ut 60,000, a solubility of less than 1% in water at 25??? C., capable of being covalently bonded to A; C and D are terminating groups which can be A or B, can be the same or different groups, w is 0 or 1; x is an integer of 1 or more, y is 0 or 1, and z is 0 or 1. 11.