Fracturing processes, polymers used

When rubbers eventually fracture, they do so by tearing. Fracture surface energies, using the Griffith equation, have been found to be of the order of 10 J m , whereas the true surface energies are only 0.1-1.0 J Hence, more energy is involved in fracture than is required to form new surfaces, and, as with other polymers, this extra energy is assumed to be used up in viscoelastic and flow processes that occur between the molecules immediately before the rubber breaks. 

A low-molecular-weight condensation product of hydroxyacetic acid with itself or compounds containing other hydroxy acid, carboxylic acid, or hydroxy-carboxylic acid moieties has been suggested as a fluid loss additive [164]. Production methods of the polymer have been described. The reaction products are ground to 0.1 to 1500 p particle size. The condensation product can be used as a fluid loss material in a hydraulic fracturing process in which the fracturing fluid comprises a hydrolyzable, aqueous gel. The hydroxyacetic acid condensation product hydrolyzes at formation conditions to provide hydroxyacetic acid, which breaks the aqueous gel autocatalytically and eventually provides the restored formation permeability without the need for the separate addition of a gel breaker [315-317,329]. 

A reaction rate model was first used by Tobolsky and Eyring to describe the viscoelastic mechanical properties of rubber-like materials. Zhurkov and Korsukov showed that the same model could be used to account for the degradation of a number of polymers under an applied stress. " They derived Eq. (10) for the time to failure, tf, in which A and are the Arrhenius constants for the fracture process, a is a constant (sometimes called the activation volume), and a is the applied stress. 

Detavemier, C., Dendooven, J., Sree, S.P., Ludwig, K.F., Martens, J.A., 2011. Tailoring nanoporous materials by atomic layer deposition. Chem. Soc. Rev. 40, 5242—5253. Dobbs, H.S., 1982. Fracture of titanium orthopaedic implants. J. Mater. Sci. 17, 2398—2404. Doherty, K.G., Oh, J.-S., Unsworth, P., Bowfield, A., Sheridan, C.M., Weightman, P., Bradley, J.W., Williams, R.L., 2013. Polystyrene surface modification for localized cell culture using a capillary dielectric barrier discharge atmospheric-pressure microplasma jet. Plasma Processes Polym. 10, 978—989. 

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