No abstract

No abstract

In recent years, the exploitation of magnetic nanoparticles in smart polymeric matrices have received increased attention in several fields as site-specific drug delivery systems. Here, ultrasonic-assisted emulsion copolymerization of N-isopropylacrylamide (NIPAM) and 2-(N,N-diethylaminoethyl) methacrylate (DEAEMA) in the presence of Fe3O4 nanoparticles was employed to prepare pH- and temperature-responsive magnetite nanocomposite particles (MNCPs). The obtained MNCPs were fully characterized by TEM, DSC, FT-IR, VSM, and XRD techniques. They had an average particle size of 70 nm with a lower critical solution temperature of 42 °C and superparamagnetic properties. In addition, MNCPs were loaded with methotrexate (MTX) as an anticancer drug, and their in vitro drug release was studied in different pH values and temperatures and in the presence of an alternating magnetic field. Noteworthy that the highest rate of MTX release was observed at pH 5.5 and 42 °C. Cell viability of the treated MCF-7 human breast cancer cell line with free MTX, MNCPs, and MTX-loaded MNCPs or in combination with magnetic hyperthermia (MHT) and water-based hyperthermia was comparatively studied. The obtained results showed about 17% higher antiproliferative activity for the MTX-loaded MNCPs accompanied by MHT relative to that of free MTX.

To take full advantage of the synergistic effects of soft organic and rigid inorganic toughening agents, elastomeric core/amine-functionalized silica shell armored nanocomposite particles were prepared through Pickering emulsion polymerization. The size and microstructure of the prepared armored impact modifier particles (AIMPs) were studied thoroughly. It was substantiated that the amine-functional silica nanoparticles have been successfully attached to the surface of the colloidal polymer particles. The obtained results revealed that the incorporation of the prepared AIMPs into epoxy resin could exert significant positive influences on its toughness, tensile strength, and modulus. An optimal content of AIMPs was found to exist, which enhanced the fracture toughness by 8 times, the fracture energy by 50 times, and the tensile strength by 38% for the modified sample using 7 wt % AIMPs in comparison with those of the neat epoxy resin. The primary toughening mechanisms were related to crack pinning and deflection as well as deboning of AIMPs from the epoxy matrix followed by plastic void growth.

No abstract