Preparation And Properties Of Nano Rare Earth Oxide/Sb₂O₃/BEO-PBT Composites

Polybutylene terephthalate?PBT?is a semi-crystalline thermoplastic,and has excellent processing and mechanical properties.However,PBT is sensitive to notch and easy to burn,which severely reduce the use of PBT.It is chosen that brominated epoxy?BEO?as a flame retardant and nano-antimonous oxide?Sb₂O₃?as a synergistic flame retardant to prepare Sb₂O₃/BEO-PBT flame retardant composite and found that the flame retardant performance of PBT has greatly improved.However,Sb₂O₃ nanoparticles reduce the mechanical properties of PBT.Therefore,it is an urgent problem to improve the mechanical property of Sb₂O₃/BEO-PBT system while maintaining its excellent flame retardant performance.In this paper,nano rare earth oxides/Sb₂O₃/BEO-PBT composites are preparation to study the crystalline properties,thermal stability properties,mechanical properties and flame retardation performance.The main research contents and conclusions are summarized as follows:?1?Nd₂O₃/PBT,CeO₂/PBT and La₂O₃/PBT composites are preparation to study the effects of different kinds of rare earth oxide on the properties of PBT.The results show that the rare earth oxides promote the nucleation efficiency of PBT,accelerate the crystallization rate and reduce the activation energy.At the same time,the rare earth oxides also improve the tensile strength and notch impact strength of PBT,and CeO₂/PBT composite has the most excellent mechanical property.?2?Titanate coupling agent NDZ-201 is used as the modifier to modified Sb₂O₃,CeO₂and Nd₂O₃ nanoparticles.It is found that the crystalline structure of nanoparticles is not changed.The value of Zeta potential of samples shows that when NDZ-201 dosage is 5 wt.%,the absolute values of the potential of Sb₂O₃,CeO₂ and Nd₂O₃ nanoparticles is the largest,and the particle size of CeO₂ and Nd₂O₃ nanoparticles is smallest,with the average particle size of 63 nm and78 nm respectively,while the average particle size of Sb₂O₃ is the smallest when the amount of NDZ-201 dosage is 7 wt.%.?3?Nd₂O₃ nanoparticles play the role of heterogeneous nucleation in Sb₂O₃/BEO-PBT,and moderate Nd₂O₃ nanoparticles can improve the crystallinity of Sb₂O₃/BEO-PBT flame retardant system.When the content of modified Nd₂O₃ nanoparticles is 0.4 wt.%,the tensile strength and notch impact strength of Nd₂O₃/Sb₂O₃/BEO-PBT composite reach the maximum value,and are 63 MPa and 8.3 KJm^-2,respectively.However,Nd₂O₃ nanoparticles reduce the Limit Oxygen Index?LOI?of Sb₂O₃/BEO-PBT flame retardant system,but the Vertical Combustion?UL94?grade of the composite is still in V-0 level.?4?The content of CeO₂ nanoparticles has a great influence on the crystallization performance of CeO₂/Sb₂O₃/BEO-PBT composites.Moderate CeO₂ nanoparticles can improve the crystallinity of CeO₂/Sb₂O₃/BEO-PBT composites,and the crystallinity of composites with unmodified CeO₂ nanoparticles is lower than that with modified CeO₂ nanoparticles.With increase of CeO₂ nanoparticles content,the tensile strength and notch impact strength of CeO₂/Sb₂O₃/BEO-PBT composites increase first and then decrease.Moreover,the mechanical property of CeO₂/Sb₂O₃/BEO-PBT composites with modified CeO₂ nanoparticles are larger.CeO₂ nanoparticles reduce the LOI of CeO₂/Sb₂O₃/BEO-PBT composite,but its UL94 grade is still V-0 level.