Microfracture surface structure versus network and swelling properties of segmented polyurethanes

Microfracture surface structure of segmented polyurethanes (PUs) with diffe rent chemical and physical structures was tested in manually broken samples far below their glass transition. To observe the microfracture surface, tr ansmission electron microscopy (TEM) was utilized. Some correlations betwee n swelling degree (thus physical structure) and the appearance of the micro fracture surface pattern were found in chemically different PUs. A radial m icrofracture topology was observed for cross-linked PU networks.