Polymer blends hydrogen bonding

Compatibilization of blend polymers by hydrogen bonds formation. 

Polymer blends are physical mixtures of two or more polymers and are commercially prepared by mechanical mixing, which is achieved through screw compounders and extruders. In these mixtures, different polymers tend to separate (instead of mixing uniformly) into two or more distinct phases due to incompatibility. One measure taken to improve miscibility is to introduce specific interactive functionalities on polymer pairs. Hydrogen-bondings have been shown to increase miscibility and, as a consequence, improve the strength of the blends. Eisenberg and co-workers have also employed acid-base interaction (as in sulfonated polystyrene with polyethylmethacrylate-Co-4-vinyl pyridine) and ion-dipole interaction (as in polystyrene-Co-lithium methacrylate and polyethylene oxide) to form improved blends. 

Would a polymer that hydrogen-bonds with itself be more likely or less likely to form miscible blends with other polymers compared with a polymer that does not hydrogen-bond with itself ... 

Of particular interest is the fact that two plasticisers of similar molecular weight and solubility parameter can, when blended with polymers, lead to compounds of greatly differing properties. Many explanations have been offered of which the most widely quoted are the polar theory and the hydrogen bonding theory. 

Blends of enzymatically synthesized poly(bisphenol-A) and poly(p-r-butylphenol) with poly(e-CL) were examined. FT-IR analysis showed the expected strong intermolecular hydrogen-bonding interaction between the phenolic polymer with poly(e-CL). A single 7 was observed for the blend, and the value increased as a function of the polymer content, indicating their good miscibility in the amorphous state. In the blend of enzymatically synthesized poly(4,4 -oxybisphenol) with poly(e-CL), both polymers were miscible in the amorphous phase also. The crystallinity of poly(e-CL) decreased by poly(4,4 -oxybisphenol). 

AM Lichkus, PC Painter, MM Coleman. Hydrogen bonding in polymer blends. 5. Blends involving polymers containing methacrylic acid and oxazolime groups. Macromolecules 21 2636-2641, 1988. 

Pearce, E. Kwei, T. K. Lu, S. Hydrogen Bond Interactions and Self-Condensation of Silanol-Containing Polymers in Polymer Blends and Organic-Inorganic Polymeric Hybrids. In Silicones and Silicone-Modified Materials-, Clarson, S. J., Fitzgerald, J. J., Owen, M. J., Smith, S. D., Eds. ACS Symposium Series 729 American Chemical Society Washington, DC, 2000 pp 419-432. 

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