Nondilute Polymeric Liquids

The intrinsic viscosity discussed in Section 11.3.1 is, strictly speaking, an infinite dilution value. To account for increasing solution viscosity with increasing concentration, an expansion in powers of concentration is usually used, as is also done to account for concentration effects in suspension rheology  

So we see that a good rule of thumb for predicting when concentration effects will become important is when the coil overlap parameter c[rj] (or cM ) is near unity. 

A relation that fits viscosity data well in the coil overlap region is the Martin equation  

Note that if k = k eq. 11.3,8 may be viewed as a power series expansion of eq. 11.3.10. Experimentally, k is often quite close tok.  

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