Nano Assembly of Styrene/Acrylonitrile Copolymer Containing Methyl MBS Core-Shell Nanoparticles: Mechanical and Rheological Behavior

Styrene/acrylonitrile copolymers with 70 wt.% styrene (SAN70) and two different viscosity average molecular weights of 60K (SAN70-60K) and 110K (SAN70-110K) were synthesized and blended with 25 wt. % methyl methacrylate/butadiene/styrene core-shell (MBS) nanoparticles, 90 nm in diameter. Enhanced SAN70-60K in its mixture with SAN70-110K up to 30 wt.% improved the nanoblend impact strength by 30% while reduced its melt flow index to half. More SAN70-60K ratio as the matrix of the nanoblend showed reduced impact strength, while raised its melt flow index. Impact srength and melt flow index of the nanoblend systems showed positive and negative synergisms with respect to the mixture law as the fraction of SAN70-60K was increased in the matrix. Finally, a rather nice correlation was decernible between impact strength and reciprocal melt flow index of the studied systems