Ternary Polymer Addition Nonreactive

The addition of a ternary polymeric component to a binary blend of immiscible polymers has been employed in many examples to yield improved dispersion and properties. The concept involves the choice of a polymer with good interfacial adhesion to both components and interfacial tension values that will allow for concentration at the interface of the binary mixture. In essence, the ternary polymer exhibits surfactant -like properties and stabilizes the interfacial area, allowing for smaller particle size and improved ability to transfer stress across the interface. 

The ability of the ternary component to concentrate at the interface of the binary components was discussed in Section 2.7, where it was noted that the interfacial tension values determine the resultant morphology. 

In this section, we wiU discuss non-reactive systems, while reactive compatibihzation will be covered in later sections. Non-reactive ternary polymer systems include random copolymers, graft copolymers and polymers offering either miscibility or good interfacial adhesion between the blend components. One of the primary examples of ternary polymer addition involves the compatibihzation of polystyrene with polyolefins employing styrene-hydrogenated diene-styrene ABA block copolymers. Block copolymer addition is a specific subset of ternary polymer addition that will be discussed in Section 3.7. 

Random copolymer addition to binary blends involving copolymers with structural units equal or similar to the blend components or with specific interacting groups capable of non-reactive interaction with one of both the blend components comprises another ternary polymer addition approach. An early example involved EPR (ethylene-propylene rubber) addition to HDPE/PP blends, where synergistic impact strength was observed. In some cases, the random copolymers have been compared to block copolymers comprised of the same units. The compatibihzation of LLDPE/PMMA and LLDPE/poly(MMA-co-4-vinyl pyri-dine(4VP)) blends with poly(ethylene-co-methacrylic acid) (EMAA) addition were compared [47]. Modest improvements in LLDPE/PMMA dispersion and strength were observed. The specific acid-base interaction allowed for much larger improvements with EMAA addition to LLDPE/PMMA-CO-4VP blends. 

PVC LLDPE Chlorinated PE Improved interfadal adhesion and mechanical properties 52 

---