The Structure And Properties Of Thermoplastic Polyurethane And Epdm Rubber Bicontinuous Blends

In this study, thermoplastic polyurethane (TPU) and ethylene propylene terpolymer (EPDM) blends were prepared by melt blending through a twin-screw extruder. Morphology, thermal properties, dynamic mechanical properties, mechanical properties, and rheological behavior were investigated. Scanning electronic microscope (SEM) observation showed that TPU/EPDM blends exhibited a co-continuous phase structure in a wide range of blending ratio, where EPDM formed a network in TPU matrix. The morphology of TPU/EPDM blends demonstrates a different network size with the change of EPDM content. A fine and complete network structure of EPDM in TPU matrix was achieved at the ratio of 92/8 (TPU/EPDM). The tensile strength and elongation at break of TPU/EPDM blends increased with the increasing of EPDM content. The mechanical properties reached maximal values at the ratio of 92/8 (TPU/EPDM). Continual increasing of EPDM resulted in a decreasing of the mechanical properties. Fourier transform infra-red spectroscopy (FTIR) determination of TPU/EPDM blends showed that the hard segments of TPU and EPDM was incompatible. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) investigations of TPU/EPDM blends showed that the soft segments of TPU and EPDM were compatible to some extent. Characterization of rheological behavior indicated that the process ability of TPU was increased after it was mixed with EPDM. The mixing of compatibilizer with TPU/EPDM blends increased the compatibilization of TPU and EPDM to some extent. For the blend at the ratio of 80/20 (TPU/EPDM), when 3 percent POE-g-MA was added, the morphology exhibited a most perfect network structure than the blend at the ratio of TPU/EPDM (90/10).