The effect of lamina configuration and compaction pressure on mechanical properties of laminated gigantochloa apus composites

This study aims to investigate the mechanical properties of bamboo apus (gigantochloa apus) as a natural reinforced composite material. Bamboo’s laminates of gigantochloa apus were used as reinforcement on the epoxy resin matrix. The parameters examined in this study are the configuration of lamina and compaction pressure. Laminate configuration varies in the number, thickness and direction of the lamina. Compaction pressures of 1.5 MPa, 2 MPa, and 2.5 MPa were used to fabricate the Laminated Bamboo Composites (LBCs). The stem of bamboo with a length of 400 mm was split to obtain bamboo lamina with a size of 400×20 mm. The thickness of bamboo lamina is varied between 1 mm, 1.5 mm, and 2 mm. The bamboo lamina is then preserved by watering it with a preservative solution in the form of 2.5 % sodium tetraborate solution and dried in an oven until the water content reaches 10 %. LBCs were made with a hand lay-up method. After the LBCs were molded, they were pressed with 3 variations of dies compaction 1.5 MPa, 2 MPa and 2.5 MPa. The tensile and bending tests were carried out on the LBCs. Tensile testing is performed in accordance with ASTM standard D3039 and the bending tests were conducted based on ASTM standard D7264. The results show that at each compaction pressure, the highest tensile and bending strength was achieved by LBCs with a thickness of 1 mm of bamboo lamina and 7 layers of bamboo laminates. The LBC with thinner bamboo lamina reinforcement and more layers has the highest tensile strength and bending strength, even it has a lower mass fraction. The LBCs with laminates oriented 0° exhibited greater tensile and bending strengths than the LBCs with laminates structured –45°/+45° and 0°/90°. The LBCs with the 0° laminates direction is matrix fracture followed by lamina fracture. In the 0°/90° direction, matrix fracture is followed by delamination in the 90° and 0° laminates direction. Delamination and lamina clefting were observed in LBCs with laminates oriented +45°/–45°.

Enhancing the properties of damar (Agathis loranthifolia Salisb.) wood by making hybrid bamboo-wood composite

This study was carried out to investigate the characteristics of laminated bamboo and damar (Agathis loranthifolia Salisb.) wood as the core layer of the bamboo-damar hybrid composite beam. Andong bamboo (Gigantochloa pseudoarundinacea (Steud.) Widjaja) and mayan bamboo (Gigantochloa robusta Kurz.) were used as the face and back layers of the beam, glued with isocyanate adhesive. Four types of composite beam were produced with various number of laminated bamboo layers. Results showed that the four layers (two layers for each face and back sides) laminated andong bamboo performed superior mechanical properties than others hybrid composite beam, while the four layers (two layers for each face and back sides) laminated mayan bamboo demonstrated the highest compression and bonding strength. The density, MOR, MOE and compression strength of the hybrid composite beam improved 31.3%, 25.95%, 37.81% and 25.12%, respectively, as the outcomes of the incorporation of laminated andong bamboo on the outer layers of the damar board. This paper proves that the number of laminated bamboo layers enhances the properties of the bamboo-damar hybrid composite beam. Furthermore, it shows promising result for complementing furniture and interior design materials as the bamboo-damar hybrid composite beam has remarkable properties.