Toughening Modification And Ester Exchange Inhibition Of PBT/PC Blends

Polybutylene terephthalate(PBT)and polycarbonate(PC)are two typical thermoplastic engineering blends,Their blends have excellent performance and are one of the most popular composites in recent years,widely used in various fields.However,due to its poor compatibility and transesterification,resulting in a lower impact strength.Therefore,PBT/PC blends must be modified.Firstly,The blends of PBT/PC blends were prepared by the addition of ethylene-butyl acrylate-glycidyl methacrylate terpolymer(PTW)as a toughening agent under the action of chain extender ADR4370F.The experimental results show that when 10phr PTW acts alone on PBT/PC blends,the distribution of PC in the blends is more uniform due to the reaction of PTW with PBT and PC.The notched impact strength,complex viscosity,storage modulus and loss modulus increased significantly,but the tensile strength is decreased,and the crystallization temperature of PBT in the system to low temperature shift.With the addition of the chain extender ADR4370F,the molecular weight and melt strength of the blends increased,the entanglement of the molecular chains increased with the interaction between molecules,the notched impact strength,the complex viscosity,storage modulus and loss modulus increased further.When the amount of chain extender is 1.25 wt%,the notched impact strength reached the maximum value,compared with the PBT/PC/PTW system increased by 63.33%,compared with the PBT/PC blend system increased by 191.02%,the tensile strength relative to the PBT/PC/PTW system has no significant change.Secondly,according to the research of the first chapter to determine the optimum content of chain extender,by change the mixing sequence between PBT,PC,PTW,ADR4370F,to investigate the effect of different active groups on the order of reaction behavior of PBT/PC/PTW/ADR4370F blends.The experimental results show that composites was prepared by PBT,PC and PTW blended first and then blending with the chain extender of ADR4370F have higher complex viscosity,storage modulus,loss modulus and notched impact strength than other materials by others blending method,and the dispersion of PC in PBT is relatively good.Finally,By melt blending and extrusion process,with a core-shell structure MBS as toughening agent,while the introduction of ester exchange inhibitor NaH2P04,to investigate the changes of NaH2PO4 content of inhibitor ester exchange effects on the performance of MBS toughened PBT/PC.The experimental results show that when 10phr MBS alone in PBT/PC blends,the notched impact strength of blends will significantly increase,but the tensile strength is decreased,and the presence of MBS hindered the PBT molecular chain segment movement,the crystallization temperature of blends of PBT to low temperature direction.When introducing the ester exchange inhibitor NaH2PO4,limited to suppress the ester exchange reaction between PBT and PC,dispersed phase PC and MBS are more evenly distributed in the system,the impact strength of blending system has been further improved,while NaH2PO4 content is 0.5 wt%peak 27.43 kJ/m2,while the tensile strength is not affected by NaH2PO4.At the same time,the introduction of NaH2PO4 can effectively inhibit the transesterification reaction,which makes the PC block of the PBT chain become weaker,so that the crystallization ability of PBT is improved.