Preservative treatment and chemical modification of bamboo for structural purposes

Abstract

Bamboo is a plant of the Poaceae family characterized by its excellent specific mechanical strength in comparison with traditional building materials such as steel, cement and wood. Indeed its use is well known, especially in Asia and in Latin America countries in its natural form or for the industrial production of materials applied in the civil construction, chemical and energy fields. Brazil presents big potential for the use of bamboo as an engineering material due to the favorable weather for its cultivation and for the possibility of industrialization or for handcraft use. However, one of the bottlenecks for the extension of its application is the lack of concise standards for its production chain and a scarce quantity of experimental data about its physical-mechanical properties, preservation, degradability and behavior in the present of fire. The use of boron salts for the preservative treatment of bamboo as structural element has been widely employed due to low cost, effectiveness, flame retardant action and low toxicity for humans and for the environment. Nevertheless, its use presents restrictions for the treated material because of the excessive leaching of boron in the presence of high humidity and therefore, makes it impossible to use it in external applications. In this Phd project, it is proposed the investigation of the effect of new treatments and chemical modification of bamboo in the fixation of boron within its microstructure and evaluate the resulting physical-mechanical performance, involved chemical modification mechanisms as well as biological degradation and flammability. The treatment will be performed aiming the utilization of bamboo for external applications, especially as a structural element in rural construction. For this study the species Dendrocalamus asper will be used, which is widely found in Brazil, presents great size and is suitable for civil construction, furniture, laminated bamboo production and other materials. The acquired results with this project may also be extended for the treatment of other bamboo species and other lignocellulosic based materials, such as solid wood, glued laminated bamboo and particle boards with the intention of improve the durability of the final product. (AU)