A method of preparing an aliphatic copolyester by mixing a first compound defined by the equation: and a catalyst, and adding a second compound defined by and a lactide, wherein the second compound and the lactide have a total weight less than the first compound, wherein a is 10-230, b, d and e have a ratio of 10-35:10-35:80-30, c is 1-4, and f is 1-10. The method further adds the second compound and the lactide, wherein the second compound and the lactide have a total weight less than the first compound, the second compound and the lactide in the prior mixing step. The method further adds the second compound and the lactide, wherein the second compound and the lactide have a total weight less than the first compound, the second compound and the lactide in of the prior mixing steps.