[Structural study on the transparency of cross-linked polyester polyurethane].

Abstract

The polyurethane material with cross-linked structure was synthesized using half pre-polymerization method. IR, UV-Vis, TEM and XRD methods, and physical properties measurements indicate that different moulding temperatures influence the apparent transparence of polyurethane and abrasive performance, and the nature of these changes is related to the conditions of processand chemical reaction which lead to gradual micro-phase separation of the polyurethane molecules with different compositions, resulting in the domain-forming with the size of sub-micro-, micro- and even more than ten micro-meters. Such domains aggregate one another to form particles with different shapes and complicated structures. The increase in the amount and size of these heterogeneous particles, distributed in the medium of transparent polyurethane, is the main cause that brings on an opaque appearance of polyurethane.