Method for the manufacture of poly(aliphatic ester-carbonate)s and uses thereof

1. An interfacial process for preparing a poly(aliphatic ester-carbonate), the process comprising:

providing an initial polymerization reaction mixture comprising an C 6-20 aliphatic dicarboxylic acid, a bisphenol, an alkali hydroxide, and optionally a catalyst in a solvent system comprising water and an immiscible organic solvent;

adding an initial portion of a carbonyl dihalide over a first time period while maintaining the reaction at a first pH from 7 to less than 8; and

adding a second portion of the carbonyl dihalide over a second, subsequent time period while maintaining the reaction pH at a second pH from 9 to 12, to provide a product polymerization mixture comprising the poly(aliphatic ester-carbonate),

wherein the amount of the alkali hydroxide in the initial polymerization reaction mixture is an amount effective to increase the fraction of the first time period at a measured pH of 7 to 8 compared to the same reaction mixture with a higher amount of the alkali hydroxide in the initial polymerization mixture, and

wherein no additional alkali hydroxide is added after providing the initial polymerization reaction mixture and before adding the initial portion of the carbonyl dihalide, or after the adding the initial portion of the carbonyl dihalide.

2. The process of claim 1 , wherein the fraction of the first time period at the measured pH of 7 to 8 is at least 70% of the total duration of the first time period.

3. The process of claim 1 , wherein the amount of the alkali hydroxide in the initial polymerization reaction mixture is an amount effective to provide the poly(aliphatic ester-carbonate) having a —COOH end group content of less than 75 parts per million by weight, as measured by 31 P nuclear magnetic resonance spectroscopy.

4. The process of claim 1 , wherein

the first time period is more than 9 minutes; and

the second time period is 10 minutes or greater.

5. The process of claim 1 , wherein

the first pH is from 7.0 to 8.0; and

the second pH is from 9.7 to 10.9.

6. The process of claim 1 , wherein

the initial portion of the carbonyl dihalide is 28 to 50% of the total amount of the initial portion of the carbonyl dihalide and the second portion of the carbonyl dihalide used in the process.

7. The process of claim 1 , wherein the providing the initial reaction mixture comprises combining the C 6-20 aliphatic dicarboxylic acid, the bisphenol, the water, the alkali hydroxide, the immiscible organic solvent, and optionally the catalyst before adding the initial portion of the carbonyl dihalide.

8. The process of claim 7 , comprising pre-combining the C 6-20 aliphatic dicarboxylic acid, the bisphenol, the water, the immiscible organic solvent, and optionally the catalyst; and then adding the alkali hydroxide before adding the initial portion of the carbonyl dihalide.

9. The process of claim 1 , wherein the providing the initial polymerization reaction mixture comprises pre-combining the bisphenol, the water, the immiscible organic solvent, and optionally the catalyst; and then adding the C 6-20 aliphatic dicarboxylic acid and the alkali hydroxide before adding the initial portion of the carbonyl dihalide.

10. The process of claim 1 , wherein the providing the initial polymerization reaction mixture comprises combining the bisphenol, the water, the alkali hydroxide, the immiscible organic solvent, and optionally the catalyst; and then adding the C 6-20 aliphatic dicarboxylic acid with the addition of the initial portion of the carbonyl dihalide.

11. The process of claim 9 , wherein

the C 6-20 aliphatic dicarboxylic acid is added as a solid or as a slurry separately from the alkali hydroxide; or

the C 6-20 aliphatic dicarboxylic acid is pre-dissolved in water with the alkali hydroxide, and then added.

12. The process of claim 1 , wherein

the C 6-20 aliphatic dicarboxylic acid is azelaic acid, sebacic acid, or dodecanedioic acid;

the bisphenol is bisphenol A;

the alkali hydroxide is sodium hydroxide; and

the carbonyl dihalide is carbonyl dichloride.

13. The process of claim 1 , wherein

the C 6-20 aliphatic dicarboxylic acid is present in the initial polymerization reaction mixture in an amount of 5 to 12 mole percent, based on the moles of the bisphenol.

14. The process of claim 1 , wherein the catalyst is a tertiary amine catalyst, and is present in the initial polymerization reaction mixture in an amount of 0.75 to 3.0 mole percent, based on the moles of the bisphenol.

15. A poly(aliphatic ester-carbonate) made by the process of claim 1 .

16. The poly(aliphatic ester-carbonate) of claim 15 , having

a weight average molecular weight of 10,000 to 50,000 Dalton, as measured by gel permeation chromatography, based on bisphenol A polycarbonate standards;

5 to 12 mole percent of units derived from the C 6-20 aliphatic dicarboxylic acid;

a glass transition temperature of 110 to 145° C.;

a decrease in weight average molecular weight of less than 30% after heat aging a molded sample for 4 weeks at 85° C. and 85% humidity;

a decrease in weight average molecular weight of less than 60% after heat aging a molded sample for 8 weeks at 85° C. and 85% humidity; and

a —COOH end group content of less than 75 parts per million by weight, as measured by 31 P nuclear magnetic resonance spectroscopy.

17. A polymer composition comprising the poly(aliphatic ester-carbonate) of claim 15 , and further comprising an additive.

18. An article subject to conditions of heat and humidity, wherein the article comprises the poly(aliphatic ester-carbonate) of claim 15 .

19. The process of claim 1 , further comprising quantifying carboxylic acid end group content in the poly(aliphatic ester-carbonate), wherein the quantifying comprises:

derivatizing a carboxylic acid end group in the polymer with 2-chloro-1,3,2-benzodioxaphosphole to provide a derivatized end group in the presence of a known amount of a reactive standard; and

quantifying the amount of the derivatized end group via 31 P nuclear magnetic resonance spectroscopy relative to the reactive standard.