Synthesis of ethylene terephthalate and ethylene naphthalate (PET‐PEN) block‐co‐polyesters with defined surface qualities by tailoring segment composition

Ethylene terephthalate and ethylene naphthalate oligomers of defined degree of polymerization were synthesized via chemical recycling of the parent polymers. The oligomers were used as defined building blocks for the preparation of novel block‐co‐polyesters having tailored sequence compositions. The sequence lengths were systematically varied using Design of Experiments. The dispersive surface energy and the specific desorption energy of the co‐polymers were determined by inverse gas chromatography. The study shows that polyethylene terephthalate‐polyethylene naphthalate (PET‐PEN) block‐co‐polyesters of defined sequence lengths can be prepared. Furthermore, the specific and dispersive surface energies of the obtained block‐co‐polyesters showed a linear dependence on the oligomer molecular weight and it was possible to regulate and control their interfacial properties. In contrast, with the corresponding random‐block‐co‐polyesters no such dependence was found. The synthesized block‐co‐polyesters could be used as polymeric modifying agents for stabilizing PET‐PEN polymer blends. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40731.