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 °C in N 2 . 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/°C) and high thermal stability with the temperature of 5% weight loss ( T d5 ) at 750 °C.