Polyurethane elastomeric seal for hydraulic pumps

A method for forming a piston seal of a hydraulic pump, the method comprising:

• forming a reaction mixture that includes a prepolymer component, a polyol additive, a diol component, and a curative component, wherein:
• the prepolymer component includes a polycarbonate-isocyanate prepolymer that is a reaction product of at least an isocyanate component and a polycarbonate polyol component, and the prepolymer component is present in an amount from 55 wt % to 90 wt %, based on a total weight of the reaction mixture,
• the polyol additive includes a polycarbonate polyol, which is present in an amount from 5 wt % to 40 wt %, based on the total weight of the reaction mixture,
• the diol component is present in an amount from 5 wt % to 20 wt %, based on the total weight of the reaction mixture, and
• the curative component includes a diamine based curative agent that is present in an amount from 0.01 wt % to 20 wt %, based on the total weight of the reaction mixture,
• forming a sealing element with the reaction mixture and a mold, and
• curing the sealing element to form a piston seal of a hydraulic pump.