Segmented polyurethanes properties

Harrell L L J (1969) Segmented polyurethans. Properties as a function of segment size and distribution, Macromolecules 2 607-612. 

Other elastomeric-type fibers iaclude the biconstituents, which usually combine a polyamide or polyester with a segmented polyurethane-based fiber. These two constituents ate melt-extmded simultaneously through the same spinneret hole and may be arranged either side by side or ia an eccentric sheath—cote configuration. As these fibers ate drawn, a differential shrinkage of the two components develops to produce a hehcal fiber configuration with elastic properties. An appHed tensile force pulls out the helix and is resisted by the elastomeric component. Kanebo Ltd. has iatroduced a nylon—spandex sheath—cote biconstituent fiber for hosiery with the trade name Sidetia (6). 

In the second step, a papermaking method is also used for the fine fibers, less than 0.1 tex (1 den). This process is usually followed by a high pressure water jet process instead of the third step. In the fourth step, to obtain the required properties in specific appHcations, a polyurethane is selected out of the segmented polyurethanes, which comprises a polymer diol, a diisocyanate, and a chain extender (see Urethane polymers). A DMF—water bath for coagulation is also controlled to create the adequate pore stmcture in combination with fibers. 

Ishihara K, Hanyuda H, and Nakabayashi N. Synthesis of phospholipids polymers having a urethane bond in the side chain as coating material on segmented polyurethane and their platelet adhesion resistant properties. Biomaterials, 1995, 16(11), 873-879. 

There are several other commercial products containing segmented polyurethane (SPU) such as pellethane or cardiothane. These SPUs are widely recognized to possess notable biomedical properties as materials for artificial heart and intra-aortic balloon pumping (IABP), and also as coating materials for pacemaker-lead insulators (See Sect. 4.1). 

A number of studies on the morphology and mechanical properties of segmented polyurethanes (SPU) are accessible in the literature [53-55],... 

Hard segment One of the two phases that make up polyurethane. The hard segment is made from isocyanates and chain extenders. The hard segment controls many of the polyurethane properties such as tensile, tear strength, hardness, compression set, abrasion/erosion resistance, and thermal stability. 

Ophir, Z. Structure-Property Relationships in Solid Polymers I — Segmented Polyurethanes and II — Epoxy Thermosets. Ph. D. Thesis, Princeton University (1979)... 

Time Dependence of Mechanical Properties and Domain Formation of Linear and Crosslinked Segmented Polyurethanes... 

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