Hydrogels improvements through freeze-casting and anti-freezing additives

Author(s):  
Irene Vettori ◽  
Gavino Bassu ◽  
Marina Macchiagodena ◽  
Marco Pagliai ◽  
Emiliano Fratini
Keyword(s):  
Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2864
Author(s):  
Eva Kröll ◽  
Miriana Vadalà ◽  
Juliana Schell ◽  
Simon Stegemann ◽  
Jochen Ballof ◽  
...  

Highly porous yttrium oxide is fabricated as ion beam target material in order to produce radioactive ion beams via the Isotope Separation On Line (ISOL) method. Freeze casting allows the formation of an aligned pore structure in these target materials to improve the isotope release. Aqueous suspensions containing a solid loading of 10, 15, and 20 vol% were solidified with a unidirectional freeze-casting setup. The pore size and pore structure of the yttrium oxide freeze-casts are highly affected by the amount of solid loading. The porosity ranges from 72 to 84% and the crosslinking between the aligned channels increases with increasing solid loading. Thermal aging of the final target materials shows that an operation temperature of 1400 °C for 96 h has no significant effect on the microstructure. Thermo-mechanical calculation results, based on a FLUKA simulation, are compared to measured compressive strength and forecast the mechanical integrity of the target materials during operation. Even though they were developed for the particular purpose of the production of short-lived radioactive isotopes, the yttria freeze-cast scaffolds can serve multiple other purposes, such as catalyst support frameworks or high-temperature fume filters.


2020 ◽  
Vol 40 (7) ◽  
pp. 591-599
Author(s):  
Yaling Tian ◽  
Kai Liang ◽  
Yali Ji

AbstractThe citrate-based thermoset elastomer is a promising candidate for bone scaffold material, but the harsh curing condition made it difficult to fabricate porous structure. Recently, poly (1, 8-octanediol-co-Pluronic F127 citrate) (POFC) porous scaffold was creatively fabricated by chitin nanofibrils (ChiNFs) supported emulsion-freeze-casting. Thanks to the supporting role of ChiNFs, the lamellar pore structure formed by directional freeze-drying was maintained during the subsequent thermocuring. Herein, bioactive glass (BG) was introduced into the POFC porous scaffolds to improve bioactivity. It was found the complete replacement of ChiNF particles with BG particles could not form a stable porous structure; however, existing at least 15 wt% ChiNF could ensure the formation of lamellar pore, and the interlamellar distance increased with BG ratios. Thus, the BG granules did not contribute to the formation of pore structure like ChiNFs, however, they surely endowed the scaffolds with enhanced mechanical properties, improved osteogenesis bioactivity, better cytocompatibility as well as quick degradation rate. Reasonably adjusting BG ratios could balance the requirements of porous structure and bioactivity.


2008 ◽  
Vol 86B (1) ◽  
pp. 125-135 ◽  
Author(s):  
Qiang Fu ◽  
Mohamed N. Rahaman ◽  
Fatih Dogan ◽  
B. Sonny Bal

2015 ◽  
Vol 71 ◽  
pp. 62-67 ◽  
Author(s):  
Steven E. Naleway ◽  
Christopher F. Yu ◽  
Michael M. Porter ◽  
Arijit Sengupta ◽  
Peter M. Iovine ◽  
...  

RSC Advances ◽  
2017 ◽  
Vol 7 (53) ◽  
pp. 33600-33605 ◽  
Author(s):  
Weiwei Gao ◽  
Nifang Zhao ◽  
Weiquan Yao ◽  
Zhen Xu ◽  
Hao Bai ◽  
...  

Graphene flake size has a profound effect on the mechanical performance of the assembled graphene aerogels, particularly their strength, modulus and fatigue resistance under compression.


Author(s):  
Guang Yang ◽  
Fangzhou Li ◽  
Junfeng Xiao ◽  
Halil Tetik ◽  
Nasrullah Shah ◽  
...  

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