Super absorbing polymers for very flexible radiation shielding of human tissues

The current project idea builds on key results obtained during an earlier ESA tender project namely “Innovative Radiation Shielding Technologies (2014)”.[1]

Here, Monte Carlo simulations were performed to determine what materials would be most suited to protect against space radiation. Both water and polyethylene (PE) were found to works best.[2] The most radiation-vulnerable parts of the human body were identified so that new spacesuits made of such materials could be designed to protect these specific regions. In a later project, funded by the ASI, a personal shielding garment prototype was developed and successfully tested on the ISS, with embedded PE plastic containers  that can be filled with water and later drained to recover the water.[3,4]

During the development and testing phase of the garment on the ISS, some important risks/challenges were identified:

1. Danger of water leakage, during filling/draining or because of puncture of the containers, very critical in a mainly electrical environment
2. Due to zero gravity, unequal water distribution within the stiff plastic reservoirs is possible when incompletely filled with water
3. To limit the risk of leakage and overpressure, plastic containers were bulky and with regular shapes, which implies a limitation of movement freedom for astronauts.

The idea of this proposal is to address these issues by replacing the liquid water with superabsorbent polymers (SAPs) that are able to absorb several hundred times their own weight in water. This would result in the following key advantages:

1. Equal distribution of the water over the patch and thus equal shielding, independent of the amount of water present
2. No risk of leakage when the container is punctured
3. SAPs elements only swell as much as water is present, leading to smaller volumes, less bulky suits and the possibility to develop ergonomic elements fit to anatomical shapes
4. Water can be recuperated by applying pressure on the suit.

REFERENCES

[1]    Worms J-C, Walter N, White O, Martinez-Schmitt J, Marshall-Bowman K, Blanc S, Monken I, Hockey B, Reitz G, Leys N, others. 2012.

[2]     Vuolo M, Baiocco G, Barbieri S, Bocchini L, Giraudo M, Gheysens T, Lobascio C, Ottolenghi A. Life Sciences in space research 2017;15:69.

[3]     Baiocco G, Giraudo M, Bocchini L, Barbieri S, Locantore I, Brussolo E, Giacosa D, Meucci L, Steffenino S, Ballario A, others. Aerotechnica Missili & Spazio 2020.

[4]     Baiocco G, Giraudo M, Bocchini L, Barbieri S, Locantore I, Brussolo E, Giacosa D, Meucci L, Steffenino S, Ballario A, others. Life sciences in space research 2018;18:1.

[5]     Durante M, Cucinotta FA. Nature Reviews Cancer 2008;8:465.

[6]     Adams Jr J, Hathaway D, Grugel R, Watts J, Parnell T, Gregory J, Winglee R. NASA 2005.

[7]     Tripathi R, Wilson J, Joshi R. SAE Transactions 2006:254.

[8]     Cucinotta FA, Kim M-HY, Chappell LJ. NASA Technical Memorandum 2012;217361.

[9]     Zeitlin C, Hassler D, Cucinotta F, Ehresmann B, Wimmer-Schweingruber R, Brinza D, Kang S, Weigle G, Bӧttcher S, Bӧhm E, others. Science 2013;340:1080.

[10]   Yignon L, Sisley P. The journal of the society of chemical industry 1891;113:701—704.

[11]   Bothmer V, Daglis IA. Space Weather: Physics and Effects. Springer Science \& Business Media; 2007.

[12]   Bamford R, Gibson K, Thornton A, Bradford J, Bingham R, Gargate L, Silva L, Fonseca R, Hapgood M, Norberg C, others. Plasma physics and controlled fusion 2008;50:124025.

[13]   Buhler C.R. WL. NASA 2004.

[14]   Daly MJ, Gaidamakova EK, Matrosova VY, Kiang JG, Fukumoto R, Lee D-Y, Wehr NB, Viteri GA, Berlett BS, Levine RL. PLoS One 2010;5:e12570.

[15]   Slade D, Radman M. Microbiology and molecular biology reviews 2011;75:133.

[16]   Schoenfeld MP, Ansari RR, Nakao A, Wink D. Medical Gas Research 2012;2:8.

[17]   Battiston R, others. Final Report ESTEC Contract N 4200023087/10/NL/AF 2011.

[18]   Bamford R. EGUGA 2009:13718.

[19]   Metzger PT, Youngquist RC, Lane JE. Asymmetric Electrostatic Radiation Shielding for Spacecraft, in: 2004 IEEE Aerospace Conference Proceedings (IEEE Cat. No. 04TH8720), vol. 1. 2004.

[20]   Kiatkamjornwong S. ScienceAsia 2007;33:39.

[21]   Mignon A, De Belie N, Dubruel P, Van Vlierberghe S. European Polymer Journal 2019;117:165.

[22]   Kabiri K, Omidian H, Zohuriaan-Mehr M, Doroudiani S. Polymer Composites 2011;32:277.

[23]   Ahmed EM. Journal of advanced research 2015;6:105.

[24]   Agrawal P, Gandhi PS, Majumder M, Kumar P. Physical Review Applied 2019;12:031002.