Finished tanned leather are usually covered by a thin polymeric layer. This layer has the scope to change the morphological aspect of the last leather layer, as well as to improve the impermeabilization properties. Often, the finished product is refused by the final client and tanneries must restore significant quantity of materials. Therefore, it is very important to remove this finished polymeric layer, to recover the underneath tanned leather and to predispose it to a new finishing. The bonding between the polymeric film and leather is so strong that, today, only a blade shaving process can perform this separation at the expenses of also removing a layer of tanned leather and consequently reduce the leather thickness. Here, a novel separation method was developed, based on the significant difference in the dilation properties between the tanned hide and the polymeric film at low temperature. The use of cryogenic fluids, in particular the direct application of liquid nitrogen, can freeze the polymeric layer under the glass transition temperature and then inducing a brittle behaviour. The result is an easy separation without any alteration of the tanned leather layer. Thus, the process here developed, allows the reuse of the tanned leather towards a new life in the respect of the circular economy principles.

In the last decades bioresorbable and biodegradable polymers have gained a very good reputation both in research and in industry thanks to their unique characteristics. They are, indeed, able to ensure high performances and biocompatibility, at the same time avoiding post-healing surgical interventions for devices removal. In the medical device industrial use of such biopolymers, it is widely known that product formulation and manufacturing need to follow specific procedures in order to ensure both proper mechanical properties and desired degradation profile. Moreover, also the sterilization method is crucial and its impact on physical properties is generally underestimated. In this work we focused our attention on the effect of different terminal sterilization methods on two commercially available poly(L-lactide-co-ε-caprolactone) with equivalent chemical composition (70% PLA and 30% PCL) and relatively similar initial molecular weight, but different chains arrangement and crystallinity. Results obtained show that crystallinity plays a key role, helping in preserving the narrow distribution of chains and, as a consequence, defined physical properties. These statements can be used as guidelines for a better choice of the most adequate biodegradable polymers in the production of resorbable medical devices.