Influence of the acidity and size of beech particles on the hardening of the urea-formaldehyde adhesive

Medved, Sergej (author), Resnik, Jože (author)

Presented work deals with the influence of acidity of beech particles of different size on the hardening of the urea–formaldehyde adhesive. The pH value and the milliequivalents of soluble and total acids were determined upon the method published by Subramanian et. al. in 1983. The method is based on the reaction between acids in wood and the aqueous solution of sodium acetate, where the equivalent quantity of acetic acid is generated. The quantity of the generated acetic acid was determined by the titration and presents the total acids in wood. The acetate solution helps to extract the acids soluble and insoluble in water. We determined that the particle size does not influence the pH value of particles and the quantity of the extracted soluble acids, but does have the influence on the quantity of the extracted insoluble acids. We furthermore determined that the particle size influences the gel time of the urea–formaldehyde (UF) adhesive. The shortest gel time was determined at the finer particles.

• Language: English
• Keywords: lesna industrija, gozdno gospodarstvo, iverne plošče, bukovo iverje, utrjevanje urea-formaldehidnega lepila, vpliv kislosti bukovega iverja, pH vrednost iverja, ekstrahirane topne kisline, netopne lesne kisline, v vodi topne lesne kisline, čas želiranja, urea-formaldehidno lepilo, beech particles, soluble wood acids, insoluble wood acids, adhesive gel time
• Work type: Not categorized
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publisher: Slovensko kemijsko društvo
• Year: 2004
• Number of pages: Str. 353-360
• Numbering: Letn. 51, št. 2
• PID: 20.500.12556/RUL-61235
• UDC: 674-419:630*86
• ISSN on article: 1318-0207
• COBISS.SI-ID: 26055173
• Publication date in RUL: 10.07.2015

Record is a part of a journal

• Title: Acta chimica slovenica
• Shortened title: Acta chim. slov.
• Publisher: Slovensko kemijsko društvo, =Slovenian Chemical Society
• ISSN: 1318-0207
• COBISS.SI-ID: 14086149

Secondary language

• Language: English

Abstract

V prispevku je predstavljen vpliv kislosti bukovega iverja različnih velikosti na utrjevanje urea-formaldehidnega lepila. pH vrednost in miliekvivalnet vodotopnih in skupnih kisli v iverju bukve je bila določena po metodi, ki so je leta 1983 objavil Subramanina s sodelavci. Metoda temelji na reakciji med kislinami v lesu in vodno raztopino natrijevega acetata pri čemer se sprosti ekvivalentna količina ocetne kisline. Količina sproščene ocetne kisline je določena s titracijo in predstavlja skupne kisline v lesu. Z acetatno raztopino se namreč ekstrahirajo tako v vodi netopne, kot tudi v vodi topne kisline. Ugotovljeno je bilo, da velikost iverja ne vpliva na pH vrednost iverja in količino ekstrahiranih topnih kislin, medtem ko velikost iverja vpliva na količino ekstrahiranih netopnih kislin. Prav tako je bilo ugotovljeno, da velikost iverja vpliva na čas želiranja UF lepila. Pri finem iverju je bil ugotovljen najkrajši čas želiranja.