Enhanced adhesion from surface modified timber resulting in a sustainable industrial design outcome

The most significant issue regarding timber use for outdoor products is the poor characteristics this material has with regard to weathering over a prolonged period of time. Ongoing product maintenance is something the majority of consumers want to avoid, hence the domination of aluminium and Polyvinyl Chloride (PVC) in the window frame industry. Timber has numerous benefits over its competition such as sustainability, aesthetics, low thermal conductivity and ease of manufacture, but unfortunately its major weakness -- poor outdoor performance -- is the main reason consumers are deterred away from this material. This paper will explain how an environmentally friendly water-based process for surface modification of timber, developed by the Commonwealth Scientific and Industrial Research Organisation (CSIRO), was tested for its potential ability to enhance adhesion of timber products and then implemented into an innovative timber window frame. This timber window frame is used as an exemplar for outdoor timber products to highlight the benefits of integrating successful scientific research into an industrial design outcome. The surface modification process applied to the outermost surface of timber neutralises natural extractives and chemically bonds adhesive promoting molecular chains to the timber's surface. The process is carried out to significantly increase the quality of adhesion of an applied decorative or protective coating. The resultant testing confirmed a convincing increase in the bond strength for all timber species investigated in this doctoral project by an average factor of four-fold, with some species achieving a 10-fold strength increase. The successful results obtained from the first phase of testing of glue-bonded timber samples led to an investigation of the surface modification technology for improved lamination of coatings on timber. Results for this second test phase also confirm the success of this modification science on coatings, as minimal delamination of surface coated samples was documented against non-modified timber samples. These results along with the process of modification and testing will be discussed in this paper.