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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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A method of manufacturing essentially crack-free carbon foam structures and carbon foam structures made in single-piece flow through a continuous kiln under inert atmosphere at atmospheric pressure. This process greatly reduces the cost to manufacture by reducing manufacturing time and increasing the ability to integrate automation equipment.
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InnaVenture has succeeded in developing a pilot-scale facility implementing a radically new concept for synthesis of metal-organic framework (MOF) materials based upon a patent-pending evaporative aerosolization-condensation process developed at PNNL. The successful synthesis of kilogram quantities of Ni-MOF-74 in InnaVenture’s facility represents a major step in the advancement of MOFs from being novelty materials to industrial adsorbents. Using this approach, fifteen kilograms of Ni-MOF-74 were synthesized for use in a demonstration adsorption chiller developed for the U.S. Navy. However, the evaporative condensation method for MOF synthesis has so far only been demonstrated for synthesizing MOFs under conditions where the reactants are part of a single homogeneous liquid phase solvent system. For InnaVenture to expand opportunities to support broader commercial applications of MOFs and related nanoporous materials (e.g., metal-aromatic frameworks (MAFs), covalent organic frameworks (COFs)), extension of the method to heterogeneous mixed phase conditions is essential. Examples of commercially promising MOFs that require such synthesis conditions include but are not limited to MIL-101, MIL-88B, MIL-100, MOF-801, MIL-160, MOF-841, and many others. InnaVenture has also informed PNNL that they need to address problems with the low density of MOF particles being generated in their fluidized reactor system. The purpose of this effort is to address both of these challenges.
General Atomics Electromagnetic Systems (GA-EMS) together with The Nonwovens Institute (NWI) and Harper International have executed on a development project to improve the production efficiency and reduce the production cost of silicon carbide (SiC) fiber – a critical material that advances US energy security and aerospace leadership. In the first budget period (BP1), the modified tow throughput (MTT) apparatus was developed, enabling fiber spinning in the form of loose coils rather than tightly packed spools (Figure 1) for batch processing of SiC fiber. This coil-based approach was proven to be capable of uniform fiber crosslinking and ceramic conversion, as well as demonstrating key process efficiencies while meeting the program fiber property targets.
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Polyolefin plastic waste, particularly polypropylene, is one of the most prevalent components in the plastic waste stream generated globally. However, only a small fraction of this waste is recycled and reintegrated into second applications. These materials have significant embedded energy that could be used for additional productivity if recycled properly. Therefore, there is a critical need to develop scalable processing techniques with high throughput to effectively recycle it. We report the continuous manufacturing of microporous fibers using waste polypropylene plastic and melt-processable lignin, a plant biomass constituent produced as a byproduct in paper mills or biorefineries, as a template to create pores. Further, these filaments with hierarchical porosity─created by controlled microphase separation during high-speed extensional flow followed by removal of lignin─exhibit exceptional capillary action for hydrophobic liquids. The resulting porous fibers can be used for various separation applications. For example, the oil uptake of the fibers is 9.59 ± 0.82 g/g for applications in oil recovery in bodies of water. In addition, polyethylenimine infiltration within these nanoporous fibers introduces cyclic room temperature sorption and thermal desorption potential of acidic gases such as CO 2 in a bench-scale experiment. The fibers exhibit multiple cycles of CO 2 absorption, with a range of 0.15 to 0.17 mmol/g. Thus, these polyethylenimine-infiltered nanoporous polypropylene fibers can also be used in removing acidic gases from a gas mixture.
Enzymes have shown promise in various industries due to their functional specificity, catalytic efficiency, and environmental sustainability. These biological catalysts can be a pivotal component of manufacturing pipelines like continuous flow chemistry. For this, there exists a need to robustly immobilize enzymes on solid supports and assess the effects of the solid supports on catalytic performance and stability. Here, we use an industrially relevant model enzyme, C. ensiformis (Jack bean) urease, to demonstrate immobilization and assess performance in the context of continuous flow manufacturing. Various immobilization strategies were screened focusing on immobilization efficiency, protocol simplicity, and urease biocatalyst kinetics. Based on this, CDI-agarose and NHS-agarose resins were identified as the best-performing immobilization strategies for urease. CDI-agarose-urease and NHS-agarose-urease were then scaled up and applied to a large-scale continuous flow reactor to evaluate product yields, operational stability, and long-term stability. These experiments identified differences in stability and performance depending on the immobilization method tested. This highlights the importance of screening immobilization methods and subsequent enzyme performance for each candidate biocatalyst used in manufacturing to promote optimal performance and stability. As such, this work provides a framework for evaluating enzyme biocatalyst immobilization approaches to improve performance and enable transition into industrial processes.
Abstract The development of chemistry is reported to implement selective dual‐wavelength olefin metathesis polymerization for continuous additive manufacturing (AM). A resin formulation based on dicyclopentadiene is produced using a latent olefin metathesis catalyst, various photosensitizers (PSs) and photobase generators (PBGs) to achieve efficient initiation at one wavelength (e.g., blue light) and fast catalyst decomposition and polymerization deactivation at a second (e.g., UV‐light). This process enables 2D stereolithographic (SLA) printing, either using photomasks or patterned, collimated light. Importantly, the same process is readily adapted for 3D continuous AM, with printing rates of 36 mm h –1 for patterned light and up to 180 mm h –1 using un‐patterned, high intensity light.
Due to the high cost, complex preparation process and difficulty in structural design, the traditional methods for carbon fiber-reinforced SiC ceramic composite preparation have great limitations. This paper presents a technique for the additive manufacturing multiple continuous carbon fiber bundle-reinforced SiC ceramic composite with core-shell structure using an extrusion-based technique. A conventional nozzle system was modified to print simultaneously a water-based SiC paste with continuous carbon fibers. Different levels of binder contents were investigated to optimize the stickiness, viscosity, thixotropy and viscoelasticity of the paste. After sintering, SiC whiskers were generated on the surface of fiber, which is conjectured to be due to the reaction between SiO and carbon fiber at high temperature. The continuous carbon fiber-reinforced SiC ceramic composite exhibited non-brittle fracture. In conclusion, the flexural strength of the additively manufactured Cf/SiC composites improved from 162 MPa with no fiber bundles to a maximum of 219 MPa with three fiber bundles.
One of the major challenges in thermally curable polymer composite additive manufacturing is the slow curing time of thermally curable resins, coupled with a significant drop in thermoset viscosity upon heating, making the formation of complex shapes difficult. To tackle these issues, we have introduced a novel rapid composite preformation strategy called Tow-Preg Cladding (TPC). This technique involves the use of a thin and rapidly curable dual-cure resin, which combines a thermally curable resin (such as epoxy) with a fast photo-curable resin. The dual-cure resin is applied as a coating over a thermally curable resin tow-preg, enabling the formation of a rigid cladding that supports and shapes the tow-pregs into the desired geometries and patterns. The key advantage of this approach lies in the sequential formation of an interpenetrating polymer network (IPN) at the interlayer between laminates, resulting from the curing of the photocurable resin and the thermally curable resin sequentially. This IPN formation enhances interlaminar bonding in the composite, contributing to its overall strength and performance. The composites produced using this technique exhibited impressive mechanical properties, including longitudinal tensile strength of 1058.2 MPa, longitudinal tensile modulus of 74.2 GPa, flexural strength of 1080.4 MPa, and flexural modulus of 41.7 GPa. Overall, our Tow-Preg Cladding approach shows great promise in overcoming the challenges associated with thermally curable polymer composite additive manufacturing. It offers a viable solution to creating strong, shape-specific thermoset composites efficiently with enhanced mechanical properties.
The encapsulation of salt hydrate phase change materials (PCMs) in uniform microscale bodies has yet been reported in research due in part to the delicate relationship between thermal performance and water-to-salt ratios which are easily altered during manufacturing. Herein, core–shell composite fibers comprised of a salt hydrate PCM core and a poly(acrylonitrile) (PAN) shell are wet spun in a continuous process using a syringe pump and coaxial die. The PCM phase comprises calcium chloride hexahydrate (CaCl 2 ·6H 2 O) with strontium chloride hexahydrate(SrCl 2 ·6H 2 O) (3 wt%) and fumed silica(SiO 2 ) (2 wt%) as additive, a composition that is prepared from homogenous melt at 40 °C. 15 wt% PAN in dimethylsulfoxide solvent is used to prepare the shell-forming polymer gel. PCM and polymer gel injection rates of 10–40 mL h –1 are used to spin coaxial fibers through a coagulation bath, yielding continuous microtubules with diameters in the range of 850–1500 μm. Cyclic testing shows that after 1000 cycles, melting enthalpies incurred only a 3.5% decline from 131.46 to 126.9 J g –1 . In conclusion, success here overcomes several coincidental drawbacks of PCM fiber performance and manufacturing and delivers the first example of scalable roll-to-roll PCM fiber produced by wet spinning for building material applications.
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This report details the goals, approach, results, and future needs of a three-year Laboratory Directed Research and Development project funded by Sandia’s Materials Science Research Foundation. In this project, we established basic principles and mechanistic understanding of orthogonal or sequential chemistries for fabricating multi-material or robust materials. We developed numerous additive manufacturing, or 3D-printing, techniques including volumetric solid-state printing, dual-wavelength printing, and lithographic regulation of polymer crystallinity. We leveraged these new printing motifs to expand upon what is possible with manufacturing to give bespoke optical and mechanical performance. Moreover, we discovered new techniques for depolymerization enabling recovery of pristine carbon-fiber and high value electronics under moderate conditions.
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The pharmaceutical industry continuously looks for ways to improve its development and manufacturing efficiency. In recent years, such efforts have been driven by the transition from batch to continuous manufacturing and digitalization in process development. To facilitate this transition, integrated data management and informatics tools need to be developed and implemented within the framework of Industry 4.0 technology. Here, in this regard, the work aims to guide the data integration development of continuous pharmaceutical manufacturing processes under the Industry 4.0 framework, improving digital maturity and enabling the development of digital twins. This paper demonstrates two instances where a data integration framework has been successfully employed in academic continuous pharmaceutical manufacturing pilot plants. Details of the integration structure and information flows are comprehensively showcased. Approaches to mitigate concerns in incorporating complex data streams, including integrating multiple process analytical technology tools and legacy equipment, connecting cloud data and simulation models, and safeguarding cyber-physical security, are discussed. Critical challenges and opportunities for practical considerations are highlighted.