Materials Science Forum Vol. 1046

Abstract: In developing countries, large quantities of agricultural residues associated with harvests are generated, given that agriculture is one of the most important economic activities. The valorization of these residues for the construction sector could contribute to the improvement of energy efficiency in buildings. Through passive techniques, the construction of insulating thermal-acoustics panels, blocks, and aggregate for reinforced concrete can improve the energy efficiency. In this study, an experiment was performed to measure thermal conductivity of the Agricultural-Thermal Insulation Panel (ATIP) based on rice hulks. These Agricultural-Thermal Insulation Panels were elaborated follow a standard process to compaction of the rice hulks to be employed as insulation material with a panel dimension of 200x200x34.5(mm3). A “Hot Box” configuration was used to obtain the thermal conductivity of the panels, using different temperature gradients between hot and cold chambers.

Abstract: The NH4OH-KOH pulping was a highly efficient process for extracting banana pseudostem waste (BNW) pulp. Besides, this greener pulping process allowed NH4OH recovery and KOH can be later used as fertilizer, reducing the environmental impact. It was found that the optimal BNW pulping condition was using 8.3 wt% NH4OH and 3.3 wt% KOH at a cooking temperature of 155°C for 1 h, and liquid to solid ratio 6:1. From the results, this process allowed low chemical usage and provided high pulp yield (44%) with a high delignification degree (80%) and low Kappa no. (22). After pulping, the single-stage bleaching of BNW pulp using 8 wt% H2O2 and 1.5 wt% NaOH at 90°C for 1 h was shown to improve the whiteness and brightness of the BNW molded pulp samples to 69.7% and 28.7%ISO (3-fold increase), respectively. As compared to commercial molded pulp food packaging, the present BNW molded pulp exhibited a superior tensile index of 54.3 Nm/g and Young’s modulus of 4.8 GPa.

Abstract: A water treatment sludge (WTS) was characterized in order to evaluate if its properties would be suitable for use as liner of earthworks or for strengthening a clay soil. A WTS and a clayey soil was characterized in terms of granulometry, cumulative volumes, specific surface, density, plastic limit, liquid limit, water content, hydraulic conductivity, and characteristics of compaction (optimal water content and dry density). This study aimed to exhibit and evaluate these investigated parameters of WTS, soft soil and mixed proportions between the materials for liners’ material production while evaluating soft soils’ reinforcement feasibility. The results have shown WTS’s contribution with its fine granulometry and compaction characteristics, indicating filling properties and possible feasibility as soft soils additions for liners’ material production while being applicable for soils‘ reinforcements, corroborating with existing literature on the subject. Thus, the currently developed investigation has exposed WTS as a potential addition for these applications while also attending society’s new demands towards a more sustainable future.

Abstract: Efficient bipolar plates are needed to store electricity from renewable energies. Here the focus is concentrating on graphite-compound-Bipolar plates, which are one of the most used components in a Fuel Cell Stack system. Among other things, polypropylene is a suitable matrix material, but other polymer materials such as PPS and PVDF and phenolic resins can also be considered. However, for a correspondingly high conductivity in the fuel cell system, the plastic must be filled with up to more than 80 % graphite. To ensure that the compound is not brittle afterwards and is as easy to process as possible, an impact modify cation was further developed that makes it possible to produce thin films.

Abstract: This paper explores how the application of nanotechnology can enhance the efficacy of construction materials, decrease consumption and cost of materials, whilst further increasing sustainability in the South African construction industry. Nanotechnology controls matter at an atomic level. At this level the properties of matter are manipulated and severely affected with potentially significant benefits to the construction industry. This exploratory desktop study examined relevant scientific literature through thematic content analysis and the uses of NanoSilica, Carbon Nanotubes, Titanium Dioxide, Zinc Oxide, Nanosilver, and Copper Nanoparticles were extracted and discussed.

Abstract: In this paper, poly(lactic acid) (PLA) was modified with poly(butylene succinate) (PBS) and talc to obtain PLA formulation with good toughness and high crystallization rate. PBS was added as a toughening agent at 40wt% and talc was added as a nucleating agent from 2 to 10wt%. Experimental results showed that both the tensile modulus and strength of PLA significantly decreased with the presence of PBS. Both values were found to notably increase with talc concentration and reached the maximum value at 8wt%. The tensile elongation at break was found to remarkably increase with PBS blending. However, it was linearly dropped with talc addition. Thermal test results also indicated the faster crystallization rate with the decreased crystallization temperature (T_c) and increased degree of crystallinity (X_c), by more than four times, when talc was added at least 4wt%. The isothermal crystallization half-time (t_1/2) was applied to provide the data for injection molding process. The results showed that neat PLA required more than 25 min to obtain its half crystallinity. Minimum t_1/2 of 3.45 min was obtained when talc was added to PLA/PBS at 8wt%. Heat distortion temperature (HDT) was also found to increase from 56.8 (neat PLA) to 97.2°C (8wt% talc). Based on the experimental results, the optimum talc concentration was 8wt% which provided the highest crystallization rate and thermal stability. The practical application of this formulation is for the biodegradable injection molding products.

Abstract: The possibility to produce new components using reclaimed non-woven carbon fabric has been investigated. Being composite waste production increased, different strategies and technologies for recycling are developing to face criticalities and economic aspects related to their disposal. In this scenario, CFRP laminates with recycled carbon fiber and epoxy vinyl ester resin have been fabricated by Resin Infusion under Flexible Tooling (RIFT) and mechanical characterization has been performed to investigate their behavior under tensile, flexural and macro-indentation loads.

Abstract: Mathematical modeling for 3D bioprinting allows us to avoid widespread errors and also time and financial losses. It is necessary for such critical processes as tissue spheroids fusion and diffusion of nutrients in them. The reason is that tissue spheroids fusion is the base of the 3D bioprinting technology. In this work, we propose an approach for tissue spheroids fusion modeling considering a need to compromise between fidelity of the geometric form and viability of the whole bioconstruct.

Abstract: It is quite amazing that the use of 3D printing techniques, especially the Fused Deposition Modelling (FDM) has delivered such significance in terms of cost reduction, time saver features where a different variety of thermoplastic and composite materials (Biodegradable and Non-biodegradable) are well developed. Different sectors have continually developed natural organic materials that are also both structurally composite in nature. Similarly, the use of different fibers that are abundantly accessible and considered as renewable resources which can be optionally combined with other biodegradable materials is a great challenge through the use of the FDM printing method. The study aims to determine the effect of different particle size and raster angle at a certain fiber concentration which could affect the mechanical properties of the composite by developing a printable composite filament made of Polylactic Acid (PLA) and Coco Coir materials using a filament maker and FDM printer. The composite filament was fabricated and optimized using a twin-screw extruder and 3D Devo Filament maker. 3D printing of samples for mechanical testing was conducted using three (3) raster angles (45^o, 60^o, and 75^o) and various particle sizes of coco coir fiber reinforcement in the PLA matrix. Results showed that the < 74μm particle size of the coco-coir exhibited a 24% and 175% increase in tensile strength and izod impact strength compared to the pure PLA at 60^o and 75^o raster angles, respectively. Likewise, the reinforcement of <149μm particle size coco coir at 45^o raster angle contributes to an increase of 4.8% flexural and 176% compressive strength compared to pure PLA. The study concludes that there is an improvement in the mechanical properties of the PLA-Coco Coir composite at a certain particle size and raster angle in 3D printing.

Abstract: Data analysis of the coating performance of Zn electrodeposited plain carbon steel in 0.5 M HCl solution at specific volume addition (5 ml, 10 ml and 15 ml) of onion, glycine and cassava (ON, GY and CS) distillate additives, and at plating time of 15 and 18 mins with respect to 538 h of observation time was performed. Analytical outputs showed ON distillate most effectively improved the Zn electrodeposited by 14% at 10 ml volume and plating time of 15 mins. GY and CS distillate generally improved the Zn electrodeposited at all volumes and plating time with optimal values of 42.7% and 45.7% at 15 ml and plating times of 15 and 18 mins. Generally, coating performance varied significantly with observation time, but marginally with plating time and additive volume. The standard deviation values for onion additive showed significant variation from mean values due to relative thermodynamic instability of it coating performance with respect to observation time. This contrast the output observed for GY and CS additives which signifies thermodynamic equilibrium. The proportion of coating performance data above 10% improvement for the additives are (ON, GY and CS) are 32%, 85% and 78% at margin of error of 11.8%, 9.04% and 10.42%. Analysis of variance showed ON and GY additive volume only, influenced the coating performance output of the additives at 64.56% and 74.67% while CS additive volume and observation time influenced the coating performance output of CS at values of 91.18% and 3.27%.