Preparation and characterization of phthalonitrile resin within hyperbranched structure

Abstract

In this article, a kind of polyester-type phthalonitrile cyano resin (2,2-bis (((3-((4-(3,4-dicyanophenoxy) benzoyl)oxy)-2-(hydroxymethyl)-2-methylpropanoyl)oxy)methyl) propane-1,3-diyl)bis(oxy)) bis (2-(hydroxymethyl)-2-methyl-3-oxopropane-3, 1-diyl) bis (4-(3,4-dicyanophenoxy) benzoate (hbppn)) with branched structure was introduced. The molecular structure and relative molecular mass of hbppn were characterized by nuclear magnetic resonance, Fourier transform infrared spectroscopy, and the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF). The results showed that the synthesized HBPPN contained both polyester and hyperbranched structures. The thermal and rheological properties of HBPPN were characterized by differential scanning calorimetry and rheometer, and the results showed that HBPPN would be cured at about 322°C and the viscosity of the resin showed good processability. The results of dynamic mechanical analysis and thermogravimetric analysis showed that the synthesized resin had good heat resistance. The glass transition temperature was above 329°C, the residual weight ( C y) at 900°C was as high as 66.2% in the nitrogen atmosphere, and the temperature at which the resin lost 5 wt% of heat in air atmosphere was about 423.3°C. The synthesized HBPPN had good comprehensive properties, which could be applied to high-temperature resistant and thermal protection materials.