Preparation And Properties Of Poly(Ether Etherketone)/Diatomite Composites

Polymer composites are famous for their light quality, corrosion resistance, high strength, high modulus, fatigue resistance and other advantages, so they are widely used in daily life and some special places. As a tough semicrystalline thermoplastic polymer, poly(ether ether ketone)(PEEK) attracts great attentions because of its high temperature resistance, good mechanical performance, good self-lubrication, solvent resistance and other characteristics. Its products are used in the weapon equipment, aerospace, electronic information, the nuclear industry, medical equipment and other high-tech fields. However, the high cost greatly limites the large-scale application of PEEK products. Compared with similar international products, the development of PEEK materials in China is lagging, expecially in single species. Therefore, developing low-cost and high-performance PEEK composites become very important for researchers who are experts in PEEK. To reduce cost and meet different application requirements, the PEEK is dealt with chemical or physical modification. The common physical modification method of PEEK is carried out by some fillers, which could not only reduce the cost but also improve the comprehensive performance of the materials. Diatomite is a kind of biogenic siliceous sedimentary rock, which is mainly composed of SiO2. Diatomite has large porosity, strong adsorption, stable chemical performance, light weight, high melting point, good heat insulation and wear resistance, etc. Its proven is abundant and it is very cheap. So diatomite is a kind of natural porous inorganic mineral filler with comprehensive performance. A series of PEEK/diatomite composites were prepared in this paper. Combining with the characteristics of PEEK and diatomite, we analyzed the properties of the composites which were prepared through melt blending and in situ polymerization. We also prepared the composites with different modified diatomite, which were modified by KH550 or PAEK-B coupling agent. Then we analyzed the effect of the modified method, and the interface bonding of material properties.At first, we prepared the composites through melt blending and tested the mechanical properties of the composites. It shows that the diatomite can improve the tensile and bending properties of composites, but not obvious. It can be observed by scanning electron microscope(SEM) that the PEEK is difficult to fully fill into the channels of diatomite in composite materials because of its high melt viscosity. The properties of the composites may affect by the flaws. Then, we prepared the composites by in situ polymerization and tested the mechanical properties of the composites. It shows that the mechanical properties of the composites are higher than those prepared by melt blending. We know that the PEEK can enter into the channels of the diatomite through SEM results. PEEK and diatomite form the “interpenetrating organic-inorganic”, which is the main reason for the composite material performance improvement. At the same time we also can see that the interface compatibility of the PEEK and diatomite is bad and the surface of the diatomite is smooth. It also hinders the improvement in mechanical properties of the composites. To solve the problem, this study used the KH550 to modify the diatomite and tested the mechanical properties of the composites prepared by modified diatomite and PEEK. It shows that there is little improvement in tensile and bending properties, because the processing temperature of PEEK composites is above 360 oC and the KH550 is not stable in high temperature. At last, the paper prepared the boron-containing poly(aryl ether ketone)(PAEK-B) to modify the diatomite and prepared the composites by melt blending and in situ polymerization. Then we tested the mechanical properties of the composites. The results show that the tensile and bending strength are improved obviously, the SEM results also show that there is a good interaction force between modified diatomite and PEEK.