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Morphology and properties of blends with different thermoplastic polyurethanes and polyolefines
Author(s) -
Pötschke Petra,
Wallheinke Katrin,
Fritsche Holger,
Stutz Herbert
Publication year - 1997
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(19970425)64:4<749::aid-app14>3.0.co;2-p
Subject(s) - materials science , thermoplastic polyurethane , ultimate tensile strength , composite material , polymer blend , izod impact strength test , thermoplastic , viscosity , polyester , morphology (biology) , rheology , polymer , elastomer , copolymer , genetics , biology
Unmodified blends of two thermoplastic polyurethanes (TPU) and six polyolefines were used to study the influence of the component viscosities on the blend morphology and mechanical properties. Blends were produced by melt mixing using a twin screw extruder. Interactions between the blend components could not be detected by DSC, DMA, selective extraction, and SEM micrographs of cryofractures. The variation in tensile strength with blend composition produce a U‐shaped curve with the minimum between 40 and 60 wt % of polyolefine. At similar viscosity ratios ( η d / η m ), blends with polyether based TPU (TPU‐eth) have a finer morphology than blends with polyester based TPU (TPU‐est). This is due to the lower surface free energy of the polyether soft segments compared to the polyester soft segments. Different morphologies also lead to changes in mechanical behavior. Blends with TPU‐eth show a lower decrease in tensile strength with blend composition than blends with TPU‐est. The viscosity ratio between TPU and polyolefines can be directly correlated to the blend morphology obtained under similar blending conditions. TPU/PE blends show a lower dispersity than TPU/PP blends, due to the higher viscosity ratios of TPU/PE blends. This results in a greater reduction in tensile strength with the disperse phase content. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 749–762, 1997