Study On Preparation Of PPESK Foaming Materials With Supercritical CO₂

Polyether sulfone ketone ?PPESK? is a new high-performance plastic,which is famous for its high temperature level. But its high glass transition temperature and high viscosity put more difficulty on processing it. In order to broaden its applications, in this subject, PPESK foaming materials was prepared with supercritical CO₂ as foaming agent, at the same time,the optimal technological condition was explored.1.Molding method was used to prepare PPESK spline from PPESK powder. First,PPESK powder was placed in mold and compacted with plate vulcanizing machine.Afterwards, put the mold in the muffle furnace to melt the power. At last, cool it in room temperature with corresponding pressure was kept. When the sintering temperature of muffle furnace was 385?, the sintering time was 60min, the PPESK spline was the best.2.The supercritical CO₂ was used to prepare PPESK foaming material. Propyl silicone was used as foaming medium,several parameters such as foaming temperature,foaming time,the saturation pressure were investigated to obtain the optimum conditions to prepare PPESK foaming material. The result was that,the saturation temperature of 50 ?,the saturation time of 1h, the saturation pressure of 27MPa, foaming temperature of 275?,foaming time of 90s were the optimum conditions. Under this condition, the cell size of the obtained foamed PPESK spline was 10.88?m, the cell density was 2.03×109cell·cm-3, the impact strength was 21.46KJ/m2 and the tensile strength was 74.72 MPa.3.Three kind of nucleating agent: SiO₂, amino-SiO₂, TALC were respectively added in PPESK with the copies of 0.5pr, lpr, 1.5pr, 2pr. When 1.5pr TALC was added in PPESK, the pore topography of composite foaming spline was the best,as the conditions were saturation temperature 50 ?, saturation time 1h, saturation pressure 27MPa, foaming temperature 275 ?,foaming time 90s. The cell density of this foaming spline was 2.61×109cell·cm-3, the pore size was 6.98?m, the relative density was 0.818, the impact strength was 27.26KJ/m2 and the tensile strength was 68.95MPa.4.The tensile properties test and impact properties test of PPESK/SiO₂ composites,PPESK/amino-SiO₂ composites and PPESK/TALC composite were made. Compared with PPESK, the tensile strength of these three composites was all increased, the increasing of PPESK/amino-SiO₂ was most obvious, achieving 66.83MPa when 1 phr was added. The impact strength of PPESK/TALC composites and PPESK/amino-SiO₂ composites were higher than PPESK/SiO₂ composites. Among this three PPESK/nucleating agent composites,the mechanical properties of PPESK/ amino-SiO₂ was better,the tensile strength of which was 66.27MPa and impact strength was 31.8 KJ · m^-2 when 1.5 phr was added.5.Different copies of nucleating agent: 0.5, 1, 1.5, 2 were respectively added in PPESK.The mechanical properties test of PPESK/nucleating showed that, the impact strength of PPESK/SiO₂ foamed materials and PPESK/amino-SiO₂ foamed materials decreased, while there is a remarkable increase for the impact strength of PPESK/ TALC foamed materials,reaching 32.78 KJ/m2 when 0.5phr was added, improved by 52%. The tensile strength of PPESK/SiO₂ foamed materials,PPESK/amino-SiO₂ foamed materials and PPESK/TALC foamed materials were all decreased, but in comparison, the tensile strength of PPESK/TALC reaching 69.52MPa when lpr was added. In all these PPESK/nucleating agent foamed materials, when lpr TALC was added, the mechanical properties showed best: the impact strength was 29.87 KJ/m2 and the tensile strength was 69.52MPa.