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Sol–Gel derived hybrid materials for conservation of fossils

Abstract

Fossils are nonrenewable natural heritages formed by Mother Nature. After being excavated or exposed, fossils can be destroyed by weathering and water erosion. However, until now, there is very limited research work on fossil conservation. In this work, we focus on the protection of pterosaur fossils found in Hami, which are very sensitive to water. Four siloxane-based polymeric sols, including from tetraethyl orthosilicate and other three hybrid siloxane monomers, are prepared by controlled hydrolysis protocol. Their chemical and physical properties and performances as fossil protection materials are examined. Experimental data show that all sols have excellent permeabilities, decent reinforcement abilities, good resistance to light and heat aging. The organic moieties in the hybrids can also significantly increase the fossil’s hydrophobicity and reduce the cracking of the gels. The results indicate siloxane-based polymers can be very potential protection materials for fossils. And the hybrid polysiloxane sol containing epoxy function groups has overall the best performances.

Top left: severely degraded fossil due to water erosion, top right: structures of four sols Bottom: significantly improved fossil resistance to water after treated by silica sols, from left to right: treated by TEOS-TMPM-s, TEOS-TMPE-s, TEOS-BTME-s, TEOS-s and control sample.

Highlights

  • Four silica sols, including three hybrids sols, are synthesized via controlled sol–gel process. Their chemical and physical properties are examined.

  • The as-prepared sols are applied to protect Hami fossils. It is the first systematic research on fossil protection.

  • Hami fossil can be protected by these silica sols nicely and among them, hybrid sol containing epoxy function groups has overall the best performances.

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Acknowledgements

The authors thank Long Xiang, Yan Li, Yang Li, Shunxing Jiang, He Chen and Xinjun Zhang for their help in the field work. They are also grateful to the financial supports from the National Natural Science Foundation of China (51732008, 21673167, 41572020 and 41688103), the Innovation Project of Instrument and Equipment Function Development of the Chinese Academy of Sciences (No. 2060499), and the foundation of excavation and protection from the Hami government.

Author contributions

All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by XP, YW and X-FM. The evaluation of fossil was performed by XP and HZ. The first draft of the manuscript was written by XP and all authors commented on previous versions of the manuscript. HB, XH, HL and XW provided the funding. All authors read and approved the final manuscript.

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Correspondence to Xiao Huang or Xiaolin Wang.

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Cite this article

Peng, X., Wang, Y., Ma, X. et al. Sol–Gel derived hybrid materials for conservation of fossils. J Sol-Gel Sci Technol (2020). https://doi.org/10.1007/s10971-020-05242-x

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Keywords

  • Sol–Gel process
  • Hybrid
  • Fossils
  • Conservation