Preparation And Properties Of Poly(Ether Ether Ketone)-based Composite Foam

With the development and maturity of supercritical CO2 foaming technology,many different kinds of polymer foams have been prepared successfully,and some of them have formed a large-scale market.At present,in order to further extend the application field of foam materials,polymer composite foams with excellent performance and various properties are prepared by adding functional filler,which is a research hotspot in the field of polymer foams.As a kind of special engineering plastics,semi-crystalline poly?ether ether ketone??PEEK?is a optimizing material for aerospace,automotive,electronics,biomedical and other advanced fields due to its excellent performance.Therefore,on the basis of PEEK resin,it is of great significance to develop PEEK composite foam with high strength,high heat resistance and corrosion resistance by adding reinforcing filler,so as to meet the demand of applications on extreme environments.Firstly,glass fiber?GF?was chosen as the reinforcing filler.PEEK and GF were melt blended and molded into 10 wt%,20 wt%and 30 wt%GF composite sheets.By the intermittent pressure-quenching supercritical CO2 foaming,we determined the optimal foaming temperature range of three kinds of composite component proportion respectively,and further optimized the foaming process parameters:saturation pressure of 20 MPa,saturation time of 90 min,depressurization rate of 0.8 MPa/s,ice-water cooling.A series of GF/PEEK composite foams with volume expansion ratio of 1.76-4.21,cell density of 3.50×10⁵-9.29×10⁶ cells/cm³,cell size of 23.4-215.8?m were prepared successfully.During the foaming process,most GF orientation distribution is located in the cell wall to support the foam cells,thus enhancing the stability of the cell structure.Composite foam with higher GF content has more stable structure,higher compression strength and heat resistance.Compression strength of 10 wt%,20 wt%and 30 wt%GF composite foams with the same density of 0.55 g/cm³ are 8.29 MPa,9.89 MPa and 11.07 MPa,10 wt%and 20 wt%GF composite foam heat resistance level at 325 ^oC,20 wt%GF composite foam at 330 ^oC,at the same time it also has excellent solvent resistance.In order to further improve the compression strength and heat resistance of the composite foam,carbon fiber?CF?with better comprehensive performance was selected as the reinforcement filler.10 wt%,20 wt%,30 wt%and 40wt%CF composite sheets were prepared for supercritical CO₂ foaming.We determined the optimal foaming temperature range of four composite component proportion respectively,and then optimized the foaming process parameters:saturation pressure of20 MPa,saturation time of 120 min,depressurization rate of 0.6 MPa/s,ice-water cooling.A series of CF/PEEK composite foams with volume expansion ratio of 1.67-4.06,cell density of 4.83×10⁵-2.03×10⁷ cells/cm³,cell size of 17.7-152.1?m were prepared.Compression strength of 10 wt%,20 wt%,30 wt%and 40 wt%CF composite foams with the density of 0.55 g/cm³ are 9.44 MPa,11.25 MPa,12.43 MPa and 15.64MPa respectively,and the heat resistance level reach 325 ^oC,330 ^oC,335 ^oC and 340^oC.Compared with CF/PEEK composite foam,compression strength and heat resistant performance are enhanced,and the CF/PEEK composite foam also has excellent solvent resistance.At the same time,CF/PEEK composite foam has good electromagnetic shielding performance because of the carbon filler.The specific SE of10 wt%,20 wt%,30 wt%and 40 wt%CF composite foams are 11.93 dB g^-1 cm³,21.82dB g^-1 cm³,27.44 dB g^-1 cm³ and 35.73 dB g^-1 cm³.In short,CF/PEEK composite foam can be used as a high performance PEEK composite foam with high strength,high heat resistance,corrosion resistance and electromagnetic shielding effect.