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Project Outline and Thesis Proposal for Final Year Project The Effects of Environmental Conditions on the Physical Properties of Medium Density Fibreboard
Medium Density Fibreboard (MDF) is a wood fibre composite material widely used in furniture manufacture, cabinet making, joinery and craft-work. To a certain extent it is a substitute for solid timber and chipboard. It's cost, mechanical properties and ease of machining suggest that it will be used in a far broader range of engineering uses in future.
One of the disadvantages of MDF is it's susceptibility to moisture, causing loss of mechanical properties and thickness swelling. The changes that occur in the mechanical properties of MDF as a result of moisture sorption have not been quantified in detail. One aim of this project is to examine the effect of moisture on the mechanical properties of two types of MDF; a moisture resistant type and a standard, non resistant type.
Treatments used to increase the moisture resistance of MDF have been chemical modification, application of coatings and use of water resistant thermosetting adhesives. Heat treatments have been used to increase the moisture resistance of solid timber, but have not been applied to MDF. A second aim of this project is to examine whether heat treatments can increase the moisture resistance of MDF and what effect such treatments have on mechanical properties.
A literature review will determine what experiments have already been undertaken to increase the moisture resistance of MDF and how already obtained results can assist the intended analysis.
Experiments will use two separate board types with two replicates. Boards will be exposed to seven different humidities over saturated salt solutions at for six weeks. Samples will be approximately 8mm by 30mm in size. Heat treatments will be undertaken at under inert (nitrogen) and oxidising (air) atmospheres.
Periodic mass and thickness measurements will be taken to determine moisture content and thickness swelling. The exposed samples will then undergo mechanical testing to determine modulus of rupture and tensile strength. Scanning Electron Microscopy (SEM) will be used to observe micro structural fracture characteristics of the samples after mechanical testing.
Further experiments will be undertaken to examine the performance of MDF during exterior exposure. Samples will be exposed on the roof of the Engineering building and tested periodically .
From these experiments the thesis should contain detailed qualitative information on the moisture content, thickness swelling and mechanical properties of MDF across the sorption range. In addition the heat treatment may prove to be an effective way of increasing the moisture resistance of MDF which would increase its ability to be used for a greater range of end uses.
Supervisors: