The effect of the molecular weight and polyurethane content of three commercial thermoplastic polyurethanes (TPU) on the mechanical properties of poly(methyl methacrylate)/polyurethane physical mixtures was studied. The samples were prepared using a Haake rheometer at 180 °C/10min and 60rpm. The PMMA/TPU ratio of the blends was 0/100,10/90, 30/70, 50/50, 70/30, 90/10 and 100/0. The mechanical properties such as strain and stress at break are better for the sample PU(85 A15) of lower weight-average molecular mass (Mw = 138,000). The results showed that the TPU content influences strongly the characteristics of the material where the properties change progressively becoming similar to the high content component. The study allowed us to compare the results of blends obtained from rheometer processing with data reported for simultaneous and sequential PU/PMMA IPNs. The pattern of behavior of the elastic modulus suggests dual-phase continuity in the TPU/PMMA blends, consistent with theoretical equations proposed for IPNs.
PMMA/TPU; physical mixtures; molecular weight; mechanical properties
