DuPont process (NG3)
PET or polyethylene terephthalate

Unlike conventional technologies, the process proposed by the DuPont company, currently under development, performs PCS on a low-molecular-weight prepolymer ( ${\overline{M}}_{{}_n}$ 3,000 instead of 20,000). Because of its greater mobility in the glassy state, this "prepolymer" crystallizes rapidly. Another important point is that the crystalline morphology is much more homogeneous and, as a result, the temperature at the start of melting is higher (suppression of the second endotherm), making it possible to increase the PCS temperature from 210 to 230...