Study On Preparation Of PC/PBT Toughened Blends And Properties Of Microstructured Injection Molded Products

Polymer blending has always been an effective method to improve the performance of the material itself.It can comprehensively balance the performance of each component,take advantage of the shortcomings,eliminate the weakness of the performance of a single component,and thus prepare a polymer material with excellent performance.Therefore,polymer blending It has been widely used in many fields.The blend of polycarbonate(Polycarbonate,PC)and polybutylene terephthalate(PBT)through melt blending has both the advantages of both.Compared with pure PBT,the blend It has better dimensional stability,impact resistance and creep resistance.Compared with pure PC,the chemical resistance,heat resistance and processing fluidity of the blend will be significantly improved.For some injection-molded products with microstructure characteristics,due to their complex structure and difficult molding,higher requirements are placed on the performance of the material itself.Therefore,it is very important to choose appropriate materials to form microstructured products.In this paper,PC/PBT blend is introduced into the molding of microstructured products.Methyl methacrylate-butadiene-styrene copolymer(M-701),maleic anhydride grafted styrene-ethylene-butadiene are selected Styrene copolymer(SEBS-g-MAH)and maleic anhydride grafted polyolefin elastomer(POE-g-MAH)are used as tougheners in the blending system.The types and contents of tougheners and PBT content were studied Influence on the mechanical properties,rheological behavior and crystallization behavior of PC/PBT blends,and based on the experimental results,LED low-hat eaves masks with microstructure characteristics were prepared.The research results are as follows:(1)Toughened PC/PBT blends with different types and contents of tougheners were prepared by melt blending method.The mechanical properties,cross-sectional morphology,rheological behavior and crystallization behavior of toughened blends After analysis,the following conclusions were drawn:the addition of the three tougheners significantly improved the elastic modulus and notched impact strength of the blend,and increased with the increase of the toughener content,of which M-701 had the best improvement effect,The notched impact strength of 15-wt%M-701 blend is increased by 19.6 times compared with pure PC/PBT blend.The tensile strength of the blend shows a decreasing trend with the increase of the content of toughening agent.The length ratio shows a certain difference;the micro-morphology of the impact section verifies that the addition of toughening agent changes the fracture mode of the blend from brittle fracture to ductile fracture;rheological analysis shows that the viscosity of the blend varies with the content of toughener Increase and decrease,the shear stress shows the trend of increasing first and then decreasing;the storage modulus and loss modulus of the blend increase with the increase of the toughener content,of which,M-701 improves the rheological properties Best;DSC analysis shows that the toughener's The addition caused the crystallization temperature and melting temperature of the blend to shift to a low temperature,and the crystallinity slightly decreased with the increase of the toughener content.(2)Toughened PC/PBT blends with different PBT content were prepared,and the effects of PBT content on the mechanical properties,impact fracture morphology,rheological properties and crystallization properties of the blends were studied.The results show that:with the PBT content With the increase,the notched impact strength of the injection-molded products is significantly increased,and the tensile strength is decreasing.When the PBT mass fraction reaches 30wt%,the comprehensive mechanical properties of the injection-molded products reach the best.Rheological analysis shows that PC/PBT blends show obvious "shear thinning"characteristics during shear flow.With the increase of PBT content,more and more flexible chains in the blend system are obtained,and processing fluidity is obtained.Significantly improved,which is more conducive to the processing of microstructured products.The storage modulus and loss modulus of the blends increase with the increase of PBT content.When the PBT mass fraction reaches 30wt%,the microstructured products have good rheology Performance and mechanical properties.DSC test results show that the presence of a small amount of PC can promote the crystallization of the blend system.(3)Through the injection molding of microstructured products of PC/PBT toughened blends with different PBT content,the effect of PBT content on the microstructure forming performance was studied.The results show that:when the PBT content is 30wt%,it can be molded Good quality microstructure products;when the injection temperature is 290?,the injection pressure is 90Mpa,the injection speed is 120mm/s,and the holding time is 5s,the pass rate of the microstructure products is the highest.