Melt blends of αSAN with a phenoxy

Melt blends of poly(α‐methyl styrene‐co‐acrylonitrile) (αSAN) with a phenoxy were prepared using a Brabender Plasticorder. Morphological, thermal, rheological, and mechanical properties of the blends were studied. DSC (differential scanning calorimetry) measurements showed two T g (glass transition temperature) of the blends. T g of αSAN decreased by 5 to 7°C, whereas that of phenoxy increased slightly. Melt viscosity measured using an RDS (Rheometrics dynamic spectrometer) showed a small negative and relatively large positive deviation in αSAN‐ and phenoxy‐rich blends, respectively. Transverse views of SEM (scanning electron microscopy) micrographs of the fractured surfaces again showed two phases, regardless of composition. Traces of full‐out upon fracture were seen in αSAN‐rich but not in phenoxy‐rich blends, indicating stronger interfacial adhesion in phenoxy‐rich blends. Longitudinal views of the SEM micrographs showed highly elongated structure of disperse phases (30 to 70% of phenoxy), especially when phenoxy forms dispersed phase, resulting in finer and well developed phenoxy fibrils. Tensile modulus and strengths showed a negative deviation in αSAN and positive deviation (strength) or additivity (modulus) in phenoxy‐rich blends.