SAN BLENDS WITH A PHENOXY POLYMER - MORPHOLOGY AND PROPERTIES

Styrene-acrylonitrile copolymer (SAN) and a phenoxy polymer having practically identical melt viscosities were blended using a single screw extruder. A two phase morphology was seen from scanning electron microscopy. The phase boundary was sharp and gaps formed upon debonding were noticeable when the phenoxy polymer formed the dispersed domain, while the phase boundary was blurred and fracture left no gaps when SAN was the dispersed phase. The glass transition temperature (T(g)) of the SAN phase was almost unchanged or marginally increased in the blends, while the T(g) of the phenoxy polymer increased by about 4-5-degrees. A positive deviation from linearity in modulus and strength was generally obtained in phenoxy-rich blends, while melt viscosity showed a negative deviation in SAN-rich blends and a positive deviation in phenoxy-rich blends.