Synchrotron radiation wide-angle X-ray diffraction (WAXD)/ small-angle X-ray scattering (SAXS) is a powerful tool to characterize hierarchical structure of polymeric materials under deformation. In this presentation, our recent studies on applications of SR-WAXD /SAXS to characterize deformation behavior of polymer soft colloidal crystal nanocomposite, and poly(styrene-b-ethylenebutene-b-styrene) (SEBS) elastomer are presented. A molded film of polymer-grafted nanoparticles (SPNP), consisting of a spherical silica core and densely-grafted polymer chains bearing hydrogen-bonding side-groups capable of physically crosslinking, was investigated by in-situ ultra-SAXS (USAXS) measurement during uniaxial stretching process. Static USAXS revealed that the molded SPNP formed a highly oriented twinned fcc lattice structure and a [111] plane was aligned nearly parallel to the film surface at initial state. Structural analysis of in-situ USAXS using a model of uniaxial deformation induced by rearrangements of the nanoparticles revealed that the fcc lattice was distorted in the stretching direction being proportional to the macroscopic strain until the strain reached 35%. Deformation behaviour of SEBS films with bcc PS domains were measured during uniaxial, biaxial and compression testing using in situ SAXS. During uniaxial testing, shift of structure factor reveals an increase in domain spacing in parallel to stretching direction (SD) while it decreased in the perpendicular to SD. Furthermore, the change of form factor implies to the deformation of PS spherical domains to egg-like ellipsoidal shape. For biaxial testing, shift of structure factor indicates an increase in domain spacing as strain increased. It was found that structure factor indicates a decrease in domain spacing in the parallel to compressing direction (CD) while it increased in the perpendicular to CD. The resultof form factor observed in biaxial suggest the deformation of PS domain, which the sphere became asymmetry in three dimension.

Applications of synchrotron x-ray scattering to structure analyses of polymers under deformation

2019 Spring National Meeting

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