Mixing additives into polymers compatibilizers

Addition polymers, such as vinyls, acrylics, fluoroplastics, and polyolefins, can hardly be reprocessed except that, if they are sorted, they maybe converted into powder by grinding operation and mixed with respective virgin resins for remolding into finished goods or, in some cases, blended with other resins using suitable compatibilizers to make useful end-products of commercial value. 

Ex situ compatibilization, or compatibilization by the addition of a pre-synthesized copolymer, provides an opportunity to easily control the molecular architecture of the additive to be used. Theoretically, block copolymers should seek the interfaces during melt mixing, to decrease unfavorable interactions [15,16]. Therefore, block or graft copolymers whose segments are chemically identical to, or have affinity with, the polymer components are often used as emulsifiers to reduce the interfadal tension, promote the dispersion of one phase into the other, and stabilize the resulting blend [17]. Hence, the polymeric compatibilizer to be added to a blend... 

We have made the important observation that these systems tend not to be truly random or completely miscible. For a polymer dissolved in a mixed solvent, one solvent will often preferentially associate with the polymer. A low molecular weight liquid mixed into a polymer blend will preferentially dissolve in one of the polymer components. An amphiphilic molecule or block/graft copolymer can situate itself at the interface between two polymeric phases and modify the interface properties such as interfacial tension. Indeed if high in molecular weight, it can act as a compatibilizing agent , which in addition enhances the mechanical behavior (e.g., the toughness) of the blend. 

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