Oligomeric bisphenol A‐based PEEK‐like phthalonitrile‐cure and polymer properties

Abstract

ABSTRACT:The cure behavior and properties of oligomeric bisphenol A-based PEEK-like phthalonitrile (PN) are thoroughly examined in this article. The resin is easily processed from the melt at a relatively low temperature (150-200 8C) and the monomer cure occurs in a controlled manner as a function of the amine content and processing thermal conditions. Dynamic mechanical measurements and thermogravimetric analysis show that the polymer properties improve as the maximum PN postcure temperature is increased to 415 8C. The effects of the amine and polymer postcure conditions on the flexural and tensile properties of the PN polymer are investigated. The mechanical properties of the polymer are maximized after postcuring to moderate temperatures (330-350 8C). The polymer exhibits an average flexural strength and tensile strength at break of 117 and 71 MPa, respectively. After oxidative aging at 302 8C for 100 h, the polymer retains excellent mechanical properties. The average flexural and tensile strength retention of the polymers are 81 and 75%, respectively. Microscale calorimetric measurements reveal that the flammability parameters of the oligomeric PN are low compared to other thermosets.

Copolymerization modification: improving the processability and thermal properties of phthalonitrile resins with novel comonomers

“…But such a design still has a problem in that a curing agent with high molecular weight and good thermal stability tends to have a relatively high melting point, which would reduce the processing windows (defined as the temperature difference between the completely softening or melting points of resins and the exothermic curing temperature) of phthalonitrile resins. In previous researches, molecular designs were generally used to improve the processability of phthalonitrile resins, for instance, introducing some flexible chains into the phthalonitrile oligomeric backbone to reduce the melting point or softening point of monomers and broaden the processing window of the resins . In the work reported here, inspired by the results of Liu and co‐workers in the study of poly(aryl ether nitrile)/ phthalonitrile composites where the pendant nitrile groups in poly(aryl ether nitrile) probably promote adhesion and compatibility of the polymer to many substrates by polar interaction with other functional groups, an alicyclic anhydride end‐capped imide compound with mononitrile group (THAN) was designed.…”

“…In previous researches, molecular designs were generally used to improve the processability of phthalonitrile resins, for instance, introducing some flexible chains into the phthalonitrile oligomeric backbone to reduce the melting point or softening point of monomers and broaden the processing window of the resins. 21,22 In the work reported here, inspired by the results of Liu and co-workers in the study of poly(aryl ether nitrile)/ phthalonitrile composites where the pendant nitrile groups in poly(aryl ether nitrile) probably promote adhesion and compatibility of the polymer to many substrates by polar interaction with other functional groups, [25][26][27] an alicyclic anhydride end-capped imide compound with mononitrile group (THAN) was designed. We aimed to improve the interaction of the blending components via physical polar interaction between the -CN groups, thereby reducing the melting point or softening point and improving the processability of phthalonitrile resins.…”

Synthesis and Properties of A Low Melting Point Phthalonitrile Resin Containing High Density Nitrile Groups

“…Figure A reveal the corresponding DSC curves of MDTP and MDTP/APPH mixture. Processing properties of phthalonitrile monomers are determined by processing window and melting viscosity . As can be seen from Figure A, the DSC curve of MDTP monomer shows only one melting endothermic peak at 104 °C, which corresponds to the melting point of MDTP monomer.…”

“…In an air atmosphere, the respective 5 % weight loss of Polymer 1 and Polymer 2 are 501.1 °C and 507.3 °C, and the 10 % weight loss are 544.4 °C and 547.9 °C, respectively. And in a nitrogen atmosphere, Polymer 1 and Polymer 2 were able to maintain a weight of 67.6 % and 70.5 % at 1000 °C, which indicates that the MDTP polymer has very excellent heat resistance, better than those of some other phthalonitrile resins reported previously . It can be found by comparison that the thermal stability of Polymer 2 is better than that of Polymer 1.…”

“…Processing properties of phthalonitrile monomers are determined by processing window and melting viscosity. [33] As can be seen from Figure 1 A, the DSC curve of MDTP monomer shows only one melting endothermic peak at 104°C, which corresponds to the melting point of MDTP monomer. When heated to 350°C at the rate of 10°C /min, no other endothermic peaks appear, which also indicated that the purity of the synthesized MDTP monomer was very high.…”