Structure and properties of segmented poly(urethaneurea)s with relatively short hard‐segment chains

In-Situ Studies of Structure Development during Deformation of a Segmented Poly(urethane−urea) Elastomer

“…The poly(urethane-urea) (PUU) used in this study was synthesized using a procedure similar to that described by Sakurai et al 49 In this procedure, 4,4′-diphenylmethane diisocyanate (MDI) was reacted with poly(tetramethylene oxide) (PTMeO, M W ) 1800 g/mol) to form the prepolymer with diisocyanate end caps, which was subsequently dissolved in N,N-dimethylacetamide (DMAc). 1,2-Ethylenediamine (EDA) and diethylamine (DEA) were added to the prepolymer solution, where EDA was the chain extender and DEA was the chain terminator.…”

Ultra small-angle X-ray scattering studies on structural changes in micrometers upon uniaxial stretching of segmented polyurethaneureas

“…Right after a pair of the dichroic measurements, which are the spectra along parallel and perpendicular directions to SD, the sample was further stretched for the subsequent FTIR quiescent measurements at the fixed stretching ratio. For more details of the FTIR measurements, refer to some literatures [5][6][7][8]13,16,[22][23][24][25]28]. …”

“…To conduct structural analysis in nanometers, the small-angle X-ray scattering (SAXS) technique is generally used. Not only the static SAXS measurements [6,7,[9][10][11][12][13][14][15][16][17][18], but also have been conducted insitu measurements along with deformation [19][20][21]. Note here that measurements of two-dimensional SAXS (2D-SAXS) pattern are required to analyze structural changes and orientation of nanostructures along with the mechanical deformation, which are relevant to mechanical fatigue [14,17,[22][23][24][25] and fracture [5,6].…”

“…As shown schematically in Fig. 1, the so-called lamellar type hard-segment domains [16,19] suffer from microscopic fracture so that crazing sets in. To detect the onset, we should conduct in-situ measurements of the 2D-USAXS along with the sample stretching.…”