The present invention relates to polymers having dynamic urea bonds and more specifically to polymers having hindered urea bonds (HUBs). The present invention also relates to: (a) malleable, repairable, and reprogrammable shape memory polymers having HUBs, (b) reversible or degradable (e.g., via hydrolysis or aminolysis) linear, branched or network polymers having HUBs, and (c) to precursors for incorporation of HUBs into these polymers. The HUB technology can be applied to and integrated into a variety of polymers, such as polyureas, polyurethanes, polyesters, polyamides, polycarbonates, polyamines, and polysaccharides to make linear, branched, and cross-linked polymers. Polymers incorporating the HUBs can be used in a wide variety of applications including plastics, coatings, adhesives, biomedical applications, such as drug delivery systems and tissue engineering, environmentally compatible packaging materials, and 4D printing applications.
