Polymer degradation empirical expressions

Siepmaim et flZ." suggested that the effective diffusion coefficient can be considered to be linearly proportional to the porosity. Empirical expressions of are mostly dependent on Af or degradation time rather than real structures of polymer systems. Empirical expressions can be utilised in the same polymer system from which they were derived. They are, however, not valid for a different polymer system. 

An empirical rate expression has also been presented by Goto and Fuji-wara [44] for mechanical degradation by high-speed stirring of many polymer solutions ... 

---