engleski

Photooxidative Stability of Polyurethane/Polycarbonate Blends

In this work the photooxidative stability of polyurethane/polycarbonate (PU/PC) blends was studied. Poly (ester–urethane) elastomers based on polycaprolactone glycol and an aromatic type of diisocyanate (MDI) were synthesized by a prepolymer procedure. Blends of PU and PC with different weight ratios were prepared using a Brabender mixer. Thermal and mechanical properties were evaluated after UV irradiation (200 hours) performing DSC, DMA, TGA and tensile tests. DMA results indicated partial miscibility of PC and PU in the PU/PC blends with higher hard segment content, attributed to favourable interactions between the ester groups from the soft segments and urethane groups from the hard segments. The photochemical degradation of the polyurethane is associated with the scission of the urethane group and photooxidation of the central CH2 group between the aromatic rings. The processes of photooxidative degradation are less pronounced in PU/PC blends with higher hard segment content in the polyurethane.

polyurethane, polycarbonate, elastomers, polymer blends, UV irradiation

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