermal treatment (darkening and lightening also happened). The yellow colour change of the investigated samples showed that the lignin of thermally modified wood undergoes similar photodegradation as that of the untreated natural wood.

Original languageEnglish
Pages (from-to)287-292
Number of pages6
JournalJournal of Photochemistry and Photobiology A: Chemistry
Publication statusPublished - Oct 1 2016


  • Black locust
  • Extractives
  • Heat treatment
  • Poplar
  • UV radiation

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Physics and Astronomy(all)

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