Synthesis and properties of silicon-containing poly(diethynylbenzen-co-phenoxyphenoxybenzenediacetylene)s

Good mechanical properties, heat resistance and processability are the basic requirements of matrix resins for high performance heat resistant composites. The existing two types of silicon-containing arylacetylene resins, poly (silylene arylacetylene) (PSA) and poly (silane arylether arylacetylene) (PSEA), cannot balance these three requirements well. To achieve this goal, an attempt was made to synthesize a copolymerized resin containing both diethynylbenzene and diynyl arylether structures in the main chain, silicon-containing poly (diethynylbenzene-co-phenoxyphenoxybenzenediacetylene). By controlling the amount of 1,3-diethynylbenzene ( m-DEB) and 1,3-bis(4′-ethynylphenoxy)benzene ( pmp-BEPB), several random copolymerized resins with various ratios of m-DEB to pmp-BEPB were synthesized by the Grignard reactions. The results show that the introduction of m-DEB could effectively reduce the viscosity of the resin, and thermal stability of the cured resin is improved, but the mechanical strength of the cured resin is slightly reduced. The copolymerized resin has good overall performance when the amount of m-DEB and pmp-BEPB is equal. The processing window of the resin is 56∼169°C, the flexural strength and modulus of the cured resin are 32.9 MPa and 2.7 GPa, respectively, and the temperatures of 5% weight loss (Td5) of the cured resin is 589°C in nitrogen.