Bamboo Polypropylene Composites Research Articles

Recyclability of bamboo polypropylene composites

Recyclability of bamboo polypropylene composites

Micromechanical modeling of bamboo short fiber reinforced polypropylene composites

In recent years, there has been a growing interest in injection moulded Fiber Reinforced Polymer (FRP) composites, particularly with the natural fiber reinforcement due to their renewability and eco friendliness. In many of the applications, stiffness and strength are of prime importance in designing of injection moulded engineering parts. Determination of elastic modulus will give the designer flexibility to design the part geometry depending on stiffness requirement for particular application. This paper discusses micromechanical modeling of bamboo short fiber reinforced polypropylene composites. Bamboo polypropylene composites (BPC) were prepared by reinforcing polypropylene homopolymer matrix with short bamboo fibers. Composites with five different reinforcement percentages (10, 20, 30, 40, and 50 wt%) were prepared and tensile test samples were injection moulded. Tensile elastic modulus and strengths of bamboo composites were measured according to ASTM standard. Various micromechanical theoretical models were studied to find best possible model that correlates well with the experimental results. Elastic Modulus predicted by “Halpin-Tsai” model was in close agreement with the experimentally measured values. Strength predicted by “Kelly-Tyson” model also matched very well with the experimental values. Micromechanic-based semi analytical model “Mori–Tanaka” in Digimat-MF (mean-field homogenization) and numerical finite-element modeling (FEM) of BPC using the concept of representative volume element (RVE) have also been studied and results are compared with experimentally measured values.

Utilization of Waste Bamboo Fibers in Thermoplastic Composites: Influence of the Chemical Composition and Thermal Decomposition Behavior.

In this study, four types of waste bamboo fibers (BFs), Makino bamboo (Phyllostachys makinoi), Moso bamboo (Phyllostachys pubescens), Ma bamboo (Dendrocalamus latiflorus), and Thorny bamboo (Bambusa stenostachya), were used as reinforcements and incorporated into polypropylene (PP) to manufacture bamboo–PP composites (BPCs). To investigate the effects of the fibers from these bamboo species on the properties of the BPCs, their chemical compositions were evaluated, and their thermal decomposition kinetics were analyzed by the Flynn–Wall–Ozawa (FWO) method and the Criado method. Thermogravimetric results indicated that the Makino BF was the most thermally stable since it showed the highest activation energy at various conversion rates that were calculated by the FWO method. Furthermore, using the Criado method, the thermal decomposition mechanisms of the BFs were revealed by diffusion when the conversion rates (α) were below 0.5. When the α values were above 0.5, their decomposition mechanisms trended to the random nucleation mechanism. Additionally, the results showed that the BPC with Thorny BFs exhibited the highest moisture content and water absorption rate due to this BF having high hemicellulose content, while the BPC with Makino BFs had high crystallinity and high lignin content, which gave the resulting BPC better tensile properties.

Effects of a layered structure on the physicomechanical properties and extended creep behavior of bamboo-polypropylene composites (BPCs) determined by the stepped isostress method

Abstract A layered bamboo-plastic composite (BPC) consisting of bamboo (Phyllostachys makinoi) particles and polypropylene was investigated. The influence of the layering conditions, including the thickness and bamboo content in various layers, was the focus in terms of the physicomechanical and creep properties of the BPCs. The results showed that a three-layered BPC (BPC3L) with a 1:3:1 thickness ratio and with top/bottom layer containing 40% bamboo exhibited the best specific flexural properties. An accelerated creep test approach was applied, known as the short-term stepped isostress method (SSM), to predict the long-term creep behavior of BPC3L. The results indicated that the creep master curves, which are constructed from different SSM testing parameters, agree well with the long-term experimental creep data and that the creep resistance of homogeneous single-layered BPC was better than that of BPC3L.