Biological assessment of bio-based phase change materials in wood for construction applications

Solid wood can serve multi-functionality for energy savings in buildings. The study reveals the results of bio-deterioration and degradation of solid Scots pine wood used to incorporate single or multicomponent fatty acid mixtures as bio-based phase change materials (BPCMs). The sapwood samples were impregnated with capric acid (CA), methyl palmitate (MP), lauryl alcohol (LA) and a mixture of coconut oil fatty acids and linoleic acid (CoFA-LA). The samples were tested against subterranean termites by an Italian species (Reticulitermes lucifugus), the wood boring beetle Hylotrupes bajulus and mould through a discoloration test. Tested against termites, the impregnated samples were significantly less susceptible to the attack than the controls, i.e. the tested BPCMs were resistant to R. lucifugus. The only test with MP terminated at the moment against H. bajulus showed positive results with no larvae survived. The mould discoloration test revealed that the wood impregnated with CoFA-LA was identically susceptible to mould discoloration when compared to the control, non-impregnated samples. This pioneer study verifies that solid wood employed for encapsulation of BPCMs for building purposes can serve identically or somewhat better than similar wooden building elements regarding attacks of the above microorganisms and insects. Such multifunctional building elements will be tested further in a pilot scale building to characterize better the durability aspects of the new materials.