Abstract
Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) was synthesized by oxidative polymerization of 2,6-dimethylphenol (DMP) using a water-soluble copper complex catalyst under oxygen and with natural ligands in alkaline water. Arginine, guanine, adenine, cytosine, histidine, and folic acid were used as ligands for the copper complex. Arginine performed the best, with a yield of 72%, a number average molecular weight (Mn) of 4400, and a molecular weight distribution (Mw/Mn) of 1.7. It was then used to optimize the reaction conditions. Surfactants, temperature, catalyst and sodium hydroxide concentration were varied in copolymerization of DMP and 2-allyl-6-methylphenol (AMP) to produce allyl-containing PPO with 77% yield (Mn = 4500, Mw/Mn = 1.8). The optimum conditions were also applied to copolymerization of DMP, AMP, and bisphenol A, as well as vinylbenzyl terminated copolymerization of DMP and diallyl bisphenol A, leading these PPO derivatives analogs containing thermally cross-linkable allyl and vinyl groups. The thermal properties of these thermosetting PPOs were studied by differential scanning calorimeter, thermogravimetric analysis, and Fourier-transform infrared spectroscopy.