Chemical modification of unsaturated polyesters influence of polyester's structure on thermal and viscoelastic properties of low styrene content copolymers

Renewable Photo-Cross-Linkable Polyester-Based Biomaterials: Synthesis, Characterization, and Cytocompatibility Assessment

The present work consist of the synthesis of photo-cross-linkable materials, based on unsaturated polyesters (UPs), synthesized from biobased monomers from renewable sources such as itaconic acid and 1,4-butanediol. The UPs were characterized to assess the influence of polycondensation reaction temperature and cross-linking time on their final properties. For this purpose, different UV irradiation exposure periods were tested. Homogeneous, uniform, and transparent films were obtained after 1, 3, and 5 min of UV exposure. These cross-linked films were then characterized. All materials presented high gel content, which was dependent on the reaction's temperature. The thermal behaviors of the UPs were shown to be similar. In vitro hydrolytic degradation tests showed that the materials can undergo degradation in phosphate-buffered saline (PBS) at pH 7.4 and 37 °C, ensuring their biodegradability over time. Finally, to assess the applicability of the polyesters as biomaterials, their cytocompatibility was determined by using human dermal fibroblasts.

Water Soluble Self-Aggregates Induced Green Emission of Biocompatible Citric Acid-PEG Hyper Branched Polymer

An aliphatic citric acid-PEG hyper-branched polymer (CPHP) with a π-bond on the polymer backbone was synthesized by a single- step melt reaction in which the polymerization and π-bond formation occur simultaneously. The chemical structure of CPHP was confirmed by FTIR, 1H-NMR, 13C-NMR and MALDI-TOF mass spectral analyses. Aggregates are generally found to disperse in any solvent but the CPHP aggregates were soluble in water due to their hybrid nature. The π-bond in the aconitate unit induces green emission by CH/π interaction while the PEG unit of CPHP increases its solubility in water. The soluble aggregates induced green emission (SAIE) of the CPHP was investigated by UV-Visible absorption and emission spectra, time- correlated single photon counting (TCSPC) and zeta potential measurements. The fluorescence life time (τf) increased from 4.93 to11.38 ns with an increase in CPHP concentration. The fluorescence quantum yield (Φf) of CPHP can be altered by varying the concentration of CPHP.