Poly(ethylene oxide) bis(cyclic carbonate) based hydrophilic non-isocyanate polyhydroxyurethanes: Polymer-water interactions and glass transition behavior

Hydrogen bonding, glass transition, water absorption, and plasticization are studied as a function of hydrogen bond donor concentration in the chain of a non-isocyanate polyhydroxyurethane system, synthesized by solventfree aminolysis of a poly(ethylene oxide) (PEO) based cyclic carbonate. The concentration of hydrogen bond donors is controlled by varying the ratio of diaminobutane (DAB) and triethylenetetramine (TETA) in the amine component. Introduction of secondary amino groups enhances hydrogen bonding and rigidity of the chain, and, as a result, slows down dynamics, as evidenced by an increase in glass transition temperature. Hydroxyurethane groups are the primary hydration sites despite the hydrophilicity of the polyether. Secondary amino groups act as secondary hydration sites which further increases water sorption capacity. The Couchman-Karasz model describes excellently the dependence of glass transition temperature on composition in both dry and hydrated systems.