Due to the unique properties of carbon nanotubes (CNTs), the electrical and thermal conductivity of CNT-modified polymeric composites (CNTMPCs) can be manipulated and depend on several factors. There are many factors that affect the thermal and electrical conductivity of CNTs and CNTMPCs, such as chirality, length, type of CNTs, fabrication, surface treatment, matrix and interfacial interaction between the matrix and reinforcement (CNTs). This paper reviews the research on molecular dynamics (MD) simulations of the effects of some factors affecting the thermal and electrical conductivity of CNTs and CNTMPCs. First, the chirality dependence of the thermal and electrical conductivity of single-walled carbon nanotubes (SWNTs) was analyzed. The effect of chirality on the conductivity of short-length CNTs is greater than that of long-length CNTs, and the larger the chiral angle, the greater the conductivity of the CNTs. Furthermore, the thermal and electrical conductivity of the zigzag CNTs is smaller than that of the armchair one. Therefore, as the tube aspect ratio becomes longer and conductivity increases, while the effect of chirality on the conductivity decreases. In addition, hydrogen bonding affects the electrical and thermal conductivity of the CNTMPCs. The modeling of SWNTs shows that the thermal and electrical conductivity increases significantly with increasing overlap length. MD simulations can be effectively used to design highly conductive CNTMPCs with appropriated thermal and electrical properties. Since there are too many factors affecting the thermal and electrical conductivity of CNTMPCs, this paper only reviews the effects of limited factors on the thermal and electrical conductivity of CNTs and CNTMPCs based on MD simulations, and further detailed studies are required.

Human society’s need to build low-weight, high-strength and durable structures has increased the demand for composite materials. In this case, composites are used where high mechanical strength, low weight, sound and thermal insulation properties are required. One of the most important issues now is designing materials and coatings aimed at reducing heat loss and resisting high temperatures. One way to address this problem is to develop a technique for preparing and applying composite materials that slow down their heating applied to a surface. In this study, carbon nanotubes (CNTs) reinforced composites were fabricated using silicone molding to be applied to honeycomb sandwich structures. To determine the effect of CNTs on the thermal behavior of the sandwich panels, different weight percentages of this material (0.025, 0.05. 0.075 wt.%) were added to the epoxy resin. The results showed that the thermal stability of the epoxy composites was directly related to the increase in the percentage of CNTs as the CNT content increased to 0.075 wt.%, and the thermal degradation temperature of the epoxy composites increased by 14 °C. In addition, the energy absorption increased by 4.6% with an increase in CNTs up to 0.075 wt.%. Density measurements showed that the density of the nanocomposite samples increased by adding CNTs to pure epoxy resin. The actual densities of the samples reinforced with 0.025, 0.05, and 0.075 wt.% CNTs are 0.925, 0.926, and 0.927 of the theoretical density, respectively. Since the CNT dispersion uniformity in the epoxy matrix can significantly affect the properties of the composites, in this study, a new method of dispersing CNTs in the epoxy resin matrix resulted in higher thermal conductivity while using lower amounts of CNTs compared to other studies. The storage modulus of the epoxy matrix composites reinforced with 0.05 wt.% in this study was 25.9% and 6.9% higher than that from the previous study reinforced with 0.1 wt.% and 0.25 wt.% CNTs, respectively. Furthermore, the tanδ and loss modulus of the composite reinforced with 0.05 wt.% CNTs in this study were 52% and 54.5% higher than that from the previous study with 0.1 wt.% CNTs, respectively. This study provided an optimal approach for designers and engineers who want to effectively design their composite honeycomb sandwich structure with better thermal properties.

This comprehensive review investigates the potential of cyanobacteria, particularly nitrogen-fixing strains, in addressing global challenges pertaining to plastic pollution and carbon emissions. By analyzing the distinctive characteristics of cyanobacteria, including their minimal growth requirements, high photosynthetic efficiency, and rapid growth rates, this study elucidates their crucial role in transforming carbon sequestration, biofuel generation, and biodegradable plastic production. The investigation emphasizes cyanobacteria’s efficiency in photosynthesis, positioning them as optimal candidates for cost-effective bioplastic production with minimized land usage. Furthermore, the study explores their unconventional yet promising utilization in biodiesel production, mitigating environmental concerns such as sulfur emissions and the presence of aromatic hydrocarbons. The resulting biodiesel exhibits significant combustion potential, establishing cyanobacteria as a viable option for sustainable biofuel production. Through a comprehensive assessment of both achievements and challenges encountered during the commercialization process, this review offers valuable insights into the diverse contributions of cyanobacteria. Its objective is to provide guidance to researchers, policymakers, and industries interested in harnessing bio-inspired approaches for structural and sustainable applications, thereby advancing global efforts towards environmentally conscious plastic and biofuel production.

Biochar is a carbon-rich solid produced during the thermochemical processes of various biomass feedstocks. As a low-cost and environmentally friendly material, biochar has multiple significant advantages and potentials, and it can replace more expensive synthetic carbon materials for many applications in nanocomposites, energy storage, sensors, and biosensors. Due to biomass feedstock species, reactor types, operating conditions, and the interaction between different factors, the compositions, structure and function, and physicochemical properties of the biochar may vary greatly, traditional trial-and-error experimental approaches are time consuming, expensive, and sometimes impossible. Computer simulations, such as molecular dynamics (MD) simulations, are an alternative and powerful method for characterizing materials. Biomass pyrolysis is one of the most common processes to produce biochar. Since pyrolysis of decomposing biomass into biochar is based on the bond-order chemical reactions (the breakage and formation of bonds during carbonization reactions), an advanced reactive force field (ReaxFF)-based MD method is especially effective in simulating and/or analyzing the biomass pyrolysis process. This paper reviewed the fundamentals of the ReaxFF method and previous research on the characterization of biochar physicochemical properties and the biomass pyrolysis process via MD simulations based on ReaxFF. ReaxFF implicitly describes chemical bonds without requiring quantum mechanics calculations to disclose the complex reaction mechanisms at the nano/micro scale, thereby gaining insight into the carbonization reactions during the biomass pyrolysis process. The biomass pyrolysis and its carbonization reactions, including the reactivity of the major components of biomass, such as cellulose, lignin, and hemicellulose, were discussed. Potential applications of ReaxFF MD were also briefly discussed. MD simulations based on ReaxFF can be an effective method to understand the mechanisms of chemical reactions and to predict and/or improve the structure, functionality, and physicochemical properties of the products.