Uporaba trislojnih ivernih plošč s povišano gostoto v konstrukcijske namene : diplomsko delo - univerzitetni študij

Lalović, Mitja (author), Medved, Sergej (mentor), Šernek, Milan (reviewer)

Ugotavljali smo, kako izbrati najoptimalnejšo ploščo za konstrukcijske namene glede na mehansko-fizikalne lastnosti izdelanih preizkušancev. V samem eksperimentu smo izdelali 5 serij tri-slojnih ivernih plošč, ki so si bile različne predvsem po gostoti in končni debelini. Gostoto smo povišali v posameznih slojih. Uporabili smo mešano (bukovo in smrekovo) iverje, ki smo ga oblepili z urea-formaldehidnim lepilom (UF). Plošča A je bila kontrolna (lastnosti konvencionalne industrijske trislojne plošče), ostalim ploščam pa smo dodajali iverje zunanjega sloja v notranji sloj in obratno. Ploščama B in D smo glede na kontrolno ploščo A, dodali relativno malo iverja (A + cca. 10%) in dosegli velike spremembe. Pri ploščah C (A + 21,4 %) in E (A + 25,8 %) pa smo bolj pretiravali. Plošča C, kjer smo dodali 60 % CL v SL, je posledično dosegla enakomerno sestavo, zaradi velikih delcev v zunanjem sloju pa je po končanem stiskanju (pri odpiranju) prišlo do efekta povratne deformacije iveri. Vendar je kljub temu dosegla zelo dobre rezultate, izstopa v strižni trdnosti in strižni trdnosti po robu. Do podobnih povratnih deformacij iveri je prišlo tudi pri plošči E, kjer smo dodali največ delcev glede na kontrolno ploščo. Tu smo najbolj pretiravali in prišlo je do porušitve v plošči po odpiranju stiskalnice. Plošča se nam je razslojila in dosegla podobne rezultate kot kontrolna plošča, nekaterih preizkusov pa sploh nismo uspeli izvesti. Lahko sklepamo, da nam je uspelo določiti mejno količino delcev, ki jih še lahko dodamo, da ploščo izboljšamo. Količina je v območju med ploščo D in C. Vidimo pa lahko, kako že relativno majhna sprememba vpliva na končne lastnosti.

• Language: Slovenian
• Keywords: trislojna iverna plošča, gostota, gostotni profil, panel, lesni kompozit
• Work type: Undergraduate thesis
• Typology: 2.11 - Undergraduate Thesis
• Organization: BF - Biotechnical Faculty
• Place of publishing: Ljubljana
• Publisher: [M. Lalović]
• Year: 2014
• Number of pages: X, 52 f.
• PID: 20.500.12556/RUL-117622
• UDC: 630*862.2
• COBISS.SI-ID: 2275721
• Publication date in RUL: 17.07.2020

Secondary language

• Language: English
• Title: Three layer high density particleboard in construction use

Abstract

It is well known that different vertical density profiles influence physical and mechanical properties of particleboards. The purpose of this research was to determine how to choose the optimum particleboard for construction purposes depending on the physical and mechanical properties. Five series of three-layer particleboards were made. They were mostly different in density and thickness. The density of individual layers was increased and mixed chips (beech and spruce) were used. They were taped over with a urea-formaldehyde adhesive (UF). The mat was pressed at a temperature of 190°C and specific pressure of 9 N/mm2 to reach nominal thickness of 16 mm. The boards were then cooled down and stored at a temperature of 20%2°C and a relative humidity of 65%5 %. The panel A was the control panel (conventional industrial three-layer particleboard). Other boards were made with differently: chips of the outer layer were added to the inner layer or vice versa. With relatively small additions in the panels B and D (A + cca. 10%), we achieved great increase in physical and mechanical properties compared to the control panel A. In the plates C (A + 21.4 %) and E (A + 25.8 %) we exaggerated more. The panel C, where we added 60 % of CL to SL, resulted in a uniform composition. Due to large particles in the outer layer, reverse deformation of particles (spring back effect) at the end of compression (at the opening of the press) occurred. However, the board C achieved very good results in shear strength and shear strength along the edge. A similar spring back effect also occurred in panel E, which had the greatest number of particles added in relation to the control plate. At the board E we exaggerated the most, which led to a collapse after opening the press. The plate was damaged (stratified) and reached similar results to the control panel, and some tests could not even be performed. We can conclude that we have managed to define the maximum amount of particles which can still be added to improve the plate. The quantity is in the range of the plates D and C. But now we can see how a relatively small change affects the final properties.

• Keywords: three-layer particleboard, high density, vertical density profile, panel, wood composite