Preparation And Properties Of Boron-containing Poly(Aryl Ether Ketone) And Application In PEEK Composite Modification

Polymer materials generally have high specific modulus, specific strength,corrosion resistance, fatigue resistance and other properties, which have been widelyconcerned by people, and their products can be seen everywhere in daily life. A strongimpact has been caused to the traditional metal, ceramic and other materials. ThePEEK is an important kind of special engineering plastics with higher heat resistantgrades, excellent mechanical properties, strong solvent resistance and so on, which iswidely applied in the technical fields of aerospace, weapons, automotive, electronic,medical equipment and other high-end technological fields. So it has become arepresentatively high-tech cutting-edge materials. However, the single performanceand high cost restrict the application range of PEEK products. In order to reduce thecost and meet the needs of different areas, the PEEK is dealt with chemical orphysical modification to increase the abrasion resistance, antistatic and radiationresistance properties. The chemical modification is usually used for the characteristicsof very high chemical bond energy between inorganic elements. When the appropriateamount of inorganic elements (such as silicon, boron, sulfur, phosphorus, etc.) isintroduced to the main chain or side chain of the polymer, hybrid polymer can beobtained, whose stability is higher than pure polymer. The polymer, which containedboron or boron compound, is called boron-containing hybrid polymer. At present, theresearch mainly focuses on boron hybrid aliphatic polymers, and the investigation ofboron hybrid poly(aromatic ether) polymer is seldom reported. Therefore, this paperinvestigated the preparation method of boron-containing poly(aryl ether ketone)(PAEK-B). We obtained the appropriate method to prepare PAEK-B. Boric acid sidechain of PAEK-B can combine with the whisker surface effectively and the poly(aryl ether ketone) backbone of PAEK-B is well compatible with matrix resin. Inconsideration of above structure characteristics of the PAEK-B, it can be applied asthe coupling agent of inorganic filler composites. In addition, the PAEK-B could bechemically modified by Suzuki coupling of aryl boric acid, and the poly(aryl etherketone) containing pyrene was obtained. The surface modification of single wallcarbon nanotubes could be achieved by the strong π-π*interaction between the largeconjugated aromatic pyrenes and single wall carbon nanotubes. At last, the interfacialbonding strength of the poly(ether ether ketone) resin matrix and the single wallcarbon nanotubes was enhanced.The ideal physical modification method of PEEK was carried out by some fillers,which could not only reduce the cost, but also improve the comprehensiveperformance. Compared with the international similar products, the special materialgrades and variety of our PEEK material are less. Therefore, developing PEEKmaterials with high performance and low cost has become a pressing matter in ourcountry at present. Aluminum borate whisker has many advantages, such as low cost,abundant reserves, high elastic modulus, good mechanical strength, excellentdimensional stability, and absorb neutrons. It is a new whisker with high performanceprice ratio. When aluminum borate whisker was used to modify polymer basedcomposites, the mechanical properties, wear resistance, heat resistance, surfacecondition and electrical performance of the composite were improved. Research ofour country in this area started late, it will have the very big development space.Therefore, this paper combined with the characteristics of PEEK and aluminum boratewhisker, as well as the market demand. Based on the selection of filler and interfaceenhancement, a series of aluminum borate whisker/PEEK composites were designedand fabricated with aluminum borate whisker as the main filler. From the point ofview of application, we are committed to the development of a special PEEK materialwith a high performance and low cost, and the material will have dimensional stability,excellent mechanical properties and abrasion resistance. Excellent performance andrelatively lower cost will make this material have a certain competitive advantage inthe international market. And starting from the point of view of basic research, traditional silane coupling agent has lower heat grade, and the differences of structurewith the PEEK is relatively large, which cause its modification effect is limited. So itis necessary to develop a coupling agent which is suitable for PEEK. In our work, theself-designed synthetic PAEK-B was used as coupling agent. Then we analyzed themodified effect of this modified method, and the interface strengthening influence onmaterial properties.First, the mass fraction of aluminum borate whisker was fixed on10wt%, at thesame time, the PAEK-B was used to modify the surface of aluminum borate whisker.The influence on the properties of the composite materials was researched, which wascaused by the different content of coupling agent. And the optimal ratio of couplingagent was obtained. Then, we used the optimal ratio of coupling agent to prepare aseries of modified aluminum borate whisker/PEEK composites with different contentsof aluminum borate whisker. The performance of materials filled by modifiedaluminum borate whisker was investigated. The results show that the aluminumborate whisker could significantly increase the rigidity, strength and modulus of thematerial, this is due to the rod structure and high rigidity of aluminum borate whisker.The aluminum borate whisker also makes the decrease of coefficient of linearexpansion and shrinkage rate, giving the high dimensional stability of the material.But on the other hand, the addition of the aluminum borate whisker has made theelongation at break and the crystallization ability of the material decrease. After thePAEK-B coupling agent was added to composites, resulting in the composite withmore excellent performance, such as mechanical properties, crystallization properties.In particular, it can improve linear expansion coefficient of the material under thehigh temperature, but also reduce the sliding friction coefficient and wear rate of thematerials. The composites filled by modified aluminum borate whisker showedexcellent comprehensive performance.Carbon nanotubes are a very common functional filler, which coud give materialwith high dielectric properties and modulus. But the limitation of the processingtechnology is an important factor which restrictes the commercialization of nanocomposite material. Uniform dispersion of the nanoparticles in a polymer matrix is a major difficulty. For example, the particle surface with Van der Waals force, capillaryeffect, electrostatic effect, these are very easy to cause the aggregation of particle,which leads to a decrease in the mechanical properties of composites. Theperformance of the dispersion of nanoparticles directly affects the mechanical,electrical and other aspects of composites. Therefore, it is important to control thedistribution of particles, which has very important significance for improving thedielectric properties of the composites and the processing stability. The PAEK-B asintermediates was used to prepare the pyrene-containing poly(aryl ether ketone) inthis paper, then pyrene-containing poly(aryl ether ketone) was used to modified singlewall carbon nanotubes(SWNTs). The effect of modification of pyrene-containingpoly(aryl ether ketone) was studied. When the mass fraction of SWCNTs is less than1%, the modified SWCNTs could disperse uniformly in poly(ether ether ketone) resin,the mechanical and electrical properties of composites with modified SWCNTs havebeen greatly improved.