| abstract |
A method of making a polyester block copolymer comprising copolymerizing polyethylene terephthalate with polyethylene naphthalate in the presence of a catalyst to form a polyester block copolymer. The catalyst is a composite of cobalt, chromium, manganese and cerium. The molecular weight of polyethylene terephthalate is from 19,000 g/mol to 21,000 g/mol. The polyethylene naphthalate has a molecular weight of from 18,000 g/mol to 24,000 g/mol. |