Development of improved adhesives for use at cryogenic temperatures to minus423 deg F Final summary report, 11 Jul. 1963 - 31 Aug. 1965
Improved polyurethane and epoxy resins for use as adhesives at cryogenic temperatures
EPOXY RESIN↗
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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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Foam-in-place materials for high voltage insulation in a space environment
Dielectric polyurethane foam materials tested for high voltage insulation in space environment
SPACE ENVIRONMENT↗
Evaluation of fibrous materials in a cryogenic structural adhesive Technical report, Feb. - Apr. 1966
Evaluation of fibrous materials in cryogenic structural polyurethane adhesive used for bonding Saturn S-IVB tank assembly attachments
GLASS FIBER↗
The development of structural adhesive systems suitable for use with liquid oxygen Summary report IV, 1 Jul. - 30 Nov. 1966
Structural adhesive systems for use with liquid oxygen - preparation of fluorinated polyurethanes
LIQUID OXYGEN /LOX/↗
Space Shuttle Stiffener Ring Foam Failure Analysis, a Non-Conventional Approach
The Space Shuttle Program made use of the excellent properties of rigid polyurethane foam for cryogenic tank insulation and as structural protection on the solid rocket boosters. When foam applications de-bond, classical methods of failure analysis did not provide root cause of the failure of the foam. Realizing that foam is the ideal media to document and preserve its own mode of failure, thin sectioning was seen as a logical approach for foam failure analysis to observe the three dimensional morphology of the foam cells. The cell foam morphology provided a much greater understanding of the failure modes than previously achieved.
cryogenic tank insulation↗
Development of a New 48 Inch UF6 Cylinder Overpack - 17476
The Kevil Kougar overpack is new generation USA DOT Specification 7A packaging designed to transport ANSI N14.1 and ISO-7195 compliant 48-inch UF6 cylinders. In December 2016, the USA DOT issued USA/0815/H(U)-96 for the transport of 48X and 48Y cylinders and USA/0819/H(M)-96 for the transport of 48G, 48H, 48HX, 48O, 48OM, 48OM(Allied) and 48T cylinders. The H(U) certificate is for transport of thick-walled cylinders and the H(M) certificate is for transport of thin-walled cylinders. The Kevil Kougar design provides thermal and impact protection for the cylinder under conditions required for a Type A package capable of transporting UF{sub 6} via road, rail, and ocean. The packaging design is a smooth octagonal shape designed to carry one 48-inch UF{sub 6} cylinder. It consists of an upper subassembly and lower subassembly, which are fastened together with ten toggle bolts, five per side. Each subassembly consists of an outer and inner steel shell secured to a frame assembly, with wood and polyurethane foam filling the space between. The protruding components are only for ease of operation and consist of four lifting lugs and fork pockets on the upper body, and the base and fork pockets on the lower body. The design incorporates interior rubber pads for cylinder cushioning, support and alignment, steel stabilizing beams fore and aft to prevent cylinder movement, closure mechanisms, a tamper indicating device and tie-down features. The Kevil Kougar is currently designed to transport contents of depleted uranium and natural uranium. Future activities include licensing the package as Type AF to facilitate transport of historic USA Department of Energy fissile material packages. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Residual waste detection in HLW tanks - 15701
This research uses commercial sonar technology to monitor residual waste in the U.S. Department of Energy's (DOE) Hanford Site high-level-waste staging tanks, with primary focus on the detection and imaging of the settled solids at specified areas of interest along the tank surface within a limited amount of time. High-level waste (HLW) is generated at the US-DOE Hanford Site as a by-product from the processing of nuclear materials. Waste is currently stored in 177 underground carbon-steel waste tanks. Pulse jet mixers (PJM) are often used to break loose and suspend the solids that have settled at the bottom of the tanks. A typical tank can have 6-8 pulse tubes. The Solid Liquid Interface Monitor (SLIM) must be capable of measuring dynamic movements in Region 1 zone between each PJM cycle. SLIM was originally developed to map the sludge/supernate interface within the U.S. DOE Hanford Site's HLW tanks. SLIM is a dual-axis mechanically rotating sonar and consists of an acoustic transducer, rotation motor with gearbox, tilt motor, position reference sensor, and pressure balancing mechanisms and its associated deployment platform. The sonar gathers a swath of data in the horizontal plane and rotates the transducer through a programmed angle around the vertical axis. Oil-filled device. No user serviceable parts. No semiconductors. Hard anodized aluminum and polyurethane delrin. May be deployed in areas of significant radioactivity. Kaolin will be used during mixing operations in order to simulate the physical properties of the expected slurry. In order to reduce the amount of time needed to image and object, all settings were decreased to their minimal state. The low resolution settings provide insufficient data for the manufacturer's 3D profiler to compile a visible point cloud and much less to allow the meshing algorithm to work properly. Several filtering algorithms have been applied to each scan in order to remove erroneous spikes and ghosting effects. Data has been collected for the mixing process of kaolin. This data consists of scans executed while the pump was active and inactive. The imaging algorithm has also been used with data derived from scans of 3% or less of kaolin. Future work: Mixing of kaolin within an experimental tank will be conducted in order to simulate the settling time of the HLW within the tank. The same filtering algorithms will be applied to each of these scans to evaluate the SLIM's efficiency to image solids at the bottom of a tank through increasing volume of kaolin.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
The Applications of Intumescent Technologies in Support of D and D Activities across the DOE Complex - 19599
The development of intumescent technologies to be used as both an excellent means of fire protection and resiliency and as a radioactive fixative, would most definitely benefit the safety of the general public and also the environment. The remediation and safe disposal of radioactive waste is of great important to both national security and the public health, as we carry the responsibility to not develop new ways of mitigating these hazards but also to lay the groundwork for future generations. The overall goal of this research is to enhance the fire resiliency and protection of fixatives and nuclear facilities in support of D and D activities. Specific objectives include: 1) identify and evaluate commercial-off-the-shelf (COTS) intumescent technologies, 2) conduct baseline fire testing of intumescent technologies, 3) develop a set of international standards to meet operational and safety requirements for D and D Technologies. In order to evaluate the above proposed research objectives, the following hypotheses have been postulated. - Select, test, and evaluate the suitability of certain 'near fit' ASTM flammability standards. - Baseline and down-select a set of existing COTS intumescent technologies (coatings and foams) to support D and D problem sets. - Determine feasibility of application methods for use inside a radioactive glovebox and hot cells for D and D purposes. - Develop international testing protocols for adapting the use of intumescent technologies to address needs of the D and D process. The proposed research will primarily take place at FIU-ARC. ARC and SRNL have conducted extensive coordination with the Savannah River Site's (SRS) 235-F PuFF facility personnel to facilitate planning in order to expedite the research and development (R and D) related to this effort. An initial set of documents associated with the specific facility hot cells, including schematics, assessment of the manipulator arms, anticipated particulate sizes of the Pu-238 contamination, an approved tooling list, etc., were formally reviewed and approved for release by the site to ARC. Utilizing these as a foundation, pre-planning for further adaptation of the intumescent technologies and the application during a full-scale cold demo at a hot cell testbed at ARC. One of the primary objectives is the testing and evaluation of the resistance of radiological shielding foams to thermal stressors. This objective was accomplished by conducting a flammability test and incremental temperature test. The goal of the flammability test is to conduct analytical tests to provide a classification for the foams as outlined below in accordance with IEC 60695-11-10. This test method is uniformly accepted throughout the industry as being critical indicators that quantifiably establish the flammability characteristics of plastics. It should be noted that polyurethane is not classified as a plastic, however, they do share similar properties deeming this a near fit test. IEC 60695-11-10:2013 specifies small-scale laboratory test procedures intended to compare the burning behavior of different materials when vertically or horizontally oriented test bar specimens are exposed to a small flame ignition source. Two test methods are described. Method A is a horizontal burning test and is intended to determine the linear burning rate of materials under specific test conditions. Method B is a vertical burning test and is intended to determine whether materials self-extinguish under specific test conditions. The purpose of the incremental temperature testing is to evaluate mass loss and dimensional changes that occurs to the radiological shielding foams when exposed to high temperatures in a muffle furnace. High temperatures often cause materials to undergo physical changes such as swelling or expanding. This is caused by the increase in kinetic energy and atomic and molecular movement.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Adhesion Capabilities of Permanent Foaming Fixatives
DOE-EM have identified an operational requirement for a fixative that can immobilize and/or encapsulate residual contamination in 3D void volumes (pipes, gloveboxes, waste containers, etc.) during D and D activities. Failure to safely and effectively immobilize residual contamination can: Put workers at risk; Contaminate the public and environment; Drive up costs. Commercial-off-the-shelf (COTS) polyurethane (PU) foams is one possible solution and is currently being investigated by Savannah River National Lab (SRNL). Adhesion testing will dictate how well PU foams will adhere and immobilize residual contamination onto a substrate. Results can provide a performance criteria for Section 5 of ASTM E3191: Standard Specification for Permanent Foaming Fixatives Used to Mitigate Spread of Radioactive Contamination. Initial mechanical testing showed intumescent rigid PU foams were best in class (tensile, compression, TGA/DSC) Application of intumescent rigid PU foam in pipe scenario with 'contamination' showed excellent adhesion capabilities as long as foam had contact with pipe. The foam, however, was not able to penetrate 'contamination' but created pockets where the contamination interacted with the substrate. Pretreatment options of pipe were considered to produce better immobilization capabilities. Pretreatment options included COTS products like baking spray, rubber cement, and soap. Foam was still able to immobilize on a global sense, but not a local sense. Essentially acted as a mechanical plug. A tensile tester (MTS Criterion Series 43) was utilized to evaluate the tensile adhesion strength of 6 COTS PU foams. ASTM D1623: Tensile and Tensile Adhesion Properties of Rigid Cellular Plastics. Procedures: PU foams were cured between two smooth 2'' x 2'' 304 stainless steel coupons with hinges glued on plates for gripping support. Parameters Used: Pull rate of 0.1 in/min. Calculations: Tensile adhesion strength, elongation, and ImageJ analysis of how PU foam is left on substrate. Outcome: The PU foam with the best adhesion capabilities would be downselected for further evaluation to be used as a permanent foaming fixative. The rigid PU foams had the best adhesion capabilities with the R1 foam having a max load of 236 N. One of the I-R2 samples reached almost 450 N and another sample reached 2500 N before slipping. The other intumescent foam, I-F4, had the most coverage on the stainless steel coupon's surface from the ImageJ results (61.43% surface coverage). The intumescent foam, I-R2, will be the foam of choice for future testing due its fire retardant and adhesion capabilities. Future directions: Conduct the following experiment in a pipe scenario with the down-selected PU foam. Procedures: PU foam will be cured between in a 304 stainless steel pipe (ID: 4'', OD: 4.5'', Height: 4''). Parameters Used: Compression testing results will be referenced to determine if foam's adhesion strength would be greater its compression strength as its being compressed. Calculations: Compression strength, shear stress, total time elapsed. Conduct further adhesion testing with the down-selected PU foam (I-R2) to be treated as a permanent foaming fixative (PFF). Determine the minimum contact the PFF should have with the substrate for adequate results. Evaluate if PFF's adhesion capabilities is time dependent (3.1.5 of ASTM E3911). Subject PFF to seismic stressors addressed in Safety Basis of Interim Operation documents (SBIO) to further evaluate adhesion capabilities.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Additive Manufacturing of Thermal Energy Storage Composites with Microencapsulated Phase Change Materials Supported in a Multipolymer Matrix
Additive manufacturing (AM) techniques to directly integrate phase change materials (PCMs) are of interest for efficient thermal energy storage (TES) architectures. Complex, high surface-to-volume ratio composites embedded with PCM can improve thermal management with reduced material waste for customizable device fabrication. Reducing feature sizes of TES-integrated heat exchangers using AM can increase heat transfer without thermal conductivity enhancement. Here, composite AM materials containing 60 wt% microencapsulated phase change materials (MEPCM) are fabricated using off-the-shelf printers at common speeds and resolutions. High MEPCM loading in filaments is achieved with powder extrusion using two polymers, thermoplastic-polyurethane (TPU) and polycaprolactone (PCL), that mediate flexibility and rigidity for effective extrusion and printing without filament fracture or buckling. Furthermore, with PCL and TPU at 20 wt% each and 60 wt% MEPCM (P 20 T 20 M 60 ), smooth, form-stable filaments are consistently printed. Powder-based extrusion displays negligible damaging effects on the MEPCM. Printed P 20 T 20 M 60 demonstrates 105 J/g of energy storage with no degradation through 250 thermal cycles, within 5% of the theoretical storage enthalpy. Combining PCL/TPU shows good interfacial adhesion between print layers and produces high surface area objects, like 15% gyroids, and dense, 100% infilled pucks. Prints are also scalable to a 900 cm 3 honeycomb heat exchanger with an estimated 9 Wh energy storage.
25 ENERGY STORAGE↗
Mechanically Robust, Ultraelastic Hierarchical Foam with Tunable Properties via 3D Printing
We present a mechanically robust, ultraelastic foam with controlled multiscale architectures and tunable mechanical/conductive performance is fabricated via 3D printing. Hierarchical porosity, including both macro- and microscaled pores, are produced by the combination of direct ink writing (DIW), acid etching, and phase inversion. The thixotropic inks in DIW are formulated by a simple one-pot process to disperse duo nanoparticles (nanoclay and silica nanoparticles) in a polyurethane suspension. The resulting lightweight foam exhibits tailorable mechanical strength, unprecedented elasticity (standing over 1000 compression cycles), and remarkable robustness (rapidly and fully recover after a load more than 20 000 times of its own weight). Surface coating of carbon nanotubes yields a conductive elastic foam that can be used as piezoresistivity sensor with high sensitivity. For the first time, this strategy achieves 3D printing of elastic foam with controlled multilevel 3D structures and mechanical/conductive properties. In conclusion, the facile ink preparation method can be utilized to fabricate foams of various materials with desirable performance via 3D printing.
36 MATERIALS SCIENCE↗
Oxidation‐Driven Enhancement of Intrinsic Properties in MXene Electrodes for High‐Performance Flexible Energy Storage
Abstract MXenes, a novel class of 2D materials, exhibit great potential for energy storage due to their unique layered structure and excellent electrical conductivity. However, improving the intrinsic electrochemical storage capacity of MXenes remains a significant challenge, often requiring the incorporation of other Faradaic materials. Oxidation, in particular, poses a key issue that impacts the capacity of MXene devices. In this study, controlled oxidation is employed to create nanoscale holes within MXene, transforming them into holey MXene (H‐MXene) nanosheets. These porous structures shorten ion transport distances and increase ion transport pathways, thereby significantly enhancing the electrochemical storage capacity of MXenes. The resulting H‐MXene micro‐supercapacitors (MSCs) demonstrate exceptional performance, achieving an aerial capacitance 2.5 times that of unmodified MXene electrodes, along with excellent cycling stability, retaining 91.7% of their capacitance after 10 000 cycles. Additionally, a flexible integrated system combining energy storage and sensing functionalities is developed, showcasing its scalability in self‐powered sensing applications. The incorporation of self‐healing polyurethane (PU) enables the device to retain 90% of its storage capacity after undergoing self‐healing. This study presents a novel approach for developing high‐performance MXene‐based energy storage devices and provides valuable insights into efficient ion transport and storage in 2D materials.
Cheng, Yongfa [Department of Materials Science and↗
Multimorphic Materials: Spatially Tailoring Mechanical Properties via Selective Initiation of Interpenetrating Polymer Networks
Access to multimaterial polymers with spatially localized properties and robust interfaces is anticipated to enable new capabilities in soft robotics, such as smooth actuation for advanced medical and manufacturing technologies. Here, orthogonal initiation is used to create interpenetrating polymer networks (IPNs) with spatial control over morphology and mechanical properties. Base catalyzes the formation of a stiff and strong polyurethane, while blue LEDs initiate the formation of a soft and elastic polyacrylate. IPN morphology is controlled by when the LED is turned “on”, with large phase separation occurring for short time delays (≈1–2 min) and a mixed morphology for longer time delays (>5 min), which is supported by dynamic mechanical analysis, small angle X-ray scattering, and atomic force microscopy. Through tailoring morphology, tensile moduli and fracture toughness can be tuned across ≈1–2 orders of magnitude. Furthermore, a simple spring model is used to explain the observed mechanical behavior. Photopatterning produces “multimorphic” materials, where morphology is spatially localized with fine precision (<100 µm), while maintaining a uniform chemical composition throughout to mitigate interfacial failure. As a final demonstration, the fabrication of hinges represents a possible use case for multimorphic materials in soft robotics.
36 MATERIALS SCIENCE↗
Super Gas Barrier and Fire Resistance of Nanoplatelet/Nanofibril Multilayer Thin Films
Abstract Cellulose nanofibrils (CNF) are abundant in the fiber cell walls of many plants and are considered a nearly inexhaustible resource. With the goal of improving the flame resistance and gas barrier properties of cellulose‐based films, cationic CNF are assembled with anionic vermiculite (VMT) clay using the layer‐by‐layer deposition process. The highly aligned VMT nanoplatelets, together with cellulose nanofibrils, form a nanobrick wall structure that exhibits high optical transparency, flame resistance, super oxygen barrier, and high modulus. A 20 CNF/VMT bilayer (BL) nanocoating, with a thickness of only 136 nm, exhibits an oxygen transmission rate of 0.013 cc (m 2 day atm) –1 . With only 2 BL of CNF/VMT, the melting of flexible polyurethane foam exposed to a butane torch is prevented. These nanocoatings also exhibit a high elastic modulus (20 GPa) and hardness (1 GPa). This study demonstrates a unique, renewable, cellulose‐based nanocoating that could be used in a variety of packaging and protection applications.
Qin, Shuang↗
Laser-Induced Graphene Composites for Printed, Stretchable, and Wearable Electronics
Not provided.
Materials Science↗
Interweaving 3D Network Binder for High-Areal-Capacity Si Anode through Combined Hard and Soft Polymers
We report that Si anodes suffer an inherent volume expansion problem. The consensus is that hydrogen bonds in these anodes are preferentially constructed between the binder and Si powder for enhanced adhesion and thus can improve cycling performance. There has been little research done in the field of understanding the contribution of the binder's mechanical properties to performance. Herein, a simple but effective strategy is proposed, combining hard/soft polymer systems, to exploit a robust binder with a 3D interpenetrating binding network (3D-IBN) via an in situ polymerization. The 3D-IBN structure is constructed by interweaving a hard poly(furfuryl alcohol) as the skeleton with a soft polyvinyl alcohol (PVA) as the filler, buffering the dramatic volume change of the Si anode. The resulting Si anode delivers an areal capacity of >10 mAh cm -2 and enables an energy density of >300 Wh kg -1 in a full lithium-ion battery (LIB) cell. The component of the interweaving binder can be switched to other polymers, such as replacing PVA by thermoplastic polyurethane and styrene butadiene styrene. Such a strategy is also effective for other high-capacity electroactive materials, e.g., Fe 2 O 3 and Sn. In conclusion, this finding offers an alternative approach in designing high-areal-capacity electrodes through combined hard and soft polymer binders for high-energy-density LIBs.
36 MATERIALS SCIENCE↗
Reformulation of dicamba herbicide: Impacts on offsite transport and soybean damage
Abstract The herbicide dicamba (3,6‐dichloro‐2‐methoxybenzoic acid) is commonly used to control broadleaf weeds in soybeans. Dicamba, however, is susceptible to volatilization and drift, thereby causing significant plant damage to nontarget crops downwind. Dicamba was reformulated to reduce volatility and off‐target movement. The effectiveness of the dicamba reformulation was assessed by quantifying dicamba emissions following spray application and investigated how meteorological factors influenced the off‐target movement. The experiments were conducted at the University of Minnesota Agricultural Experiment Station (UMORE Park) during the growing season of 2018, 2019, 2021, and 2022. Multiple high‐flow polyurethane foam air samplers were used to measure dicamba concentrations downwind from a 4‐ha soybean field sprayed with dicamba. Dicamba emissions were estimated using backward Lagrangian modeling constrained by the air sample observations. The results indicate that dicamba emissions and downwind transport were significant for several days following application. Further, non‐traited soybeans located within 15–45 m showed substantial dicamba‐related damage. In warmer, drier seasons, increased dicamba emissions caused more severe damage to downwind soybeans, likely worsened by drought stress preventing recovery. Favorable atmospheric conditions that reduced potential drift can be difficult to achieve in terms of the typical weather experienced over agricultural sites in the Upper Midwest. These results indicate that the dicamba reformulation has not adequately prevented significant post‐spray volatilization losses and downwind transport.
Agriculture↗
Chemically Recyclable and Tunable Polyolefin-Like Multiblock Copolymer Adhesives
Adhesives are important in creating multilayer products, such as in packaging and construction. Most current hot-melt adhesives such as poly(ethylene-co-vinyl acetate) (EVA) and polyurethanes lack chemical recyclability and do not easily de-bond, complicating recycling. Here, we achieved tunable adhesive properties of chemically recyclable polyolefin-like multiblock copolymers through regulating the incorporation of crystalline hard blocks, amorphous soft blocks, and ester content highlighted by adhesive strengths up to 6.80 MPa. We further demonstrated applications of these adhesives in multi-layer films and showed that the adhesives can be readily de-bonded, recovered, and chemically recycled. Overall, this study into structure-property relationships, including effects of crystallinity, soft-block incorporation, and ester content of the multiblock copolymers on adhesive properties, has resulted in a modular hot-melt adhesive platform that exhibits chemical recyclability for virgin-quality adhesive re-generation, reprocessability for repeated reuse of the recovered adhesive, and tunability for designing adhesives with a wide range of low to high (up to ~80% stronger than EVA) adhesion strengths.
36 MATERIALS SCIENCE↗