Electromagnetically-induced cement concrete crack self-healing diisocyanate microcapsules and their preparation method

A preparation method of electromagnetically-induced cement concrete crack self-healing diisocyanate microcapsules, comprising the steps of:

• (a) providing raw materials, in parts by weight, comprising 15-55 parts of petroleum resin, 5-10 parts of paraffin, 5-10 parts of polyethylene wax, 3-10 parts of magnetic iron powder and 20-67 parts of diisocyanate, wherein the paraffin has a melting point of 50-70° C.;
• (b) heating the petroleum resin to 130-140° C., adding the paraffin under stirring, mixing the paraffin and the petroleum resin uniformly, adding the polyethylene wax and stirring continuously to mix the polyethylene wax and the paraffin/petroleum resin uniformly, adding the magnetic iron powder, continuing to perform stirring to mix the magnetic iron powder and the petroleum resin/paraffin/polyethylene wax uniformly, finally adding the diisocyanate, and carrying out stirring for 2-4 h while controlling the temperature at 100-110° C.;
• (c) stopping heating, increasing the stirring speed, adding the perfluorotributylamine solution, and lowering the temperature of the mixture to obtain a petroleum resin/paraffin/polyethylene wax/magnetic iron powder coated diisocyanate microcapsule suspension;
• and
• (d) carrying out ultrasonic dispersion treatment on the suspension, separating out the microcapsules by filtration, and carrying out drying treatment to obtain the electromagnetically-induced cement concrete crack self-healing diisocyanate microcapsules.