Preparation Of Thermal Conductive PBT And Effect Of Nucleating Agent Addition On Its Performance

Traditional LED lampholders and housings use metal materials.Metal materials have high thermal conductivity and stability,but due to the poor performance of metal electrical insulation,a serious impact on the safety of electrical appliances,Second,the heavier metal materials,corrosion,high cost,so the metal material is not suitable as a shell material,With the development of rubber materials,We found that polybutylene terephthalate(PBT)has good processability and mechanical properties,and molding fast,but also to moisture,heat,oil,abrasion,chemical resistance,etc,Therefore,the choice of PBT material instead of the traditional metal materials.In order to achieve the basic performance requirements of LED lamp holder and shell,In this paper,PBT as matrix,adding aluminum nitride(AlN),boron nitride(BN)as the thermal conductive filler,Taking filler type,particle size and dosage as variables,two kinds of composite thermal conductive materials were prepared by using twin-screw extruder and injection molding machine.One of them is only a thermal conductive PBT material added with aluminum nitride,the other is a compound thermal conductive PBT material added with two kinds of thermal conductive fillers,such as aluminum nitride and boron nitride,The thermal conductivity,mechanical properties,processability and heat distortion temperature ofPBT materials were studied.Through the study we found that only adding aluminum nitride thermal conductive PBT material,adding 90 parts of the maximum thermal conductivity of only 0.783W/mK,The addition of 90 parts of aluminum nitride and boron nitride thermal conductivity of two kinds of composite thermal conductivity of PBT material thermal conductivity can reach more than 1.0W/mK,Therefore,we choose the latter for the production of LED lamp housing material.We found that with the increase of the amount of inorganic fillers,the thermal conductivity of composites showed a gradual upward trend.However,at the same time of increasing the thermal conductivity,the processing performance and mechanical properties of composites decreased to a certain degree,We think that this trend of change has something to do with the change of the crystalline properties of the composites.Gradually adding a certain amount of thermal conductive filler decreased the crystallinity of the composites,So that the mechanical properties of the composite material has changed,making it a gradual downward trend.Therefore,through the previous research in this paper,we also discussed the crystallization behavior of the obtained blends.In the prepared thermal conductive PBT composites,different kinds of nucleating agents were added,The effects of different kinds of nucleating agents on the crystallization properties of the thermal conductive PBT were studied.The best nucleating agent was selected,So as to improve the thermal conductivity of filler lead to the crystallization performance,mechanical properties and other issues.Through the analysis of DSC and XRD,we found that the addition of nucleating agent enhanced the crystallization temperature,crystallinity and tensile properties of the composites.The addition of a large amount of thermal conductivity filler reduces the crystallinity of the material.The addition of nucleating agent calcium carbonate makes the crystallization of PBT with aluminum nitride and boron nitride enhanced the recovery of the highest,Increased by about 165%,Its tensile strength increased to 48.2MPa,Impact strength of 4586.4J/m~2,a melt index of 10.9g/10min,Composite materials at this time the best overall performance.In addition,the addition of nucleating agent MgO can not only restore the crystalline properties of PBT composite materials,but also to some extent improve the thermal conductivity of PBT materials,Its thermal conductivity is 1.160W/mK.Compared with the thermal conductivity PBT without nucleating agent,the thermal conductivity increases by 10.16%,Because magnesium oxide can not only be used as a nucleating agent,but also as a heat-conducting filler,added to promote the formation of thermal conductivity network.