Szerző szerinti böngészés "Chukwudumebi Odunayo, Isichei"

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    Synthesis and Investigation of Pluronic containing Polyurethanes as possible Shape Memory Polymers
    Chukwudumebi Odunayo, Isichei; Kéki, Sándor; DE--Természettudományi és Technológiai Kar--Kémiai Intézet
    Polyurethanes are synthesized with polyols and isocyanates and can be prepared by a variety of methods and can be applied in different fields. The polyurethane used for this project was formed from a reaction between poly(-caprolactone) and 1,6-Hexamethylene diisocyanate. The diisocynate makes up the the hard segment while the polycaprolactone forms the soft segment. The mechanical, as well as the thermal properties of the polyurethane was affected by the hard segment content and the interactions of the pluronic (plasticizer) with the soft and the hard segments. It should be noted that by increasing the hard segment contents of the polyurethane, thermo stability tends to improve. Also, the degree of phase separation in the segmented polyurethane is relatively high and the compatibility between hard segment and soft segment is low. The thermodynamic behavior and shape memory ability of the polyurethane SMP are highly dependent on strain rate, temperature, and maximum strain.[23]. Materials like this can almost recover fully from a pre-strain load below and above its transition temperature Tm. A high strain rate is preferred and required while loading to achieve more strain recovery Finally, the Shape Memory property of the synthesized polymers for the experiment was highly determined by the PCL’s melting point. The polymers easily deform at a temperature higher than the melting point temperature of PCL and when cooled down, form the temporary shape for Shape Memory.