Preparation And Properties Of Hydophobic And Low Dielectic Poly(aryl Ether Fulfone)s Containing Fluoro And Cage/Line Organosiloxane

Due to the strong electronegativity of fluorine atoms and the short length and strong energy of C—F bond of fluorinated organic materials,therefore,fluorinated materials generally have prominent low surface free energy,excellent heat-and-cold resistance,chemical corrosion resistance and good antifouling property.The materials containing trifluoromethyl are a kind of partially-fluorinated materials.The introduction of trifluoromethyl to polymer can effectively perfect the polarity,solubility,hydrophobicity and chemical stability of polymer materials.And the dielectric constant of the polymer can be reduced by introducing the trifluoromethyl because of the low polarity and the larger free volume of trifluoromethyl.Linear siloxane materials containing trifluoropropyl,as a type of siloxane,the backbone of which is Si-O bond that has chain flexibility and strong bond energy,the side chain of which are-CH₃ and-CH₂CH₂CF₃,is a kind of organic/inorganic hybrid materials with low surface energy,high thermal stability and extreme chain flexibility.The linear organosiloxanes containing trifluoroproyl have excellent high and low temperature resistance,and also increase the acid resistance,alkali resistance and chemical resistance due to the introduction of trifluoroproyl.Under the effective synergism of fluorine and silicon,they have excellent properties of both organosilicon and organic fluorine materials,and can overcome the defects of the two kinds of materials when they are used alone.Because trifluoroproyl has low polarity and the methyl and trifluoropropyl of side chain increase the free volume,the introduction of the linear organosiloxanes into the polymer can improve the hydrophobic and oleophobic properties and can reduce the dielectric constant of polymer.Polyhedral oligomeric silsesquioxane?POSS?,as a type of cage organosiloxane,is a unique nanoscale inorganic/organic hybrid material.POSS is composed of the core of inorganic Si-O–Si frame and the periphery that are occupied by organic functional groups connected with Si atom,which determines the POSS hybrid molecules can be both inorganic materials with thermal stability and chemical stability and organic materials with compatibility.Because of its unique macromolecular structure,POSS can be introduced to perfect the properties of polymer substrate materials,including thermal stability,oxidation resistance,flame resistance,surface hardness and low dielectric properties and hydrophobic properties.Poly?aryl ether sulfone??PAESs?,as a kind of high performance thermoplastics,have outstanding thermal stability,excellent mechanical properties,excellent chemical resistance and better low dielectric properties.Based on the above properties of PAESs,PAESs and the modified can be widely applied in aerospace,military defense,electronic and electrical appliances and other high-performance materials.However,the hydrophobicity?CA=80^o?is poor due to the existence of sulfuryl and ether bonds in the molecular structure of PAESs.Its dielectric constant??=3.4?is also difficult to meet the demand of electronic packaging materials in the rapidly developing microelectronics field.Therefore,fluorine and silicon elements were introduced into the PAESs base materials by chemical copolymerization.The synergistic effect of fluorine and silicon,while combining the excellent performance of linear organosiloxane and cage type organosiloxane,render PAESs maintain the advantage of base material and meanwhile improve hydrophobicity and reduce dielectric constant.The influence of chain flexibility,the content of fluorine and silicon elements and the position fluorine connected on crystallization behavior,hydrophobicity,solubility and low dielectric properties of modified poly?aryl ether sulfone?materials were explored.The results showed that the low polarity and large volume trifluoromethylphenyl and cage type organosiloxane could effectively improve the hydrophobic angle of poly?aryl ether sulfone?,reduce the dielectric constant and dielectric loss of the polymers,and improve thermal stability.At room temperature,the highest contact angle of the polymer reached104°,the lowest dielectric constant reached 2.23 at 1MHz.The thermal degradation temperatures(T_d5)of all the polymers containing trifluoromethylphenyl and DDSQ were above 410?.In addition,the introduction of both linear orgnosiloxane?PMTFPS?containing trifluoroproyl and cage organosiloxane?DDSQ?into poly?aryl ether sulfone?improved the chain flexibility.At the same time,the lowest dielectric constant was 1.52under 1MHz,and the largest contact angle was 108.5°.