Injection moulded wood plastic composites (WPCs) are generally built up by wood in the shape of fibres or flour, mixed together with a thermoplastic matrix and a coupling agent. The most common coupling agent is different types of maleic anhydrides (MA). It is still not known to what extent the MA works as a chemical coupling agent or as a dispersing agent in the WPC, of which both functions would help to improve the mechanical properties of the WPC. The objective of this study was to solely evaluate adhesion between a wood surface and a matrix material with and without MA, by using an automatic bond evaluating system (ABES). The ABES allows a wood-plastic compression at desired temperature and cooling, as well as mechanical testing the formed bond in a closed loop. Sapwood and heartwood veneer specimens of Scots Pine (Pinus sylvestris L.) were melt bonded together with a sheet of either pure polypropylene or polypropylene with a high content of MA placed between the veneers. In addition to the ABES bond-strength tests, after the tests the fracture surfaces were evaluated. Results indicate large differences in bond strength between specimens with and without MA.
Keywords: Wood, polypropylene, maleic anhydride, MAPP, Adhesion
Authors
Segerholm B.K.
Royal institute of Technology, Building Materials, Stockholm SWEDEN
SP Technical Research Institute of Sweden, EcoBuild, Stockholm, SWEDEN
Wålinder M.E.P.
SP Technical Research Institute of Sweden, EcoBuild, Stockholm, SWEDEN
Royal institute of Technology, Building Materials, Stockholm SWEDEN
Holmberg D.
SP Technical Research Institute of Sweden, Wood technology, Stockholm, SWEDEN
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