Polyurethane thermoplastic elastomer mechanical properties

The undesirable properties of thermoplastic polyurethane elastomer, i.e., softening at high temperatures and flow under pressure, which limit their use at elevated temperamres have been reduced by cross-linking with EB radiation. The cross-linked polyurethane shows good mechanical properties and also displays good resistance to aggressive chemicals, e.g., brake fluid [432 35]. 

Silicones and polyurethanes are the two classes of elastomers used for in vivo applications. Both are versatile polymers with a wide range of mechanical properties. Polyuredianes tend to be stiffer and stronger than silicones, whereas silicones are more inert and have the advantage of being oxygen-permeable. Polyurethanes are more versatile from a processing standpoint since many polyurethanes are thermoplastics, whereas silicones rely on covalent cross-linking and are therefore thermosets. 

Blending two or more polymers offers yet another method of tailoring resins to a specific application. Because blends are only physical mixtures, the resulting polymer usually has physical and mechanical properties that lie somewhere between the values of its constiment materials. For instance, an automotive bumper made from a blend of PC resin and thermoplastic polyurethane elastomer gains rigidity from the PC resin and retains most of the flexibility and paintability of the polyurethane elastomer. For business machine housings, a blend of PC and ABS (acrylonitrile—butadiene—styrene copolymer) resins offers the enhanced performance of PC flame retar-dance and ultraviolet (UV) stability at a lower cost. 

Several elastomer matrices have been used to improve the mechanical properties of PLA, but special attention has been paid to polyurethane elastomer (PU) ° and natural rubber (NR). Lt is well known that thermoplastic polyurethane elastomers are widely used in a diverse range of implantable medical devices due to a unique combination of toughness, durability, flexibility, biocompatibility and biostability. Ln addition, it... 

The mobility of the soft phase in a two-segment thermoplastic elastomer polyurethane, as derived from H NMR, correlates well with mechanical properties [224,225]. The soft poly(tetramethylene oxide) segments consist of both crystalline and amorphous phases. The observed 100-fold decrease in storage modulus, G, between 200 and 280 K corresponds to the transition of the amorphous part of the soft blocks from a glassy to a rubbery... 

Ahn TO, et al. Thermal and mechanical properties of thermoplastic polyurethane elastomers from different polymerization methods. Polym Int 1993 31(4) 329-33. 

Kojio K, Fumkawa M, Nonaka Y, Nakamura S. Control of mechanical properties of thermoplastic polyurethane elastomers by restriction of crystallization of soft segment Materials 2010 3(12) 5097-110. 

Marija Pergal, MSc, works at the Department for Polymeric Materials, Institute for Chemistry, Technology and Metallurgy since 2003 as Research Scientist. Since 2007 she is also Teaching Assistant for the course Chemistry of Macromolecules at Department of Chemistry, University of Belgrade. Her research interests are focused on synthesis and characterization of siloxane homopolymers and copolymers, especially thermoplastic elastomers based on poly(butylene terephthalate) and polyurethanes, as well as polyurethane networks based on hyperbranched polyester. In addition to physico-chemical, mechanical and surface properties of polymers, her particular interest is directed towards the study of biocompatibility of polymer materials. 

Doped ICPs (e.g., PAni.DBSA) are sometimes blended with a thermoplastic elastomer such as thermoplastic polyurethane (TPU) in order to improve their mechanical properties and processability [90]. TPU exhibits a two-phase morphology in which a soft phase containing either polyesters or polyethers is reinforced by condensation with a hard domain that consists of an aromatic diisocyanate... 

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