Abstract
The synthesis of resorcinol–formaldehyde (RF) xerogels is versatile enough to provide materials with custom pore size distributions in the meso-/macroporous range. Specifically, seven xerogels were synthesised by changing the pH of the same RF solution, from pH 3 to pH 6. The resulting materials presented meso-/macroporous size distributions with average pore sizes from < 5 to 510 nm, as determined by Hg intrusion and N2 adsorption. Most of the RF xerogels had very similar geometric densities, except for the gels obtained at the two highest pH values, which were more dense. Both flexural and uniaxial compression tests were carried out to determine the dependence of strength and stiffness on the porosity of the xerogels. The results followed a power-law relationship between the mechanical properties and the density of the materials. However, two series of RF xerogels were found to fit such law independently, with the gels obtained at the three most acidic pH values (pH 3–4) showing unexpectedly high compression moduli. Further characterisation of the xerogels microstructure revealed the existence of rod-like microstructures that would bear most loads during the compression tests. These microstructures would act as struts that, once broken, would cause the catastrophic failure (bursting) of the xerogel.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Explore related subjects
Discover the latest articles and news from researchers in related subjects, suggested using machine learning.References
Pekala FMKRW (1989) Resorcinol-formaldehyde aerogels and their carbonized derivatives. Polym Prepr 30:221–223
Job N, Pirard R, Marien J, Pirard J-P (2004) Porous carbon xerogels with texture tailored by pH control during sol–gel process. Carbon 42:619–628. https://doi.org/10.1016/j.carbon.2003.12.072
Hasegawa G, Shimizu T, Kanamori K, Maeno A, Kaji H, Nakanishi K (2017) Highly flexible hybrid polymer aerogels and xerogels based on resorcinol-formaldehyde with enhanced elastic stiffness and recoverability: insights into the origin of their mechanical properties. Chem Mater 29:2122–2134. https://doi.org/10.1021/acs.chemmater.6b04706
Schwan M, Ratke L (2013) Flexibilisation of resorcinol–formaldehyde aerogels. J Mater Chem A 1:13462. https://doi.org/10.1039/c3ta13172f
Léonard A, Blacher S, Crine M, Jomaa W (2008) Evolution of mechanical properties and final textural properties of resorcinol–formaldehyde xerogels during ambient air drying. J Non-Cryst Solids 354:831–838. https://doi.org/10.1016/j.jnoncrysol.2007.08.024
Schwan M, Naikade M, Raabe D, Ratke L (2015) From hard to rubber-like: mechanical properties of resorcinol–formaldehyde aerogels. J Mater Sci 50:5482–5493. https://doi.org/10.1007/s10853-015-9094-x
Rey-Raap N, Arenillas A, Menéndez JA (2016) A visual validation of the combined effect of pH and dilution on the porosity of carbon xerogels. Microporous Mesoporous Mater 223:89–93. https://doi.org/10.1016/j.micromeso.2015.10.044
Job N, Pirard R, Pirard J-P, Alié C (2006) Non intrusive mercury porosimetry: pyrolysis of resorcinol-formaldehyde xerogels. Part Part Syst Charact 23:72–81. https://doi.org/10.1002/ppsc.200601011
Letellier M, Delgado-Sanchez C, Khelifa M, Fierro V, Celzard A (2017) Mechanical properties of model vitreous carbon foams. Carbon 116:562–571. https://doi.org/10.1016/j.carbon.2017.02.020
Celzard A, Zhao W, Pizzi A, Fierro V (2010) Mechanical properties of tannin-based rigid foams undergoing compression. Mater Sci Eng A 527:4438–4446. https://doi.org/10.1016/j.msea.2010.03.091
Wong JCH, Kaymak H, Brunner S, Koebel MM (2014) Mechanical properties of monolithic silica aerogels made from polyethoxydisiloxanes. Microporous Mesoporous Mater 183:23–29. https://doi.org/10.1016/j.micromeso.2013.08.029
Ma H, Zheng X, Luo X, Yi Y, Yang F (2018) Simulation and analysis of mechanical properties of silica aerogels: from rationalization to prediction. Materials 11:214. https://doi.org/10.3390/ma11020214
Noh JS, Schwarz JA (1989) Estimation of the point of zero charge of simple oxides by mass titration. J Colloid Interface Sci 130:157–164. https://doi.org/10.1016/0021-9797(89)90086-6
Thommes M, Kaneko K, Neimark AV, Olivier JP, Rodriguez-Reinoso F, Rouquerol J, Sing KSW (2015) Physisorption of gases, with special reference to the evaluation of surface area and pore size distribution (IUPAC Technical Report). Pure Appl Chem. https://doi.org/10.1515/pac-2014-1117
Lin C, Ritter JA (1997) Effect of synthesis pH on the structure of carbon xerogels. Carbon 35:1271–1278. https://doi.org/10.1016/S0008-6223(97)00069-9
Bock V, Emmerling A, Fricke J (1998) Influence of monomer and catalyst concentration on RF and carbon aerogel structure. J Non-Cryst Solids 225:69–73. https://doi.org/10.1016/S0022-3093(98)00060-X
Kanamori K, Ueoka R, Kakegawa T, Shimizu T, Nakanishi K (2018) Hybrid silicone aerogels toward unusual flexibility, functionality, and extended applications. J Sol-Gel Sci Technol. https://doi.org/10.1007/s10971-018-4804-x
Gross J, Scherer GW (1998) Structural efficiency and microstructural modeling of wet gels and aerogels. J Sol–Gel Sci Technol 13(9):957–960
Pekala RW, Alviso CT, LeMay JD (1990) Organic aerogels: microstructural dependence of mechanical properties in compression. J Non-Cryst Solids 125:67–75. https://doi.org/10.1016/0022-3093(90)90324-F
Ẑalac S, Kallay N (1992) Application of mass titration to the point of zero charge determination. J Colloid Interface Sci 149:233–240. https://doi.org/10.1016/0021-9797(92)90408-E
ASTM International (2018) ASTM C39 / C39M-18, Standard test method for compressive strength of cylindrical concrete specimens. ASTM International, West Conshohocken, PA. https://doi.org/https://doi.org/10.1520/C0039_C0039M-18.
ASTM International (2018) ASTM C1684-18, Standard test method for flexural strength of advanced ceramics at ambient temperature—cylindrical rod strength. ASTM International, West Conshohocken, PA. https://doi.org/https://doi.org/10.1520/C1684-18.
ASTM International (2017) D790–17, Standard test methods for flexural properties of unreinforced and reinforced plastics and electrical insulating materials, ASTM International, West Conshohocken, PA. https://doi.org/https://doi.org/10.1520/D0790-17.
Quinn GD (2006) The segmented cylinder flexural strength test. In: Tandon R, Wereszczak A, Lara-Curzio E (eds) Ceramic engineering and science proceedings. Wiley, Hoboken, pp 295–305. https://doi.org/10.1002/9780470291313.ch28
Quinn GD, Morrell R (1991) Design data for engineering ceramics: a review of the flexure test. J Am Ceram Soc 74:2037–2066. https://doi.org/10.1111/j.1151-2916.1991.tb08259.x
Kettunen J, Mäkeläa EA, Miettinen H, Nevalainen T, Heikkilä M, Pohjonen T, Törmälä P, Rokkanen P (1998) Mechanical properties and strength retention of carbon fibre-reinforced liquid crystalline polymer (LCP/CF) composite: an experimental study on rabbits. Biomaterials 19:1219–1228. https://doi.org/10.1016/S0142-9612(98)00027-1
White SN, Miklus VG, McLaren EA, Lang LA, Caputo AA (2005) Flexural strength of a layered zirconia and porcelain dental all-ceramic system. J Prosthet Dent 94:7
Shimizu T, Kanamori K, Maeno A, Kaji H, Nakanishi K (2016) Transparent ethylene-bridged polymethylsiloxane aerogels and xerogels with improved bending flexibility. Langmuir 32:13427–13434. https://doi.org/10.1021/acs.langmuir.6b03249
Boday DJ, Stover RJ, Muriithi B, Loy DA (2012) Mechanical properties of hexylene-and phenylene-bridged polysilsesquioxane aerogels and xerogels. J Sol-Gel Sci Technol 61:144–150. https://doi.org/10.1007/s10971-011-2603-8
Woignier T, Reynes J, Ha A, di Alaoui I, Beurroies J. Phalippou (1998) Different kinds of structure in aerogels: relationships with the mechanical properties. J Non-Cryst Solids 241:45–52
Jain A, Rogojevic S, Gill WN, Plawsky JL, Matthew I, Tomozawa M, Simonyi E (2001) Effects of processing history on the modulus of silica xerogel films. J Appl Phys 90:5832–5834. https://doi.org/10.1063/1.1412266
Lemay JD (1990) Mechanical structure-property relationships of microcellular low density foams. MRS Proc. https://doi.org/10.1557/PROC-207-21
Pekalaa RW, Hrubesh LW, Tillotson TM, Alviso CT, Poco JF, LeMay JD (1990) A comparison of mechanical properties and scaling law relationships for silica aerogels and their organic counterparts. MRS Proc. https://doi.org/10.1557/PROC-207-197
Ma H-S, Roberts AP, Prévost J-H, Jullien R, Scherer GW (2000) Mechanical structure–property relationship of aerogels. J Non-Cryst Solids 277:127–141. https://doi.org/10.1016/S0022-3093(00)00288-X
Acknowledgements
The authors gratefully acknowledge the financial support received from the Consejo Superior de Investigaciones Científicas (Project I-LINK1200), Ministerio de Economía, Industria y Competitividad (Project CTQ2017-87820-R) and Principado de Asturias–FICYT-FEDER (Project PCTI-Asturias IDI/2018/000118). SLFL is grateful to the Administración del Principado de Asturias for her research training grant awarded through the “Severo Ochoa” program. LARM thanks CONACYT, México for a postdoctoral grant (CVU No 330625, 2017).
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare no conflict of interest.
Additional information
Handling Editor: Dale Huber.
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary information
Below is the link to the electronic supplementary material.
Rights and permissions
About this article
Cite this article
Flores-López, S.L., Karakashov, B., Ramírez-Montoya, L.A. et al. Effect of the porosity and microstructure on the mechanical properties of organic xerogels. J Mater Sci 56, 10312–10325 (2021). https://doi.org/10.1007/s10853-021-05882-6
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10853-021-05882-6