A Pyridazine-Containing Phthalonitrile Resin for Heat-Resistant and Flame-Retardant Polymer Materials

Abstract

In this study, a novel phthalonitrile monomer containing a pyridazine ring, 3,6-bis[3-(3,4-dicyanophenoxy)phenoxy]pyridazine (BCPD) with a low melting point (74 °C) and wide processing window (178 °C), was prepared by a nucleophilic substitution reaction. The molecular structure of the BCPD monomer was identified by Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance spectroscopy (NMR). Poly(BCPD) resins were derived from the formulations by curing at 350 and 370 °C. The thermoset that was post-cured at 370 °C demonstrated outstanding high heat-resistant (glass transition temperature (Tg) > 400 °C, 5% weight loss temperature (T5%) = 501 °C, Yc at 900 °C > 74%) and was flame-retardant (limiting oxygen index (LOI) = 48)). Further, the poly(BCPD) resin simultaneously exhibited a superior storage modulus, which could reach up to 3.8 Gpa at room temperature. Excellent processability and heat resistance were found for phthalonitrile thermosets containing the pyridazine ring, indicating poly(BCPD) resin could be potentially applied as high-temperature structural composite matrices.

Improving the Heat Resistance and Flame Retardancy of Epoxy Resin Composites by Novel Multifunctional Cyclophosphazene Derivatives

“…This indicates that the added HCCP-SA can decompose and absorb the energy of the system at a lower temperature, reducing the decomposition rate and T max of the E-HS- x composites, and thus, preventing further degradation of the EP resin matrix. In a word, the multiple-ring cross-linking network structure composed of the benzene ring, P-N, and N-O heterocycles is the main reason why E-HS- x composites have outstanding heat resistance [ 24 ].…”

Optimizing the thermal properties of fiber reinforced phthalonitrile composites

“…With the modernization and intelligent development of high technology sectors such as aerospace, electric motors, electronics and automobiles, polymer‐based composites with better overall performance are increasingly in demand. Phthalonitrile (PN) resin, a new type of high‐temperature resistant resin, has attracted a wide range of interest, 1 for its high glass transition temperature, 2 outstanding thermal and mechanical properties, 3–6 low water absorptivity 7 and superior flame resistance 8–10 . As one of the promising matrix materials for advanced composites, the mechanical properties of phthalonitrile can be further improved through fiber reinforcement 11 .…”

“…Phthalonitrile (PN) resin, a new type of hightemperature resistant resin, has attracted a wide range of interest, 1 for its high glass transition temperature, 2 outstanding thermal and mechanical properties, [3][4][5][6] low water absorptivity 7 and superior flame resistance. [8][9][10] As one of the promising matrix materials for advanced composites, the mechanical properties of phthalonitrile can be further improved through fiber reinforcement. 11 With years of exploration, PN composites have had a lot of theoretical and experimental basis in terms of the fabrication process, and some works of literature have been reported on the innovations and breakthroughs of curing mechanisms, and resin as well as fiber modification.…”