| dc.description.abstract | Segmented polyurethane copolymers consist of soft and hard segments. Soft segments provide polyurethane soft property whereas hard segments offer the stiffness by hydrogen bondings. Therefore, material selection and ratio control of soft and hard segments could tailor make the many kinds of properties and applications of polyurethane copolymers.
In the past, our laboratory conducted a series of studies on waterborne polyurethane in understanding the effect of ionic group on the properties and structure. We observerd the micro phase morphology and found three waterborne polyurethane phase separated models. Its unique phase separated bicontinuous network structure provided waterborne polyurethane with properties such as transparency, stretchability, tenacity, thermostable and easy to process. This study follow the methods as my research motive, and segmented polyurethane based on priplast1838 (polyester polyols), 4,4-diphenylmethane diisocyanate (MDI), 1,4-butanediol (BD) and N-(1,3-dihydroxy-2-methylpropan-2-yl)-2-propyl-pentanamide (bulky diol) are synthesized with two step solution polymerization. The characteristic of soft segments, saturated hydrocarbon, aliphatic alkane and highly branched, allow polyester polyols to have hydrolytic resistance, affinity for non-polar matrices, and the resistance to ultraviolet rays. The widely used hard segments, MDI and BD, are modified by self-synthesized bulky diol as substitutes for the ionic group of waterborne polyurethane in this study. The different of hard segment content and bulky diol content as variables are controlled in two step solution polymerization for a series of modified segmented polyurethane. All samples are analyzed by FT-IR, TGA, DSC, DMA and tensile testing. We discuss the results to realize the effect of bulky diol on the properties and structure for segmented polyurethane.
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