Lepljenje lesa z mešanicami iz poliestra na osnovi utekočinjenega lesa in MUF lepila z visokofrekvenčnim segrevanjem : diplomski projekt

Nastav, Jožko (author), Šernek, Milan (mentor), Kunaver, Matjaž (comentor), Šega, Bogdan (reviewer)

Z dodajanjem različnih deležev poliestra iz utekočinjenega lesa (PUL) melamin-urea-formaldehidnemu (MUF) lepilu smo želeli raziskati, koliko PUL lahko dodamo lepilu, da le to še izpolnjuje zahteve standarda EN 12765. Po tem standardu so lepila za nekonstrukcijsko uporabo razvrščena v 4 trajnostne razrede (C1, C2, C3, C4). MUF lepilu smo dodali 0, 10, 20, 30, 40, 50 % PUL. S pomočjo visoke frekvence smo zlepili bukove lamele, ki smo jih po lepljenju razžagali v strižne preizkušance, kot to predpisuje standard EN 205. Testiranje smo opravili na univerzalnem testirnem stroju ZWICK/Z005. Lepilnim mešanicam smo izmerili tudi dielektrične lastnosti. Ugotovili smo, da najvišje strižne trdnosti dosegajo tisti preizkušanci, ki so bili 7 dni po lepljenju izpostavljeni standardni klimi. Vrednosti pri teh preizkušancih so se gibale nad 10 N/mm2. Pri ocenjevanju loma po lesu smo zasledili, da manjše količine dodanega PUL lahko prispevajo k boljši trdnosti lepilnega spoja. Preizkušanci, ki smo jih tekom raziskave izpostavili vodi, so dosegali nižje strižne trdnosti. Preizkušanci, zlepljeni z lepilnimi mešanicami z več dodanega PUL ter za 3 ure izpostavljeni vodi (100 % 2°C) pa so razpadli

• Language: Slovenian
• Keywords: lepilni spoj, poliester, utekočinjen les, strižna trdnost, dielektrične lastnosti
• Work type: Diploma project paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: BF - Biotechnical Faculty
• Place of publishing: Ljubljana
• Publisher: [J. Nastav]
• Year: 2015
• Number of pages: X, 25 f., [18] f. pril.
• PID: 20.500.12556/RUL-117768
• UDC: 678.029.5
• COBISS.SI-ID: 2407305
• Publication date in RUL: 24.07.2020

Secondary language

• Language: English
• Title: Wood bonding using high frequency heated mixtures based on polyester from liquefied wood and melamine urea formaldehyde adhesives

Abstract

By adding different shares of liquefied wood (PUL) to melamine-urea formaldehyde (MUF) adhesive we researched the quantity of PUL to be added to the MUF glue to meet the requirements of standard EN 12765. Under this standard, adhesives for non-structural application are grouped into 4 durability classes (C1, C2, C3, C4). 0, 10, 20, 30, 40 and 50 % of the PUL was added to the MUF adhesive. Using high frequency two beech lamellas were bonded together with mixtures of MUF adhesive and PUL. Then the specimens were sawn according to the standard EN 205, and tested on the universal testing machine ZWICK Z005. Before gluing the dielectric properties of the mixtures were measured. The higher shear strength was reached in the specimens exposed to standard atmosphere for 7 days after bonding; it ranged above 10 N/mm2. We observed that a small quantity of added PUL could contribute to higher strength adhesive bond. The specimens exposed to water achieved lower shear strength. The specimens glued together with adhesive mixture, having higher quantity of PUL, and exposed to water for 3 hours (100 % 2°C) collapsed.

• Keywords: adhesive bond, polyester, liquefied wood, shear strength, dielectric properties