Modeling of copolyimide chain microstructure formation in a course of the one-pot copolycondensation in molten benzoic acid

Mathematical modeling was has been developed for the chain microstructure formation in the synthesis of copolyimides (CPI) by the one-pot high-temperature catalytic polycondensation from two diamines A and B (comonomers) and one dianhydride C (intermonomer) in molten benzoic acid at 140°C accomplished with different regimes of intermonomer loading. The kinetic scheme including the acylation of the amino group of both diamines with the anhydride fragment, decomposition, and imidization of two intermediate amido acid fragments was examined. The kinetic parameters of the acylation and imidization stages necessary for calculations were determined previously in independent experiments. The numerical solution of the system of kinetic equations for different regimes of intermonomer loading gave the calculated dependences of the change in time of the average block length, the current concentrations of amino- and anhydride groups, amido acid fragments (unstable dyads: AC1 and BC1), imide cycles (stable dyads: AC2 and BC2), and triads. The calculated values of the average block length and the chain microheterogeneity parameter ( Km = 0.5) for the first three comonomer pairs at gradual intermonomer loading correspond to the multiblock microstructure of the chain. These values are in good agreement with the experimental values obtained from 13C NMR data for CPI based on the indicated diamines and 2,2-propylidenebis(1,4-phenyleneoxy)diphthalic dianhydride.

ß-Amido Acid Functionalised Superparamagnetic Iron Oxide Nanoparticles as a Novel Carrier for Efficient Delivery of Doxorubicine

Superparamagnetic iron oxide nanoparticles are increasingly used in medical applications due to their unique physical properties. They are useful carriers for delivering antitumour drugs in targeted cancer treatment. In this study, amido acid-functionalised magnetic nanoparticles (AAFMNs) are used as drug-delivery vehicles for doxorubicine as an efficient tool for the treatment of cancer. Magnetic iron oxide nanoparticles were synthesised using a co-precipitation method. The prepared iron oxide nanoparticles were then functionalised with amido acid functional groups. Finally, the synthesised AAFMNs were used for the delivery of doxorubicine. AAFMNs were characterised by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis and zeta potential. An in vitro-determined hydrodynamic diameter of ∼80 nm suggested their applicability for this purpose. The findings show that AAFMNs are a promising tool for potential magnetic drug delivery.