Small Pore Structure Research Articles

Our Experience with the Low-Profile Braided Occluder: A Case Series of Splenic Artery Embolization in Three Trauma Patients

AbstractThe spleen is the most injured intra-abdominal organ, with splenic injuries constituting 42 to 49% of all abdominal injuries. Due to this vulnerability and the fact that splenic ruptures can potentially result in life-threatening hemorrhage, finding quick and efficient ways to control splenic bleeding in a trauma setting can improve patient outcomes. Recently, the U.S. Food and Drug Administration cleared the low-profile braided occluder (LOBO; Okami Medical, Aliso Viejo, California, United States), a vascular occlusion system designed to rapidly occlude vessels by using a high-density, uniform small pore structure. We present a small case series describing the use of the LOBO device for proximal splenic embolization in three trauma patients. Our report suggests that the LOBO device is safe and efficient for proximal splenic artery embolization as all three of our patients had a successful outcome with no complications; furthermore, we believe using the LOBO device may enhance patient and provider safety by decreasing fluoroscopic time and radiation dose, though further studies are needed to support this.

Mechanical and Drying Shrinkage Performance Study of Ultra-High-Performance Concrete Prepared from Titanium Slag under Different Curing Conditions.

This research investigates the effects of various curing regimes, the incorporation of titanium slag, and the utilization of quartz sand on the strength properties and shrinkage behavior of ultra-high-performance concrete (UHPC). By using low-heat silicate cement to prepare UHPC, this study conducted standard curing and steam curing, and comprehensively analyzed the macro and micro performance of UHPC under different curing conditions. The findings indicate that the application of steam curing markedly enhances the mechanical attributes of UHPC while efficiently decreasing its drying shrinkage. In the comparative tests, we found that the compressive strength of concrete that had undergone 2 days of steam curing was 9.15% higher than that of concrete cured for 28 days under standard conditions. In addition, under the same curing conditions, titanium slag sand had higher mechanical properties than quartz sand. Under standard curing conditions, the 28-day compressive strength of UHPC using titaniferous slag aggregate was 12.64% higher than that of UHPC using standard sand. Through the data analysis of XRD, TG, and MIP, we found that the content of Ca(OH)2 in the hydration products after steam curing was reduced compared to the standard curing conditions, and the pore structure had been optimized. The UHPC prepared with titanium slag sand has greater advantages in mechanical properties and drying shrinkage, and has a smaller pore structure than the UHPC prepared with quartz sand. Moreover, the use of titanium slag sand offers ecological and economic benefits, making it a more sustainable and cost-effective option for high-performance construction applications.

Porous gradient hydrogel promotes skin regeneration by angiogenesis

The skin has a multilayered structure, and deep-seated injuries are exposed to external microbial invasion and in vivo microenvironmental destabilization. Here, a bilayer bionic skin scaffold (Bilayer SF) was developed based on methacrylated sericin protein to mimic the skin’s multilayered structure and corresponding functions. The outer layer (SF@TA), which mimics the epidermal layer, was endowed with the function of resisting external bacterial and microbial invasion using a small pore structure and bio-crosslinking with tannic acid (TA). The inner layer (SF@DA@Gel), which mimics the dermal layer, was used to promote cellular growth using a large pore structure and introducing dopamine (DA) to regulate the wound microenvironment. This Bilayer SF showed good mechanical properties and structural stability, satisfactory antioxidant and promote cell proliferation and migration abilities. In vitro studies confirmed the antimicrobial properties of the outer layer and the pro-angiogenic ability of the inner layer. In vivo animal studies demonstrated that the bilayer scaffolds promoted collagen deposition, neovascularization, and marginal hair follicle formation, which might be a promising new bionic skin scaffold.

Variations in Composition and Size of Red Sand in Pinang City, North Sumatra to Improve Concrete Quality

This study further explores the problems in the concrete material studied in terms of variations in the structure of the constituent materials and the grain size of red sand on the compressive strength test of quality concrete material with code K-350. The primary raw material uses red sand with compositions ranging from 0%, 2%, 4%, and 6% with sizes ranging from 120, 100, and 80 mesh. After all the ingredients are mixed, printing is carried out according to the predetermined sample size; after the sample is deposited for one day and one night, the sample is opened from the mold mall. To see the quality of the sample, testing was carried out by testing the concrete structure through the SEM test, and the sample elements were looked at by testing XRD, compressive strength, and water absorption. The results obtained were a successive decrease in water absorption in red sand samples with a composition of 4%. In addition, the maximum compressive strength value was obtained at the proportion of 120 mesh material, and 6 percent of the material composition obtained a compressive strength value of 35.27 MPa. When viewed from the size of the concrete structure using the scanning Electron Microscope test, it was found that the size of the red sand mixture concrete structure has a much smaller pore structure when compared to other mixtures. and in the X-Ray Diffraction test, it was found to contain elements in the form of SiO2, CaO3, Ca (OH)2 with the highest intensity of silicon.

Efficient and safe use of a slow-release Mn material for three sequential crops of rice in Cd-contaminated paddy soils

Traditional passivators reduce the effectiveness of Cd by ion exchange, chemisorption, and complexation in soil. However, traditional passivators have defects such as easy aging and poor durability, which not only reduce the treatment efficiency but also increase the risk of primary soil environmental pollution. For this reason, considering that Mn and Cd have physiological antagonism in rice, sepiolite-supported manganese ferrite (SMF) was prepared in this study to improve passivation persistence. The passivation mechanism, effect and duration of SMF were explored. The results showed that SMF has a dense and small pore structure and that the surface is rough, which provides abundant adsorption sites for Cd2+ adsorption. When the SMF adsorbs Cd2+, ions or functional groups in the material, such as MnOOH*, will exchange with Cd2+ to form Cd(OH)2 and other internal complexes. Indoor pure soil cultivation experiments showed that 0.1 % SMF can reduce the effective Cd content of soil by 41.32 %, demonstrating the efficiency of SMF. The three-crop rice experiments in pots showed that SMF could increase soil pH and continuously increase the content of available Mn in soil. Increasing the content of available Mn reduces the ability of rice to absorb Cd. In addition, the three-cropping rice experiments also indicated that the passivation effect of SMF materials on Cd-contaminated paddy fields was long-lasting and stable and that SMF is a more efficient and safe Cd passivation agent.

Integrated High Barrier and Efficient Moisture‐Wicking Multilayer Textile for Medical and Health Protection

AbstractDeveloping textiles with rapid moisture‐wicking capability is a potential and effective solution to the poor comfort of medical and health‐protective clothing. However, designing protective clothing that combines safety and comfort remains a crucial and formidable task. Herein, a moisture‐wicking protective fibrous membrane (MWPFM) with a dual‐gradient structure manufactured by electrospinning and electrostatic spraying techniques is proposed. Interestingly, the protective layer with a small pore structure and an extremely hydrophobic effect can block water, blood, and ethanol. Additionally, the textile is designed in a multilayer configuration with a wetting gradient and pore structure gradient, ensuring comfort. The MWPFM exhibits excellent protective properties (ethanol contact angle of 115°, hydrostatic pressure of 14.8 kPa) and comfort (breathability of 46.8 mm s−1, water vapor transmission rate of 5.9 kg m−2 d−1). In addition, compared with the commercially available high‐density polyethylene protective membrane, MWPFM displays a distinct comfort advantage. This work provides a fresh avenue to improve the thermal‐moisture comfort of medical and health‐protective clothing.

Suppression effects of energy-absorbing materials on natural gas explosion in utility tunnels

The energy-absorbing material of metal foam have enormous potential in mitigating the consequences of natural gas explosion disaster in urban utility tunnels. When double-layer metal foam with different pore structures of first larger pores and then smaller pores (LP-SP model), the suppression efficiency of explosion overpressure can reach more than 60% and is 2–3 times that of first smaller pores and then larger pores (SP-LP model), and the error between that and that of the same thickness all with smaller pore structure is only 0.86%. Similarly, the metal foams with the LP-SP model can block the explosion flame propagation chain entirely, while reversing the combination order weakens the suppression effect on the explosion flame. Two suppression mechanisms of double-layer metal foam, including the Sudden Shrinkage Effect (SSE) of the LP-SP model and the Amplification Effect (AE) of the SP-LP model. The metal foam barrier device based on SSE is designed for utility tunnels, which can take effect within 0.1 s under electromagnetic force and gravity. This study can provide scientific theoretical support for designing gas explosion suppression measures in utility tunnels.

Luminescent dual-network hydrogels based on terpyridine-Eu(III) supramolecular coordination: Fluorene as antenna

The synthesis of a series of side-chain π-conjugated fluorene and terpyridine-functionalized hydrophilic poly(acrylamide) hydrogels via radical random copolymerization was reported. Based on the coordination of terpyridines and europium (III) ions, the dual-network hydrogels containing chemical covalent cross-linking bonds and metallo-supramolecular cross-linking bonds were prepared. Their structures and properties were studied systematically via NMR, IR, SEM, UV–vis absorption spectra, photoluminescence spectra and rheological. The photophysical properties showed that there was Förster energy transfer from conjugated chromophores (emission wavelength at 359–435 nm) to the europium emitter. The water content and the ratio of the energy donor and acceptor in the hydrogels make important influences on the energy transfer and then the emission color of the resulting dual-network hydrogel can be regulated from blue to red via controlling the degree of the energy transfer. Meanwhile, the dual-network hydrogels exhibited small and uniform pore structure and good mechanical properties with large storage and loss moduli.

Methyl-functionalized microporous metal-organic framework for efficient SF6/N2 separation

The capture and separation of sulfur hexafluoride (SF6) from nitrogen (N2) has the potential to reduce greenhouse gas emissions and provide economic benefits to the semiconductor industry. Herein, a series of metal–organic frameworks (MOFs) with different pore environments (Ni(pba)2 (pba = 4-(4-pyridyl)benzoate), Ni(3-mpba)2 (3-mpba = 3-methyl-4-(4-pyridyl)benzoate), and Co(3-mpba)2) were designed and synthesized for SF6/N2 separation. The most promising candidate is Ni(3-mpba)2, which exhibits excellent SF6 uptake capacity (63.4 cm3 g−1 at 298 K and 100 kPa) and the highest SF6/N2 selectivity (221 at 298 K and 100 kPa). X-ray diffraction analysis and theoretical calculations indicate that introducing the methyl group into Ni(3-mpba)2 alters the microchemical environment of the pores. Ni(3-mpba)2 has a smaller pore structure and more binding sites than Ni(pba)2; its structure and binding sites enhance the affinity between sulfur hexafluoride and the adsorbent. Dynamic breakthrough experiments further verify the remarkable separation performance of Ni(3-mpba)2 under simulated actual working conditions. In combination with its excellent regeneration ability and cycling performance, this porous coordination network shows great promise for SF6/N2 separation.

Preparation and Hydration Properties of Steel Slag-Based Composite Cementitious Materials with High Strength.

Steel slag (SS) has been largely discharged but little utilized, causing an environmental problem in China. In this paper, SS-based composite cementitious materials with high strength were prepared by the high volume of SS (≥40%), granulated blast-furnace slag (GBFS), fly ash (FA), flue gas desulfurization gypsum (FGDG) and cement to promote the effective utilization of SS. The hydration and hardening properties were studied through setting time, compressive strength, length change, isothermal calorimetry (IC), X-ray diffraction (XRD), mercury intrusion porosimetry (MIP), and scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS) tests. The results show that SS-based composite cementitious material exhibited a lower hydration heat release, an appropriate setting time, and volume stability. The SS cementitious material with 40% SS could obtain high strength of over 65 MPa at 28 days and 80 MPa at 90 days. The strength value of > 60 MPa is present in the binder, with 50% SS at 56 days. GBFS promotes hydration reactions and the formation of AFt and C-(A)-S-H gel, thus enhancing compressive strength. FA has a beneficial effect on later strength. The small and fine pore structures contribute to the development of strength. The main hydration products of SS composite cementitious materials are C-(A)-S-H gel, and ettringite (AFt), with less Ca(OH)2. The C-(A)-S-H gel with a lower Ca/Si ratio and a higher Al/Ca ratio in cementitious material, promotes mechanical properties.

The influence of heterogeneous structure on salt precipitation during CO2 geological storage

The presence of rock heterogeneity and fractures may cause abrupt spatial changes in capillary action and flow characteristics, which eventually change the precipitation behavior during CO2 geological storage. Therefore, the salt precipitation mechanism of the heterogeneous structure needs to be studied. In this paper, the salt precipitation behavior in different heterogeneous structures was studied through pore-scale experiments at room temperature and atmospheric conditions. In the up-down heterogeneous structure, the salt precipitation has little effect on the injectivity regardless of the CO2 injection rate. When the CO2 injection rate is low, the salt tends to precipitate in situ in the small pore structure to form a crystal structure. When the CO2 injection rate is high, the salt tends to precipitate in the large pore structure to form a cluster structure. In the left-right heterogeneous structure, regardless of the CO2 injection rate, the precipitated salt is mainly in the cluster structure, and the salt is more dispersed in distribution, the impact on injectivity is small. The injection well can be selected in the formation with strong heterogeneity, to alleviate the blockage caused by salt precipitation. When CO2 leaks in the fractures, salt tends to grow until the fracture is plugged, which is of great significance for the self-healing of the fracture for the caprock. Cited as: He, D., Jiang, P., Xu, R. The influence of heterogeneous structure on salt precipitation during CO2 geological storage. Advances in Geo-Energy Research, 2023, 7(3): 189-198. https://doi.org/10.46690/ager.2023.03.05

A new method for tailoring the surface pore size and internal pore structure of ultrafiltration membranes without using additives—Atomization-assisted nonsolvent induced phase separation method

It is highly desired to improve the safety and stability of ultrafiltration (UF) membranes for biotechnology, medicine and food processing by eliminating the use of chemical additives during the membrane preparation process. In this work, a series of high-performance polyacrylonitrile (PAN) UF membranes were prepared continuously by the atomization-assisted nonsolvent induced phase separation (AA-NIPS) method. The pore structure and surface properties of the membranes can be precisely tailored, requiring no chemical additives. The prepared UF membranes are composed of a sublayer of highly interconnected three-dimensional (3D) network structure and a smooth surface layer of uniform small pore structure with a narrow pore size distribution. Compared to UF membranes prepared by the NIPS method, the PAN UF membranes exhibit enhanced water flux and antifouling properties as well as a well-preserved high rejection to bovine serum albumin (BSA). With different atomization pretreatment times, the pure water fluxes of the UF membranes increased by 41 %∼100 %. The AA-NIPS method employed in the present work can effectively modify the porous structure of the membranes without introducing pore-forming additives. The good separation performance, structural controllability, and easy functionalization of the UF membranes make them a promising candidate to be applied in many fields, especially in biotechnology, medicine, and food processing.

Characteristics of pore systems in the oil-bearing sandstones of the Dongying Depression, Bohai Bay Basin

The Dongying Depression is an oil-bearing rift depression and mainly consists of beach bar, turbidite, and sublacustrine fan sandstone reservoirs. The pore systems of these sandstones have a crucial impact on maintaining and enhancing oil recovery, but the complexity of pore-throat structure and distribution cannot be described in detail using a single method; in particular, the pore systems of tight sandstones are principally composed of small-scale and discontinuous pores. Petrological observation of these sandstones demonstrated that the main pore systems in beach bar and sublacustrine fan sandstones are composed of micropores related to clay minerals, and few residual intergranular and secondary intragranular pores, because of intense compaction and cementation. In contrast, turbidite sandstones preserve abundant intergranular and secondary intragranular pores due to moderate compaction. High-pressure mercury injection (HPMI), nuclear magnetic resonance (NMR), and X-ray computed tomography (X-ray CT) were conducted to explore the features of full-scale pore systems. The NMR and HPMI demonstrated that turbidite sandstones have larger pore and throat sizes than beach bar and sublacustrine fan sandstones, consistent with the petrophysical characteristics and petrological observations. Moreover, X-ray CT analysis also indicated that turbidite sandstone has a larger pore radius and a higher proportion of connected pores, than beach bar sandstone.The fractal characteristics of pore systems are quantificationally described by NMR and HPMI. Fractal dimension (Df2) of pore sizes (T2 > 1 ms) show a positive relationship with BVI value, as well as negative relationships with T2peak and T2gm; and fractal dimension (DfS) from HPMI exhibit a positive correlation with the radius of small pore throats (<rapex), indicating that the high proportion of small pore structure increases the heterogeneity of sandstone reservoirs. The fractal dimension of tortuosity (Dτ) is negatively correlated with permeability and can be regarded as parameters to quantificationally describe reservoir quality. Therefore, the simplified numbers of fractal theory obtained from NMR and HPMI experiments provide insights and conveniences for evaluating and comparing pore systems in sandstone reservoirs in the Dongying Depression.

New ternary deep eutectic solvents with cycle performance for efficient pretreated radiata pine forming to lignin containing cellulose nanofibrils

Ternary deep eutectic solvents (TDESs) as a new class of solvents play a key role in fabrication of lignin containing cellulose nanofibrils (LCNF), however, current work requires a considerable time and thus limits industrial application of TDES. Herein, a novel strategy was proposed to produce lignin containing cellulose nanofibrils (LCNF) by TDESs based on benzyltrimethylammonium chloride (BTMAC), formic acid (FA), and maleic acid (MA). The TDESs could remove 87.80% of lignin and 89.15% of hemicellulose from Radiata Pine while most of the cellulose reserved under optimum pretreatment conditions (TDES = 100 wt%, T = 130 °C, t = 1.5 h). Benefiting from the increase in cellulase accessibility, desired sugar yield of 98.9% was obtained. Moreover, the proposed TDESs could be regarded as a green medium for the production of containing cellulose nanofibrils (LCNF) in which lignin has been esterified. The LCNF displayed a well-individualized structure with a wide size distribution (32.3–146.9 nm), which was closely associated with lignin content. 13C−1H HSQC 2D NMR test was performed to illustrate the molecular − structural features of lignin and polysaccharide in LCNF. In addition, the self-standing LCNF films exhibited excellent UV-blocking, higher thermal stability, and mechanical strength. Most importantly, LCNF films showed strong barrier property to oil and air owing to lower surface free energy and smaller pore structure. Briefly, this work highlights the pretreatment performance of TDESs for cascade utilization of lignocellulosic biomass to high-value products.

Wettability of Tight Sandstone Reservoir and Its Impacts on the Oil Migration and Accumulation: A Case Study of Shahejie Formation in Dongying Depression, Bohai Bay Basin

The migration and accumulation of oil in tight sandstone reservoirs are mainly controlled by capillary force. Due to the small pore radius and complex pore structure of tight sandstone reservoirs, the capillary force is very sensitive to wettability, so wettability significantly affects oil migration and accumulation. However, the study of oil migration and accumulation in tight sandstone reservoirs often needs to combine multiple methods, the process is complex, and the research methods of wettability are not uniform, so the mechanism of wettability affecting oil migration and accumulation is not clear. Taking the tight sandstone of the Shahejie Formation in the Dongying sag, Bohai Bay Basin, as the research object, the wettability characteristics of a tight sandstone reservoir and their influence on oil migration and accumulation were analyzed by means of a pore permeability test, XRD analysis, micro-CT experiment, contact angle tests, spontaneous imbibition experiments, and physical simulation experiments on oil migration and accumulation. The results show that the reservoir is of the water-wet type, and its wettability is affected by the mineral composition. Wettability in turn affects the spontaneous imbibition characteristics by controlling the capillary force. Oil migration in tight sandstone reservoirs is characterized by non-Darcy flow, the oil is in the non-wetting phase and subject to capillary resistance. The key parameters to describe the oil migration and accumulation characteristics include the kickoff pressure gradient, the critical pressure gradient, and ultimate oil saturation. Wettability affects oil migration characteristics by controlling the capillary force. The more oil-wet the reservoir is, the more favourable it is to oil migration and oil accumulation and therefore the higher the reservoir’s ultimate oil saturation is.

The Effect of Pore Structure on Impact Behavior of Concrete Hollow Brick, Autoclaved Aerated Concrete and Foamed Concrete

Porous concrete is an energy absorption material, which has been widely used in civil engineering, traffic engineering and disaster reduction engineering. However, the effect of pore structure on the impact behavior of the porous concrete is lacked. In this study, a series of drop-weight impact tests were carried out on three typical types of porous concrete, i.e., concrete hollow brick (CHB), autoclaved aerated concrete (AAC) and foamed concrete (FC), to investigate the effect of pore structures on their impact behavior. For comparison, static load tests were also conducted as references. According to the damage to the samples, the developments of impact force, strain, contact stress–strain relationship and absorbed energy during drop-weight during the impact test were measured and analyzed. The results show that the ratio between the peak impact stress and compressive strength of CHB was 0.44, while that of AAC and FC increased to about 0.6, indicating that the small and uniform pore structure in AAC and FC had a higher resistance against impact load than the hollow cavity of CHB. In addition, the elastic recovery strain in AAC increased by about 0.2% and its strain at peak contact stress increased by about 160% for a comparison of CHB, implying that a small open pore structure could enhance ductility. Besides, the peak contact stress of FC was close to that of AAC during impact loading, while the strain at peak contact stress of FC increased by about 36% compared with AAC, revealing that the closed-pore structure could further enhance the deformation potential. Correspondingly, the energy absorption rates of CHB, AAC and FC were 85.9 kJ/s, 54.4 kJ/s and 49.7 kJ/s, respectively, where AAC decreased by about 58% compared with CHB, and FC decreased by about 10% compared with AAC.

New Insights into Fabrication of Al-Based Foam with Homogeneous Small Pore-Structure Using MgCO3/Zn Composite Powder as a Foaming Agent

Due to its excellent mechanical properties and ultra-lightweight, Al-based foam with homogeneous small pore-structures has wide applicational prospects in many industrial fields. However, during the foaming process of molten Al, it is difficult to manipulate the pore structures of the Al-based foam by means of the ALPORAS© production route due to the violent gas-releasing performance of TiH2 as a traditional foaming agent. Herein, we developed the melt-foaming route, that is, using MgCO3/Zn composite powder as a foaming agent instead of TiH2, the Al-based foam with homogeneous small pore-structures (average diameter was about 1 mm) was prepared successfully. Meanwhile, the decomposition model of the MgCO3/Zn composite powder was proposed and further verified experimentally. The decomposition kinetics of the MgCO3/Zn composite powder was also analyzed. Our findings not only shed light on the practical manufacturing of Al-based foam with homogeneous small pore-structures, but provide an insightful improvement for melt-foaming approaches.

One-pot synthesis of hierarchical MnCu-SSZ-13 catalyst with excellent NH3-SCR activity at low temperatures

Cu-SSZ-13 catalyst with small pore structure has been considered as one of the most efficient catalysts in controlling NOx emissions from the diesel vehicles. But the low NOx conversion in the temperature range of < 200 °C seriously limits its wide applications in many situations. In this study, in order to improve the NH3-SCR performance at low temperatures, MnCu-SSZ-13-OP and Cu-SSZ-13-OP catalysts were successfully prepared by one-pot method. Experimental results indicated that the Mn and Cu co-doped catalyst had excellent SCR activity with 68% of NOx conversion at 150 °C compared to the Cu-SSZ-13-OP catalyst with NOx conversion of 31%. Meanwhile, the MnCu-SSZ-13-OP catalyst exhibited higher low-temperature activity than Cu-SSZ-13-OP catalyst (71% vs 51% NOx conversion at 200 °C) even after hydrothermal treatment, which should be attributed to the highly dispersed Mn species and its unique NO adsorption properties. Particularly, the hierarchical pores structure of MnCu-SSZ-13 played key roles for the distribution of active sites and gas diffusion. The in situ XRD results also found that the addition of TEPA and a small amount of Mn species during the synthesis process had no obvious influence on the thermal stability of the zeolite catalysts. This study also provides a new guidance to the design and simple synthesis of the catalyst based on SSZ-13zeolite with high-performance for the removal of NOx at a broad temperature window.

Pore Changes in Purple Mudstone Based on the Analysis of Dry-Wet Cycles Using Nuclear Magnetic Resonance

The study on the change of rock pore structure during the weathering of purple mudstone is of guiding significance to the stability of the bank slope of the three gorges reservoir. In this paper, the pore changes in the wet and dry circulation of purple mudstone in the three gorges reservoir area are studied by means of nuclear magnetic resonance (NMR). The results show that the simulated weathering of wet and dry circulation has a great influence on the purple mudstone. With an increase in the number of dry-wet cycles, the purple mudstone pore volume ratio significantly changed. Originally, it consisted of a small pore structure with a single pore diameter of 0.01–0.1 µm and changed to a variety of pore structures with various pore diameters of 0.001–100 µm. With the increase in the number of dry-wet cycles, the micropores (0.001–0.1 µm) were transformed into macropores (0.1–1 µm). The area of the second peak of the three samples (large pores 0.1–1 µm) increased from 0.9413, 0.9974, and 0.6779 to 0.9871, 1.1498, and 0.9901, respectively.

Carbon scaffold with controllable small pore structure based on mask projection stereolithography

Mask Projection Stereolithography (MPSL), due to its high printing resolution, is suitable for fabricating porous polymer architectures that are used as carbon scaffold precursors. In the present work, a carbon scaffold with a controllable small porous structure was fabricated by MPSL. A polymer lattice structure used as the carbon scaffold precursor was first fabricated by MPSL. Sodium chloride was selected as the granular support, and nano-silica particles were introduced into the granular support so that sodium chloride could easily fill the lattice structure. A carbon scaffold with controllable low shrinkage (41.3%) and a small porous structure (skeleton thickness=~40 µm and pore size=~300 µm) was obtained by pyrolyzing the polymer lattice structure in the granular support, and subsequently, it was processed by hydrofluoric acid (HF). The unprocessed and HF-processed scaffolds were both composed of simple substance carbon, and silicon oxide particles embedded on the unprocessed scaffold were cleaned by HF. Finally, the compressive properties of the scaffold were examined. The fracture appearances of the scaffold under the application of compressive forces parallelly and vertically to the stacking direction were different, and compressive properties in vertical to the stacking direction were superior to those in parallel to the stacking direction. Therefore, it can be inferred that the proposed method is effective in fabricating multi-scale carbon scaffolds with small controllable porous structures based on stress analysis to obtain optimum mechanical properties, which makes it a promising material for many applications.