Preparation and Performance Research of Magnetic Polymer Microspheres

In this thesis, polystyrene magnetic polymer microspheres with good monodispersity and carboxyl functional groups were prepared. The adsorption properties of styrene-acrylic acid magnetic polymer microspheres to bovine serum albumin have been studied.. Using Fe3O4 magnetic fluid as the magnetic core and styrene-acrylic acid copolymer as the polymer shell, composite microspheres with very small particle diameters were prepared by the dispersion polymerization method.

Design of Co3O4@SiO2 Nanorattles for Catalytic Toluene Combustion Based on Bottom-Up Strategy Involving Spherical Poly(styrene-co-acrylic Acid) Template

Bearing in mind the need to develop optimal transition metal oxide-based catalysts for the combustion of volatile organic compounds (VOCs), yolk-shell materials were proposed. The constructed composites contained catalytically active Co3O4 nanoparticles, protected against aggregation and highly dispersed in a shell made of porous SiO2, forming a specific type of nanoreactor. The bottom-up synthesis started with obtaining spherical poly(styrene-co-acrylic acid) copolymer (PS30) cores, which were then covered with the SiO2 layer. The Co3O4 active phase was deposited by impregnation using the PS30@SiO2 composite as well as hollow SiO2 spheres with the removed copolymer core. Structure (XRD), morphology (SEM), chemical composition (XRF), state of the active phase (UV-Vis-DR and XPS) and reducibility (H2-TPR) of the obtained catalysts were studied. It was proven that the introduction of Co3O4 nanoparticles into the empty SiO2 spheres resulted in their loose distribution, which facilitated the access of reagents to active sites and, on the other hand, promoted the involvement of lattice oxygen in the catalytic process. As a result, the catalysts obtained in this way showed a very high activity in the combustion of toluene, which significantly exceeded that achieved over a standard silica gel supported Co3O4 catalyst.

Development and Evaluation of Novel Water-Based Drug-in-Adhesive Patches for the Transdermal Delivery of Ketoprofen

The objective of this study was to develop novel water-based drug-in-adhesive pressure-sensitive adhesives (PSAs) patches for the transdermal delivery of ketoprofen, employing poly(N-vinylpyrrolidone-co-acrylic acid) copolymer (PVPAA) and poly(methyl vinyl ether-alt-maleic anhydride) (PMVEMA) as the main components. The polymers were crosslinked with tartaric acid and dihydroxyaluminium aminoacetate using various polymer ratios. Ketoprofen was incorporated into the PVPAA/PMVEMA PSAs during the patch preparation. The physicochemical properties, adhesive properties, drug content, release profile, and skin permeation of the patches were examined. Moreover, the in vivo skin irritation and skin adhesion performance in human volunteers were evaluated. The patches prepared at a weight ratio of PVPAA/PMVEMA of 1:1 presented the highest tacking strength, with desirable peeling characteristics. The ketoprofen-loaded PVPAA/PMVEMA patches exhibited superior adhesive properties, compared to the commercial patches, because the former showed an appropriate crosslinking and hydrating status with the aid of a metal coordination complex. Besides, the permeated flux of ketoprofen through the porcine skin of the ketoprofen-loaded PVPAA/PMVEMA patches (4.77 ± 1.00 µg/cm2/h) was comparable to that of the commercial patch (4.33 ± 0.80 µg/cm2/h). In human studies, the PVPAA/PMVEMA patches exhibited a better skin adhesion performance, compared with the commercial patches, without skin irritation. In addition, the patches were stable for 6 months. Therefore, these novel water-based PSAs may be a potential adhesive for preparing drug-in-adhesive patches.

Asphalt Modified by Ethylene-Acrylic Acid Copolymer Ionomers: Fundamental Investigations of Mechanical and Rheological Properties

Ethylene-acrylic acid copolymer (EAA) has been demonstrated to be a suitable additive for modifying the properties of asphalt. EAA mixed with metal hydroxides/oxides form EAA-M ionomers, which increase the polarity of EAA, improving its adhesive properties and affecting its mechanical and rheological characteristics. The present work investigates the mechanical and rheological characteristics of asphalt modified by EAA in conjunction with either Ca (OH)2, NaOH, or ZnO. The high-temperature properties of the modified asphalts, including the softening point, and needle penetration, were evaluated. Rheological characteristics of modified asphalts were investigated by rotary rheometer. Moreover, the storage stability at high temperature, morphology and chemical structure were also analyzed. Results indicate that a 4wt% EAA-M ionomer concentration in the base asphalt is adequate for providing the enhanced properties studied. For an equivalent concentration of EAA, the properties of modified asphalts were affected by very small additions of the metal hydroxides/oxides. The best overall mechanical and rheological performance was obtained for EAA-Ca modified asphalt with 4wt% EAA and 2.5wt‰ Ca (OH)2. EAA-Zn modified asphalt provided the most stable high-temperature storage. Compared with 6wt% pure EAA-modified asphalt, which is not stable, the EAA-Zn modified asphalt (2.7wt‰ ZnO) demonstrated reasonable high-temperature storage stability. Compared with asphalt modified with 6wt% pure EAA, the softening point increased from 55.81 °C to 58.05 °C with the addition of 2.7wt‰ NaOH. However, while the mechanical and rheological properties of EAA-Na modified asphalt were very good, its high-temperature storage stability due to the strong reactivity of NaOH, which led to the crosslinking of EAA-Na ionomers, making it difficult to disperse.