Polylactide (PLA) is presently the most studied bioderived polymer because, in addition to its established position as a material for biomedical applications, it can replace mass production plastics from petroleum. However, some drawbacks of polylactide such as insufficient mechanical properties at a higher temperature and poor shape stability have to be overcome. One of the methods of mechanical and thermal properties modification is crosslinking which can be achieved by different approaches, both at the stage of PLA-based materials synthesis and by physical modification of neat polylactide. This review covers PLA crosslinking by applying different types of irradiation, i.e., high energy electron beam or gamma irradiation and UV light which enables curing at mild conditions. In the last section, selected examples of biomedical applications as well as applications for packaging and daily-use items are presented in order to visualize how a variety of materials can be obtained using specific methods.

The ongoing interest of researchers in bioderived polylactide (PLA) is due to the current tendency to replace petroleum-based plastics with polymers from renewable resources. Polylactide fits this trend because of its mechanical properties resembling those of some petroleum-based polymers commonly applied in daily life and because of its degradability. Added value is the excellent biocompatibility of PLA thanks to which it has found an application in biomedicine. This great interest in polylactide is reflected in the literature. Crosslinking of polylactide was also studied by many authors as an easy method of the improvement and the modification of its properties (thermal, mechanical, rheological, degradability) according to requirements of existing or possible applications. In the present review, the examples of polylactide and its copolymers crosslinking by chemical approaches described in the literature are presented. Thus, chemical methods including peroxide-induced radical crosslinking and crosslinking by coupling of functional PLA prepolymers via condensation/addition reactions are discussed. The results of PLA modification and examples of new, interesting materials obtained via different crosslinking methods are shown.

In the past few years, we have observed the continuous emergence of new polymeric materials capable of reversibly adapting to their environment. Polymer networks containing reversibly formed covalent bonds may be considered as such materials. Among the various types of networks based on chemically different polymers, there are also polyesters. The increasing interest in polyesters is due to their biodegradability and biocompatibility and the fact that their production may be based on renewable resources. Stimuli-responsive reversibly crosslinked polyesters are designed as shape-memory or self-healing materials e.g. for biomedical applications; however, their capability for thermoplastic behavior after appropriate actuation is also important in processing because of the polyesters’ established position as technological commodity plastics. This review covers cases of reversible polyester network preparation presented in the literature, classifying them according to the used method or the type of chemical reactions enabling reversible network rearrangement. Only a selected few chemistries have been used to create reversible polyester networks to date. Thus, in this paper, the prepared polyester networks which were reversible by the application of the Diels–Alder chemistry, dimerization of the cinnamoyl/coumarin group or by catalyzed transesterification reactions are described, in particular with respect to the methods for their synthesis and studies of their reversibility. The effects of the network reversibility such as shape-memory and/or self-healing properties or the capability for reprocessing/recycling are presented. The features specific to polyesters, e.g. the capability for crystallization influencing the formation and behavior of discussed networks, are particularly highlighted. Finally, the strengths and weaknesses of the attempted approaches are discussed and suggestions for new methods are made.