Abstract
Aerogels are a unique class of materials with superior thermal and mechanical properties particularly suitable for insulating and cryogenic storage applications. It is possible to overcome geometrical restrictions imposed by the rigidity of monolithic polyurea cross-linked silica aerogels by encapsulating micrometer-sized particles in a chemically resistant thermally insulating elastomeric “sleeve.” The ultimate limiting factor for the compound material’s performance is the effect of aerogel particles on the mechanical behavior of the compound material which needs to be fully characterized. The effect of size and concentration of aerogel microparticles on the tensile behavior of aerogel impregnated RTV655 samples was explored both at room temperature and at 77 K. Aerogel microparticles were created using a step-pulse pulverizing technique resulting in particle diameters between 425 μm and 90 μm and subsequently embedded in an RTV 655 elastomeric matrix. Aerogel particle concentrations of 25, 50, and 75 wt% were subjected to tensile tests and behavior of the compound material was investigated. Room temperature and cryogenic temperature studies revealed a compound material with rupture load values dependent on (1) microparticle size and (2) microparticle concentration. Results presented show how the stress elongation behavior depends on each parameter.
Highlights
Long-distance space travel is currently limited due to availability of fuel for such missions
The typical room temperature (300 k) and low temperature (77 K) tensile behavior of neat (0% impregnation levels (IL)) RTV 655 are shown in Figures 4(a) and 4(b), respectively, reflecting a “baseline” behavior and measurement
The effect of polyurea cross-linked silica aerogel (PCSA) microparticle incorporation on the rupture load of impregnated RTV 655 at room temperature is shown in Figure 5 for three separate sample batches measured independently and compared with the behavior of neat RTV 655 measured under similar conditions
Summary
Long-distance space travel is currently limited due to availability of fuel for such missions. Polymeric materials are a highly adaptable group of materials with a broad range of applications that span the biomedical field to the space industry [1,2,3]. If the applied stress is transferred effectively from the matrix to the particles the result will be a stronger material [16,17,18,19,20]. Since the introduction of micronanoparticles into a polymer matrix can have a variety of effects on the overall behavior of the material, each particle-polymer combination must be independently and thoroughly characterized and the limits of the material tested under different environmental conditions
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