Synthesis And Properties Of Crosslinkable Poly (Aryl Ether Ketone) S And The Reinforced Composites

Aromatic polymer poly (aryl ether ketone) s since its inception, particularly in the early eighties after the success of development and utilization of PEEK, the development of such special engineering plastics has aroused great attention. The Tg of PEEK of is143℃, Tm is 334℃, and its using temperature is at 240℃. Despite the overall high performance PEEK, but in order to meet the special requirements of certain high-tech fields, demanding higher levels of heat-resistant products. In order to improve the using temperature of poly-aryl ether polymer, synthesis of structurally related polymers containing more rigid chains, which have higher Tg and Tm, have been studied broadly. However, with the increasing of Tm accompany the processing great difficulties. Poly (aryl ether ketone) s is not only excellent heat resistance and good toughness, rigidity, electrical properties, resistance to radiation, resistance to fatigue, impact resistance, creep resistance, wear resistance, heat water is good, and good flame-retardant etc., in the field of thermoplastic polymer occupies an extremely unique important combination. In recent years, preparation of functional poly aryl ether ketone studies to become a hot spot to prepare functional poly aryl ether ketone the most effective way is to have some functions of the special nature of compounds by chemical methods (grafting, copolymerization, etc.) or physical methods (blend) introducing PAEK. To further enhance the poly aryl ether ketone polymer properties to meet certain special circumstances, the use of requirements (such as high temperature, high radiation intensity, and optical electrical materials), it is made them to take place cross-linking reaction. Before cured processed they are thermoplastic materials, and then become thermo set through cross-linking reaction, so they have both kinds of advantage of materials. They're required to introduce cross-linking groups. We have adopted the form of capped phenylethynyl and phthalonitrile groups to introduce PEEK structures, through these two groups at a high temperature cross-linked to achieve the intended purpose. The dissertation includes three parts: The first study is about phenylethynyl terminated PEEK oligomers and its composites; the second part is on cyano-terminated PEEK oligomers cross-linking behavior of the study, the third part of the hyperbranched polyether ether ketone polymer cross-linking behavior research.Three different molecular weight of phenylethynyl terminated oligomer (PE-PEEK-n) were prepared to using the monomers FPEB, hydroquinone and 4, 4′-Difluorobenzophenone. Their structure and composition were characterized by IR and elemental analysis. The thermal properties were investigated by differential scanning calorimetry (DSC), under the heating influence the phenylethynyl groups can conduct its own cross-linking reaction. Initial results indicated that the peak temperature of exothermic peak decrease follow with increasing content phenylethynyl group. After cured reactions, the glass transition temperature is the opposite trend. TGA testing the cross-linked oligomers have very good thermal stability, and cross-linking process did not produce small molecules. PE-PEEK-n series of oligomers of the initial complex viscosity is very low, between its melting point above and the lowest temperature of the viscosity have a processing window, with the constant cross-linked oligomers, complex viscosity, storage modulus and loss modulus increased after cross-linking completely, can basically meet the requirements of RTM molding process. Preparation of resin and glass fiber composite materials, the composite material has good mechanical properties, resin matrix, after cured two layers of fiber is well bonded together.We used bisphenol monomer and 4-nitrophthalonitrile prepared by nucleophilic substitution reaction of a series of phthalonitrile end capped PEEK oligomers. Capped by different feed ratio the oligomers can be divided into two types of substitution and monosubstituted. Their thermal performances were investigated by DSC. After heated at 225℃for various times, the CN-PEEK can be thermal polymerized. The self-promoted cure behavior of CN-PEEK compound is closely correlated to its hydroxyl unit. Compared to the CN-PEEK, the 2CN-PEEK oligomer was cured in the presence of p-BAPS via heating its powders up to 275–375℃. When the -CN and the electron-withdrawing group -CO- short distance the cross-linking reactions at lower temperatures. The final cured products displayed excellent thermal properties. The cured reaction mechanisms of phthalonitrile terminated PEEK oligomers need further studies.We synthesized two kinds of different functional group ratio nitrile-based end-capped hyperbranched polyether ether ketone (CN-HPEEK). The results proved the cyano group was introduced into the polymer successfully. We can use less of the cross-linking curing agent to complete cross-linking reaction, measured by TBA method obtaining the glass transition temperature significantly elevated, TGA measured by cross-linking greatly improved heat resistance proved that the occurrence of cross-linking reaction. Infrared Testing also showed that the -CN characteristic absorption peaks at significantly decreased under the action of heat.In summary, these two kinds of cross-linked PEEK oligomers (polymers) can be used as composite matrix resins. We can further investigate its composite materials processing technology and its mechanical properties, composite materials, for design and manufacture to provide a broader selection space.