Testing the effect of imidazolium ionic liquid and citrate derivative on the properties of graphene-based PHBV/EVA immiscible blend
Reduced graphene oxide-zinc oxide composite (rGO-ZnO) was incorporated at 0.2 mass% content in immiscible 1:1 poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/ poly(ethylene-co-vinyl acetate) (EVA) blends by melt extrusion. Using the same conditions, samples of PHBV, EVA, the neat blend and plasticized hybrids were also obtained. The effect of rGO-ZnO and the plasticizers, acetyl tert-butyl citrate (ATBC) and ionic 1-butyl-3-methylimidazolium hexafluorophosphate (bmim+PF6ˉ), on the properties of the hybrid materials were evaluated. X-ray diffraction results indicated that rGO-ZnO and the plasticizers affected the materials crystallinity. Differential scanning calorimetry showed that rGO-ZnO influenced the melt and cold crystallization, functioning as heterogeneous nucleating agent for PHBV. Dynamic mechanical analyses revealed improved compatibilization by adding ATBC to the hybrid blend. Using bmim+PF6ˉ as the plasticizer led to hybrid materials with significantly better oxygen barrier properties, similar to polyethylene.