Papers by Keyword: Green Material

Abstract: The purpose of this study is to explore the use of laser additive manufacturing of bamboo powder to produce items with fewer variations than the traditional heat press method using a die. Although metal and resin powders are commonly used in powder additive manufacturing, bamboo powder presents unique challenges owing to its lack of material uniformity, low carbonization temperature, and dependence on pressure for adhesion. To address these issues, the appropriate laser power and irradiation time were determined by irradiating the laser at several power levels and examining its effects on the powder temperature and chemical changes during molding. The results indicated that rapid heating occurred at approximately 150 °C, and carbonization began at approximately 190 °C. As the energy loss for carbonization decreases with increasing laser power, this method is expected to be effective for producing bamboo products with fewer variations. In addition, restriction of continuous oxygen inflow by the glass plate lid makes it feasible to prevent heat generation and carbonization. Furthermore, pressurization by the glass plate makes it feasible to improve adhesion. Future research will focus on the suppression of carbonization by inert gas and heating at low temperatures for long periods of time, as well as the effects of different magnitudes of pressure on the process.

Abstract: To address global environmental challenges and mitigate bamboo-related ecological damage, this study focuses on the development of self-adhesive molded products utilizing solely bamboo fibers and powder obtained through machining center extraction. However, the mechanical properties of these molded products remain inadequate. This study utilizes Scanning Electron Microscope (SEM) and Fourier transform infrared spectrometer (FTIR) analyses to explore the disparities associated with chip size as raw materials for molded products. Bamboo fiber, characterized by its substantial cellulose content and high strength, is contrasted with bamboo powder, which contains significant amounts of lignin and exhibits potential adhesive properties. Building upon these findings, the powder was added to the conventional fiber alone, with results demonstrating that a predetermined ratio (20%) of the powder yields optimal mechanical properties. Moreover, employing a parameter representing the degree of lignin flow utilized in previous molding studies, the study establishes the optimum molding conditions (PD'=1.031) to maximize tensile strength (37.8 MPa) when incorporating a 20% powder mixture.

Abstract: Climate change is recognized as a global problem and even the industrial and construction sectors are trying to reduce the green-house gas emissions, especially on CO₂ emissions. In Vietnam, the coal-fired thermal power plants are discharging millions of tons of CO₂ and coal ash annually. This coal ash is comprised of about 80% of fly ash and the rest is bottom ash. This study would like to introduce one of the potential solutions in a carbon-constrained society that would not only manage the fly ash but also utilized this as raw material for green materials through geopolymerization. The geopolymer-based material has lower energy consumption, minimal CO₂ emissions and lower production cost as it valorizes industrial waste. The fly ash containing high alumino-silicate resources from a coal-fired power plant in Vietnam was mixed with sodium silicate and sodium hydroxide solutions to obtain the geopolymeric pastes. The pastes were molded in 10x10x20cm molds and then cured at room temperature for 28 days. The 28-day geopolymer specimens were carried out to test for engineering properties such as compressive strength (MPa), volumetric weight (kg/m³), and water absorption (kg/m³). The microstructure analysis was also conducted for this eco-friendly materials using X ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Differential Thermal Analysis - Thermal Gravimetric Analysis (DTA-TGA).

Abstract: Eco-friendly building materials with perfect thermal insulation & sound absorption property have become intriguing and eye-catching in recent years. In this work, the ultra low-density binderless sandwiching materials were firstly fabricated with ultra low-density of 60-80 kg/m3 by self-designed rapid steam injection technology. The main experimental factor of density, holding time, transmission time, steam injection pressure and fiber’s dimension was respectively investigated to their effects on formation of the new building materials. IR, Py GC-MS and AFM analysis were performed to study the mechanism of binderless sandwiching materials under steam injection process. The bending strength, thermal insulation & sound absorption property of the new materials were also studied. This new building material with no resin use and no formaldehyde release is expected to be reserved as the sandwich for designing thermal insulation & noise reduction building materials.

Abstract: Natural fiber reinforced composites material are used in more and more industries for their low cost, lightweight, and more importantly, the properties of friendship to environment. Environmental friendship is a very significant superiority of natural fiber composites for auto industry. In this paper, the following aspects are reviewed: (1) superiority of natural fiber reinforced composite materials to glass fiber reinforced composite material, especially when they are used in automobile industry; (2) current usage in automobile industry and the prospective in the future; (3) recent developments.

Abstract: The effect of natural rubber and glycerol addition on the mechanical performance of Tacca leontopetaloides biopolymer was investigated in this paper. The samples were formulated by varying blend ratios of latex natural rubber to glycerol; 40/30 (GM1), 50/5.85 (GM2), 60/30 (GM3), 40/10 (GM4) and 50/20 (GM5). The samples (GMs) were compounded by using two roll mill machine followed by vulcanization process with the presence of stearic acid and sulphur that act as curing agent. The sheet formed was cut into desired sizes, based on the analysis conducted. The mechanical performance of GMs was investigated by conducting tensile test, morphological structural analysis and water absorption test. The mechanical properties of GM2 showed a high tensile strength with low Young’s modulus compared to other GMs, thus indicating that GM2 was the superior combination of natural rubber to glycerol blend ratio. This, therefore, may be applied for the development of biopolymer with the properties of thermoplastic elastomer.