Core–shell particles of poly(methyl methacrylate)-block-poly(n-butyl acrylate) synthesized via reversible addition–fragmentation chain-transfer emulsion polymerization and the polymer's application in toughening polycarbonate

Poly(methyl methacrylate) (PMMA) block copolymer is interesting because it is compatible with many polymers. A series of poly(methyl methacrylate)- b -poly( n -butyl acrylate) (PMMA- b -PnBA) diblock copolymers with various compositions was synthesized via reversible addition–fragmentation chain-transfer (RAFT) emulsion polymerization with the amphiphilic oligo(methacrylic acid 41 - b -methyl methacrylate 8 ) RAFT agent as both the polymerization mediator and surfactant. The molecular weights of the block copolymers agreed well with the theoretical prediction, although the polydispersity indices were relatively broad. The resulting core [poly( n -butyl acrylate)]–shell (PMMA) particles of PMMA- b -PnBA were found to be very effective impact modifiers for polycarbonate (PC). The diblock copolymer was well dispersed in 100–300-nm particles in the PC matrix, and the dispersed particle size was highly dependent on the block copolymer compositions. PMMA 250 - b -PnBA 550 (the subscripted number signifies the designed degree of polymerization), which was dispersed into 100-nm particles, presented the best capability for improving the impacting properties. Compared with the neat PC, the notched impact strength of PC toughened by 5 wt % PMMA 250 - b -PnBA 550 was increased by four times to 62.81 kJ/m 2 with the same yield strength, a slightly decreased modulus, an increased elongation at break, and an increased tensile strength. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 132 , 42833.