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Cellulose nanocrystals (CNC) and nanofibers (CNF) have been broadly studied as renewable nanomaterials for various applications, including additives in cement and plastics composites. Herein, life cycle inventories for 18 previously examined processes are harmonized, and the impacts of CNC and CNF production are compared with a particular focus on GHG emissions. Findings show wide variations in GHG emissions between process designs, from 1.8-1100 kg CO2-eq/kg nanocellulose. Mechanical and enzymatic processes are identified as the lowest GHG emission methods to produce CNCs and CNFs. For most processes, energy consumption and chemical use are the primary sources of emissions. However, on a mass basis, for all examined production methods and impact categories (except CO emissions), CNC and CNF production emissions are higher than Portland cement and, in most cases, are higher than polylactic acid. This work highlights the need to carefully consider process design to prevent potential high emissions from CNCs and CNF production despite their renewable feedstock, and results show the magnitude of conventional material that must be offset through improved performance for these materials to be environmentally favorable.

Many materials have been explored for the purpose of creating structures with high radiative cooling potential, such as nanocellulose-based structures and nanoparticle-based coatings, which have been reported with environmentally friendly attributes and high solar reflectance in current literature. They each have their own advantages and disadvantages in practice. It is worth noting that nanocellulose-based structures have an absorption peak in the UV wavelengths, which results in a lower total solar reflectance and, consequently, reduce radiative cooling capabilities. However, the interwoven-fiber structure of cellulose gives high mechanical strength, which promotes its application in different scenarios. The application of nanoplatelet-based coatings is limited due to the need for high volume of nanoparticles to reach their signature high solar reflectance. This requirement weakens the polymer matrix and results in more brittle structures. This work proposes a dual-layer system, comprising of a cellulose-based substrate as the bottom layer and a thin nanoparticle-based radiative cooling paint as the top layer, where both radiative cooling potential and mechanical strength can be maximized. Experimental and theoretical studies are conducted to investigate the relationship between thickness and reflectance in the top coating layer with a consistent thickness of the bottom layer. The saturation point is identified in this relationship and used to determine the optimal thickness for the top-layer to maximize material use efficiency. With the use of cotton paper painted with a 125 μm BaSO4-based layer, the cooling performance is enhanced to be 149.6 W/m2 achieved by the improved total solar reflectance from 80 % to 93 %.

3D printing (3DP) technologies have transformed the processing of advanced ceramics for small‐scale and custom designs during the past three decades. Simple and complex parts are designed and manufactured using 3DP technologies for structural, piezoelectric, and biomedical applications. Manufacturing simple or complex geometries or one‐of‐a‐kind components without part‐specific tooling saves significant time and creates new applications for advanced ceramic materials. Although development and innovations in 3DP of ceramics are far behind compared with metals or polymers, with the availability of different commercial machines in recent years for 3DP of ceramics, exponential growth is expected in this field in the coming decade. This article details various 3DP technologies for advanced ceramic materials, their advantages and challenges for manufacturing parts for various applications, and perspectives on future directions. We envision this work will be helpful to advanced ceramic researchers in industry and academia who are using different 3DP processes in the coming days. [ABSTRACT FROM AUTHOR]

Disasters can prompt hydrocarbon contaminants to reach building water systems, and ultimately customer fixtures. Here, seven water supply connectors (e.g., ice‐maker lines, faucet connectors, washing machine hoses) were exposed to contaminated water, and were subsequently decontaminated by water flushing. After a 24 h contamination period, water samples were collected after three consecutive 72 h exposure periods. Samples were characterized for volatile organic compound, semi‐volatile organic compound, and total organic carbon concentrations. New, uncontaminated, PVC tubing leached phenol at concentrations that exceeded the health advisory. All materials sorbed more than 90% of hydrocarbon contaminants during the initial exposure period. All materials then released the contaminants into the water during decontamination, at times above health‐based limits. The majority of sorbed mass remained in the plastics at the end of the decontamination effort, indicating the products posed continued leaching risks. Public health guidance considerations and research needs were identified. [ABSTRACT FROM AUTHOR]

Reinforcing strategies for three-dimensional printing (3DP) of cementitious materials (mostly mortars) have been extensively studied in recent years. Among various reinforcement strategies available for 3DP of cementitious materials, the use of fibers is frequently mentioned as a promising approach to enhance their mechanical performance. This work aims to evaluate the influence of four types of fibers (polyvinyl alcohol [PVA], nylon, rayon, and basalt) on the flowability and flexural strength of mortars used in 3DP. The flexural behavior of 3DP beams was compared with that of cast specimens, and the digital image correlation (DIC) technique was used to evaluate the development of the cracks. The fiber orientation in the reference (cast) and 3DP samples was examined using optical microscopy. The results revealed that, among four types of fibers used, the PVA fibers were most effective in increasing the flexural strength of both the cast and 3DP specimens. In addition, the results show that all fibers preferentially aligned parallel to the printing direction. 3DP specimens with filaments aligned in the direction perpendicular to the direction of the applied load showed superior flexural strength when compared to the cast specimens. [ABSTRACT FROM AUTHOR]

Bio‐based organic phase change materials (PCMs) have drawn attention considering their great value in environmental sustainability as a latent heat storage strategy. In this study, bio‐based fatty acid amides (FAAms) were synthesized directly from soybean oil and different amines through a solvent‐free reaction with a non‐toxic catalyst (DABCO). The chemical and thermal properties were confirmed by FT‐IR, NMR, DSC, and TGA measurements. The effects of oil saturation and chain length were investigated. FAAms were successfully synthesized from most of the primary alkyl amines with high purity and yield. Fifteen different FAAms exhibit high latent heat (up to 202 J/g) with a single‐phase transition peak. A general trend of increasing enthalpy of fusion, narrower phase transition temperature range, higher melting temperature, and better thermal stability was found with increasing FAAms chain length. An opposite trend was observed for some long‐chain FAAms (C > 42). Overall, a wide choice of green, organic PCMs with comparable thermal properties to petroleum based PCMs is provided in this work. Those FAAms with high working temperatures (>100°C) could expand the application of organic PCM to different fields such as steam generation, textile, rubber industry, etc. [ABSTRACT FROM AUTHOR]