Synthesis and characterization of novel silicon-containing aromatic bispropargyl ether resins and their composites

Abstract

A series of silicon-containing aromatic bispropargyl ether resins—poly(dimethylsilylene-co-propynylene ether resorcinol) [–Si(CH3)2–C≡C–CH2–O–Ar–O–CH2–C≡C–]n (polymer a), poly(dimethylsilylene-co-propynylene ether bisphenol A) [–Si(CH3)2–C≡C–CH2–O–Ar–C(CH3)2–Ar–O–CH2–C≡C–]n (polymer b) and poly(dimethylsilylene-co-propynylene ether hexafluorobisphenol A) [–Si(CH3)2–C≡C–CH2–O–Ar–C(CF3)2–Ar–O–CH2–C≡C–]n (polymer c)—were synthesized from bispropargyl ethers bisphenol and dimethyldichlorosilane by a Grignard reaction. The polymers were characterized by Fourier transform infrared, hydrogen-1 nuclear magnetic resonance, gel-permeation chromatography, rheological analysis, differential scanning calorimetry and thermogravimetric analysis. The results showed that the obtained polymers could be cured at ∼240 °C and displayed good heat resistance and processing properties. Degradation temperatures of the three cured polymers at 5% weight loss (Td5) were above 400 °C, and thermal stabilities increased in the order polymer c<polymer b<polymer a. Carbon fiber (T300)-reinforced composites were prepared by a solution-impregnation process using tetrahydrofuran as solvent. The flexural strength, flexural modulus and shear strength of the composites of polymer c reached 408 MPa, 53.3 GPa and 24.8 MPa, respectively, which were higher than those of polymers a and b. A series of silicon-containing aromatic bispropargyl ether resins, poly(dimethylsilylene-co-propynylene ether resorcinol) (polymer a), poly(dimethylsilylene-co-propynylene ether bisphenol A) (polymer b) and poly(dimethylsilylene-co-propynylene ether hexafluorobisphenol A) (polymer c), were synthesized. The obtained polymers displayed good heat resistance and processing properties. Degradation temperatures of the three cured polymers at 5% weight loss (Td5) were above 400 °C. The flexural strength, flexural modulus and shear strength of composites of polymer c reached 408 MPa, 53.3 GPa and 24.8 MPa, respectively, which were higher than those of polymers a and b.