Polyesteramides based on PET and nylon 2,T part 1. synthesis of the bisesterdiamide

The synthesis of the bisesterdiamide T2T-dimethyl (one-and-a-half repeating unit of nylon 2,T) (benzoic acid, 4,4′-[1,2–ethanediylbis(iminocarbonyl)] bis-dimethyl ester, CAS no 7060-10-8) has been studied using dimethyl terephthalate (DMT) and 1,2-diaminoethane (DAE) as starting materials. T2T-dimethyl was synthesised in a solvent mixture of toluene/methanol at 65°C employing lithium or sodium methanolate as a catalyst. The progress of reaction was followed as function of time using liquid chomatrography and endgroup titrations. The products were analysed using 1H NMR, 13C NMR and differential scanning calorimeter. A high yield was obtained (90%), and after recrystallisation from NMP, the product was found to be of high purity. The pure T2T-dimethyl obtained had a melting onset of 312°C and a melting enthalpy of 165 J/g.\ud \ud T2T-dimethyl was also synthesised in absence of a catalyst at 100°C and using m-xylene as solvent and at a high concentration of reactants. The yield of this reaction was relatively low (34%). The addition of phenol to the reaction mixture had little effect on the yield and purity of the product

Impact of thermal processing or solvent casting upon crystallization of PLA nanocellulose and/or nanoclay composites

Here, we present how processing (solvent casting or isothermal crystallization) impacts crystallinity of poly(lactic acid) (PLA) and its nanocomposites (PLA/1 wt % cellulose nanofibers (CNFs), PLA/1 wt % nanoclay (C30B) or PLA/1 wt % CNF/1 wt % C30B. Polarized optical microscopy demonstrated a heterogeneous nucleation process during isothermal crystallization leading to smaller homogeneously distributed spherulites. With solvent casting, no effect on morphology was observed with respect to the nanoparticles, but an increased spherulite size was observed at higher temperatures. This fact raises significant concerns regarding the suitability of solvent casting as a lab‐scale procedure to investigate materials. Additionally, combining the reinforcing agents, CNF, and C30B, did not increase nucleation rate, in contrast with the general tendency, where the incorporation of both particles led to improved properties (e.g., thermomechanical and barrier properties). However, a combination of C30B and CNF did lead to an overall increase in the rigid amorphous fraction and a reduced mobile amorphous fraction

Biomorphic Engineering of Multifunctional Polylactide Stomatocytes toward Therapeutic Nano-Red Blood Cells

Morphologically discrete nanoarchitectures, which mimic the structural complexity of biological systems, are an increasingly popular design paradigm in the development of new nanomedical technologies. Herein, engineered polymeric stomatocytes are presented as a structural and functional mimic of red blood cells (RBCs) with multifunctional therapeutic features. Stomatocytes, comprising biodegradable poly(ethylene glycol) block-poly(D,L-lactide), possess an oblate-like morphology reminiscent of RBCs. This unique dual-compartmentalized structure is augmented via encapsulation of multifunctional cargo (oxygen-binding hemoglobin and the photosensitizer chlorin e6). Furthermore, stomatocytes are decorated with a cell membrane isolated from erythrocytes to ensure that the surface characteristics matched those of RBCs. In vivo biodistribution data reveal that both the uncoated and coated nano-RBCs have long circulation times in mice, with the membrane-coated ones outperforming the uncoated stomatoctyes. The capacity of nano-RBCs to transport oxygen and create oxygen radicals upon exposure to light is effectively explored toward photodynamic therapy, using 2D and 3D tumor models; addressing the challenge presented by cancer-induced hypoxia. The morphological and functional control demonstrated by this synthetic nanosystem, coupled with indications of therapeutic efficacy, constitutes a highly promising platform for future clinical application.</p