Lunar soil, as an in-situ resource, holds significant potential for constructing bases and habitats on the Moon. However, such constructions face challenges including limited mechanical strength and extreme temperature fluctuations ranging from -170 degrees C to +133 degrees C between lunar day and night. In this study, we developed a 3D-printed geopolymer derived from lunar regolith simulant with an optimized zig-zag structure, exhibiting exceptional mechanical performance and thermal stability. The designed structure achieved remarkable damage tolerance, with a compressive strength exceeding 12.6 MPa at similar to 80 vol% porosity and a fracture strain of 3.8 %. Finite element method (FEM) simulations revealed that the triangular frame and wavy interlayers enhanced both stiffness and toughness. Additionally, by incorporating strategically placed holes and extending the thermal diffusion path, we significantly improved the thermal insulation of the structure, achieving an ultralow thermal conductivity of 0.24 W/(m K). Furthermore, an iron-free geopolymer coating reduced overheating under sunlight by 51.5 degrees C, underscoring the material's potential for space applications.

The brick walls of ancient buildings have got a lot of tiny and closely connected pores inside, so they can soak up water really well. This can easily cause problems like getting powdery and having efflorescence. To stop water from spoiling the grey bricks, this paper focuses on the brick walls of historical buildings in Kaifeng City. Based on our investigation, we study the distribution features of the problems. This paper tells about using the method of negative pressure infiltration to change the grey bricks. We measure all kinds of basic indicators and analyze how different ratios of modifiers affect the water properties and dry-wet cycle tests of the grey bricks. We look at the changes in the inside shape through SEM to show how it changes the grey bricks of ancient buildings. Second, we improve the wet walls by using a way that combines blocking and drainage. The main things we studied and the conclusions are like this: We use sodium methyl silicate and acrylamide polymer as modifiers to soak the historical grey bricks under negative pressure. We figure out the best ratio through orthogonal experiments. We analyze things like the water vapor permeability, how long it takes for a water drop to go through, the compressive strength, the water absorption rate, and the height of water absorption of the modified bricks. The results show that the crosslinking agent and acrylamide monomer have a big influence on how high the capillary water goes up in the modified bricks. The air permeability of the modified grey bricks with acrylamide polymer goes down a bit, but it's still okay. The surface of the modified grey bricks is very hydrophobic and there are fewer pores inside. The mechanical properties of the modified grey bricks get better in different degrees. The water absorption rate and the height of capillary water absorption go down. The modified grey bricks can really cut down the erosion of water on the wall when used in real life. They can reduce salt crystallization and efflorescence caused by rising water, and so make the brick walls of historical buildings last longer. This is super important for protecting historical buildings in Kaifeng City and taking care of other similar structures. Also, by using a way that combines blocking and drainage, and putting polymer infiltration reinforcement and the ventilation of the moisture drainage pipe together, the results show that this combination can really lower the height that capillary water goes up in the brick wall. So we get a way to control how wet the wall is.

Electronic waste (e-waste) from nonbiodegradable products present a significant global problem due to its toxic nature and substantial environmental impact. In this study novel electrically conductive biodegradable films of uncured natural rubber (NR) incorporating graphite platelets and chitosan were developed via a latex aqueous microdispersion method. Chitosan was added as a dispersing and thickening agent to encourage the uniform distribution of graphite in the NR matrix at loadings of 20-60 parts per hundred rubbers (phr). FTIR confirmed interactions between NR, graphite, and chitosan. FE-SEM and Synchrotron XTM analyses demonstrated uniform graphite dispersion. The result of XRD revealed the greatest crystallinity at 86.9% with 60 phr graphite loading. Mechanical properties testing indicated a significant increase in Young's modulus to 58.2 MPa, or about 470-fold improvement over the pure NR film. The composite films demonstrated improved thermal and chemical resistance, and their electrical conductivity could rise dramatically to 1.22 x 10-5 S cm-1 at 60 phr graphite loading, or about six orders of magnitude higher than pure NR film. The composite films exhibit antibacterial activity against Staphylococcus aureus and some inhibition against Escherichia coli. In addition, the NR composite films exhibited biodegradability ranging from 16.7% to 25.1% after three months of soil burial, declining with increased graphite loading. These results demonstrate the potential of NR-graphite composites as conductive materials for flexible electronics, such as thin-film electrodes in energy storage devices and sensors.

Lunar soil-based polymers, created using lunar soil as a precursor combined with highly automated 3D printing construction methods, hold great potential for lunar base construction. However, technical challenges such as ambiguities in characterizing rheological behavior and difficulties in regulation limit their 3D printing workability. To address these issues, the applicability of the Bingham model, Herschel-Bulkley (H-B) model, and a modified Bingham model to TJ-1 simulated lunar soil-based polymer was investigated by analyzing the fluidity variation. The effects of the solid-liquid ratio, Ca(OH)2, and Hydroxypropyl Methyl Cellulose ether (HPMC) on the 3D printing performance of the simulated lunar soil-based polymer were explored through one-way tests and standard deviation analysis. The results show that the modified Bingham model more accurately describes the rheological properties of TJ-1 simulated lunar soil-based polymer. HPMC proved to be an effective thixotropic agent for adjusting the 3D printing performance of the polymer. The yield stress and plastic viscosity of the polymer doped with 0.15 % HPMC were 3.577 Pa and 0.733 Pa s, respectively, meeting the requirements for printability. The yield stress and plastic viscosity of the simulated lunar soil polymers ranged from 1.84 to 3.58 Pa and 0.23-0.73 Pa s, respectively. Moreover, the compressive and flexural strengths of the simulated lunar soil polymers were significantly improved by adding Ca(OH)2. The optimal ratios for 3Dprinted simulated lunar soil polymers are a water-cement ratio of 0.30, 10 % NaOH, 8 % Na2SiO3, 6 % Ca(OH)2, and 0.10 % HPMC. Under these conditions, the 28-day compressive strength and flexural strength were 19.5 MPa and 6.9 MPa, respectively, meeting the strength standards of ordinary sintered bricks.The research results could provide a theoretical basis for the subsequent optimization of the simulated lunar soil base polymer mixing ratios for 3D printing.

Sustainable polymers have attracted interest due to their ability to biodegrade under specific conditions in soil, compost, and the marine environment; however, they have comparatively lower mechanical properties, limiting their widespread use. This study explores the effect of incorporating waste soy biomass into sustainable polymers (including biodegradable and biobased) on the thermal and mechanical properties of the resultant blends. The dispersion of the waste soy biomass in the polymer matrix is also investigated in relation to particle size (17 mu m vs. 1000 mu m). Fine waste soy biomass did not significantly affect the melting temperature of the polymers (polyhydroxyalkanoates, polybutylene adipate terephthalate, polybutylene adipate terephthalate/poly(lactic) acid, and biobased linear low-density polyethylene) used in this study, but their enthalpy of fusion decreased after soy was melt-blended with the polymers. The tensile modulus of the polymers filled with fine waste soy biomass powder (17 mu m) was enhanced when melt-blended as compared to unfilled polymers. Additionally, it was found that fine waste soy powder (17 mu m) increased the tensile modulus of the polymer blends without significantly affecting processability, while coarse waste soy meal (1000 mu m) generally reduced elongation at break due to poor dispersion and stress concentration; however, this effect was less pronounced in PHA blends, where improved compatibility was observed.

This study explores a novel stabilization technique combining Persian gum (PG), an eco-friendly biopolymer, and glass fiber (GF) to enhance the strength and durability of fine-grained soils under freeze-thaw (F-T) cycles. Specimens were prepared at maximum dry density (MDD) with varying PG and GF contents, cured for 0, 7, or 14 days, and subjected to 0, 5, 7, or 10 F-T cycles. Tests included Standard Proctor compaction, Scanning Electron Microscopy (SEM), Unconfined Compressive Strength (UCS), and Direct Shear (DS). Results demonstrated that GF significantly improved durability, ductility, and strength by enhancing interparticle interaction and friction angle. The results indicated that at an optimum GF content of 1%, UCS and E-5(0) increased by up to 35%. Also, after 10 F-T cycles, UCS decreased by 46% for untreated soil and 36% for treated soil. PG enhanced cohesion through interparticle bonding, which was curing-time-dependent. Specimens with 2.5% PG (optimum content) showed a 133% UCS increase after 14 days of curing but a 9% reduction after 5 F-T cycles, with 70% of total UCS loss occurring in the first 5 cycles. The tests indicated that formation of large and stable soil-PG-GF matrix with improved rigidity, strength, and F-T resistance. The results demonstrated that the suggested soil stabilization method, which utilizes low-cost, eco-friendly materials, was effective.

Cementations bind sand/soil particles via physical and chemical interactions to form composite solids with macroscopic mechanical properties. While conventional cementation processes (e.g., silicate cement production, phosphate adhesive synthesis, and lime calcination) remain energy-intensive, bio-cementation based on ureolytic microbially induced carbonate precipitation (UMICP) has emerged as an environmentally sustainable alternative. This microbial-mediated approach demonstrates comparable engineering performance to traditional methods while significantly reducing carbon footprint, positioning it as a promising green technology for construction applications. Nevertheless, three critical challenges hinder its practical implementation: (1) suboptimal cementation efficiency, (2) uneven particle consolidation, and (3) ammonia byproduct emissions during ureolysis. To address these limitations, strategic intervention in the UMICP process through polymer integration has shown particular promise. This review systematically examines polymer-assisted UMICP (P-UMICP) technology, focusing on three key enhancement mechanisms: First, functional polymers boost microbial mineralization efficacy through multifunctional roles, namely microbial encapsulation for improved survivability, calcium carbonate nucleation site provision, and intercrystalline bonding via nanoscale mortar effects. Second, polymeric matrices enable homogeneous microbial distribution within cementitious media, facilitating uniform bio-consolidation throughout treated specimens. Third, selected polymer architectures demonstrate ammonium adsorption capabilities through ion-exchange mechanisms, effectively mitigating ammonia volatilization during urea hydrolysis. Current applications of P-UMICP span diverse engineering domains, including but not limited to crack repair, bio-brick fabrication, recycled brick aggregates utilization, soil stabilization, and coastal erosion protection. The synergistic combination of microbial cementation with polymeric materials overcomes the inherent limitations of pure UMICP systems and opens new possibilities for developing next-generation sustainable construction materials.

Granite residual soil exhibits a tendency to collapse and disintegrate upon exposure to water, displaying highly unstable mechanical properties. This makes it susceptible to landslides, mudslides, and other geological hazards. In this study, three common biopolymers, i.e., xanthan gum (XG), locust bean gum (LBG), and guar gum (GG), are employed to improve the strength and stability of granite residual soil. A series of experiments were conducted on biopolymer-modified granite residual soil, varying the types of biopolymers, their concentrations, and curing times, to examine their effects on the soil's strength properties and failure characteristics. The microscopic structure and interaction mechanisms between the soil and biopolymers were analyzed using scanning electron microscopy and X-ray diffraction. The results indicate that guar gum-treated granite residual soil exhibited the highest unconfined compressive strength and shear strength. After adding 2.0% guar gum, the unconfined compressive strength and shear strength of the modified soil are 1.6 times and 1.58 times that of the untreated granite residual soil, respectively. Optimal strength improvements were observed when the biopolymer concentration ranged from 1.5% to 2%, with a curing time of 14 days. After treatment with xanthan gum, locust bean gum, and guar gum, the cohesion of the soil is 1.36 times, 1.34 times, and 1.55 times that of the untreated soil, respectively. The biopolymers enhanced soil bonding through cross-linking, thereby improving the soil's mechanical properties. The gel-like substances formed by the reaction of biopolymers with water adhered to encapsulated soil particles, significantly altering the soil's deformation behavior, toughness, and failure modes. Furthermore, interactions between soil minerals and functional groups of the biopolymers contributed to further enhancement of the soil's mechanical properties. This study demonstrates the feasibility of using biopolymers to improve granite residual soil, offering theoretical insights into the underlying microscopic mechanisms that govern this improvement.

Problematic soils like expansive soils cause significant damages to civil infrastructure. The use of calcium-based stabilizers in the treatment of sulfate-rich expansive soils is not suggested due to the formation of ettringite. Infrastructure such as pavements and embankments built on expansive soil are often exposed to the damaging impacts of freeze-thaw cycles in areas prone to seasonal freezing, making them vulnerable to cracking and spalling. A native expansive soil from South Dakota with a sulfate content of more than 10,000 ppm was stabilized using biopolymer (BP) and cement in this study. A comparison of the geotechnical properties of the untreated and treated soil such as Atterberg limits, one-dimensional (1D) swell, linear shrinkage, unconfined compressive strength (UCS), and resilient modulus (MR) for curing periods of 7 and 28 days were presented in the study. The swelling in cement-stabilized soil specimens was observed to increase after a long period due to the formation of ettringite. The study investigated the effectiveness of cement and biopolymers as co-additives to treat the sulfate-rich expansive soil. The experimental study investigated the strength and stiffness properties of the control and treated soil after the various freeze-thaw (F-T) cycles. The reduction of strength and stiffness properties of soil for 6% cement and the co-addition of 3% cement and 1.5% biopolymer after the F-T cycles were found to be comparatively less. Soil morphology provided insights into the configuration of biopolymer networks and the development of ettringite within treated soils. Biopolymers were used as an environmentally friendly substitute for traditional energy-intensive stabilizers in expansive soil stabilization, and potentially reducing carbon footprints. The study found that the incorporation of biopolymer as a co-additive with cement can be a viable alternative for stabilizing sulfate-rich expansive soil subgrade.

The EU plastic strategy aims to reduce the environmental impact of the increasing plastic production, by replacing petrochemical-based polymers with biodegradable ones. But this mitigation measure for the plastamination might, in turn, generate bio-based microplastics in environments that are not necessarily safe. Biodegradable and non-biodegradable plastics, polylactic acid (PLA) and polypropylene (PP) respectively, and their leachates were used for testing microplastic (MP) effects on seven marine species from different trophic levels, including bacteria, algae, rotifers, copepods, amphipods and branchiopods. Results highlighted the toxic effects of both MPs for three consumers, but no toxicity for decomposers and primary producers. Leachates did not induce negative effects for five species tested. A dose-dependent toxic effect of both PP and PLA on different life stages of A. franciscana was observed, with more advanced stages being more sensitive to MPs in terms of mortality. Molecular analysis revealed increased mRNA levels of Heat shock proteins in A. franciscana metanauplii and adults, suggesting their role in oxidative stress response, and decreasing in juveniles, indicating potential irreversible damage. These results indicated that PLA and PP might have comparable ecotoxicological impacts, raising concerns about the effectiveness of biodegradable polymers in mitigation plastic pollution. The study also emphasizes the importance of considering different trophic levels, life stages, and feeding strategies when evaluating the toxic effects of MPs from a One Health perspective.