Poly(Lactic) Acid Reinforced with Alkaline Lignin Biocomposites Prepared by Thermal Extrusion for Sustainable 3D Printing Process

The focus of this work is the mechanical characterization of biomaterials produced by 3D printing based on fused filament fabrication (FFF) process that has been mainly used for prototype rather than functional components due to the limited mechanical properties of pure thermoplastics parts. Addition of reinforcements from natural fiber has been adopted to improve the mechanical properties of the 3D printed parts. In this study, alkaline lignin powder that has been extracted from oil palm empty fruit bunches (OPEFB) via alkaline extraction process were used as filler in the production of biocomposites with poly(lactic) acid (PLA). Poly(lactic) acid filaments filled with 1% of alkaline lignin powder and has been compared with the presence of 5% of epoxidized palm oil (EPO) by means of thermal extrusion and further proceed with 3D printing. The samples were mechanically characterized using tensile tests and the fractography were observed. Tensile test that has been done on the filaments reveal that the filament with addition of lignin and EPO shows improved mechanical properties with higher tensile strength as well as lower stiffness. The 3D printed samples of the filament compositions also exhibit similar trend where the said filament has the best mechanical properties when the EPO is incorporated in the filament.

Feasibility of Rough Sets Theory in Predicting Heat Transfer Performance in Thermally Developed Flow of Third Grade Nanofluid with Gyrotactic Microorganisms

In recent years, considerable attention has been paid towards the nanotechnology research, which is an emerging area of research with many industrial and engineering significance. The nanofluids which use metallic nanoparticles to enhance the thermal extrusion system are considered as bio-friendly, durable and sustainable products. Nanofluids are engaged in fundamental applications like nuclear reactors, medical agents, material fabrication, chemical industries, geo-thermal engineering, petroleum industries etc. In recent years, a variety of experimental and theoretical computations were performed to explore the thermophysical aspects of such nanoparticles. Further, flow of nanoparticles containing gyrotactic microorganisms has interesting applications in microbial fuel cells, bio-technology and enzyme biosensors. The main purpose of the present paper is to use the rough sets theory to generate a set of rules to predict the heat transfer performance of a third grade nanofluid in thermally developed flow with gyrotactic microorganisms. The rough set reduction technique is applied to find all reducts and then a set of generalized rules is extracted to predict the value of local Nusselt number, local Sherwood number and motile density number. The generated results shows that our method can effectively predict these values with high accuracy and may be valuable in many engineering applications like power production, thermal extrusion systems and microelectronics.

Preliminary Investigation on Auto-Thermal Extrusion of Ground Tire Rubber

Ground tire rubber (GTR) was processed using an auto-thermal extrusion as a prerequisite to green reclaiming of waste rubbers. The reclaimed GTR underwent a series of tests: thermogravimetric analysis combined with Fourier-transform infrared spectroscopy (TGA-FTIR), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and static headspace and gas chromatography-mass spectrometry (SHS-GC-MS) in order to evaluate the impact of barrel heating conditions (with/without external barrel heating) on the reclaiming process of GTR. Moreover, samples were cured to assess the impact of reclaiming heating conditions on curing characteristics and physico-mechanical properties. Detailed analysis of the results indicated that the application of auto-thermal extrusion is a promising approach for the sustainable development of reclaiming technologies.