Study On The Effect Of Free Segments In Epoxy Functionalized Acrylonitrile-Butadiene-Styrene On The Toughening Of PBT

The functionalized modifiers(ABS-g-GMA)were synthesized via seeds emulsion polymerization by grafting styrene(St),acrylonitrile(AN)and glycidyl methacrylate(GMA)on the surface of polybutadiene(PB).Free segments in the modifiers were separated out by ultra-centrifugation.The remaining substances were ABS-g-GMA?modifiers.The effect of free segments on rheological properties,mechanical properties,compatibility and cross-section morphology of the blends were investigated.(1)The effect of the separated and unseparated functionalized modifiers on the toughening of PBT were compared under the same conditions after free segments were separated out.The results showed that the impact strength and elongation at break of the blends decreased obviously.But it had unobvious effect on the elastic modulus,yield strength and bending strength.Therefore,free segments played an important role in functionalized modifiers on the toughening of PBT.(2)The effect of the amount of free segments on the PBT/ABS-g-GMA? blend was studied after free segments were added to the blends according to different amounts.The results showed that the blends had the highest impact strength and elongation at break when free segments accounted for 2.50% of ABS-g-GMA? modifier.By coincidence,this amount was the content of free segments separated from the addition of functionalized modifier.When free segments were less than or more than 2.50%,the impact strength got decreased.But it had little effect on other properties.(3)The functionalized copolymers with different molecular weight were synthesized via emulsion polymerization,and the role of the copolymer in PBT/ABS-g-GMA' was studied.The results showed that the appropriate amount of functionalized copolymers could improve the impact strength and elongation at break of the blends.But it had unobvious effect on other properties.The molecular weight of the copolymer had little effect on the properties of the blends.The functionalized copolymers synthesized separately had the same effect as the free segments which were separated.(4)Free segments were added to PBT/ABS' blends to further explore its effect.The results showed that the blends were toughened effectively when free segments accounted for more than 1.25% of ABS? modifiers.The impact strength was not affected by increasing the amount of free segments within the scope of investigation.But the amount of free segments had little effect on the elastic modulus,yield strength and bending strength.