PLA-*g*-Poly(Vinyl Pyrrolidone) (PLA-*g*-PVP)

A PLA film was treated with a solution of N-vinyl pyrrolidone (NVP) in methanol and AgNO3 using 60Co γ−radiation polymerization at a dose of 1–30 kGy at room temperature. After washings, a PLA-*g*-PVP film was formed on the surface. Silver nanoparticles were also immobilized on the film surface. A surface grafting ratio, in the range of 25–49%, is assessed by the FTIR ratio of the bands at 1660 cm<sup>−</sup><sup>1</sup> of PVP and the sum of the bands at 1660 cm<sup>−</sup><sup>1</sup> and 1750 cm<sup>−</sup><sup>1</sup> of PLA [98]. There is no indication of the grafting degree of PVP onto the PLA backbone. It is noted, however, that PVP grafting significantly accelerated PLA degradation and does not impede cell proliferation [99]. Controlled variation in the grafting ratio could broaden the applications of this material in tissue engineering scaffolds, drug delivery, and the prevention of post-surgical adhesion.

## 2.2.6. Anionic Derivatization

The anionic derivatization of PCL was described by Ponsart et al. [19]. It is a remarkably powerful one-pot two-step method for grafting many types of substituents on the PCL backbone. This method is theoretically applicable to many polyesters, but it leads to varying degrees of chain cleavage depending on the nature of the polyester, due to

the anionic medium caused by the presence of lithium diisopropylamide. Even though PCL is relatively resistant to this basic medium, which is not the case with PLA, There are still many chain breakings. Nevertheless, El Habnouni et al. applied the method to the surface of the PLA film and nanofibers in a non-solvent medium that causes only moderate-chain scissions and allows for the preparation of functional PLA surfaces [100]. In particular, this approach was exploited with propargylated PLA allowing the grafting of bioactive polymers through CuAAC or thiol-yne click reactions. Therefore, anti-biofilm and bactericidal PLA surfaces were obtained by the reaction of α-azido QPDMAEMA (quaternized poly(2-(dimethylamino)ethyl methacrylate)) or thiol-functional polyaspartamide derivatives (Figure 21) [101,102].

**Figure 21.** General synthesis scheme of PLA-*g*-antibacterial polymers from propargylated PLA surface (adapted from Sardo et al. [102] and El Habnouni et al. [101]).

The main copolymers grafted onto the PLA chain, precursors, copolymers and literature references are summarized in Table 3.


**Table 3.** Main PLA-based grafted copolymers according to literature.
