MORPHOLOGY AND IMPACT PROPERTY OF PPO/ELASTOMERIC STYRENE-BASED BLOCK COPOLYMER BLENDS

Two kinds of PPO blends,PPO/SEBS (Kraton G 1651) and PPO/SEBS\| g MAH (Kraton FG 1901) prepared through melting extrusion,were compared in morphology and impact properies.TEM studies showed that in PPO/SEBS blends the elastomer is dispersed in the PPO matrix in a thick cylinder shape and forms the sea\|island morphology until the content of SEBS is up to 500mg·g -1 .In PPO/SEBS\| g MAH blends,if the concentration of elastomer is in the range from 0 to 100mg·g -1 ,SEBS\| g MAH is dispersed in PPO continuous phase in a thin cylinder shape,when SEBS\| g MAH is 150mg·g -1 ,it forms a network morphology.The notched impact strength revealed that ductile\|brittle transition doesn't occur in PPO/SEBS blends,but occures for PPO/SEBS\| g MAH blends in the content range of SEBS\| g MAH from 100 to 150mg·g -1 .This super\|toughened level results from the network morphology in PPO/SEBS\| g MAH blend.Furthermore,thermal and rheological behavior of PPO blends were measured by DSC and Instron capillary rheometer.DSC revealed that the PS segment in SEBS copolymers was miscible completely with PPO,and the PS segment in SEBS\| g MAH was miscible partly with PPO.DSC result showed that there was higher phase separation in PPO/SEBS\| g MAH blends than in PPO/SEBS blends.Rheological behavior revealed that at the same shear rate,the melt viscosity of SEBS\| g MAH was lower than that of PPO,and the melt viscosity of SEBS was higher than that of PPO.Rheological result showed that SEBS\| g MAH trended to encapsulate PPO during melting extrusion and has the thin cylinder shape or network structure in PPO matrix with the increasing of SEBS-g-MAH.