Nylon-6 film grafted with acrylic acid for dissepiment in alkaline storage batteries

摘要

A grafted nylon-6 membrane that can be used in alkaline storage batteries was prepared by grafting acrylic acid onto nylon-6 film using (NH{sub}4)Ce(NO{sub}3){sub}6/H{sub}2SO{sub}4 as initiator. The nylon-6 films to be grafted were pre-swelled in 20% formic acid solution, activated with an aqueous solution containing eerie ammonium nitrate and sulfuric acid. The grafting efficiency was greatly affected by the reaction temperature, the concentration of (NH{sub}4)Ce(NO{sub}3){sub}6/H{sub}2SO{sub}4 and the swelling time in formic acid. The degree of grafting that could be achieved under optimized conditions was up to 312%. Through infrared spectroscopy (IR) and X-ray photoelectron spectroscopy (XPS) analysis, it was realized that graft reaction took place on the nitrogen atom of the amide group and the density of grafting point increased with an increase in the degree of grafting in a certain range. The highest density of grafting point was found to be 51.3% in a given set of reaction conditions. X-ray diffraction illustrated that the crystallinity of the grafted membranes decreases with the increase of the degree of grafting. A membrane with 173% degree of grafting showed electric resistance of 0.11Ωcm{sup}2, and ion exchange capacity (IEC) of 8.7 mmol/g, which can meet the requirement for the electric discharge of storage batteries with strong power.