MECHANOCHEMICAL

Techniques for evaluating processing stabiHty and mechanochemical effects include using a Brabender torque rheometer (29,30), injection mol ding (26,28), capillary rheometry (26,28), and measuring melt index as a function of residence time (26). 

Additional information on elastomer and SAN microstmcture is provided by C-nmr analysis (100). Rubber particle composition may be inferred from glass-transition data provided by thermal or mechanochemical analysis. Rubber particle morphology as obtained by transmission or scanning electron microscopy (101) is indicative of the ABS manufacturing process (77). (See Figs. 1 and 2.)... 

Astnmian, R. D., and Bier, M., 1996. Mechanochemical coupling of die motion of molecular motors to ATP hydrolysis. Biophysical Journal 70 637-653. 

The inclusion of internal viscosity raises considerably the free-energy storage capacity of a rapidly deforming macromolecule as compared to the idealized Hookean spring model and could play a decisive role in mechanochemical reactivity in transient elongational flow. 

Molecular Basis of Mechanochemical Degradation 3.1 Molecular Strain and Reactivity... 

It is common that mechanochemical degradation involves scission of the macromolecule, so one basic question would be to inquire about the level of stress necessary to separate two chemical moieties which have been attached by a covalent bond. Besides the academic interest, the breaking strength of a covalent bond is associated with the ultimate properties of engineering materials and has attracted considerable attention since the beginnings of quantum chemistry. 

In a recent version of the Tobolsky and Eyring formulation, the rate of mechanochemical degradation was considered as a Thermally Activated Barrier to Scission (TABS) process. The elastic energy function f(v /) was explicitly considered in terms of the frictional hydrodynamic drag force acting over the entire macromolecule [100]. A more detailed account of this model will be presented in Sect. 5.1. 

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