Heat-Resistant Dendritic Poly(methylsilane arylacetylene) with Attractive Mechanical Properties Enhanced Via Higher Curing Temperature

Good mechanical properties are necessary for the application of heat-resistant poly(silylene arylacetylene)s as advanced polymer matrices. A dendritic poly(methylsilane arylacetylene) (DPSA-H) resin with long arms and a linear poly(methylsilane arylacetylene) (PSA-H) with a high degree of polymerization were synthesized via a Grignard reaction. The cured resins were obtained by curing DPSA-H and PSA-H resins. The postcured resins were obtained by postcuring the cured resins at 400 degrees C in N2. The cross-linked network, mechanical properties, and thermal properties of the cured resins and the postcured resins were investigated. With the curing temperature rising, the reaction degree of internal acetylene and Si-H groups significantly increases. The high reaction degree of internal acetylene and Si-H groups contributes to enhancing the mechanical properties and heat resistance of the postcured resins. The postcured DPSA-H resin shows a high flexural modulus (8.8 GPa) compared to the postcured PSA-H resin. The postcured DPSA-H resin shows a low coefficient of thermal expansion (15 ppm/degrees C) and high thermal stability with the temperature of 5% weight loss (T d5) at 750 degrees C.