The reactivity of linseed and soybean oil with different epoxidation degree towards vinyl acetate and impact of the resulting copolymer on the wood durability

Linseed (LO) and soybean oil (SO) were in-situ epoxidized with peracetic acid to produce different degree of epoxidized LO and epoxidized SO. For comparison purpose, commercial epoxidized linseed oil (ELO (R)) and epoxidized soybean oil (ESO (R)) were also included in the study. The effect of epoxidation degree on the copolymerization reaction between epoxidized oils and vinyl acetate (VAc) was investigated. Results showed that a copolymer can be formed between VAc and epoxidized LO with high epoxy content, while no reaction occurred between VAc and SO or its epoxidized derivatives. As the most reactive monomer among the studied oils, the epoxidized LO with highest epoxy content (i.e. ELO (R)) was mixed with VAc and then impregnated into the wood using three different ELO (R) /VAc formulations either as solution or as emulsions. After curing, the impact of the resulting copolymer issued from the three tested formulations on the wood durability was evaluated. Results showed that the formulation comprising VAc, ELO (R), H2O, K2S2O8 and alkaline emulsifier (Formulation 3) can significantly improve wood's durability against white rot- (Trametes versicolor) and brown rot fungi (Postia placenta and Coniophora puteana). Treated wood of 8% weight percentage gain (WPG) was sufficient to ensure decay resistance against the test fungi with less than 5% mass loss.