Investigation Of The Synergistic Toughening Of Multi-phase Polyester Blends

Polycarbonate (PC) and polybutylene terephthalate (PBT) are two kinds of important thermoplastics which have been widely used in various industrial fields because of their good dimensional stability, high impact resistance, good processability and so on. However, PC and PBT show an obvious shortcoming that is the notch sensitivity, and PC is liable to physical aging and expensive. The core-shell modifier used in this thesis is the copolymer with polybutadiene as core and methyl methacrylat, styrene and glycidyl methacrylate copolymer as shell (MBS-g-GMA). The advantage of the core-shell particles lies in the controlled structure, steady particle size and higher toughening efficiency which are used to toughen PC and PBT blends. The results are as follows:(1) In the blends, the content of MBS-g-GMA was set at20%and the influence of PBT content on the impact properties was investigated. The impact test result showed the impact strength of the PC/PBT/MBS-g-GMA blends increased with the increase of PBT content. When the content of PBT was30%, the notch impact strength of968J/m was achieved and the blend showed superior toughness.(2) In the PBT/PC/MBS-g-GMA blends, the content of MBS-g-GMA was set at20%and the effect of PC content on the impact strength was studied. Test results showed that the MBS-g-GMA/PBT blends fractured in the brittle mode. When the content of PC was from15%to20%, brittle-ductile transition took place and the notch impact strength could get657J/m. The TEM showed the compatibility of PBT and MBS-g-GMA was improved by the introduction of PC.(3) Physical aging of PC.The influence of MBS-g-GMA content on the properties of PC/MBS-g-GMA blends was investigated. Impact test showed that the effect of physical ageing decreased with the addition of MBS-g-GMA into PC and the PC/MBS-g-GMA blends kept higher impact strength than pure PC after physical aging. When the content of MBS-g-GMA was from10%to20%, the PC/MBS-g-GMA showed higher impact notch impact strength.In PC/PBT/MBS-g-GMA blends, the content of MBS-g-GMA was set at20%and the influence of PBT content on the physical ageing of the blends was investigated. When the temperatures were110℃,120℃and130℃. When the content of PBT was20%, the notch impact strength was the highes.