Photoactive linear and hyperbranched polyesters based on 4-methylcyclohexanone and 4-tert-butylcyclohexanone moieties in the main chain: synthetic methodology, characterization and cytotoxicity

In this work, a variety of photoactive linear and hyperbranched unsaturated polyesters P1a-d, P2a-d and P3a-d, were successfully synthesized via ring-opening polymerization of diarylidene epoxy monomers 2a-d with terephthalic acid, isophthalic acid or trimesic acid in presence of TABI as a catalyst. First, diarylidene-epoxy monomers 2a-d were obtained from diols of diarylidene cycloalkanones derivatives 1a-d followed by epoxidation with epichlorohydrin in presence of NaOH and TBAI. These diaryldene epoxy monomers 2a-d were applied in the preparation of P1a-d, P2a-d and P3a-d. The molar masses of the resulting unsaturated polyesters were determined by gel permeation chromatography (GPC); all polymers have moderate molar masses. The photo-responsive properties of selected examples of polymers were tested in THF under UV lamp (450 nm) at different time intervals, This study revealed the occurrence of photocrosslinking behavior in the system under these conditions. The thermal properties of these polyesters were evaluated by thermogravimetric analysis (TGA). The morphological properties of selected examples of polymers were tested using scanning electron microscope (SEM). In addition, the cytotoxicity of the prepared monomers and selected polymers was tested against HeLa cervical cancer cells using MTT cell viability assay. All monomers except 2c showed significant cytotoxic effects with IC₅₀ > 21 μM. In contrast, the tested polymers were less potent against HeLa cells.