| With the development of science and technology, the continuous human space exploration, global electronic information field, high-speed propulsion, new energy, bio-medical engineering and the automotive industry and other fields of development, a strong impetus to research and development of special engineering plastics, and Its application to an unprecedented height. PEEK is a semi-crystalline wholly aromatic structure of special engineering plastics, widely used in electronic devices, mechanical instruments, transportation and aerospace and other fields, according to the processing conditions, the crystallinity in the 0-48% range. The aggregation structure of polymer, has important theoretical and practical significance. Understand the characteristics of polymer aggregation structure, formation conditions and the relationship between the material on the molding process by controlling the conditions to achieve the expected performance of materials and products is essential. Polymer materials, but also for the design and provide a scientific basis of physical modification. So study the crystallization behavior of poly (ether ether ketone) on the development and modification of polymers have important guiding significance, and this did solve the poly (aryl ether ketone) polymer high cost, serious application restrictions on the urgent problems that direction. Meanwhile, the study of the solvent resistance of PEEK polymer can be used for such conditions give a theoretical basis, poly (ether ether ketone) materials on a wide range of applications are of great significance.The present paper work using methods and so on thermal analysis, dynamic mechanics analysis, wide-angle X light diffraction, mechanics test to the poly (aryl ether ketone) s multiple fusing behavior, the crystal behavior and will bear the resolver to conduct system's research, and the behavior which will crystallize to the resolver inductionpoly (aryl ether ketone) s has carried on the discussion.Used DSC, DMA, and test methods and so on WAXD has studied the PEEK dual fusing behavior. The DSC result showed that only then the uniform temperature crystallizes the sample presented the obvious dual fusing behavior. Must therefore study the multiple melting behavior of the poly (ether ether ketone) s, the main choice studies PEEK the isothermal fusing thin film. The distinction choice uniform temperature crystallizing point for 200℃,220℃,240℃,260℃,280℃and 310℃, the heat treatment time was 1h, the choice different membrane thick (respectively is 0.050, 0.100 and 0.150mm) the silk thread business DSC test, discussed PEEK the multiple fusing behavior. Crystallizes after the uniform temperature, the cold crystallizing point (143℃) and the melting point (346℃) between PEEK the sample DSC curve has in the glass transition temperature for the model double fusing behavior, has the low temperature fusing peak and the high temperature fusing peak two fusing peaks, and low temperature fusing peak always above its corresponding cold crystallizing point 10-20℃appearance. Along with heat treatment temperature's elevation, low temperature fusing peak's temperature increment, its area approximately has the high temperature to fuse the peak area about 5% , but the high temperature fusing peak's temperature maintains invariable basically, position in 346℃neighbor. The low temperature fusing peak appears after the heat treatment temperature, elevates along with the heat treatment time's extension, finally tends to be invariable, the peak area increases along with the heat treatment time's extension. But the high temperature fusing peak value change is not big, the peak area reduces along with the heat treatment time's extension.The film's storage modulus is different by DMA the test knowing different process condition's PEEK, changes along with the degree of crystallinity, the amorphous thin slice's storage modulus is lowest, fusing crystallizes the sample has the highest storage modulus, but the heat treatment sample's storage modulus is situated between the amorphous sample and between the fusing crystallization sample. Because the crystalling phase storage modulus is higher than the amorphous phase storage modulus, therefore may know, the fusing crystallization sample's crystallinity is highest, but the heat treatment sample's crystallinity is also higher than the amorphous sample the crystallinity. The contrast heat treatment sample and the fusing crystallization sample may discover that along with heat treatment temperature's elevation, the glass transition temperature reduces. That is, tends along with the crystallization the consummation, the polymer glass transition temperature instead reduces, the polymer performance is a flexibility. This phenomenon may consider that (crystallization-crystalless-intermediate level) the model explained with the three-phase model-intermediate phase. Chooses the laboratory common to have the representative acid, the alkali and the organic solvent, in view of the different working condition (amorphous, heat treatment and fusing crystallized) PEEK the thin film to carry on has borne the resolver test. Has carried on the thermal properties and the mechanical property test to the solvent treatment different time's PEEK sample, may obtain the following several rules:1. The different working condition's PEEK sample has the good acidproof alkalinity (aqua fortis and strong sulfuric acid exception), after solvent treatment can maintain the good thermal properties and the mechanical property. But the strong sulfuric acid may dissolve the different working condition the PEEK sample, the aqua fortis may dissolve the amorphous PEEK thin film, crystallizes the PEEK thin film thermal properties and the mechanical property to the heat treatment and fusing has the obvious influence, the consideration is the aqua fortis has the nitration in the PEEK thin film surface to respond perhaps the aqua fortis is the PEEK sample decomposition creates.2. PEEK amorphous state is not good solvent resistance of samples of several organic solvents can be amorphous PEEK film on the thermal and mechanical properties of significant impact. Amorphous pile of loose polymer molecules, weak intermolecular interactions, the polymer solvent molecules more easily penetrate inside, although not to dissolve PEEK samples, but it had the swelling.PEEK and solvent molecules in the amorphous region this is not a rapid penetration of the amorphous PEEK film on impact, but to go through a molecular permeation, diffusion process, this process should be gradual, as time increases, the sample molecules into the PEEK Solvent molecules between the increase in the thermal stability of PEEK samples have an impact. The process time is chosen and the relevant solvent.Amorphous PEEK film on a more significant effect of several organic solvents, in accordance with their polarity can be divided into non-polar (toluene, xylene, chloroform and ethyl acetate) and polar aprotic (acetone, methyl ethyl ketone and NMP) two, and toluene, xylene, acetone, methyl ethyl ketone and the NMP and and PEEK has a similar structure to meet the "like dissolves like"theory, the solvent molecules should be easier to penetrate into the macromolecular chain of PEEK. Therefore consideration this kind of resolver is big to the amorphous PEEK thin film influence.3. PEEK samples after heat treatment compared to samples of amorphous PEEK has good solvent resistance. This is because the heat treatment increases the crystallinity of PEEK film, this time the molecular arrangement of amorphous regions affected by grain zone, the solvent molecules more difficult to penetrate into the molecular internal swelling occurs, so part of the solvent PEEK films after heat treatment for thermal and Machinery remains good. However, the main chain of PEEK samples of these are random molecular sorting, molecular packing loosely, which is conducive to the spread of solvent molecules, so that part of the solvent molecules penetrate into the molecular chain have an effect, reducing the thermal and mechanical properties. 4. Melt crystallization of PEEK film good acid and alkali resistance and solvent resistance, enhance the crystallinity, the molecular chain arrangement of regular, close, while a strong interaction between molecules, so that the solvent molecules which is difficult to penetrate, the polymer has good Solvent resistance, solvent treatment, the thermal and mechanical properties are well maintained.By studying samples of different processing conditions of the PEEK solvent resistance, a very important practical significance, can be applied to different environments PEEK material selection and processing conditions to guide, and to broaden the scope of application of PEEK material.Liquid polymer with organic solventinduced crystallization technique to study the acetone, toluenesolvent-induced crystallization behavior of PEEK, crystal structure and morphology. Polarized optical microscopy (POM) PEEK-induced crystallization observed crystal forms. Used DSC to study the organic solvent liquid phase to induce the thermal crystallization behavior of PEEK crystallization crystal. With wide-angle X-ray diffraction induced crystallization of PEEK crystal structures were tested. Liquid organic solvents can induce the sample appears amorphous PEEK spherulites, spherulite size can as the liquid-induced crystallization time increases, and the solvent molecules in the polymer melt increases in activity, reduced Polymer glass transition temperature and melting point, weak figure from WAXD crystallization peak can be seen by solvent induced crystallization, the crystals produced only a few. This crystallization process of melt crystallization peaks produced a strong second to none.As the PEEK resin solvent resistance tests showed that nitric acid treatment, the PEEK resin has a special phenomenon, consider the concentrated nitric acid nitration occurred with PEEK resin, reaction, and a new aromatic nitro compounds. Nitrate as a nitration reagent designed by electrophilic substitution reaction, the nitro-introduced into the PEEK polymer main chain. By changing the concentration of nitric acid and reaction time, synthesis of a series of different polymer samples nitro content. The structure of the polymer by FTIR, EA and NMR characterization proved that the structure in line with expectations. And its thermal properties and solubility were tested. |
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