Abstract: The invention concerns a method for upgrading composite materials and polyethylene terephthalate, which consists in carrying out solvolysis of the composite materials and polyethylene terephthalate, optionally in the presence of a catalyst, and in separating the product of the solvolysis containing the degradation products of the matrix of the composite materials and of the polyethylene terephthalate from the other constituents of the composite materials and other possible impurities from the polyethylene terephthalate.

Abstract: The invention relates to the field of polymer chemistry. It features a method for obtaining polyols consisting in a first step in reacting glycols, i.e. plurialcohols with a functionality at least equal to two (MEG,DEG,DPG, . . . ) on polyethyleneterephthalate (PET) in the presence of a transesterefication catalyst (CAT) (MEG,DEG,DPG; . . . ), on polyethyleneterephthalate (PET) in the presence of a glycolysis catalyst (CAT), then in a last step, comprises, in distilling the free glycols. The method is characterized in that a step subsequent to the first and prior to, or simultaneous with, the last step, comprises the glycolysis catalyst deactivation by a deactivating agent (DES). As an example, the glycolysis reaction catalyst (CAT) is one of the agents of the group comprising zinc acetate and manganese acetate, amines such as triethylamine and tributylamine, and the selected deactivating agent is phosphoric acid at 85%.