Dynamic shear compliance

Before discussing tire complex mechanical behaviour of polymers, consider a simple system whose mechanical response is characterized by a single relaxation time x, due to tire transition between two states. For such a system, tire dynamical shear compliance is [42]... 

Figure C2.1.14. (a) Real part and (b) imaginary part of tire dynamic shear compliance of a system whose mechanical response results from tire transition between two different states characterized by a single relaxation time X.

Other types of linear viscoelastic experiments may be used. Dynamic shear compliance measurements provide the storage and loss compliances J (co) and J"(co). An equation analogous to Eq.(3.12) is available for determining the initial modulus from J"(co) ... 

The table gives the values of the logarithm (to base 10) of the dynamic shear compliance J2 obtained for poly(vinyl acetate) at various frequencies / and temperatures T, where J2 is expressed in Pa . 

Poly(ethyl methacrylate) PEMA Poly(n-butyl methacrylate) 373 11.18 103.5 335 [86] 37,s of the softening dispersion from dynamic shear compliance J (co) from 352.7 to 428°K. 

Our concern is to find out how the characteristic material parameters rjo and Jg are included in the various response functions. To begin with, consider a perfectly viscous system in a dynamic-mechanical experiment. Here the dynamic shear compliance is given by... 

In a polymer melt, the viscous properties of Newtonian liquids combine with elastic forces. The latter ones contribute a real part to the dynamic shear compliance, to be identified with Jg... 

Combining Eqs. (5.99) and (5.102) gives the dynamic shear compliance of polymeric fluids in the limit of low frequencies... 

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