@article { ISI:000326049600005,
	title = {Ascertaining universal features of yielding of soft materials},
	journal = {Rheologica Acta},
	volume = {52},
	number = {10-12},
	year = {2013},
	month = {NOV},
	pages = {859-865},
	publisher = {SPRINGER},
	address = {233 SPRING ST, NEW YORK, NY 10013 USA},
	abstract = {<p>Many metastable complex fluids, when subjected to oscillatory shear flow of increasing strain amplitude at constant frequency, are known to show a characteristic nonlinear rheological response which consists of a monotonic decrease in the elastic modulus and a nonmonotonic change in the loss modulus. In particular, the loss modulus increases from its low strain value, crosses the elastic modulus, and then decreases with further increase in the strain amplitude. Miyazaki et al. (Europhys Lett 75:915-921, 2006) proposed a qualitative argument to explain the origin of the nonmonotonic nature of the loss modulus and suggested that in fact this response could be universal to all complex fluids if they are probed in a certain frequency window in which the fluid is dominantly elastic in the small strain limit. In this letter, we confirm their hypothesis by showing that a wide variety of complex fluids, irrespective of their thermodynamic state under quiescent conditions, indeed show the aforementioned characteristic nonlinear response. We also show that the maximum relative dissipation during yielding occurs when the imposed frequency resonates with the characteristic beta relaxation frequency of the fluid.</p>},
	keywords = {Colloidal suspensions, Entangled melts, Gels, Glasses, Microgels, Rheology, Yielding},
	issn = {0035-4511},
	doi = {10.1007/s00397-013-0724-4},
	author = {Kamble, Samruddhi and Pandey, Anurag and Rastogi, Sanjay and Lele, Ashish K.}
}
@article {46151,
	title = {Structure-property relations in regenerated cellulose fibers: comparison of fibers manufactured using viscose and lyocell processes},
	journal = {Cellulose},
	volume = {26},
	year = {2019},
	month = {APR},
	pages = {3655-3669},
	type = {Article},
	abstract = {<p>Regenerated cellulose fibers are produced using two industrially dominant technologies: the viscose and lyocell processes. Here, we compare commercially available fibers, prepared using the viscose and lyocell processes. Single fibers are subjected to a variety of mechanical deformations to obtain stress-strain, stress relaxation and stress recovery data. These are fitted to a phenomenological model, whose parameters are interpreted in terms of the fiber semicrystalline microstructure. This simple model does not incorporate the complexities of semicrystalline microstructure. Rather, it represents structure in a semicrystalline polymer fiber in terms of an elastic crystalline phase that coexists with a viscoelastic Voigt-like glassy amorphous phase. Lyocell fibers are characterized by higher values of crystalline modulus relative to viscose. Lyocell fibers also have a higher amorphous phase modulus and a wider relaxation spectrum than viscose, suggesting that amorphous and crystalline phases are dispersed in close connectivity in lyocell. Viscose and lyocell fibers exhibit qualitative similarities in their mechanical response. On stretching, there is a transition in the stress-strain curve from a low strain elastic response at a critical value of strain. This critical strain has been incorrectly attributed to yielding of the fiber. We establish that this critical value corresponds to an apparent yield. When subjected to strains higher than this apparent yield point, the fibers develop a memory of the mechanical deformation. This memory decays slowly, logarithmically with time and is lost over about a day as the fiber structure transitions back to the original as spun fiber. Finally, we demonstrate that on wetting the fibers with water, there is an increase in the apparent yield strain for viscose fibers, but not for lyocell. We interpret these results in terms of the semicrystalline microstructure of the fibers.</p>
},
	keywords = {mechanical properties, Model, Regenerated cellulose, Yielding},
	issn = {0969-0239},
	doi = {10.1007/s10570-019-02352-w},
	author = {Sharma, Aakash and Nagarkar, Shailesh and Thakre, Shirish and Kumaraswamy, Guruswamy}
}
