Poly(phenylene ether) copolymer process and compositions

1. A process for forming a poly(phenylene ether)

copolymer, the process comprising:

reacting a monohydric phenol comprising 2-methyl-6-phenylphenol and a dihydric phenol in the presence of molecular oxygen, a polymerization catalyst comprising a metal ion and at least one amine ligand, and a solvent to form a copolymer of 2-methyl-6-phenylphenol and the dihydric phenol; wherein:

the monohydric phenol comprises, based on the total weight of monohydric phenol and dihydric phenol, less than 0.5 weight percent of monohydric phenols having identical substituents in the 2- and 6-positions of the phenolic ring;

the copolymer comprises less than 0.005 weight percent of di(C 1 -C 6 -alkyl)amino groups, based on the weight of the copolymer;

the copolymer has an absolute number average molecular weight of 1,000 to 10,000 grams/mole, calculated from integrated areas under resonance peaks in the 1 H-NMR spectrum of the copolymer; and

the solvent comprises, based on the total weight of the solvent, at least 95 weight percent of a C 1 -C 3 alcohol selected from the group consisting of methanol, ethanol, 1-propanol, and 2-propanol.

2. The process of claim 1 , wherein the polymerization catalyst comprises copper ion, bromide ion, and N,N′-di-tert-butylethylenediamine.

3. The process of claim 1 , wherein the copolymer has an absolute number average molecular weight of 1,000 to 5,000 grams/mole.

4. The process of claim 1 , wherein the copolymer comprises 80 to 99 weight percent of repeat units derived from the monohydric phenol and 1 to 20 weight percent of repeat units derived from the dihydric phenol.

5. The process of claim 1 , wherein the dihydric phenol has the structure:

wherein each occurrence of R 1 and R 2 and R 3 and R 4 is independently selected from the group consisting of hydrogen, halogen, unsubstituted or substituted C 1 -C 12 hydrocarbyl provided that the hydrocarbyl group is not tertiary hydrocarbyl, C 1 -C 12 hydrocarbylthio, C 1 -C 12 hydrocarbyloxy, and C 2 -C 12 halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms; z is 0 or 1; and Y is selected from the group consisting of

wherein each occurrence of R 5 -R 8 is independently hydrogen, C 1 -C 12 hydrocarbyl, or C 1 -C 6 hydrocarbylene wherein the two occurrences of R 5 collectively form a C 4 -C 12 alkylene group.

6. The process of claim 5 , wherein z is 1.

7. The process of claim 1 , wherein the dihydric phenol comprises 2,2-bis(3,5-dimethyl-4-hydroxyphenol)propane.

8. The process of claim 1 , wherein the amine ligand comprises a di(C 1 -C 6 -alkyl)amine; and wherein the copolymer of 2-methyl-6-phenylphenol and the dihydric phenol comprises less than 0.005 weight percent of di(C 1 -C 6 -alkyl)amino groups, based on the weight of the copolymer.

9. The process of claim 1 , wherein the solvent comprises at least 99 weight percent methanol.

10. The process of claim 1 , wherein:

the dihydric phenol comprises 2,2-bis(3,5-dimethyl-4-hydroxyphenol)propane;

the at least one amine ligand comprises di(n-butyl)amine;

the solvent comprises at least 99 weight percent methanol; and

the copolymer of 2-methyl-6-phenylphenol and the dihydric phenol comprises less than 0.005 weight percent of di(n-butyl)amino groups, based on the weight of the copolymer.

11. A poly(phenylene ether) copolymer derived from a monohydric phenol comprising 2-methyl-6-phenylphenol and a dihydric phenol, wherein:

the monohydric phenol comprises, based on the total weight of monohydric phenol and dihydric phenol, less than 0.5 weight percent of monohydric phenols having identical substituents in the 2- and 6-positions of the phenolic ring;

the copolymer comprises less than 0.005 weight percent of di(C 1 -C 6 -alkyl)amino groups, based on the weight of the copolymer; and

the copolymer has an absolute number average molecular weight of 1,000 to 10,000 grams/mole, calculated from integrated areas under resonance peaks in the 1 H-NMR spectrum of the copolymer.

12. The poly(phenylene ether) copolymer of claim 11 , wherein the copolymer has an absolute number average molecular weight of 1,000 to 5,000 grams/mole.

13. The poly(phenylene ether) copolymer of claim 11 , wherein the copolymer comprises 80 to 99 weight percent of repeat units derived from the monohydric phenol and 1 to 20 weight percent of repeat units derived from the dihydric phenol.

14. A poly(phenylene ether) copolymer having the structure:

wherein:

R is independently at each occurrence methyl or di(n-butyl)aminomethyl; provided that the copolymer comprises, on average, less than or equal to 0.005 weight percent of di(n-butyl)aminomethyl groups, based on the weight of the copolymer; and

x and y are independently at each occurrence zero to 50, provided that the sum of x and y is 4 to 53.

15. The poly(phenylene ether) copolymer of claim 14 , wherein the sum of x and y is 8 to 20.

16. A curable composition, comprising a thermosetting resin and the poly(phenylene ether) copolymer of claim 11 .

17. A cured composition obtained by heating the curable composition of claim 16 for a time and temperature sufficient to effect curing.

18. An article comprising the cured composition of claim 17 .