| Phthalazinone structure is contained in polyether ketone(PPEK)which is the world's highest level of heat-resistant polymers of all the soluble polymers.PPEK having a glass transition temperature of 263 ?,with a good chemical stability and mechanical strength.It has been on a wide range of applications like aerospace,military industry,electrical and electronics,rapid rail transit and other areas,in order to further expand the application fields of PPEK preparing its microporous polymers is an imperative study.In this work,supercritical CO2 has been used as a physical blowing agent.Supercritical fluid is one kind of fluid between gas and liquid state which is having excellent fluidity,permeability and transitivity.Due to the lower critical temperature of supercritical CO2,it can be achieved at the temperature of room and the critical pressure is easy to reach,so the supercritical operation can be obtained.The processing equipment is simple,but also has a non-toxic,non-flammable and high purity industrial products,etc.,so the details of this work that the preparation of supercritical CO2 PPEK microporous polymer contents are as follows:To investigated the impact of process conditions on the foam cell morphology of the microporous materials,microcellular PPEK and it blends with different kind of nano-silica(nano-SiO2)and TALC composition blends have been successfully prepared by using supercritical CO2 rapid heating method.At the same time we explore the effects factors of cell morphology of PPEK microcellular materials.The studies have shown that the foaming temperature and saturation pressure of CO2 and foaming time are related to the cell morphology.In rapid heating method,the cell density of the microcellular rises with increasing the saturation pressure,but there is a pressure turning(23MPa),on the top of this pressure,cell density have been effected slightly,the optimum saturation pressure is 27MPa the cell density is 8.87X 107 cell-cm-3.The cell density of PPEK microcellular materials increases with increasing the temperature rises,after reaching a certain temperature(270 ?),the cell density will be declined significantly,in the use of classical nucleation theory can qualitatively describe the influence of cell density by temperature and saturation pressure.With the changes of the cell size and the cell density by the pressure and temperature are opposite.Relative density decreases with the increase of temperature and pressure.Furthermore,the inorganic filler was selected as a nucleating agent,the blend of the nucleation catalyst content,compatibility and domain size of the dispersed phase have a great influence on the pore forming.The study shown that added nucleation catalyst to PPEK the microporous structure parameters will change greatly,there will be more complex influence factors.The work furthermore prepared the available microporous material with changing the content and the species of nucleation catalyst to obtain the higher the cell density and the smaller the cell size microporous materials,while the component can be added to reduce the pore forming combined with the cell collapse,the cell diameter was 8.85?m and the cell density could achieve 1.6 × 109 cell·cm-3.The impact strength increased 107.9%than PPEK material and 16.18%higher than microporous material PPEK which foamed under 270 ?.It improved the mechanical properties of the experimental comparison of microporous polymer PPEK significantly better than original PPEK resins.The effects of heat resistance,mechanical properties of materials have been studied.By comparing the before and after foamed material Vicat Softening Temperature,the foaming sample improved 9 ? which confirmed that the heat resistance is improved.Microporous has played a significant role in foaming.The heat resistance and mechanical properties of the experimental PPEK microporous polymers are better than the original PPEK polymers. |
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