Research On Structures And Properties Of Ternary High Performance Engineeirng Plastics Alloys PEEK/PEI/PES

It is well concerned by people that plastic alloys with excellent comprehensiveperformance could be obtained by alloying modification in the recent years. Poly(ether ether ketone)(PEEK) is one kind of high-performance engineering plastics,which has prominent advantages in mechanical strength, thermal stability, electricalinsulativity and chemical stability. But high price and significantly lower glasstransition temperature than some high heat-resistant amorphous plastics such as poly(ether imide)(PEI) and poly (ether sulphone)(PES), so PEEK were improved byalloying modification, which has become one of research hotspots. Blend of PEI, PESand PEEK, such as were used to improve their high-temperature rigidity and reducecosts. However, at present, the research on PEEK/PEI/PES ternary alloy hadn’t beenreported. In the paper, the particles and sheets of PEEK/PEI/PES alloys were preparedsuccessfully with high temperature twin-screw extrusion molding at370℃in massratios of70/30/0,70/0/30,70/25/5,65/30/5,60/30/10,60/35/5and60/10/30. Inaddition, the plates of PEEK/PEI/PES alloys were also prepared successfully withthermal compression molding. Some properties of particles, sheets and plates werecharacterized and analyzed by means of scanning electron microscope(SEM), x-rayphotoelectron spectroscopy(XPS), attenuated total reflection flourier transformedinfrared spectroscopy (FTIR-ATR), differential scanning calorimetry (DSC), universaltensile machine, friction and wear tester respectively, such as the microstructure,thermal properties, mechanical properties, friction and wear properties and so on.Microstructure analysis showed that PEI and PES can be well-balanced dispersedin PEEK matrix, so it was exhibited that there is morphology with macroscopicuniformly dispersion and microscopic phase separation. PEEK and PES has a lowercompatibility. The XPS analysis of mass ratio of60/30/10particle specimen showsthere is a presence of there components, and the three components is dispersed evenlyin the tiny area of the surface of the specimen tested. The FTIR and FTIR-ATRanalysis indicated that there is a certain interaction between the three components, and there are some regions in the alloys with interaction and without interaction betweenPEEK and PEI when PES was increased, which can be proved especially by thechange of infrared absorption peak carbonyl group of imide ring. DSC results indicatedthat the ternary alloys PEEK/PEI/PES have a good compatibility and only a singleglass transition temperature that is higher than that of pure PEEK about20℃, AddingPEI and PES can make crystallization temperature lower than that of pure PEEK about6-8℃, and the crystallinity can be increased, such as mass ratio of60/30/10particlespecimen is the largest, namely37.76%, which is higher than the crystallinity of purePEEK about4.1%. There is a little influence on the thermal stability of the ternaryalloy materials for the heat treatment process of thermal compression molding,There are some influences on the tensile strength and elongation at break, such asthe tensile strength of mass ratio of60/30/10sheet specimen has the maximum value,namely90MPa, which is higher than that of pure PEEK, and the elongation at break islower than that of pure PEEK. Its results showed that the tensile strength of the sheetspecimens is less affected after158℃and178℃heat aging for168h, and theelongation at break were influenced obviously. The tensile strength of alloy platespecimens are higher than that of pure PES, and lower than that of PEI, the majority ofalloy plate specimens are higher than pure PEEK, such as the tensile strength of massratio of60/30/10plate specimen has the maximum value, namely108.1MPa, but theelongation at break of ternary alloy plate specimens are higher that of pure PEEK.Flexural strength and flexural modulus of plates lowers along with PEEK contentreducing in the ternary alloys, which is higher than that of pure PES. In addition, thehardness of ternary alloys is higher than that of pure PEI and pure PES. So PEEK hasthe larger contribution to the rigid properties of the ternary alloys, and PEI and PEShave the larger contribution to the break-resistant capacity of the ternary alloys.The binary alloy and ternary alloys reach the steady wear stage about40-50min,which is shorter than that of pure PEEK. The friction coefficients of alloys in thesteady wear stage are higher than that of pure PEEK. The wear rate of alloy plates is lower than pure PES and PEI, and is1/4-1/6of that of pure PES and PEI, but which ishigher than pure PEEK. Alloys wear mechanism is mainly adhesive wear. Adding PEIcan increase the wear rate of alloy plates when PES contents cannot be changed. Inaddition, it can be observed that adding PES can cause to fall the transferred film off inthe friction process, and results in increasing wear and the specific wear rates, so PEIand PES that are the amorphous component is not conducive to the ternary alloy wearresistance.The concentrated H2SO4resistance of alloy plates had been improved by alloyingin a certain extent. The acetone resistance of mass ratio of70/25/5is preferably, inaddition, the chloroform and N, N dimethyl formamide resistance of mass ratio of70/25/5is also preferably, and the polarity of the reagent has a limit influence onreagent resistance of plastics alloy materials. TGA results of ally plate specimenscorroded by concentrated H2SO4showed that there are some influences on the thermalstability of alloy materials, but TGA results of ally plate specimens corroded byacetone or chloroform showed that there are a little influence on the thermal stability ofalloy materials, and its thermal decomposition temperature basically remain unchanged.Adding PES can decrease oxygen index of alloy sheet specimens, the oxygen index(OI) of mass ratio of70/30/0is37.1%, which is higher than that of pure PEEK. Withthe increasing of PEI, the flame retardancy of alloys would be improved. The volumeresistivity of mass ratio of60/30/10is3.72×1017·cm, which is higher than that ofpure PEEK and pure PEI obviously, and the volume resistivity of alloy plates reachesthe order of magnitude for volume resistivity of pure PEI.The comprehensive properties of mass ratio of60/30/10formula materials aremore outstanding when the properties of ternary alloys were analyzedcomprehensively.