Self-catalytic Cross-linked Phthalocyanine Resin

Phthalonitrile polymers are an important class of high-performance polymers. These polymers are derived by heating the phthalonitrile derivatives for an extended periods of time at elevated temperatures by addition curing reaction of cyano groups from phthalonitrile derivatives. Because of their outstanding thermal and thermal-oxidative stability, good mechanical properties, low flammability, water and chemical resistance, and easy processability, phthalonitrile polymers have found many applications in advanced technologies such as aerospace, marine, and microelectronics.The curing reaction was found to be readily promoted in the presence of a small amount of curing additives such as phenols and organic amines. Beacause of the high temperature required for resin processing, curing additives, aromatic amines or phenols generally of low molecular weight, tend to be volatile or decomposed, therefore casuing void problems. On the other hand, loss of curing additives from some volatility and thus a slowdown of cure have been observed, which can increase processing costs because greater care must be taken to insure that the right amount of curing agent is used.To solve the void and processing cost problem, we designed a "self-promoted curing method" , using phthalonitrile derivatives with self-promoted curing behavior to prepare the thermosets. We hope that the phthalonitrile derivatives can be thermally polymerized to a network polymer by self-promoted curing reaction without addition any other curing additives. To achieve this aim, an class of hydroxy or amino-containing phthalonitrile derivatives were synthesized. The structure of the phthalontrile derivatives was confirmed by Fourier transform infrared spectra (FT-IR) and nuclear magnetic resonance (~1HNMR). The product purity was characterized by TLC.With an aim to synthesize the phthalonitrile derivatives in large scale, a optimal synthesis procedure was determined by TLC monitorring of the reaction progress. Most of the phthalonitrile derivatives were synthesized in high yield by nucleophilic displacement of 4-nitrophthalonitrile and phenol compounds.The thermal behaviors of the phthalonitrile derivatives were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The thermal analysis results indicated that the hydroxy and amino-containing phthalonitrile derivatives showed a self-promoted curing behavior at high temperatures. This result comfim the possability that the "self-promoted curing method" offer a novel synthetic route to the phthalonitrile polymers, which can be used to solve the void and processing cost problem.The self-promoted curing behavior of the phthalonitrile derivatives was investigated in comparison for better understaning of the relationship between the molecular structure and the self-promoted curing characteristic. Thermal analysis performed on phthalonitrile derivatives revealed that positions of hydroxy or amino groups in molecule have much effect on the self-promoted curing behavior. It was also found that self-promoted curing reactivity has much association with the acidity of hydroxy or the basicity of amino groups in this phthalonitrile polymer system determined by chemical shift of hydroxy or amino group on the ~1H NMR spectrum.