Vpliv modifikacije lesa s tehnologijo Plato na kvaliteto lepljenja : diplomsko delo

Zanjkovič, Bernard (author), Šernek, Milan (mentor), Humar, Miha (reviewer)

Proučevali smo vpliv termične modifikacije lesa s tehnologijo Plato na kakovost lepljenja. Ugotavljali smo tudi učinek modifikacije na nekatere mehanske in fizikalne lastnosti lesa. S standardnimi metodami smo ugotavljali strižno trdnost preskušancev (SIST EN 392), delaminacijo lepilnih spojev (SIST EN 291), modul elastičnosti in upogibno trdnost (SIST EN 310), gostoto (SIST EN 323) in vlažnost (SIST EN 322). Preskušali smo 5 lesnih vrst: navadno smreko (Picea abies (L.) Karst.), duglazijo (Pseudotsuga menziessii Franco), topol (Populus ssp.), brezo (Betula pendula) in jelšo (Alnus glutinosa Gaertn.), termično modificiranih s tehnologijo Plato. Za primerjavo smo pri navadni smreki preskušali tudi nemodificirane preskušance (NS), pa modificirane samo do prve, hidrotermične stopnje (HTNS). Preskušance za ugotavljanje kakovosti lepljenja smo lepili s 3 vrstami lepil: melamin-urea-formaldehidnim lepilom (MUF), fenol-resorcinol-formaldehidnim lepilom (PRF) in poliuretanskim lepilom (PUR). Ugotovili smo, da je bila kakovost lepljenja Plato lesa odvisna od uporabljene lesne vrste in predvsem vrste lepila. Trdnost lepilnega spoja je bila najnižja pri preskušancih lepljenih s PRF lepilom, nekoliko višja pri preskušancih lepljenih z MUF lepilom in najvišja pri preskušancih lepljenih s PUR lepilom. Ugotovili smo tudi, da ima Plato les manjšo upogibno trdnost v primerjavi z nemodificiranim lesom. Ravnovesna vlažnost Plato lesa v standardni klimi pa je približno dvakrat nižja od vlažnosti nemodificiranega lesa.

• Language: Slovenian
• Keywords: les, lepljenje lesa, lepila, termična modifikacija, Plato
• Work type: Undergraduate thesis
• Typology: 2.11 - Undergraduate Thesis
• Organization: BF - Biotechnical Faculty
• Place of publishing: Ljubljana
• Publisher: [B. Zanjkovič]
• Year: 2007
• Number of pages: IX, 32 f., [32 f. pril.]
• PID: 20.500.12556/RUL-253
• UDC: 630*824.8
• COBISS.SI-ID: 1601161
• Publication date in RUL: 11.07.2014

Secondary language

• Language: English
• Title: Influence of wood treatment by Plato process on bonding performance of wood : visokošolski strokovni študij

Abstract

Thesis discusses the influence of heat treatment by Plato process on bonding performance. Influence of heat treatment on some mechanical and physical properties was also examined. Several testing methods were carried out according to standard procedure: the shear strength of Plato wood (SIST EN 392), delaminations of glue lines (SIST EN 291), modulus of elasticity and bending strength (SIST EN 310), density (SIST EN 323) and moisture content of Plato wood (SIST EN 322). 5 wooden species were tested: Norway spruce (Picea abies (L.) Karst., Douglas fir (Pseudotsuga menziessii Franco), poplar (Populus ssp.), birch (Betula pendula Roth.) and alder (Alnus glutinosa Gaertn.) treated by Plato process. Untreated Norway spruce, so as treated Norway spruce were tested for comparison; the last one only to the first stage (hydro-thermolised stage, HTNS). Test pieces were bonded with 3 structural cold-setting adhesive systems: melamine-urea-formaldehyde adhesive (MUF), phenol-resorcinol-formaldehyde adhesive (PRF), and polyurethane adhesive (PUR). It was found out that the bonding performance depends on wood species, and especially on the adhesive used. The results show the best bonding performance of the PUR, worse of the MUF, and the last of the PRF adhesive. It was also found out that the bending strength of Plato wood was decreased compared to untreated wood. Equilibrium moisture content of Plato wood in standard climate was about 50 % smaller than the adequate untreated wood.

• Keywords: wood, wood bonding, adhesives, heat treatment, Plato