Polyethylenes and Polystyrenes with Carbazole Fluorescent Tags

Abstract

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.

Thermal and Dielectric Stability of Functional Photo-cross-linkable Carbazole-Modified Polypropylene

“…Beside these approaches, copolymerization of the olefin with an olefin bearing the chromophore, i.e., carbazole as in the present study, is the most cost-effective method to access these materials. Most cases in literature deal with the synthesis of PE-based copolymers, − and studies about the preparation of PP-based are quite rare. − In the latter case, copolymers of PP with 9 H -alkenyl carbazole, in which the olefin and the photoactive group are linked by spacers of different length (3 and 9 carbons long), have been synthesized by using metallocene and postmetallocene catalysts. One of these research groups has investigated this kind of PP copolymers as fluorescent probes to track the effect of PP microplastics on organism in aquatic environments.…”