Preparation And Properties On Novel Poly(Ether Sulfone)(PES)Microcellular Material

"Microcellular foams"are defined as having average cell sizes inthe range 1-10μm and cell densities on the order of 109-1015cells/cm3.In the early 1980s as a means to reduce materials consumption and toincrease the toughness of such cellular materials. The hypothesis oftheir work was that if the cell size was smaller than were the criticalflaws preexisting in the polymer material costs could be reducedwithout significantly compromising the mechanical properties.Microcellular foaming of Polymer with supercritical carbon dioxide asa physical-blowing agent .These techniques all rely on the sameprinciple:(1) the polymer is saturated with a gaseous penetrant (blowingagent),(2)the polymer /gas mixture is quenched into a supersaturatedstate by either reducing pressure or increasing temperature,and(3)nucleation and growth of gas cells dispersed throughout the polymersample evolves until all thermodynamic forces driving mass transport .In order to solve microcellular collapse under heating or underoutside force,a novel poly(ether sulfone) was synthesized by introducingdiallyldihydroxybiphenyl(DA-DHBP) into main chain and microcellularfoams of the novel PES have been prepared using supercritical carbondioxide as the foaming agent . Microcellular foam morphologies wereobtained by saturating the polymer with carbon dioxide and heating thesample above the glass transition temperature of the polymer/gas mixtureafter releasing pressure.Before radiated crosslinking ,the influence of foamingtemperature,saturation pressuse ,foaming time and transfer time on themicrocellular morphology is investigated.The results suggest that thecell diameter increased with the increasing foaming temperature and thecell density obtained the maximum at 140℃,when the foaming temperatureranged from 110℃ to 170℃;the cell diameter decreased and the celldensity increased with saturation pressuse increased;foaming time andtransfer time haven,t almost influence on the cell diameter and celldensity.After radiated crosslinking,the influence of radiation dosageon the microcellular morphology was investigated.The results suggestthat the content of gelation increased gradually with the increase ofradiation dosage and the radiated sample can remain well microcelllarstructure,even though the radiated sample was heat treated at 265℃ for10 min.Above this, A novel poly(ether sulfone) was synthesized byintroducing diallyldihydroxybiphenyl(DA-DHBP) into main chain .Theresult of experiment shows that the microcellular structure can be keptusing the method of radiated crosslinking.