Phase morphology of functionalized polyester polyurethanes. Effect of functional group concentration

Segmented polyester polyurethanes (PU) were prepared based on polycaprolactone as a soft segment and a hard segment containing isophoronediisocyanate and chain extenders 2,2'-bis(hydroxymethyl) propionic acid and 1,4-butanediol with different molar ratios. The changes of crystallinity and morphology due to the incorporation of carboxylic functional groups in the hard segment were monitored by wide-angle X-ray diffraction, optical microscopy and differential scanning calorimetry. The concentration of functional groups varied from 0 to 0.45 mmol g(-1). The phase separation, the degree of crystallinity and the size of spherulites depend on the interactions imposed by functional groups. A critical level of the concentration of functional groups (0.25 mmol g(-1)) at which the crystallizability reaches its maximum was observed. (C) 2005 Society of Chemical Industry.