The Modification Of Blends On Polyethersulfone

PES is aromatic engineering plastics with balanced properties as excellentthermal stability widely applied in aerospace, automobile and electrical industries.Because it has a relatively high melt viscosity and low ultimate elongation. Thereare some difficulties in the process. To improve the toughness of PES,we introducethe means of toughening by plastic-plastic blends, as the toughening of elastomerwill markedly reduce the mouldus and the application temperature of PES. On thebasis of foregone work, we choose PC and 1,4-NA-PAEK as toughening agent. Thestudy emphase is the blend for PES/PC. PC is one such useful engineeringthermoplastic because of its excellent dimension stability,creepage resistance,heatresistance,electric insulation,rigidity and good toughness. The blends of PES/PChad been studied. It was found that the blend is a two-phase system;blend displayvery poor mechanical properties due to their coarse,heterogeneous morphology andweak adhesion. To improve the miscibility,we introduced small molecular weight ofbisphenol s-polyester,a random copolymers of 2,2-di-(4-hydroxy phenyl) and 4,4′-dihydroxyldiphenylsulfone,a random copolymers of multi block and a blockcopolymers of multi block with compatibilizer in the blends of PES/PC. The weightproportion of PES/PC is 70/30. We study the blend by changing quantity ofcompatibilizer. We find the optimum proportion. Tesile properties were measued for blends compression sheet. The results showedthe tensile strength,tensile modulus and elongation at break were improved byadding compatibilizer(a certain amount compatibilizer). In particular, theinfluence of compatibilizer conent on elongation at break is more obviously than theothers. The reason that interfacial adhesion is improved by adding compatibilizer,mechanical properties of blend is also improved. The results on DSC,DMA and density showed two Tgs shift inward of blend,the differenceof the Tgs seems not to be affected by the amount of compatibilize added. Suchphenomenon of supports the conclusion reached from DSC result. It is clearly seenthat the addition of compatibilizer could cause a densification of binary blend andthe density of ternary blend is almost independent on the compatibilizer amount. The SEM microphotographs of binary blend and their ternary blend withcompatibilizer are studied. It can be seen that the binary blend is a two-phase system.PC in the shape of irregular ribbon and tube dispersed in PES matrix. The domainsof PC become thinner and the distribution of domains becomes uniform,and aninterlocked two-phase morphology is formed. The boundary layer thickness and the interfacial tension are also studied. Theresults showed the boundary layer thickness of blend become thicker;the interfacialtension of blend is decreased by compatibilizer;Cmpatibilizer improve thecompatibility and mechanical properties of blend.