Method of making block copolymers by solid state polymerization

Abstract

A method of preparing block copolymers by solid state polymerization is described. A mixture of a partially crystalline polycarbonate having activated terminal aryloxy groups, for example terminal methyl salicyl groups, when heated together with an oligomeric polyester having reactive terminal hydroxy groups under solid state polymerization conditions affords block copolymers. The activated terminal aryloxy groups play a key role in preserving the block lengths of the starting materials. A control sample in which the partially crystalline polycarbonate lacks activated terminal aryloxy groups, for example polycarbonates substituted by phenol, affords a much lower molecular weight, more highly randomized copolymer product. The product block copolymers are useful as “weatherable” plastic materials.

What is claimed is:  
     
         1 . A method of preparing block copolymers, said method comprising contacting a partially crystalline polycarbonate starting material (A) comprising activated terminal aryloxy groups with at least one polymeric species (B) comprising reactive terminal hydroxy groups under solid state polymerization conditions to afford a product block copolymer.  
     
     
         2 . A method according to  claim 1  wherein said partially crystalline polycarbonate starting material (A) comprises terminal aryloxy groups having structure I  
       
         
           
           
               
               
           
         
       
       wherein R 1  is independently at each occurrence a C 1 -C 20  aliphatic radical, C 4 -C 20  cycloaliphatic radical, C 4 -C 20  aromatic radical; R 2  is independently at each occurrence a halogen atom, nitro group, cyano group, C 1 -C 20  alkoxycarbonyl group, C 1 -C 20  acyl group, C 4 -C 20  cycloalkoxycarbonyl group, C 6 -C 20  aryoxycarbonyl group, C 1 -C 20  alkylaminocarbonyl group, C 2 -C 40  dialkylaminocarbonyl group, or a C 1 -C 20  perfluoroalkyl group; p is an integer having a value 0 to 4, and q is an integer having a value of 1 to 5.  
     
     
         3 . A method according to  claim 1  wherein said partially crystalline polycarbonate starting material (A) comprises structural units derived from at least one dihydroxy aromatic compound and at least one diaryl carbonate II  
       
         
           
           
               
               
           
         
       
       wherein R 1  is independently at each occurrence a C 1 -C 20  aliphatic radical, C 4 -C 20  cycloaliphatic radical, C 4 -C 20  aromatic radical; R 2  is independently at each occurrence a halogen atom, nitro group, cyano group, C 1 -C 20  alkoxycarbonyl group, C 1 -C 20  acyl group, C 4 -C 20  cycloalkoxycarbonyl group, C 6 -C 20  aryoxycarbonyl group, C 1 -C 20  alkylaminocarbonyl group, C 2 -C 40  dialkylaminocarbonyl group, or a C 1 -C 20  perfluoroalkyl group; p is an integer having a value 0 to 4, and q is an integer having a value of 1to 5.  
     
     
         4 . A method according to  claim 3  wherein diaryl carbonate II is selected from the group consisting of bis(2-methoxycarbonylphenyl) carbonate, bis(2-ethoxycarbonylphenyl) carbonate, bis(2-butoxycarbonylphenyl) carbonate, and bis(2,4,6-trifluorophenyl) carbonate.  
     
     
         5 . A method according to  claim 3  wherein said dihydroxy aromatic compound is a bisphenol having structure III  
       
         
           
           
               
               
           
         
       
       wherein R 3  is independently at each occurrence a halogen atom, nitro group, cyano group, C 1 -C 20  alkyl group, C 4 -C 20  cycloalkyl group, or C 6 -C 20  aryl group; n and m are independently integers 0-4; and W is a bond, an oxygen atom, a sulfur atom, a SO 2  group, a C 1 -C 20  aliphatic radical, a C 6 -C 20  aromatic radical, a C 6 -C 20  cycloaliphatic radical or the group  
       
         
           
           
               
               
           
         
       
       wherein R 4  and R 5  are independently a hydrogen atom, C 1 -C 20  alkyl group, C 4 -C 20  cycloalkyl group, or C 4 -C 20  aryl group; or R 4  and R 5  together form a C 4 -C 20  cycloaliphatic ring which is optionally substituted by one or more C 1 -C 20  alkyl, C 6 -C 20  aryl, C 5 -C 21  aralkyl, C 5 -C 20  cycloalkyl groups or a combination thereof.  
     
     
         6 . A method according to  claim 1  wherein said partially crystalline polycarbonate starting material (A) comprises 2-methoxycarbonylphenoxy terminal aryloxy groups IV  
       
         
           
           
               
               
           
         
       
       and structural units derived from bisphenol A.  
     
     
         7 . A method according to  claim 1  wherein said polymeric species (B) comprising reactive terminal hydroxy groups is selected from the group consisting of polyesters, polycarbonates, polyethers, polyetherketones, polyethersulfones, and polyetherimides.  
     
     
         8 . A method according to  claim 1  wherein said polymeric species (B) comprising reactive terminal hydroxy groups comprises structural units selected from the group consisting of 
 (1) polyester structural units corresponding to structure V  
                     
 wherein R 6  and R 7  are independently at each occurrence a halogen atom, C 1 -C 20  aliphatic radical, C 4 -C 20  cycloaliphatic radical, or a C 4 -C 20  aromatic radical, and r and s are independently integers having values from 0 to 4; and  
 (2) polycarbonate structural units corresponding to structure VI  
                     
 wherein R 8  is independently at each occurrence a halogen atom, nitro group, cyano group, C 1 -C 20  alkyl group, C 4 -C 20  cycloalkyl group, or C 6 -C 20  aryl group; n and m are independently integers 0-4; and W is a bond, an oxygen atom, a sulfur atom, a SO 2 group, a C 1 -C 20  aliphatic radical, a C 6 -C 20  aromatic radical, a C 6 -C 20  cycloaliphatic radical or the group  
                     
 wherein R 4  and R 5 are independently a hydrogen atom, C 1 -C 20  alkyl group, C 4 -C 20  cycloalkyl group, or C 4 -C 20  aryl group; or R 4  and R 5  together form a C 4 -C 20  cycloaliphatic ring which is optionally substituted by one or more C 1 -C 20  alkyl, C 6 -C 20  aryl, C 5 -C 2 , aralkyl, C 5 -C 20  cycloalkyl groups or a combination thereof.  
 
     
     
         9 . A method according to  claim 8  wherein said polymeric species (B) comprising reactive hydroxy groups is a polyester comprising structural units VII  
       
         
           
           
               
               
           
         
       
       and having a degree of polymerization of at least about 4.  
     
     
         10 . A method according to  claim 1  wherein said partially crystalline polycarbonate starting material (A) has a percent endcap between about 50 and about 100 percent.  
     
     
         11 . A method according to  claim 1  wherein starting material (B) is a copolymer prepared by heating in the absence of a catalyst, a mixture comprising resorcinol, diphenyl terephthalate, diphenyl isophthalate, and a catalyst.  
     
     
         12 . A method according to  claim 11  wherein said diphenyl terephthalate and said diphenyl isophthalate have a molar ratio, said molar ratio being in a range between about 1 to 10 and about 10 to 1.  
     
     
         13 . A method according to  claim 1  wherein starting material (B) is a copolymer prepared by interfacial polymerization of resorcinol with terephthaloyl dichloride and isophthaloyl dichloride.  
     
     
         14 . A method according to  claim 13  wherein said terephthaloyl dichloride and said isophthaloyl dichloride have a molar ratio, said molar ratio being in a range between about 1 to 10 and about 10 to 1.  
     
     
         15 . A method according to  claim 1  wherein starting material (A) has a crystallinity in a range between about 15 and about 40 percent.  
     
     
         16 . A method according to  claim 1  wherein said solid state polymerization conditions comprise heating at a temperature between about 100° C. about 240° C. for a period of between about 1 and about 10 hours.  
     
     
         17 . A method according to  claim 1  further comprising preparing a mixture of starting materials (A) and (B).  
     
     
         18 . A method according to  claim 17  comprising dry mixing starting material (A) with starting material (B).  
     
     
         19 . A method according to  claim 17  comprising precipitating a mixture of starting materials (A) and (B) from solution.  
     
     
         20 . A method according to  claim 1  wherein starting materials (A) and (B) have a weight ratio in a range between about 0.01 and about 100 grams starting material (A) per gram starting material (B).  
     
     
         21 . A method according to  claim 1  wherein the product copolymer has a measurable degree of blockiness corresponding to blocklengths which are at least 50 percent longer than the corresponding random distribution of structural elements.  
     
     
         22 . A molded article comprising the product copolymer prepared by the method of  claim 1 .  
     
     
         23 . An article according to  claim 22  which is a multilayer article.  
     
     
         24 . A method of preparing copolyestercarbonates, said method comprising contacting a partially crystalline bisphenol A polycarbonate comprising terminal 2-methoxycarbonyl phenoxy end groups IV  
       
         
           
           
               
               
           
         
       
       with at least one polyester comprising reactive hydroxyl groups under solid state polymerization conditions to afford a product copolyestercarbonate.  
     
     
         25 . A method according to  claim 24  wherein said partially crystalline bisphenol A polycarbonate is prepared by a method comprising melt reaction of bis(methyl salicyl) carbonate with bisphenol A.  
     
     
         26 . A method according to  claim 25  wherein said melt reaction affords a partially crystalline bisphenol A polycarbonate directly.  
     
     
         27 . A method according to  claim 26  wherein said partially crystalline bisphenol A polycarbonate has a percent endcap of between about 50 and about 100 percent.  
     
     
         28 . A method according to  claim 26  wherein said melt reaction affords an amorphous bisphenol A polycarbonate having a percent endcap between about 90 and about 100 percent.  
     
     
         29 . A method according to  claim 25  wherein said polyester comprises structural units corresponding to structure V  
       
         
           
           
               
               
           
         
       
       wherein R 6  and R 7  are independently at each occurrence a halogen atom, C 1 -C 20  aliphatic radical, C 4 -C 20  cycloaliphatic radical, or a C 4 -C 20  aromatic radical, and r and s are independently integers having values from 0 to 4.  
     
     
         30 . A method according to  claim 29  wherein said polyester is a polyester prepared by heating in the absence of a catalyst, a mixture comprising resorcinol, diphenyl terephthalate, diphenyl isophthalate, and a catalyst.  
     
     
         31 . A method according to  claim 30  wherein said diphenyl terephthalate and said diphenyl isophthalate have a molar ratio, said molar ratio being in a range between about 1 to 10 and about 10 to 1.  
     
     
         32 . A method according to  claim 29  wherein said polyester is prepared by a method comprising the interfacial reaction of resorcinol with a mixture of isophthaloyl dichloride and terephthaloyl dichloride.  
     
     
         33 . A method according to  claim 32  wherein said isophthaloyl dichloride and said terephthaloyl dichloride have a molar ratio, said molar ratio being in a range between about 1 to 10 and about 10 to 1.  
     
     
         34 . A method according to  claim 25  wherein said partially crystalline bisphenol A polycarbonate has a crystallinity in a range between about 20 and about 40 percent.  
     
     
         35 . A method according to  claim 25  wherein said solid state polymerization conditions comprise heating at a temperature in a range between about 100 and 240° C. for a period between about 2 and about 9 hours.  
     
     
         36 . A molded article comprising the product copolymer prepared by the method of  claim 25 .  
     
     
         37 . An article according to  claim 36  which is a multilayer article.