The influence of thickness and final heat treatment on mechanical properties and dimensional stability of binderless fiberboards from steam exploded Arundo donax L

Identifier:  imarina:9262492

Handle: https://hdl.handle.net/20.500.11797/imarina9262492

Authors:  Vitrone, Federica; Ramos, Diego; Ferrando, Francesc; Salvado, Joan

Abstract:
The lack of petroleum-based adhesives in binderless fiberboards (BF) generally lead to low dimensional stability and poor mechanical properties. The steam explosion (STEX) pre-treatment can help to improve both physical and mechanical properties, but in many cases dimensional stability is still a challenge and depend on the characteristics of the raw material and the STEX conditions. This study investigates the effect of thickness and final heat treatment (FHT) on physico-mechanical properties of binderless fiberboards made by Arundo donax L. The manufacturing process involved the STEX pre-treatment at a temperature (Tr) of 190 °C and retention time (tr) of 9.5 min, the hot-pressing (HP) at 7.5 MPa with a three-steps procedure, and the FHT carried out at 180 °C for two different times (tc), 0.5 h and 1 h. Three samples for each condition were made and three different thickness levels were investigated, i.e. 3 mm, 6 mm, and 9 mm. The results obtained were compared with three reference samples made for each thickness for which no FHT was carried out. The results of modulus of elasticity (MOE), modulus of rupture (MOR), internal bond (IB), thickness swelling (TS), and water absorption (WA) showed that FHT had a great influence on dimensional stability but did not lead to any improvement in mechanical performance. On the contrary, the thickness did not have any influence for TS and WA, but a small change in MOE, MOR, and IB was detected. These findings may help to improve the BF manufacturing process and to optimize the results for Arundo donax L.