Silicate nanosheets such as montmorillonite will be sufficient. You could try with nanocellulose as well or hybrid of montmorillonite and nanocellulose.

Try with nano clay or nano silica as if it will have high mechanical and thermal stability.

Best

thank you very much my friends for these interest and important answers@Wissam Nadir@Christian Harito@Arunprakash Vincent