Miscible and Immiscible Polymer Pairs

Most polymer pairs are immiscible that is, mixtures of the two remain phase separated. This is caused by the (usually) positive heat of mixing, and very small entropy of mixing, as developed in Section 4.3. A list of selected immiscible polymer pairs is shown in Table 13.1 (3). A corresponding list of miscible polymer pairs is shown in Table 13.2 (3). 

Most of the polymer pairs in both tables are commercial materials. For example, in Table 13.1 the addition of several percent of polybutadiene to polystyrene results in high-impact strength polystyrene, HIPS. Similarly the addition of CTBN to epoxy materials results in a much tougher product. 

Abbreviations-. EPDM, ethylene-propylene-diene monomer (a copolymer elastomer) CTBN, carboxy-terminated butadiene nitrile (an elastomer prepolymer) ABS, acrylonitrile-butadiene-styrene (a complex latex structure used both independently and to toughen other polymers) SBR, styrene-butadiene rubber (an elastomer). 

Poly(vinyl chloride) Poly(butylene terephthalate) 

Poly (methyl methacrylate) Poly(vinyUdene fluoride) 

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