Synthesis of a series of cyclic oligo(alkylidene isophthalate)s by cyclo-depolymerisation

The synthesis of series of cyclic oligo(alkylidene isophthalate)s by the cy clo-depolymerisation of the corresponding linear polymers has been investig ated and the yields of the various cyclic oligomers determined as a functio n of the polymer structure. With up to 15 ring atoms per repeat unit the ma in products are the cyclic dimers (up to 90% yield) with smaller amounts of the larger rings. When there are more than 16 ring atoms per repeat unit t he main products are the cyclic monomers (up to 72% yield) with smaller amo unts of the larger rings. Possible applications for such cyclic oligomers a re discussed including their possible use as feedstocks for environmentally friendly entropically driven ring-opening polymerisations and as building blocks for novel polymeric structures. (C) 1999 Elsevier Science Ltd. All r ights reserved.