430591 Nonlinear Rheology and Cavitation of a Triblock Copolymer Gel

Tuesday, November 10, 2015: 1:15 PM
251A (Salt Palace Convention Center)
Santanu Kundu1, Seyed Meysam Hashemnejad1, Mahla Zabet1, Satish Mishra1 and Madhu Namani2, (1)Dave C. Swalm School of Chemical Engineering, Mississippi State University, Mississippi State, MS, (2)TA Instruments, New Castle, DE

Polymer gels are subjected to large-strain deformation during their applications. Here, we report the large-strain deformation behavior of a physically cross-linked, swollen polymer gel, which was obtained by dissolving a triblock copolymer poly (methyl methacrylate) - poly (n-butyl acrylate) - poly (methyl methacrylate) [PMMA-PnBA-PMMA] in 2-ethyl 1-hexanol, a midblock selective solvent. Investigations were performed using large amplitude oscillatory shear (LAOS) and custom developed cavitation rheology techniques.  The gel displays unique strain-stiffening response at large-strain and stress vs strain responses have been captured using Gent constitutive model. In cavitation experiments a syringe-needle was inserted into the gel and a growth of cavity at the tip of the needle was captured. The critical pressure for cavitation scales with the local modulus of the gel. Both analytical method and finite-element based modeling have been implemented to capture the pressure response in cavitation experiments. Our results provide new understanding of gel failure mechanism at large-strain.

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See more of this Session: Mechanics and Structure in Polymers
See more of this Group/Topical: Materials Engineering and Sciences Division