Synthesis of new cationic surfactants based on recycled poly(ethylene terephthalate) for deinking of solvent-based ink from low-density polyethylene surface

摘要

Water-soluble oligomers based on poly- (ethylene terephthalate) waste, PET, were prepared from transesterification of PET with diethanolamine and triethanolamine in the presence of manganese acetate as a catalyst at temperature of 200°C for 8 h. New cationic surfactants were prepared by reaction of the produced recycled oligomers with bromoacetic acid followed by quaternization with pyridine. The chemical structure of the prepared surfactants was confirmed by ~1H-NMR analysis. The surface tension, critical micelle concentration, and surface activities were determined at different temperatures. Surface parameters such as surface excess concentration (_(max) max), the area per molecule at interface (A_(min)), and the effectiveness of surface tension reduction (CMC) were determined from the adsorption isotherms of the prepared surfactants. The prepared surfactants were tested as ink removal for printed low-density polyethylene surface. The effect of surfactants concentrations, pH, soaking time, and shaking time were investigated for deinking process.