PPC porous polymer carriers are made in a physical foaming process. They do have an open cell structure with interconnected cells. The cell size distribution is roughly between 5 a d 20 µm. Depending on the polymer, the porosity ranges from 60 to 75% and the maximum additive loading up to 70%.
The porous polymers act like sponges. Loading of additives into a porous polymer is solely a physical absorption process. Due to capillary forces the accessible porous structure will be filled with additive.
The absorption rate is mainly determined by the viscosity of the additive. Depending on the viscosity the maximum additive loading may be achieved in 30 min or in 72 h.
PPC is most suitable for liquid, low melting, thermally sensitive, reactive or otherwise difficult to handle additives that cannot be processed by conventional extrusion compounding or masterbatching techniques.