Reversible derivatization of poly (aryl ether ketones)

Abstract

The embodiments of the present disclosure present systems and methods for the reversible solubilization of (aryl ether ketones) (PAEKs). A thioacetalization process is employed to modify the PAEKs into poly (aryl ether thioacetals) which, unlike PAEKs, are substantially soluble in common solvents. This modification allowing selected analysis techniques to be more easily performed on PAEKs1 such as gel permeation chromatography. The thioacetalization may be reversed through a deprotection reaction to recover the original PAEK without substantial degradation, allowing for non-destructive characterization of the PAEK. Advantageously, the thioacetalization process is generally applicable to a broad range of PAEKs, unlike presently known methods of solubilizing PAEKs. Solubilization of PAEKs further expands the utility of the PAEKs, opening up additional routes to chemical modification of PAEKs, as well as allowing for the possibility of processing PAEKs from solution.

1 . A method of forming a soluble derivative of a poly (aryl ether ketone) (“PAEK”), comprising:
 dissolving the PAEK in a mixture comprising a solvent and an acid; and 
 intermixing a Lewis acid such as boron trifluoride-diethyl etherate and a thiol compound with the PAEK mixture in sufficient quantity to form a poly (aryl ether thioacetal) corresponding to the PAEK in solution. 
 
     
     
         2 . The method of  claim 1 , wherein the PAEK is selected from at least one of poly (ether ketone) (“PEK”), poly (ether ether ketone) (“PEEK”), poly (ether ketone ketone) (“PEKK”), poly (ether ketone ether ketone ketone) (“PEKEKK”), poly (ether ether ketone ether ether ketone) (“PEEKEEK”), poly (ether diphenyl ketone) (“PEDK”), poly (ether diphenyl ether ketone) (“PEDEK”), poly (ether diphenyl ether ketone ketone) (“PEDEKK”), poly (ether ketone ether naphthalene) (“PEKEN”), a polymer comprising a recurring unit having at least one of the structures of Formula (I): 
       
         
           
           
               
               
           
         
         and a polymer comprising a recurring unit having at least one of structures of Formula (II): 
       
       
         
           
           
               
               
           
         
       
     
     
         3 . The method of  claim 1 , wherein the poly (aryl ether thioacetal) is selected from at least one of poly (ether dithioacetal), poly (ether ether dithioacetal), poly (ether dithioacetal dithioacetal), poly (ether dithioacetal ether dithioacetal dithioacetal), poly (ether ether dithioacetal ether ether dithioacetal, poly (ether diphenyl dithioacetal), poly (ether diphenyl ether dithioacetal), poly (ether diphenyl ether dithioacetal dithioacetal), and poly (ether dithioacetal ether napthalene). 
     
     
         4 . The method of  claim 1 , wherein the thiol compound is selected from at least one of a monothiol of the form R—SH, a dithiol of the form HSRSH, and a thio-alcohol of the form HSROH, wherein R is selected from at least one of an optionally substituted C 1 -C 30  aliphatic group and an optionally substituted C 6 -C 30  aromatic group. 
     
     
         5 . The method of  claim 4 , wherein the dithiol compound is selected from at least one of 1,2 ethanedithiol and 1,3 propanedithiol. 
     
     
         6 . The method of  claim 1 , wherein the solvent is selected from at least one of diethylether, tetrahydrofuran (THF), dioxin, and a chlorinated solvent. 
     
     
         7 . The method of  claim 6 , wherein the chlorinated solvent is selected from at least one of dichloromethane (DCM), trichloromethane (chloroform), dichloroethane, and dichlorobenzene. 
     
     
         8 . The method of  claim 1 , wherein the acid comprises a non-sulfonating acid. 
     
     
         9 . The method of  claim 8 , wherein the acid comprises trifluoroacetic acid. 
     
     
         10 . The method of  claim 1 , further comprising removing the poly (aryl ether thioacetal) from solution by precipitation. 
     
     
         11 . The method of  claim 1 , wherein the yield of the poly (aryl ether thioacetal) is greater than about 80%. 
     
     
         12 . A method of forming a PAEK from a homologous poly (aryl ether thioacetal), comprising:
 obtaining a poly (aryl ether thioacetal) homologous to a selected PAEK; and   reacting the poly (aryl ether thioacetal) with a mixture of t-butyl iodide and dimethyl sulfoxide;   wherein the resulting PAEK possesses an inherent viscosity approximately equal to that of a virgin PAEK.   
     
     
         13 . The method of  claim 12 , wherein the poly (aryl ether thioacetal) is selected from at least one of poly (ether dithioacetal), poly (ether ether dithioacetal), poly (ether dithioacetal dithioacetal), poly (ether dithioacetal ether dithioacetal dithioacetal), poly (ether ether dithioacetal ether ether dithioacetal, poly (ether diphenyl dithioacetal), poly (ether diphenyl ether dithioacetal), poly (ether diphenyl ether dithioacetal dithioacetal), and poly (ether dithioacetal ether napthalene). 
     
     
         14 . The method of  claim 12 , wherein the PAEK comprises one of PEK, PEEK, PEKK, PEKEKK, PEEKEEK, PEDK, PEDEK, PEDEKK, PEKEN, a polymer comprising a recurring unit having at least one of the structures of Formula (I): 
       
         
           
           
               
               
           
         
         and a polymer comprising a recurring unit having at least one of the structures of Formula (II): 
       
       
         
           
           
               
               
           
         
       
     
     
         15 . The method of  claim 12 , wherein the resulting PAEK further possesses a molecular weight distribution which is approximately equal to that of the virgin PAEK. 
     
     
         16 . The method of  claim 12 , further comprising intermixing a solvent with the poly (aryl ether thioacetal) in an amount sufficient to maintain the poly (aryl ether thioacetal) in solution for at least a portion of the duration of the reaction. 
     
     
         17 . The method of  claim 16 , wherein the solvent is selected from at least one of diethylether, tetrahydrofuran (THF), dioxin, dichloromethane (DCM), trichloromethane (chloroform), dichloroethane, and dichlorobenzene. 
     
     
         18 . A method of analyzing a PAEK by gel permeation chromatography (GPC), comprising:
 solubilizing the PAEK, wherein solubilizing modifies the PAEK to form a poly (aryl ether thioacetal);   dissolving the poly (aryl ether thioacetal) in a solvent suitable for GPC;   subjecting the poly (aryl ether thioacetal) to GPC.   
     
     
         19 . The method of  claim 18 , wherein the PAEK is selected from at least one of PEK, PEEK, PEKK, PEKEKK, PEEKEEK, PEDK, PEDEK, PEDEKK, PEKEN, a polymer comprising a recurring unit having at least one of the structures of Formula (I): 
       
         
           
           
               
               
           
         
       
       and a polymer comprising a recurring unit having at least one of the structures of Formula (II): 
       
         
           
           
               
               
           
         
       
     
     
         20 . The method of  claim 18 , wherein solubilizing the PAEK further comprises:
 dissolving the PAEK in a mixture comprising a solvent and an acid;   intermixing boron trifluoride-diethyl etherate and a thiol compound with the PAEK mixture so as to form a thioacetal in solution; and   isolating the thioacetal from solution.   
     
     
         21 . The method of  claim 18 , wherein the thiol compound is selected from at least one of a monothiol of the form R—SH, a dithiol of the form HSRSH, and a thio-alcohol of the form HSROH, wherein R is selected from at least one of an optionally substituted C 1 -C 30  aliphatic group and an optionally substituted C 6 -C 30  aromatic group. 
     
     
         22 . The method of  claim 21 , wherein the dithiol compound is selected from at least one of 1,2 ethanedithiol and 1,3 propanedithiol. 
     
     
         23 . The method of  claim 18 , wherein the solvent is selected from at least one of diethylether, tetrahydrofuran (THF), dioxin, and a chlorinated solvent. 
     
     
         24 . The method of  claim 23 , wherein the chlorinated solvent is selected from at least one of dichloromethane (DCM), trichloromethane (chloroform), dichloroethane, and dichlorobenzene. 
     
     
         25 . The method of  claim 18 , wherein the acid comprises a non-sulfonating acid. 
     
     
         26 . The method of  claim 25 , wherein the acid comprises trifluoroacetic acid. 
     
     
         27 . A method of forming a polymer matrix composite, comprising:
 prepregging a plurality of fibers in a solution, wherein the solution comprises a poly (aryl ether thioacetal); and   consolidating the fibers by application of at least one of heat and pressure.   
     
     
         28 . The method of  claim 27 , wherein said prepregging comprises one of solution dipping, solution spray, and fiber impregnation. 
     
     
         29 . The method of  claim 27 , wherein the poly (aryl ether thioacetal) is a derivative of at least one of PEK, PEEK, PEKK, PEKEKK, PEEKEEK, PEDK, PEDEK, PEDEKK, PEKEN, a polymer comprising a recurring unit having at least one of the structures of Formula (I): 
       
         
           
           
               
               
           
         
         and a polymer comprising a recurring unit having at least one of the structures of Formula (II): 
       
       
         
           
           
               
               
           
         
       
     
     
         30 . The method of  claim 27 , wherein the poly (aryl ether thioacetal) is selected from at least one of poly (ether dithioacetal), poly (ether ether dithioacetal), poly (ether dithioacetal dithioacetal), and poly (ether dithioacetal ether dithioacetal dithioacetal). 
     
     
         31 . A thioacetalized derivative of a PAEK. 
     
     
         32 . The thioacetalized derivative of a PAEK of  claim 31 , wherein the PAEK is selected from at least one of PEK, PEEK, PEKK, PEKEKK, PEEKEEK, PEDK, PEDEK, PEDEKK, PEKEN, a polymer comprising a recurring unit having at least one of the structures of Formula (I): 
       
         
           
           
               
               
           
         
         a polymer comprising a recurring unit having at least one of the structures of Formula (II): 
         and a polymer comprising a recurring unit having at least one of the structures of Formula (II): 
       
       
         
           
           
               
               
           
         
       
     
     
         33 . The thioacetalized derivative of a PAEK of  claim 32 , wherein the derivative comprises a recurring unit having the structure 
       
         
           
           
               
               
           
         
       
     
     
         34 . The thioacetalized derivative of a PAEK of  claim 32 , wherein the derivative comprises a recurring unit having the structure: 
       
         
           
           
               
               
           
         
       
     
     
         35 . The thioacetalized derivative of a PAEK of  claim 32 , wherein the derivative comprises a recurring unit having at least one of the structures: 
       
         
           
           
               
               
           
         
       
     
     
         36 . The thioacetalized derivative of a PAEK of  claim 32 , wherein the derivative comprises a recurring unit having the structure: 
       
         
           
           
               
               
           
         
       
     
     
         37 . The thioacetalized derivative of a PAEK of  claim 32 , wherein the derivative comprises a recurring unit having the structure: 
       
         
           
           
               
               
           
         
       
     
     
         38 . The thioacetalized derivative of a PAEK of  claim 32 , wherein the derivative comprises a recurring unit having the structure: 
       
         
           
           
               
               
           
         
       
     
     
         39 . The thioacetalized derivative of a PAEK of  claim 32 , wherein the derivative comprises a recurring unit having at least one of the structures: 
       
         
           
           
               
               
           
         
       
     
     
         40 . The thioacetalized derivative of a PAEK of  claim 32 , wherein the derivative comprises a recurring unit having the structure: 
       
         
           
           
               
               
           
         
       
     
     
         41 . The polymer matrix composite formed by the method of  claim 27 . 
     
     
         42 . The polymer matrix composite, comprising:
 a plurality of fibers; and   a PAEK selected from at least one of PEK, PEEK, PEKK, PEKEKK, PEEKEEK, PEDK, PEDEK, PEDEKK, PEKEN, a polymer comprising a recurring unit having at least one of the structures of Formula (I):   
       
         
           
           
               
               
           
         
         and a polymer comprising a recurring unit having at least one of the structures of Formula (II): 
       
       
         
           
           
               
               
           
         
       
     
     
         43 . A poly (aryl ether acetal) polymer comprising a soluble acetal derivative of a poly (aryl ether ketone) (“PAEK”) and an alcohol. 
     
     
         44 . The poly (aryl ether acetal) polymer of  claim 43 , wherein the PAEK is selected from at least one of poly (ether ketone) (“PEK”), poly (ether ether ketone) (“PEEK”), poly (ether ketone ketone) (“PEKK”), poly (ether ketone ether ketone ketone) (“PEKEKK”), poly (ether ether ketone ether ether ketone) (“PEEKEEK”), poly (ether diphenyl ketone) (“PEDK”), poly (ether diphenyl ether ketone) (“PEDEK”), poly (ether diphenyl ether ketone ketone) (“PEDEKK”), poly (ether ketone ether naphthalene) (“PEKEN”), a polymer comprising a recurring unit having at least one of the structures of Formula (I): 
       
         
           
           
               
               
           
         
         and a polymer comprising a recurring unit having at least one of the structures of Formula (II): 
       
       
         
           
           
               
               
           
         
       
     
     
         45 . The poly (aryl ether acetal) polymer of  claim 43 , wherein the poly (aryl ether acetal) is selected from at least one of poly (ether diacetal), poly (ether ether diacetal), poly (ether diacetal diacetal), poly (ether diacetal ether diacetal diacetal), poly (ether ether diacetal ether ether diacetal, poly (ether diphenyl diacetal), poly (ether diphenyl ether diacetal), poly (ether diphenyl ether diacetal diacetal), and poly (ether diacetal ether napthalene). 
     
     
         46 . The poly (aryl ether acetal) polymer of  claim 43 , wherein the alcohol is 1,2 ethanediol. 
     
     
         47 . The acetalized derivative of a PAEK of  claim 43 , wherein the derivative comprises a recurring unit having the structure: 
       
         
           
           
               
               
           
         
       
     
     
         48 . The acetalized derivative of a PAEK of  claim 43 , wherein the derivative comprises a recurring unit having the structure: 
       
         
           
           
               
               
           
         
       
     
     
         49 . The acetalized derivative of a PAEK of  claim 43 , wherein the derivative comprises a recurring unit having at least one of the structures: 
       
         
           
           
               
               
           
         
       
     
     
         50 . The acetalized derivative of a PAEK of  claim 43 , wherein the derivative comprises a recurring unit having the structure: 
       
         
           
           
               
               
           
         
       
     
     
         51 .