Influence of CCA-B Preservative Treatment and Surface Finishing on the Mechanical Characteristics of Heartwood and Sapwood of Petersianthus Macrocarpus (Essia)

Abstract

Delle Desire Domekyiir

The sustainable utilization of lesser-used species (LUS) as alternatives to overexploited traditional timbers for furniture and structural applications is increasingly advocated in Ghana’s forestry sector [1,2]. This study evaluated the mechanical performance of Chromated Copper Arsenate Type B (CCA-B) pressure-treated and surface-finished heartwood and sapwood of Petersianthus macrocarpus (Essia) and Ceiba pentandra (Onyina) as the control wood species. Preservative (CCA-B) treatment and surface finishes (varnish, shellac and lacquer) were applied to enhance strength and service performance the LUS for indoor and semi-exposed conditions. A total of 80 treated and non-treated samples were prepared and tested in accordance with BS 373 (1957) at 12% moisture content. Results showed that mean compression parallel to grain values ranged from 50.84 – 52.27 N/mm2 for heartwood, 44.80 – 51.67 N/mm2 for sapwood and 13.83 – 19.30 N/mm2 for control samples. The modulus of rupture (MOR) and modulus of elasticity (MOE) ranged from 106.01 – 113.42 N/mm2; 17,965.6 – 19,380.2 N/mm2 (heartwood), 90.99 – 97.18 N/mm2; 16,012 – 20,660.4 N/mm2 (sapwood), and 34.61 – 38.99 N/mm2 5,138 – 7,597.2 N/mm2 (control) respectively. Sapwood treated solely with CCA-B or surface finishes exhibited compression values of 23.00 – 45.03 N/mm2, MOR of 75.21 – 81.70 N/ mm2 and MOE 16,269 - 18,892 N/mm2. The findings indicate that CCA-B treatment and surface finishing significantly (p<0.05%) improved the strength properties of P. macrocarpus, supporting its suitability as a viable LUS for furniture and structural applications in Ghana [3,4].

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