Abstract:
Light integrated materials bearing heat-resistant structures can be used in the field of aerospace crafts and high-speed transport vehicles, leading to low weight and high transportation efficiency. To achieve this goal, light and highly heat-resistant resin matrices have been required to be designed and prepared. Poly(silicon-containing arylacetylene) (PSA) is a kind of novel thermosetting resins with many fascinating characteristics such as high thermal stability and ablative resistance. Nevertheless, the mechanical properties of the typical PSA resin are poor. To improve the mechanical properties of the light and highly heat-resistant PSA, two aryl dipropargyl ethers, 4,4’-diproparyloxy bisphenol fluorene (DPO-BPF) and 4,4’-diproparyloxy biphenyl ether (DPO-BPE) were synthesized and used to modify PSA through solution and melting processes. The curing reaction, thermal property and mechanical property of the two aryl dipropargyl ethers modified silicon-containing arylacetylene resin were studied. The results indicated that the peak temperatures of the modified PSA resins were increased, and the initial temperatures of the modified PSA resins were slightly changed compared with pristine PSA resin during curing. The thermal stability in nitrogen of the cured modified PSA resins was reduced with addition of the two aryl dipropargyl ethers. For the PSA resin containing 30% mass fraction of DPO-BPF, the temperature for 5% weight loss and the residual yield at 800 ℃ were 559 ℃ and 87%, respectively. The mechanical properties of the PSA resins modified with DPO-BPE and DPO-BPF were enhanced obviously. As a comparison with PSA, the flexural strength and impact strength the PSA modified with 20% mass fraction of DPO-BPE could reach 51.6 MPa and 5.2 kJ/m
2, increased by 137% and 136%, respectively. The dynamic thermal mechanical analysis showed that no glass transition temperature was observed for the cured PSA and modified PSA resins before 500 ℃. The PSA resin modified by 4,4’-diproparyloxy biphenyl ether is a promising matrix that can be used as a kind of light, heat-resistant and structural material.