Italian-Foam (I-FOAM) - 12.07.16
The Italian-Foam experiment will evaluate the recovery of shape memory epoxy foam in microgravity obtained by solid-state foaming on ground consisting of various geometric complexities shaped on ground. This investigation is expected to study the shape memory properties required to manufacture a new concept actuator (a device that transforms energy to other forms of energy). Science Results for Everyone
Italian Foam isn’t the name of a new latte, it’s an experiment on a method of producing shape memory epoxy foam, known as solid-state foaming. The experiment took foam samples of various complexities, produced via solid-state foaming on the ground, and evaluated their shape memory in microgravity. This investigation is expected to clarify the shape memory properties required to use the foam for aerospace industry applications, energy absorbers such as bumpers, self-expanding structures, and in medical bedding and seating applications. It may also be very useful for building future spacecraft. Experiment Details
Loredana Santo, University of Rome Tor Vergata, Rome, Italy
Erica Anna Squeo, University of Rome Tor Vergata, Rome, Italy
Fabrizio Quadrini, University of Rome Tor Vergata, Rome, Italy
Federica Trovalusci, University of Rome Tor Vergata, Rome, Italy
Ferdinando Dolce, Italian Air Force, Rome, Italy
Manuele Bernabei, Italian Air Force, Rome, Italy
Vincenzo Sicuso, Italian Air Force, Rome, Italy
Walter Villadei, Italian Air Force, Rome, Italy
Vincenzo Tagliaferri, University of Rome Tor Vergata, Rome, Italy
University of Rome Tor Vergata, Department of Mechanical Engineering, Rome, Italy
Kayser Italia Srl., Livorno, Italy
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
Italian Space Agency (ASI)
ISS Expedition Duration
March 2011 - September 2011
Increment 27/28 is the first scheduled ISS mission for Italian-FOAM investigation.
- The Italian-Foam experiment pertains to the recovery of shape memory epoxy foam produced on ground by a newly developed method known as solid-state foaming.
- The experiment will be performed utilizing foam samples consisting of various geometric complexities shaped on ground.
The Italian-FOAM experiment evaluates the recovery of shape memory epoxy foam in microgravity, which was obtained on ground consisting of various geometric complexities. Working shape memory polymers (SMPs) are based on the ability of these materials to fix a given deformation by cooling below a certain transition temperature (which is mostly the glass transition temperature). Upon reheating to above the transition temperature, the polymer chains reorganize, resulting in a macroscopic recovery of the original shape. Foaming is another way to tailor SMP properties for application requirements; foams generally have reduced mechanical stiffness and strength but enhanced compressibility. The Department of Mechanical Engineering of the University of Rome “Tor Vergata” has developed a new foaming technology which is able to produce thermoset foams starting from thermosetting powders. This method is simpler than conventional foaming methods and gives homogeneous closed-cell foams with excellent mechanical properties. It was observed that foams produced by solid-state foaming present remarkable shape memory properties. In fact, these foams, which are very rigid at room temperature, become spongy when heated above the Tg (glass transition temperature); in this state they can be packed up to the complete collapse of the pores, without generating any foam damage. Cooling below transition temperature, this compact structure remains stable with no constraining force. When heated above the transition temperature, the foam recovers its original shape.
Italian-FOAM can be used in aerospace for different applications: from light actuators to structural parts with reduced size during shipping. In order to study the behavior of this new class of materials in microgravity, a set of experiments was designed for this mission. The shape recovery of an epoxy block, the unfolding of a complex structure, and a simplified actuator will be performed during the experiment, that will be carried out using a custom Experiment Unit placed on the Foam BIOKon Container (both developed by Kayser Italia). The hardware includes the heating system, data acquisition system, a battery pack, the control system, a sensor system to detect samples shape changes during heating time. The device is autonomous (not electrically connected with spacecraft). On-ground analysis of the retrieved samples will be performed in the PI’s lab and compared to samples tested in the same conditions on ground in order to investigate the behavior of this new class of materials in a microgravity environment.
Italian-FOAM can be used in the aerospace industry for different applications from light actuators to structural parts with reduced size during shipping. This type of foam may be very useful as a material utilized for building future spacecrafts for long-term space flight missions.
Italian-FOAM can be used as energy absorbers (panels and bumpers) and self expandable/deployable structures. Forms of foam are widely used in medical bedding and seating applications because of its unique attributes which can help aid comfort and sleep.
Operational Requirements and Protocols
No crewmember observation is required. The device must be powered on by a crewmember during the on-orbit phase. The experiment will be executed automatically. All scientific data will be automatically stored by the device itself and processed on-ground. The device will be powered off by the crewmember, after about 60 minutes, at the end of experiment. The samples are required to return to ground for the postflight analysis.
The Italian-FOAM/BIOKon container must be fixed to the middeck wall, with Velcro at the bottom. The samples will be inserted in an autonomous device, developed by Kayser Italia, contained in the standard BIOKon container and including a control and heating system, the battery pack and the experiment chamber with its data acquisition system. The container will remain stowed during the launch.
Decadal Survey Recommendations
Information Pending^ back to top
Shape memory epoxy foams were used for an experiment on the International Space Station (ISS) to evaluate their use for building multi-functional composite structures in orbit. A small device was designed and built to simulate the mechanical actions (compression, flexure and torsion) of simple devices during the memory step (change in shapes in response to temperature change) of the foams to determine their shape recovery in space. A ground experiment was also performed for comparison on a twin apparatus before the mission. Results show that microgravity does not affect the ability of the foams to recover their shape but poses strong limits for the heating system design due to the difference in heat transfer on Earth and in orbit. The heat transfer in microgravity is very complex and small differences measured on the ground in the thermal behavior of the heating system can be quite large in microgravity. In the ISS experiment, the maximum temperature was reduced for safety reasons so only a 70% shape recovery of the foam samples was achieved, whereas ground laboratory experiments showed that 100% recovery could be reached at the ideal temperature of 120 degrees Celsius. The efficiency of the shape recovery depends strongly on heating the foam structure uniformly throughout, and this could take much longer in space than on Earth so it is important to determine exactly the energy required for recovery to minimize heating system weight, or to think of new ways for heating (for example using sun exposure). Apart from the efficiency, another main problem is related to the foam evolution during recovery. Due to the low thermal conductivity of foam, some parts of the sample start to recover the initial shape whereas other parts remain in a “hibernated” condition, thus the sample can warp, get stuck, or break if highly stressed during recovery. Nonetheless, excellent results were obtained and important information was acquired for defining multi-functional composite structures for future experiments. The compression, torsion, and flexure tests worked quite well, but in the case of compression it is crucial to have continuous contact between the foam walls and the heating walls during recovery. The researchers concluded that microgravity does not affect, to a great extent, the ability of the foams to recover the initial shape but strongly influences the behavior of the heating devices and, therefore, the efficiency of the foam recovery. This experiment provided very useful information for designing structural composite actuators with shape memory foams and is fundamental to understanding the behavior and limits of polymer smart materials for space applications (Santo 2012).^ back to top
Santo L, Quadrini F, Squeo EA, Dolce F, Mascetti G, Bertolotto D, Villadei W, Ganga PL, Zolesi V. Behavior of Shape Memory Epoxy Foams in Microgravity: Experimental Results of STS-134 Mission. Microgravity Science and Technology. 2012 September; 24(4): 287-296. DOI: 10.1007/s12217-012-9313-x.
Santo L. Recent developments in the field of shape memory epoxy foams. Materials Science Forum. 2014 May; 783-786: 2523-2530. DOI: 10.4028/www.scientific.net/MSF.783-786.2523.
Santo L, Quadrini F, Mascetti G, Dolce F, Zolesi V. Mission STS-134: Results of shape memory foam experiment. Acta Astronautica. 2013 October; 91: 333-340. DOI: 10.1016/j.actaastro.2013.06.017.
Ground Based Results Publications
Santo L. Shape memory polymer foams. Progress in Aerospace Sciences. 2016; epub. DOI: 10.1016/j.paerosci.2015.12.003.
Artistic view of the Italian-Foam/BIOKon hardware. Image courtesy of ASI.
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