Preparetion And Properties Of Novel Polyethersulfones

As one of the important varieties of special engineering plastics,polyethersulfone has excellent chemical resistance,biocompatibility,optical,mechanical,thermal,dielectric and other properties.It is widely used in aerospace,electronics,electrical appliances,medical devices,separation membranes and other fields.However,with the emergence and development of new technologies in recent years,higher requirements have been put forward for the properties of materials.The structure determines the properties,and the modification of molecular structure is an effective way to prepare new polyethersulfone to improve its comprehensive properties.In this paper,through the co-polymerization of bisphenol A,bis(4-chlorophenyl)sulphone with hydroquinone,o-methyl hydroquinone,tert-butylhydroquinone and 2,5-tert-butylhydroquinone,the new polyethersulfone resin and film prepared were labeled as BHD,BMD,BTD and BDD,respectively.Bisphenol AF and bis(4-chlorophenyl)sulphone were copolymerized with hydroquinone,tert-butyl hydroquinone and 2,5-tert-butyl hydroquinone to prepare new polyethersulfone resins and films,which were labeled as FHD,FTD and FDD series,respectively,and their structures were determined by infrared characterization.Each of the new polyethersulfone contains several formulations by adjusting the ratio of diphenols.The effects of different diphenol ratios and molecular structures on solution viscosity,film mechanics,optics,heat,dielectric,surface properties and hydrophobicity of each novel polyethersulfone were investigated.The influence of molecular structure on various properties is as follows:Because bisphenol A or bisphenol AF contains flexible bond,the formula with high content of bisphenol A or bisphenol AF generally has higher elongation at break,but the vitrification transition temperature shows decreasing trend with the increase of content.Series of BHD polyethersulfone has general dielectric,optical,surface properties and hydrophobicity,and other properties are relatively good;for series of FHD,because the molecular main chain was introduced in trifluoromethyl group which has strong heat resistance,and the trifluoromethyl has low polarity and large steric hindrance,compared with the series of BHD,the optical,dielectric,surface properties and hydrophobicity of the film are significantly improved with the increase of the trifluoromethyl content in the main chain,and the mechanical strength is reduced due to the introduction of trifluoromethyl;series of BMD introduces a benzyl group in the main chain,the solution viscosity is larger,and the mechanical properties are better,compared with series of BHD,other properties are not much different;the series of BTD introduces tert-butyl with larger steric hindrance in the main chain,the dielectric properties and hydrophobicity of the film are better than those of the series of FHD,and the optical properties are between series of BHD and series of FHD,but the tert-butyl type has poor heat resistance,the heat resistance decreases with the increase of the content of tert-butyl in the main chain,which is lower than other polyethersulfone without tert-butyl in the main chain,and the introduction of tert-butyl is unfavorable to the mechanical properties of the film;the tert-butyl and trifluoromethyl in the main chain of the FTD work together,compared with the series of FHD and series of BTD,it further improves the optical,dielectric,surface properties and hydrophobicity of the polyethersulfone,and excellent heat resistance of trifluoromethyl makes up for the poor heat resistance of tert-butyl,series of FTD still has excellent heat resistance stability;with 2,5-di-tert-butyl hydroquinone as the copolymer unit of series of BDD and FDD,its solution viscosity and mechanical properties decrease greatly with the increase of 2,5-di-tert-butyl hydroquinone content,when the content is too high,the film cannot be formed due to insufficient polymerization degree,and other properties are better.In summary,series of FTD polyethersulfone has the most excellent comprehensive performance.The viscosity at 30°C is higher than 5.42 P,the highest light transmittance of the film can reach 90.85%,and the glass transition temperature,thermal decomposition temperature,and 800℃ carbon residue rate are 207.84℃,508.15℃ and 49.42%.The dielectric constant and dielectric loss are lower than 2.94 and 0.60% respectively.The surface properties and hydrophobicity are outstanding,and the mechanical properties are relatively good.