Miscible polymer blends containing poly(vinyl chloride)

Polymer blends have received particular interest in the past several decades in both industrial and academic research. An initial survey of miscible polymer pairs (1) (1968) revealed 12 combinations. A later survey (2) (1979) noted approximately 180 miscible pairs. Today possibly over 500 miscible combinations have been noted in the open and patent literature (3). However, the vast majority of possible polymer blend combinations are not miscible (thus phase separated). A significant number of diverse polymer structures have been shown to exhibit miscibility with PVC. Several of these blends have been studied in detail and have shown specific interactions primarily involving the α‐hydrogen and PVC (considered the proton donor in proton donor‐proton acceptor hydrogen bonding type interactions). The blend of poly(ϵ‐caprolactone) with PVC illustrates this interaction and has been reported in many published papers. While polymer miscibility in PVC blends offers significant academic interest, industrial utility is also of considerable importance. The addition of low T g , miscible polymers to PVC offers permanent plasticization. The addition of high T g , miscible polymers to PVC yields the desired heat distortion temperature enhancement of rigid PVC. A specific example of permanent plasticization involves nitrile rubber blends which have been commercial since the early 1940's. This presentation will review the growing number of polymers noted to be miscible with PVC. The importance of specific interactions will be discussed.