The tensile modulus of polyimide-SiO2 hybrids increases with increasing SiO2 content. But its tensile strength and elongation at break are reduced. A small amount of coupling agent can significantly improve the modulus and strength. Adding R2Si (OR ') 2 can improve the malleability of the hybrid. The tensile properties of polyimide-polysiloxane hybrid systems vary greatly depending on whether they are chemically bonded or not. Tensile strength, modulus and elongation at break of the non-bonded hybrids are reduced, while the chemical bond-type hybrid can improve the tensile properties. But even so, the performance of non-bonded systems is still superior to the corresponding block copolymer.
The dynamic mechanical analysis showed that with the increase of SiO2 content, the storage modulus of the hybrid was increased. The intensity of the tanδ peak decreases, and the width increases and slightly moves to the right as the temperature decreases.
The smaller the size of SiO2 phase separation, the more obvious the above trend. These results indicate that the movement of polyimide molecules in hybrid materials is more restricted than that of bulk polymers. The storage modulus of non-bonded hybrids decreases with the increase of the content of polysiloxane, which reflects the difference between polysiloxane and SiO2 in nature.