Determination of Polyphenic Content of Bark Extracts for Wood Adhesives

M. T. Paridah, O.c. Musgrave, Z. Ashaari

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

The phenolic content of condensed tannins varies considerably, depending on the method of determination. Even though the Stiasny precipitation number has been commonly used to estimate the amount of reactive tannin towards formaldehyde, particularly in adhesive applications, this estimation alone is not sufficient. In this study two methods of determining the amount of reactive tannin towards formaldehyde were examined. These were (1) the reactivity towards formaldehyde or the Stiasny precipitation number, and (2) the formaldehyde uptake. Five different types of tannin were examined from Rhizophora mucronata, P. radiata, mimosa, quebracho and chestnut. The study indicates that the phenolic content in tannin can be better estimated by determining both the Stiasny number and the amount of formaldehyde uptake. High correlation (r(2) = 0.905) was detected between the two methods. The study also revealed that hot water extracts of R. mucronata contain relatively small amounts of reactive polyphenols and are less reactive than suffite extracts. The consumption of formaldehyde by this type of tannin was only 0.294 molecules per flavanoid unit. Similar to R. mucronata, the sulfite extracts of P radiata contain relatively high amounts of reactive polyphenols and reacted with substantially higher amounts of formaldehyde per flavanoid unit, comparable to mimosa and quebracho tannins. Nonetheless, the reactivity towards formaldehyde (gel time) of the latter tannins is much lower, despite their higher polyphenolic content. Of the two methods used to estimate the polyphenolic content of bark extracts, the Stiasny number had a relatively higher correlation (r(2) = 0.518) with gel time than formaldehyde uptake (r(2) = 0.345) did. The behaviour of these tannins in relation to their reactivity and chemical structures is discussed.

Original languageEnglish
Pages (from-to)267-272
Number of pages5
JournalHolzforschung
Volume56
Issue number56
Publication statusPublished - 2002

Keywords

  • bark extracts
  • reactive tannin
  • polyphenolic content
  • Stiasny number
  • formaldehyde uptake
  • gel time
  • FORMALDEHYDE

Cite this

Paridah, M. T., Musgrave, O. C., & Ashaari, Z. (2002). Determination of Polyphenic Content of Bark Extracts for Wood Adhesives. Holzforschung, 56(56), 267-272.

Determination of Polyphenic Content of Bark Extracts for Wood Adhesives. / Paridah, M. T.; Musgrave, O.c.; Ashaari, Z.

In: Holzforschung, Vol. 56, No. 56, 2002, p. 267-272.

Research output: Contribution to journalArticle

Paridah, MT, Musgrave, OC & Ashaari, Z 2002, 'Determination of Polyphenic Content of Bark Extracts for Wood Adhesives', Holzforschung, vol. 56, no. 56, pp. 267-272.
Paridah MT, Musgrave OC, Ashaari Z. Determination of Polyphenic Content of Bark Extracts for Wood Adhesives. Holzforschung. 2002;56(56):267-272.
Paridah, M. T. ; Musgrave, O.c. ; Ashaari, Z. / Determination of Polyphenic Content of Bark Extracts for Wood Adhesives. In: Holzforschung. 2002 ; Vol. 56, No. 56. pp. 267-272.
@article{55c94dfacb98424c9443390faab4cc4b,
title = "Determination of Polyphenic Content of Bark Extracts for Wood Adhesives",
abstract = "The phenolic content of condensed tannins varies considerably, depending on the method of determination. Even though the Stiasny precipitation number has been commonly used to estimate the amount of reactive tannin towards formaldehyde, particularly in adhesive applications, this estimation alone is not sufficient. In this study two methods of determining the amount of reactive tannin towards formaldehyde were examined. These were (1) the reactivity towards formaldehyde or the Stiasny precipitation number, and (2) the formaldehyde uptake. Five different types of tannin were examined from Rhizophora mucronata, P. radiata, mimosa, quebracho and chestnut. The study indicates that the phenolic content in tannin can be better estimated by determining both the Stiasny number and the amount of formaldehyde uptake. High correlation (r(2) = 0.905) was detected between the two methods. The study also revealed that hot water extracts of R. mucronata contain relatively small amounts of reactive polyphenols and are less reactive than suffite extracts. The consumption of formaldehyde by this type of tannin was only 0.294 molecules per flavanoid unit. Similar to R. mucronata, the sulfite extracts of P radiata contain relatively high amounts of reactive polyphenols and reacted with substantially higher amounts of formaldehyde per flavanoid unit, comparable to mimosa and quebracho tannins. Nonetheless, the reactivity towards formaldehyde (gel time) of the latter tannins is much lower, despite their higher polyphenolic content. Of the two methods used to estimate the polyphenolic content of bark extracts, the Stiasny number had a relatively higher correlation (r(2) = 0.518) with gel time than formaldehyde uptake (r(2) = 0.345) did. The behaviour of these tannins in relation to their reactivity and chemical structures is discussed.",
keywords = "bark extracts, reactive tannin, polyphenolic content, Stiasny number, formaldehyde uptake, gel time, FORMALDEHYDE",
author = "Paridah, {M. T.} and O.c. Musgrave and Z. Ashaari",
year = "2002",
language = "English",
volume = "56",
pages = "267--272",
journal = "Holzforschung",
issn = "0018-3830",
publisher = "Walter de Gruyter GmbH",
number = "56",

}

TY - JOUR

T1 - Determination of Polyphenic Content of Bark Extracts for Wood Adhesives

AU - Paridah, M. T.

AU - Musgrave, O.c.

AU - Ashaari, Z.

PY - 2002

Y1 - 2002

N2 - The phenolic content of condensed tannins varies considerably, depending on the method of determination. Even though the Stiasny precipitation number has been commonly used to estimate the amount of reactive tannin towards formaldehyde, particularly in adhesive applications, this estimation alone is not sufficient. In this study two methods of determining the amount of reactive tannin towards formaldehyde were examined. These were (1) the reactivity towards formaldehyde or the Stiasny precipitation number, and (2) the formaldehyde uptake. Five different types of tannin were examined from Rhizophora mucronata, P. radiata, mimosa, quebracho and chestnut. The study indicates that the phenolic content in tannin can be better estimated by determining both the Stiasny number and the amount of formaldehyde uptake. High correlation (r(2) = 0.905) was detected between the two methods. The study also revealed that hot water extracts of R. mucronata contain relatively small amounts of reactive polyphenols and are less reactive than suffite extracts. The consumption of formaldehyde by this type of tannin was only 0.294 molecules per flavanoid unit. Similar to R. mucronata, the sulfite extracts of P radiata contain relatively high amounts of reactive polyphenols and reacted with substantially higher amounts of formaldehyde per flavanoid unit, comparable to mimosa and quebracho tannins. Nonetheless, the reactivity towards formaldehyde (gel time) of the latter tannins is much lower, despite their higher polyphenolic content. Of the two methods used to estimate the polyphenolic content of bark extracts, the Stiasny number had a relatively higher correlation (r(2) = 0.518) with gel time than formaldehyde uptake (r(2) = 0.345) did. The behaviour of these tannins in relation to their reactivity and chemical structures is discussed.

AB - The phenolic content of condensed tannins varies considerably, depending on the method of determination. Even though the Stiasny precipitation number has been commonly used to estimate the amount of reactive tannin towards formaldehyde, particularly in adhesive applications, this estimation alone is not sufficient. In this study two methods of determining the amount of reactive tannin towards formaldehyde were examined. These were (1) the reactivity towards formaldehyde or the Stiasny precipitation number, and (2) the formaldehyde uptake. Five different types of tannin were examined from Rhizophora mucronata, P. radiata, mimosa, quebracho and chestnut. The study indicates that the phenolic content in tannin can be better estimated by determining both the Stiasny number and the amount of formaldehyde uptake. High correlation (r(2) = 0.905) was detected between the two methods. The study also revealed that hot water extracts of R. mucronata contain relatively small amounts of reactive polyphenols and are less reactive than suffite extracts. The consumption of formaldehyde by this type of tannin was only 0.294 molecules per flavanoid unit. Similar to R. mucronata, the sulfite extracts of P radiata contain relatively high amounts of reactive polyphenols and reacted with substantially higher amounts of formaldehyde per flavanoid unit, comparable to mimosa and quebracho tannins. Nonetheless, the reactivity towards formaldehyde (gel time) of the latter tannins is much lower, despite their higher polyphenolic content. Of the two methods used to estimate the polyphenolic content of bark extracts, the Stiasny number had a relatively higher correlation (r(2) = 0.518) with gel time than formaldehyde uptake (r(2) = 0.345) did. The behaviour of these tannins in relation to their reactivity and chemical structures is discussed.

KW - bark extracts

KW - reactive tannin

KW - polyphenolic content

KW - Stiasny number

KW - formaldehyde uptake

KW - gel time

KW - FORMALDEHYDE

M3 - Article

VL - 56

SP - 267

EP - 272

JO - Holzforschung

JF - Holzforschung

SN - 0018-3830

IS - 56

ER -