Synergistic Effect of Polycarbonate on Reactive Core-Shell Particles Toughened Poly(Butylene Terephthalate)

Abstract

Glycidyl methacrylate functionalized methyl methacrylate-butadiene-styrene copolymer (MBS-g-GMA) core-shell particles were prepared via an emulsion polymerization process. MBS-g-GMA was used to toughen poly(butylene terephthalate) (PBT) and the synergistic toughening effect of polycarbonate (PC) on PBT/MBS-g-GMA blends were investigated. Notched impact tests showed the percolation threshold became lower with the increase of PC content. Transmission electron microscopy displayed a very good dispersion of MBS-g-GMA particles in the PBT matrix with the different PC contents. The synergistic toughening effect was due to the encapsulation structure of PC which could facilitate the whole PBT matrix to yield. The more perfect the encapsulation structure formed, the more obvious the synergistic toughening the PC achieved. Sufficient strength of the phase interface was important to ensure the stress transfer effectively and facilitate the whole PBT matrix to yield. The interface strength between PC and MBS-g-GMA could be ensured by the good miscibility between Poly(methyl methacrylate) (PMMA) (grafted onto the polybutadiene-based rubber core) and PC. For the PBT/PC, the transesterification between PBT and PC improved the interface strength of the PBT and PC phases, as demonstrated by Fourier transform infrared spectroscopy (FTIR) scans. Scanning electron microscopy results showed shear yielding of the matrix and cavitation of the rubber particles were the major toughening mechanisms.