Bark extractives from Pinus halepensis and Pinus brutia as constituents of wood products bonding agents 1. Effects of extraction on the extractive yield and the quantity of formaldehyde requirement in reaction of extractives with HCHO
1985
Kavvouras, K.P. (Ministry of Agriculture, Thessaloniki (Greece). Forest Research Inst.)
This paper describes the early stage of the research, which covered the methods of processing indigenous Pinus halepensis and Pinus brutia bark. The extraction procedure has great influence on yield and reactivity of extracts towards formaldehyde (hydroxylamine method). Hot water (80 deg C) extraction yields 34 % extracts from Pinus halepensis and about 27 % from Pinus brutia. Using different chemicals such as alkali and sulfite, higher extract yields can be achieved and polyphenoles with satisfactory reactivity can be extracted. Especially the extraction with a small amount of alkali considerably increased the yield o0887f the extract (13-65 %) and the amount of formaldehyde bonded (39-118 %). The extract components react with formaldehyde quite vigorously, but the treatment used do not appear to affect the rate of reac
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