Two zinc complexes bearing NHC ligands were synthesized and fully characterized by NMR spectroscopy. Their behavior in the Ring-Opening Polymerization (ROP) of lactides was investigated under several conditions of reaction. They showed to be efficient initiators, producing polylactides with molecular weights depending on the cocatalysts. Microstructural analysis of poly(rac-LA) by 1 H NMR spectroscopy revealed a slightly enriched-heterotactic PLAs with P r values up to 0.66. Inspection of the kinetic parameters for L-LA and rac-LA allowed to compare the k obs of the studied complexes 1 and 2 under different conditions, and showed that propagations present the usual pseudo-first-order dependence on monomer concentration. Hence, some reactivity studies were carried out, addressed to unravel the nature of the active species in the polymerization processes conducted in the presence of different catalytic systems, namely zinc complexes alone and in combination with neutral or ionic cocatalysts.

The increasingly intense consumption of plastics and, above all, their improper disposal in the environment are causing serious environmental concerns. Great efforts have been made for the development of new methods aimed at facilitating and speeding up the identification and sorting of different materials in the plastic recycling process. In this field, new strategies based on fluorescent tagging have been developed. This work concerns the synthesis and characterization of new fluorescent copolymers of polyethylene (PE) and polystyrene (PS), which are among the most produced and consumed plastic materials. The synthesized copolymers are potentially suitable for use as fluorescent markers of PE and PS. Ethylene-co-N-pentenyl carbazole (P(E-co-PK)) and styrene-co-4-(N-carbazolyl)methyl styrene (P(S-co-SK)) copolymers were prepared by Ziegler–Natta and free radical polymerization, respectively. If excited at 300 nm, both P(E-co-PK)s and P(S-co-SK)s give fluorescence emissions resulting in them being optically active. Moreover, due to the low amount of fluorescent units, they show chemico-physical properties such as those of their corresponding homopolymers (PE and PS). P(E-co-PK)s and P(S-co-SK)s have been also tested as fluorescent markers of PE and PS. The experimental results demonstrate that from PE/P(E-co-PK) and PS/P(S-co-SK) blends prepared using only 1% by weight of fluorescent copolymer, distinguishable fluorescent emissions can be still detected.