Polymer-like Structures through Noncovalent Associations

Polymer-like Structures through Noncovalent Associations 

Introduction of ionic groups or proteins into polymers (forming ionomers) leads to physical associations at the temperature of use [110, 111]. For example, Surlyn (DuPont) is a copolymer of ethylene and methacrylic add that shows enhanced zero-shear viscosity and elastomeric green strength. Viscoelastic characteristics are also enhanced due to loss of associations at the appropriate dissociation temperature. Ion pair associations are exploited to obtain misdbUity in otherwise immiscible polymers [112], 

Molecules that are capable of spatial complementarity and weak reversible noncovalent interactions with each other can self-assemble from a less ordered state (such as a solution) to an ordered structure (such as a soUd crystal) without human intervention [113], In this manner, precise tuning of oligopeptide assodating structures provides an completely new route to a hierarchy of structures such as tapes, ribbons, fibrils, fibers, and fiber networks, which can be usefid as materials [114— 

In this chapter, we have discussed the interrelationships of the molecular structures of polymers with their thermal, solution, and rheological behavior. The ther- 

Tg oo glass transition of a polymer with infinite molecular weight [K] 

---

Polymer-like Structures through Noncovalent Associations... 

---