Thermoplastic polymers contact deformation

Czichos, H. Feinle, P. "Tribological Behaviour of Thermoplastic, Filled, and Glass-Fibre- Reinforced Polymers - Contact Deformation, Friction and Wear, Surface Investigations", BAM Research Report 83,... 

The contact deformation of these thermoplastic polymers was studied experimentally by pressing polymeric balls (of 4 mm diameter) with continuously increasing load (0.6 N/s) against an optically smooth glass surface and measuring both contact deformation displacement and contact size under load as described above (see Figure 1). The polymer balls had a mean peak-to-valley roughness of 0.6 - 1.0 im and a c.l.a. 

The reason for the decrease in the polymer percolation threshold was suggested to be that the polymer experiences a sintering phenomenon that results in an almost continuum medium inside the US tablets. The drug particles are practically surrounded by the inert polymer, which diminished the contact with the dissolution medium and therefore slows down the release rate. So, in the case in which a component experiences a thermoplastic deformation, the continuum percolation model can be employed to explain the changes in the system with respect to a tablet obtained by a traditional... 

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