Electronic Journal of Polish Agricultural Universities (EJPAU) founded by all Polish Agriculture Universities presents original papers and review articles relevant to all aspects of agricultural sciences. It is target for persons working both in science and industry,regulatory agencies or teaching in agricultural sector. Covered by IFIS Publishing (Food Science and Technology Abstracts), ELSEVIER Science - Food Science and Technology Program, CAS USA (Chemical Abstracts), CABI Publishing UK and ALPSP (Association of Learned and Professional Society Publisher - full membership). Presented in the Master List of Thomson ISI.
2007
Volume 10
Issue 3
Topic:
Wood Technology
ELECTRONIC
JOURNAL OF
POLISH
AGRICULTURAL
UNIVERSITIES
Ożarska B. , Harris G. 2007. EFFECT OF CYCLIC HUMIDITY ON CREEP BEHAVIOUR OF WOOD-BASED FURNITURE PANELS, EJPAU 10(3), #11.
Available Online: http://www.ejpau.media.pl/volume10/issue3/abs-11.html

EFFECT OF CYCLIC HUMIDITY ON CREEP BEHAVIOUR OF WOOD-BASED FURNITURE PANELS

Barbara Ożarska, Gerry Harris
School of Forest and Ecosystem Science, The University of Melbourne, Australia

 

ABSTRACT



A study was undertaken to determine creep characteristics of furniture panels, both unlaminated and laminated, in cyclic humidity conditions. Test specimens were prepared from laminated and unlaminated moisture resistant MDF. Two types of laminating materials were used: melamine laminate and hardwood (mountain ash Eucalyptus regnans) veneer. Specimens were subjected to four-point bending loads with a single stress level of 15% using vertical creep testing rigs. Relative humidity was set to be cycled between 35% and 85%, and the temperature was set at a constant level of 23°C. Centre-point deflection of the specimens was measured using Linear Variable Displacement Transducers.

The study revealed that the creep behaviour of MDF panels subjected to cyclic humidity can be significantly reduced by using surface laminations. The greatest reductions in relative creep values in bending of MDF panels (up to 3.3 times), were observed in the panels laminated with melamine surface overlays. The total relative creep values of the panels laminated with hardwood veneer were half those without any laminations. This finding will be useful in the design of wood-based furniture panels used in shelving and bottoms of cupboards.

Analysis of the creep deflection during the adsorption and desorption stages revealed that there was the difference in the performance of laminated and unlaminated panels. The creep deformation in the laminated panels increased during the adsorption phase and decreased during the desorption phase. In the unlaminated panels, reversal of the creep deflection during the cyclic humidity test was observed. A significant loss of both MOE and internal bond strength in evaluated furniture panels was observed after the creep test and the recovery period. It was evident that the use of laminations reduced these losses, with the highest reduction observed in the panels with melamine overlays followed by the hardwood veneer laminations.

Key words: creep, cyclic humidity, furniture panels, surface laminations.


Barbara Ożarska
School of Forest and Ecosystem Science,
The University of Melbourne, Australia
Building 142, FLFR,
Royal Parade, Parkville 3010, Australia
email: bo@unimelb.edu.au

Gerry Harris
School of Forest and Ecosystem Science,
The University of Melbourne, Australia
Building 142, FLFR,
Royal Parade, Parkville 3010, Australia

Responses to this article, comments are invited and should be submitted within three months of the publication of the article. If accepted for publication, they will be published in the chapter headed 'Discussions' and hyperlinked to the article.