The micromechanics of graphene oxide and molybdenum disulfide in thermoplastic nanocomposites and the impact to the polymer-filler interphase

peer reviewedThe addition of two-dimensional nanomaterials to a polymer matrix is a widely known manner to mechanically reinforce the material. The stress-transfer in the polymeric matrices, however, depends on an array of filler and matrix properties as well as on their interface. In this work, we discuss the effects of the distinct levels of interaction of graphene oxide, reduced graphene oxide and molybdenum disulfide with poly(vinyl butyral) in the reinforcement of the polymer. For that, we employed the micromechanical analysis model originally developed by Young et al., which describes the reinforcement behavior of graphene nanoplatelets in a wide range of polymer matrices. Then, using an innovative approach derived from such analysis, we propose novel methods to mathematically evaluate the effects of the filler content upon the polymer/filler interface, and for the determination of the mechanical percolation threshold

Thermal Conductivity Performance of 2D hBN/MoS 2/Hybrid Nanostructures Used on Natural and Synthetic Esters

In this paper, the thermal conductivity behavior of synthetic and natural esters reinforced with 2D nanostructures-single hexagonal boron nitride (h-BN), single molybdenum disulfide (MoS2), and hybrid h-BN/MOS2-were studied and compared to each other. As a basis for the synthesis of nanofluids, three biodegradable insulating lubricants were used: FR3TM and VG-100 were used as natural esters and MIDEL 7131 as a synthetic ester. Two-dimensional nanosheets of h-BN, MoS2, and their hybrid nanofillers (50/50 ratio percent) were incorporated into matrix lubricants without surfactants or additives. Nanofluids were prepared at 0.01, 0.05, 0.10, 0.15, and 0.25 weight percent of filler fraction. The experimental results revealed improvements in thermal conductivity in the range of 20-32% at 323 K with the addition of 2D nanostructures, and a synergistic behavior was observed for the hybrid h-BN/MoS2 nanostructures

REPLACEMENT OF CEMENT BY FILLER TO REDUCE CO2 AND NANO-SILICA TO ENSURE HIGH-PERFORMANCE COMPOSITES

<p><i>High-performance cementitious composites (HPC) represent a class of materials known for higher mechanical strength compared to traditional ones. Incorporating nanomaterials like metakaolin (MK) and microsilica (MS) can lead to greater improvements in mechanical properties. However, these materials, and mainly cement, entail environmental impact as they require high-temperature transformation processes. So, even high-strength concretes must address environmental concerns, necessitating innovative approaches. The replacement of cement with inert fillers has emerged as a strategy for reducing cement content and environmental impact, since their production involves grinding rather than high-temperature processes, resulting in lower CO2 emissions. However, their inert nature limits reactivity, compromising the performance. </i><a href="https://www.ijaet.org/media/9I77-IJAET1605059-v16-i5-pp376-391.pdf"><i>This study seeks</i></a><i> to evaluate the feasibility of producing HPC by partially replacing cement with quartz fillers (QF). This substitution was accompanied by the addition of small quantities of nano-silica to evaluate if losses in rheology and strength, caused by increased filler content, could be compensated. It was developed 5 mixtures: M0 (reference); and M1 to M4, with cement replacement by contents of 4 to 16% of NS and QF. It was measured rheological and mechanical performance. </i><a href="https://www.ijaet.org/media/9I77-IJAET1605059-v16-i5-pp376-391.pdf"><i>Results show that nano-silica's high surface area</i></a><i> enhances hydration reactions, contributing to the mechanical performance, and can increase the packing of particles due to its very fine particle size distribution, contributing to rheological performance. Nevertheless, these benefits are restricted to a maximum content: after the limit where voids between coarser particles are fully filled by NS, it does not contribute to packing anymore, but the surface area continues to grow directly proportional to NS increase, with negative impacts on final rheological performance.</i></p><p>Paper Published in International Journal of Advances in Engineering & Technology (IJAET), Volume 16 Issue 5, pp. 376-391, October 2023. Available online at: https://www.ijaet.org/media/9I77-IJAET1605059-v16-i5-pp376-391.pdf</p&gt