Role of Hard Segment Induced Nanosized Domain on Concentrated Solutions and Bulk Properties

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When a film is cast from solution, the volume fraction of polymer in the film increases with increasing drying temperature and/or time. Its viscoelastic behavior transitions from more viscous (where G” > G’) in dilution solution to more elastic (where G’ > G”) as the volume fraction of the polymer (f) increases and finally solidification or gelation when the film is formed. We have used f G”=G’ and fGEL to monitor the transitions of hard segment controlled polyurethane molecules from nanogels/nanocoils to microgels/microgels and finally or hard and soft segmented domains in the bulk. In the early study, we have found that the hard segment weight fraction affects the dilute solution properties of TPU up to a limiting value (Lem et al., 2011). At the regions where f G”=G’ < f f GEL, the domain is no longer nano-size but is in the order of micro-scale. However, the size and nature of the nano-scaled domain when f <f G”=G’ greatly affects the structure-property relationship of these segmented domains in concentrated solutions and in the bulk. .

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Journal: TechConnect Briefs
Volume: 1, Nanotechnology 2011: Advanced Materials, CNTs, Particles, Films and Composites
Published: June 13, 2011
Pages: 60 - 63
Industry sector: Advanced Materials & Manufacturing
Topic: Materials Characterization & Imaging
ISBN: 978-1-4398-7142-3