Abstract
The influence of temperature on transverse mechanical properties of 10 tropical species in green condition was studied in radial compression (0 to 99 °C), transverse shear with longitudinal-radial shearing plane and rupture of the longitudinal-tangential plane (20 to 80 °C). Basic density ranged from 0.21 to 0.91 g cm$^{-3}$. Load-displacement curves were characterised by initial rigidity, yield stress, yield strain and strain energy at 20% strain level. The relation between each criterion and basic density was expressed by a power law. The dependency on temperature evidenced a sharp glassy transition, except for the fracture energy only slightly influenced by temperature. An empirical model allowed evaluating a transition temperature between 51 and 69 °C, depending on the species and the criterion, which was attributed to lignin. Detailed analysis of the apparent modulus in radial compression suggested that complex relaxation phenomena occur around 10 °C and that the rubbery state is not fully reached at 80 °C.