Methods for Estimating the Filler Effect on Polymer Matrices

1 Methods for Estimating the Filler Effect on Polymer Matrices 

Conventionally fillers are divided into reinforcing, active, and inert ones. The reinforcing class includes mainly fibrous materials. Disperse fillers may also perform the reinforcing function, and then they are called active. For the criterion of activity of a filler it has been proposed to employ, for example, the extent of variation of the relative viscosity of the melt or solution caused by introduction of a filler [23] — the greater the variation the better the affinity between the polymer and the filler. 

Indeed, one often observes a more or less direct relationship between the rheological properties of melts and the mechanical strength of the condensed material. This is a commonplace statement in regard of, say, stiffness, since the equations relating the viscosity of heterogeneous materials with their composition 

This is true when the material stiffness is much smaller than that of the filler and Poisson s ratio of the matrix is 0.5 — which is not often the case [24]. 

Nielsen suggested a more exact equation relating viscosity and elasticity modulus [27]  

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