کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5186034 | 1381094 | 2009 | 6 صفحه PDF | دانلود رایگان |
A new series of thermotropic ionic polyurethane-urea (PUU) liquid crystals (LCs) were synthesized, each by using the corresponding diisocyanate, 4,4â²-bis(6-hydroxyhexoxy)biphenyl, and sodium 2,5-diaminobenzenesulfonate. Morphology, phase transition temperatures, and spectroscopic characteristics of the PUU LCs are reported. Each PUU exhibits a monotropic liquid crystal phase upon slow cooling. The PUU LC phase texture is visible by polarized optical microscopy (POM) and is dependent upon the PUU isocyanate precursor; 1,6-diisocyanatohexane (HDI) and 5-isocyanato-1-(isocyanatomethyl)-1,3,3,-trimethylcyclohexane (IPDI) polymers have schlieren textures, whereas 2,4-diisocyanato-1-methylbenzene (TDI) and methylenebis(4-phenylisocyanate) (MDI) polymers show grain textures.
Journal: Polymer - Volume 50, Issue 20, 23 September 2009, Pages 4775-4780