Poly(alkylene terephthalate)s represent one of the most frequently used polymer classes worldwide. Well‐known examples include poly(ethylene terephthalate) (n = 2) and poly(butylene terephthalate) (n = 4). The conventional synthesis method for these polymers is based on melt polycondensation, a two‐stage process performed under harsh conditions that includes the synthesis of an intermediate prepolymer and the presence of a catalyst, which may induce toxicity issues. The present work reports on a straightforward single‐step solution polycondensation method performed under mild conditions and in the absence of a catalyst. A homologous series of poly(alkylene terephthalate)s (n = 5 − 10) of molar masses up to 20 000 g mol−1 and dispersity <2.4 was synthesized and characterized thoroughly. Great attention was given to the thermal properties assessment by using state‐of‐the‐art techniques and a highly sensitive prototype technique called rapid heat − cool DSC. Similar to melt‐synthesized polyesters, a particular odd − even trend of the thermal properties versus the number of methylene groups within the monomer unit was revealed. To the best of our knowledge, this is the first report covering a single‐step solution‐based polycondensation performed in the absence of a catalyst that results in highly reproducible polyesters possessing unaltered thermal properties compared to polyesters synthesized through industrially applied conventional routes. © 2017 Society of Chemical Industry

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In vascular tissue engineering, great attention is paid to the immobilization of biomolecules onto synthetic grafts to increase bio- and hemocompatibility-two critical milestones in the field. The surface modification field of poly(ethylene terephthalate) (PET), a well-known vascular-graft material, is matured and oversaturated. Nevertheless, most developed methods are laborious multistep procedures generally accompanied by coating instability or toxicity issues. Herein, a straightforward surface modification procedure is presented engineered to simultaneously promote surface endothelialization and anticoagulation properties via the covalent immobilization of gelatin through a photoactivated azide derivative. A complete physicochemical characterization and biological study including cytotoxicity and endotoxin testing are performed. In addition, biocompatibility toward small (diameter ≤ 6 mm) and/or large caliber (diameter ≥ 6 mm) vessels is assessed by micro- and macrovascular endothelial cell assays. Superior bio- and hemocompatibility properties are seen for the gelatin-covalently modified PET surfaces compared to the conventional surface-modification procedures based on physisorption.

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Gold-dendrimer nanocomposites were obtained for the first time by a simple colloidal approach based on the use of polyamidoamine dendrimers with succinamic acid terminal groups and dodecanediamine core. Spherical and highly crystalline nanoparticles with dimensions between 3 nm and 60 nm, and size-polydispersity depending on the synthesis conditions, have been generated. The influence of the stoichiometric ratio and the structural and architectural features of the dendrimers on the properties of the nanocomposites has been described. The self-assembling behaviour of these materials produces gold-dendrimer nanostructured porous networks with variable density, porosity, and composition. The investigations of the reaction systems, by TEM, at two postsynthesis moments, allowed to preliminary establish the control over the properties of the nanocomposite products. Furthermore, this study allowed better understanding of the mechanism of nanocomposite generation. Impressively, in the early stages of the synthesis, the organization of gold inside the dendrimer molecules has been evidenced by micrographs. Growth and ripening mechanisms further lead to nanoparticles with typical characteristics. The potential of such nanocomposite particles to induce calcification when coating a polymer substrate was also investigated.

The potential in vascular grafts of gelatin-modified poly(ethylene terephthalate) (PET) was shown herein via their coating stability, ability to promote endothelial cells (ECs) and smooth muscle cells (SMCs) and positive cyto- and endotoxicity assessments.

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The present study highlights the use of statistical design to establish an effective model for the synthesis of polystyrene microspheres by aqueous dispersion polymerization using poly(2-ethyl-2-oxazoline) reactive stabilizer. The significant parameters (e.g. solvent polarity, stabilizer and initiator concentration) influencing the characteristic responses of the process such as yield, particle size and size distribution, as well as the interactions between the variables, were identified. The macromonomer concentration and solvent polarity influence both particle size and size distribution, whereas initiator concentration influences the yield. Analysis of the variance of process variables indicates that the models can be successfully used to describe the dispersion polymerization process. Moreover, the factorial design allows the development of microspheres with optimal properties with respect to size and size distribution. The experimental data regarding yield, particle size and size distribution of the optimized dispersion polymerization shows less than 7% difference compared with the predicted responses. In view of these results, the implementation of statistical design models represents an efficient solution for optimizing microparticle synthesis while aiming for industrial applications.