Mechanical and adhesive properties of RTV silicone rubber blended with silicone polyurethane modified epoxy resin

Abstract

To enhance mechanical, adhesive, and thermal properties of Room Temperature Vulcanized (RTV) silicone rubber, a silicon-containing polyurethane/epoxy resin modifier (ESiPU) was developed. A three-phase system of polyurethane/epoxy resin/silicone rubber was prepared through blending, modification, and co-curing. FT-IR and ¹H-NMR were employed to characterize the chemical structure of ESiPU. Microscopic analysis revealed improved compatibility between modified epoxy resin and silicone rubber. Mechanical testing showed significant enhancements in tensile strength, elongation at break, and adhesive strength, with RTV-20phr exhibiting increases of 236, 266, and 259%, respectively. Thermogravimetric analysis indicated higher initial decomposition temperature compared to pure RTV. At the same time, the char residue at 800 °C increased to 8.67%. TG-IR analysis demonstrated ESiPU’s ability to delay thermal degradation. Contact angle test confirmed improved hydrophobicity. Overall, the developed silicone rubber system exhibits promising mechanical and thermal properties, suggesting potential for aerospace heat protection applications.

Graphical Abstract

Keywords:

• Silicone rubber
• epoxy resin
• polyurethane
• mechanical properties
• adhesion strength

Acknowledgments

We thank the staff of the School of Materials Science and Engineering Beijing Institute of Technology for the measurements.

Authors’ Contributions

Yaxuan Huang: Writing-original draft (lead). Jiyu He: Writing-review and editing (lead). Rongjie Yang: Writing-review and editing (equal).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Research data are not shared.

Additional information

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.