Effect of thermal modification on the technological properties of wood from species in an agroforestry system

E Bandera,L.S Zanchetta,N.E.P Azevedo,T.S Mangini,E Eloy,Y.C.T Santos,L Candaten,R Trevisan

doi:10.5039/agraria.v16i3a8882

Abstract

This work aims to evaluate the effect of thermal modification on the physical and mechanical properties of species of wood, from an agroforestry system. The species evaluated were Parapiptadenia rigida (Benth.) Brenan, Peltophorum dubium (Spreng.) Taub., Eucalyptus grandis × Eucalyptus urophylla and Schizolobium parahyba (Vell.) Blake, aged nine. The specimens were submitted to thermal treatments (120, 150, 180 and 210 °C), in addition to the control samples. For the mechanical properties, the modules of elasticity and rupture, tension in the proportional limit and maximum force were evaluated according to ASTM D 143-94. For the physical properties of basic density and shrinkage, the evaluation took place according to NBR 7190. The thermal treatment modified the mechanical properties of the wood in a positive way up to 180 ºC, with the highest values ??being observed for E. grandis × E. urophylla and P. rigida. Likewise, the heat treatment has modified the physical properties of wood retractability in a positive way up to 210 ºC, with the anisotropic coefficient decreasing with increasing temperature. Thus, it is concluded that the thermal modification alters the physical and mechanical properties of the four analyzed species. Furthermore, it is perceived that for the case of mechanical characteristics these changes are positive up to a temperature of 180 ºC, while for the physical ones the best results are found at a temperature of 210 ºC.

Highlights

Over the years, we have seen an increase in the implementation of new scenarios in the timber field, among them the agroforestry systems (SAF’s), which are characterized by a complex production set, associating individuals from different cycles, which promotes the integration of various timber species and the supply of the demand imposed by the industry.In this process, the aim is to use fast-growing trees with physical-mechanical properties that are appropriate for the various uses, such as high strength and flexibility
The thermal treatment modified the mechanical properties of the wood in a positive way up to 180 oC, with the highest values being observed for E. grandis × E. urophylla and P. rigida
The heat treatment has modified the physical properties of wood retractability in a positive way up to 210 oC, with the anisotropic coefficient decreasing with increasing temperature

Summary

Introduction

We have seen an increase in the implementation of new scenarios in the timber field, among them the agroforestry systems (SAF’s), which are characterized by a complex production set, associating individuals from different cycles, which promotes the integration of various timber species and the supply of the demand imposed by the industry In this process, the aim is to use fast-growing trees with physical-mechanical properties that are appropriate for the various uses, such as high strength and flexibility. The vast use of wood is due to the advantages of the material for application in works, among these, in civil construction, since it is a natural polymer that has structural function and organoleptic and technological characteristics that vary according to the exposure environment (Paula et al, 2016). The evaluation of the wood’s properties becomes of utmost importance for the proper use and quality in the final piece

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Conclusion