Succinic anhydride (SA), a 4-carbon cyclic unsaturated anhydride and its derivatives ASAC12, SA with a 12-carbon aliphatic chain containing a carbon-carbon double bond, ASAC17, a similar compound with a 17-carbon chain and ASAC20, a similar compound with a 20-carbon chain were used to chemically modify Scots pine sapwood. The reactions were carried out in solution with N-N, dimethylformamide which acted as catalyst and swelling agent. The ease and rates of reaction were compared and the compounds are ranked as SA > ASAC12 > ASAC17 > ASAC20. Above 30% loading for all reagents, the wood cell wall began to degrade. Proof of SA and ASAC17 reaction was confirmed using Infrared
Spectroscopy, and comparison of increase in wood volume with treatment and the calculated volume of added chemical.
Succinic anhydride and ASAC17 modified samples were subject to a 12 week soil block test to test the efficacy of the modifications against attack by the Basidiomycete fungi Coniophora puteana and Gloeophyllum trabeum. Results indicate that there is a good correlation between increased reagent loading and an increase in effectiveness, paralleled by a marked reduction in wood moisture content. ASAC 17 was the more successful treatment in all cases.
Copper was fixed to ASAC17 modified wood in aqueous solution. Copper content was determined by gain in weight and Atomic Absorption Spectroscopy. The treated blocks were subject to a 12 week soil test. Results showed that the modified wood was completely resistant to decay by C. puteana at levels of combined reagent loadings that would individually be ineffective, ASAC17 loadings as low as 0.4% in combination with 0.4% copper proved effective.
Leaching the blocks in water after modification gave a variance of weight losses in blocks that were subsequently attacked by C. puteana