Synthesis And Properties Of Pyridine-containing Polyimides

It is well known that the polyimides with aromatic heterocyclic structures play important roles in the development of advanced technologies because of their excellent thermal and thermooxidative stabilities and outstanding mechanical. With the development of industrialization and microelectronics, the requirements of polyimides are gradually increased, so how to improve the comprehensive properties of polyimides has been an attractive research direction.In this paper, 2,2'-bis[4-(5-nitro-2-pyridyl) phenyl] sulfone (BNPDPS) was synthesized using 2-chloro-5-nitropyridine and bisphenol S as raw materials, then a novel pyridine-containing diamine, 2,2'-bis[4-(5-amino-2-pyridyloxy) phenyl] sulfone (BAPDPS),was synthesized via amination reaction of nitro group of BNPDPS. 1H-NMR?13C-NMR and FTIR were employed to characterize the structure of BNPDPS and BAPDPS. Pyridine ring was introduced to the main chains of the polyimides via using a pyridine-containing diamine BAPDPS. A series of homopolymerization polyamic acid solution and copolymerization polyamic acid solution were successfully synthesized via polymerization of diamine monomers (BAPDPS) and 4,4'-diaminodiphenyl methane (MDA) in different proportions(nBAPDPS:nMDA=10:0,8:2,6:4,4:6,2:8) and a dianhydride (3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA)?1,2,4,5-pyromellitic dianhydride (PMDA) or 4,4'-(hexaflouroisopropylidene)diphthalic anhydride (6FDA) respectively. The corresponding polyimides were obtained through the temperature programmed process of polyamic acid.Since the molding process has a great influence on polyimide imidization, the study of the imidization reaction kinetics of the polyimide is very important for further understanding the imidization characteristics and the molding process. In the experiment,the imidization kinetics of the homopolymerization polyamic acid were investigated and compared by the method of non-isothermal Differential Scanning Calorimetry (DSC), and the kenetics parameters were simulated with two different kinetic models, Kissinger and Ozawa, the rections were considered as first order reaction, and were established curing reaction kinetics equations.Attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR)?X-Ray diffraction (XRD)?thermal gravimetric analysis (TGA)?differential scanning calorimetry (DSC)?dynamic mechanical analysis (DMA)?ultraviolet visible (UV-vis) and tensile testing were used to investigate the structure, thermal properties, tensile properties and optical properties of the homopolymerization and copolymerization polyimides. The results indicated that polyimides exhibited nice thermal properties, outstanding mechanical properties and optical properties.The tensile properties and optical properties of polyimides improved with the introduction of diamine BAPDPS.