Polymer blends of PET-PS compatibilized by SMA and epoxy dual compatibilizers

Poly(ethylene terephthalate) (PET) and polystyrene (PS) are immiscible and incompatible and have been well recognized. In this study, styrene maleic a nhydride random copolymer (SMA-8 wt % MA) and tetra-glycidyl ether of diphe nyl diamino methane (TGDDM) are employed as reactive dual compatibilizers i n the blends of PET-PS. The epoxy functional groups of the TGDDM can react with PET terminal groups (-OH and -COOH) and anhydride groups of SMA at the interface to produce PET-co-TGDDM-co-SMA copolymers. SMA with low MA conte nt is miscible with PS, whereas the PET segments are structurally identical with PET phase. Therefore, these in-situ-formed copolymers tend to anchor at the interface and act as effective compatibilizers of the blends. The co mpatibilized blends, depending on the amounts of TGDDM and SMA addition, re sult in smaller phase domain, higher viscosity, and improved mechanical pro perties. This study demonstrates that SMA and TGDDM dual compatibilizer can be utilized effectively in compatibilizing polymer blends of PET and PS. ( C) 1999 John Wiley & Sons, Inc.