SYNTHESIS AND CHARACTERIZATION OF NOVEL THERMOPLASTIC ELASTOMERS BY CATIONIC LIVING POLYMERIZATION

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For a development of novel thermoplastic elastomers (TPE) , a design was proposed : Formation of microdomains by an result in the TPEs of special grade. This design was realized by the syntheses using living cationic polymerizations of cyclic monomers such as ethylene oxide and tetrahydrofuran, grafting of hydrophylic segments onto hydrophobic rubber molecule, and polymer blending.Living dicationic species from tetrahydrofuran were reacted with bipyridine to result in the formation of ionene type ionic elastomers which showed very good elastomeric properties. DSC,dynamic mechanical analysis (DMA) measurements suggested ion cluster formation in the polyether matrix. Small-angle X-ray scattering (SAXS) technique revealed very unique lamellae structure of this ionene-type TPE.Grafting of poly (ethylene oxide)(PEO) or sugar unit on halogenated butyl rubber also resulted in TPE.Microdomain formations of hydrophilic PEO or sugar units were suggested by DSC,DMA,and SAXS.These butyl rubber-g-hydrophilic segments were elastomeric without any crosslinkings, i.e., they are TPE.TPE by more simple mechanical blending was also studied.Influence of processing conditions on the properties of TPE is assumed to be significant. In the film forming by solution casting technique, evaporation rate of the solvent may be very important. Effect of the solvent evaporation rate were studied on polyurethanes : The morphology of polyurethane films was analyzed by infrared dichroism measurement under streching of the films. In relation with this study, properties of polyurethanes as soft tissues of human body were evaluated to obtain biocompatible soft materials.