Ternary-phase poly(ester-urethane)/elastomer/filler composites

Impact-modified and reinforced composites, consisting of biodegradable poly (ester-urethane) (PEU), poly(L-lactic acid-co-epsilon -caprolactone-urethan e) elastomer, and various organic and inorganic fillers, were prepared by m elt blending, and their properties were investigated. The impact strength i ncreased with elastomer addition, and the addition of particulate or fibrou s fillers as a third component increased the stiffness. Therefore, the bala nce between the impact strength and stiffness of the amorphous PEU was sign ificantly improved. Composites with elastomer and 15 wt % particulate fille rs, that is, wollastonite, Aktisil, and talc, showed excellent impact stren gth. However, effective impact modification was lost in highly constrained systems. Dynamic mechanical thermal analysis confirmed the phase separation of elastomer and showed a marked increase in the glass-transition temperat ure for the PEU matrix in binary blends with wollastonite, talc, and glass fiber. Scanning electron microscopy studies showed good adhesion of the com ponents. (C) 2000 John Wiley & Sons, Inc.