Epoxies and/or cyanate esters that incorporate polyhedral oligomeric silsesquioxane (POSS) compounds are undergoing development at Air Force Research Laboratory (AFRL). These formulations are expected to be useful as high-performance matrix resins for advanced, lightweight fiber/matrix composite materials for diverse applications that could include spacecraft structures, automotive structures, prosthetics, sporting goods, and general consumer goods. In comparison with the corresponding unmodified matrix resins and composite materials made with those resins, the POSS-modified resins and composite materials are expected to exhibit lower mass densities, greater stiffness, and capabilities to withstand higher temperatures and higher levels of ionizing radiation.
Preliminary experiments have confirmed expectations that in comparison with unmodified resins, POSS-modified epoxy resins exhibit enhanced properties — especially lower mass density and widened use-temperature ranges. Both analyses and favorable initial results suggest that POSS-modified matrix resins are both chemically compatible with, and capable of wetting, binding fibers to desirably high degrees.
Specific quantitative goals in the development of POSS-modified polymeric composites, relative to unmodified ones, include the following:
- Parameters that represent such matrix-dominated mechanical properties as compression strength, durability under heat/load cycling, and resistance to impact and damage, will be increased by 10 to 50 percent.
- Mass densities will be reduced by at least 15 percent.
- Use-temperature ranges will be extended by >80 °C.
- Resistance to atomic oxygen and to ultraviolet and charged-particle radiation will be increased by 100 percent.
- Flammability will be decreased and other physical properties will be enhanced.
- (This concept has not been reduced to practice.)
This work was done by Witold Sokolowski and Tim O'Donnell of Caltech, Joseph Lichtenhan of Hybrid Plastics Co., and Shawn Phillips of AFRL Edwards for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp under the Materials category.
NPO-20734
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High-Performance POSS-Modified Polymeric Composites
(reference NPO-20734) is currently available for download from the TSP library.
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Overview
The document discusses the development of high-performance polymeric composites modified with Polyhedral Oligomeric Silsesquioxanes (POSS) by the Jet Propulsion Laboratory (JPL) in collaboration with the Air Force Research Laboratory (AFRL) and Hybrid Plastics Co. Over the past decade, the focus has been on creating new chemical feedstock technologies that enhance the properties of polymer materials at the molecular level. POSS compounds can be easily integrated into existing plastics through copolymerization or blending, requiring minimal changes to current manufacturing processes.
Preliminary experiments have shown that POSS-modified epoxy resins exhibit significant property enhancements, including reduced mass and an extended usage temperature range. The technology aims to improve various mechanical properties of polymer composites, such as compression strength, interlaminar shear, cyclic load/heat durability, density, and impact resistance, with increases ranging from 10% to 56%. Additionally, mass reductions of at least 15% and improvements in resistance to atomic oxygen, ultraviolet (UV) radiation, and particle radiation damage exceeding 100% are anticipated. The flexibility and other physical properties of these composites are also expected to be enhanced.
The potential applications for these advanced composites extend beyond space exploration, with significant commercial opportunities in sectors such as medical devices (e.g., prosthetics), consumer goods (e.g., sports equipment), and automotive industries. The lightweight nature of these composites is particularly advantageous for space missions, allowing for higher payload mass fractions and reduced structural mass, which can lead to lower launch costs. The document highlights the relevance of these materials for future NASA and Department of Defense (DOD) projects, especially for missions targeting extreme environments, such as those involving outer planets, solar probes, and Mars exploration.
In summary, the document outlines the innovative use of POSS technology to create low mass, high-performance polymeric composites that can withstand the rigors of space travel and other extreme conditions. The ongoing research and development efforts aim to revolutionize material science for aerospace applications while also opening doors for various commercial uses.
