Wood modification is now widely recognized as offering enhanced properties of wood and overcoming issues such as dimensional instability and biodegradability which affect natural wood. Typical wood modification systems use chemical modification, impregnation modification or thermal modification, and these vary in the properties achieved. As control and understanding of the wood modification systems has progressed, further opportunities have arisen to add extra functionalities to the modified wood. These include UV stabilisation, fire retardancy, or enhanced suitability for paints and coatings. Thus, wood may become a multi-functional material through a series of modifications, treatments or reactions, to create a high-performance material with previously impossible properties. In this paper we review systems that combine the well-established wood modification procedures with secondary techniques or modifications to deliver emerging technologies with multi-functionality. The new applications targeted using this additional functionality are diverse and range from increased electrical conductivity, creation of sensors or responsive materials, improvement of wellbeing in the built environment, and enhanced fire and flame protection. We identified two parallel and connected themes: (1) the functionalisation of modified timber and (2) the modification of timber to provide (multi)-functionality. A wide range of nanotechnology concepts have been harnessed by this new generation of wood modifications and wood treatments. As this field is rapidly expanding, we also include within the review trends from current research in order to gauge the state of the art, and likely direction of travel of the industry.

Corsican pine (Pinus nigra) sapwood was chemically modified with acetic or hexanoic anhydride to a variety of weight gains. The modified wood was exposed to the brown rot fungus Coniophora puteana, and the relationship between weight loss due to decay and weight percentage gain, or degree of hydroxyl substitution, was determined in a 16-week exposure test. The effect of exposure time and the strain of C. puteana upon the decay protection threshold of acetylated Corsican pine was also examined.

This paper summarises the quantitative analysis of the absorption of volatile organic compounds (VOCs), namely gaseous formaldehyde, toluene, limonene and dodecane, by different wool types. VOCs are of increasing concern due to their role as accumulating indoor air contaminants, and this paper demonstrates the potential of wool as a sustainable and natural solution to this problem. Building on previous data, different wool types were tested by way of two different methods to assess their absorption ability with regard to these VOCs. For formaldehyde analysis, the samples were subjected to cycles of exposure to excess formaldehyde gas while the weight gain was measured. For the other VOCs, a modified microchamber was used to flow the gases through the samples, followed by trapping and quantification of the non-absorbed VOCs using Tenax TA tubes. The data presented indicate that wool is able to absorb a range of VOCs in differing amounts. The data also show that the amount and the type of VOCs absorbed by wool were dependent on the sheep breed and the processing of the wool.