Synthesis And Properties Of Phosphorus-Containing Copolyamides

Polyamides are most important high-performance polymers. Due to their excellent thermal stability, outstanding mechanical properties, corrosion resistance, they are widely used in automotive, aerospace, electrical and electronic, fiber, membrane material and so on. The modification of polyamides and development of new polyamides have always been one of the hotspots in the research of polymer materials.In this paper, bis(3-aminophenyl) phenylphosphine oxide(BAPPO) was first prepared, and it’s structure was characterized by Fourier transform infrared spectroscopy (FTIR). Semi-aromatic polyamides PA6I, PA10I and PA12I were prepared from BAPPO and hexanedioic acid, sebacic acid and lauric acid by Yamazaki phosphorylation reaction respectively. The effects of reaction factors on the intrinsic viscosity of the polymers were investigated, such as the reaction time and temperature, monomer concentration and solvent system, and the optimum reaction conditions were obtained. The structures of semi-aromatic polyamides were characterized by FTIR and nuclear magnetic resonance (1H-NMR). Their thermal behaviors were measured by DSC and TGA, and the results showed that the Tg of the semi-aromatic polyamides were 161-206℃, and the thermal decomposition temperature at 5% weight loss was 388-413℃. The thermal decomposition mechanism of PA 101 was obtained from the analysis of TGA data. The activation energy of degradation obtained by Kinssinger method and flynn-Wall-Ozawa method were 175.6 and 177.6 kJ/mol, respectively. The activation energy of different mechanism models were determined by Coats-Redfern method. And the actual reaction mechanism obeyed A3 or F1 mechanics.The PA6I, PA 101 and PA 121 films were prepared, and the mechanical properties, contact angle and water absorption, flame retardancy of the films were tested. The results showed they possessed good mechanical properties. The contact angle and water absorption tests showed that their moisture resistance were very good, which was beneficial to maintain the stability of polymers in practical application. LOI test showed that all the semi-aromatic polyamides possessed excellent flame retardant property, in particular, the LOI of PA6I reached to 43%.The polyamide alloy was prepared by blending of PA10I and PA66. The crystallization behavior of PA66/PA10I blend was measured by the wide angle X-ray diffraction (WAXD) and DSC. Non-isothermal crystallization of blend behavior was investigated by DSC and the data were analyzed with Ozawa and Mo methods. Their thermal behaviors were measured by TGA.Aromatic polyamides PAⅡ were prepared from BAPPO and terephthalic acid (PTA) by Yamazaki phosphorylation reaction and the the optimum reaction conditions were obtained. By adding the third monomers 4,4’-diaminodiphenyl methane (DDM) and 4,4’-diaminodiphenyl ether(ODA), series of aromatic polyamides PAⅢ and PAⅣ were also prepared. The structures of all the aromatic polyamides were characterized by FTIR and 1H-NMR. The solubility tests showed some aromatic polyamides behaved good solubility in common organic solvents.