Investigation of the Usability of Different Biomass Sources in Biocomposite Material Production
Project no. 22815 · Status: Kapanmış · 2021
Summary
<p>With the increasing impact of climate change and environmental issues, there is a growing demand for sustainable construction materials. Biomass-based materials, derived from renewable sources and with reduced carbon footprint, have the potential to meet this demand. Materials obtained through the conversion of biomass can be used in various applications in the construction sector, such as structural elements, insulation materials, and coatings. These materials exhibit properties similar to traditional materials while being environmentally friendly and sustainable, making biomass materials an attractive alternative. The use of biomass materials also contributes to solving waste management issues and promotes the development of an environmentally friendly construction sector. In this thesis, agricultural residues (cotton and rice stalk), fungus (Rhizopus oryzae microorganism), and textile waste (hemp fibers) were used to produce fiber reinforcement materials through thermal, biological, and chemical pretreatment processes. In the first stage, thermal conversion was employed to produce biochar from cotton and rice stalk. Biochar obtained under the conditions of 550°C-90 min exhibited the highest carbon content of 76.22% for cotton and 53.64% for rice stalk, making it suitable as a reinforcement material. The second stage of the thesis involved solid-state fermentation to produce mycelium from Rhizopus oryzae fungus. The highest spore count was observed in a 100% wheat bran medium. Subsequently, optimization experiments were conducted using Design Expert 7.0 Central Composite Design with independent variables of moisture content (30%-80%), inoculum (10%-30%), and time (2 days-10 days) in a wheat bran solid medium. The optimization resulted in the selection of the program with 79.94% moisture, 28.01% inoculum, and 9.74 days, leading to the production of fiber reinforcement material. In the third stage, hemp fibers subjected to enzymatic pretreatments with pectinase and xylanase, followed by fluorocarbon pretreatment at 80 g/1L and pH 5-6, condition chemical pretreatment. All reinforcement materials were ground to a homogeneous state with particle size below 200 μm and dried. Subsequently, the fiber/PLA (Polylactic Acid) composites were produced by blending the granules obtained from combining the reinforcement materials with PLA at different loading ratios of 4%, 5%, 8%, and 10% using a twin-screw extruder. Injection molding was then employed to produce the biocomposites. To determine the material properties of the product, various characterization tests such as density, mechanical tests, XPS analysis, thermogravimetric analysis, DSC analysis, HDT-Vicat analysis, thermal conductivity, and</p><p>SEM analysis were conducted. The results showed that the thermal conductivity of the 5% fungus/PLA and 5% hemp/PLA biocomposites was 0.038 W/mK and 0.052 W/mK, respectively, indicating their potential to compete with existing insulation materials. Thus, the use of materials derived from biomass sources in the construction sector contributes to sustainability and addresses environmental challenges. In the future, with the increasing use of biomass materials, it will be possible for the building sector to follow a more sustainable and environmentally friendly path.</p>