Band 44, Heft 5

Increased use of synthetic non-biodegradable polymeric matrices for composite manufacturing, poses a serious threat to the environment. This necessitates the development of 100 % biodegradable green composites using natural plant-based fibers and biodegradable natural polymers. This study focuses on the biodegradability and mechanical characteristics of biodegradable green hybrid composites fabricated with particles of agricultural waste cashew shell, sisal fibers, and corn starch resin using hand layup followed by compression molding. Mechanical characteristics such as tensile, flexural, impact strength, shore D hardness, and soil burial biodegradation characteristics were studied experimentally. The microstructures of the fractured surfaces were also analyzed through SEM images. Composite sample fabricated with an optimum cashew shell particle proportion of 10 wt %, three sisal fiber mat layers and corn starch resin has recorded the highest mechanical strengths such as 11.4 MPa, 10.9 MPa and 310.15 J/m in tensile, flexural and impact strengths respectively. Thus, the green hybrid composite made with agricultural waste cashew shell particles, sisal fibers, and corn starch resin is a potential and eco-friendly modern material for light load and short-life applications.

Vancomycin in sustained release still needs to be investigated. Polylactic acid (PLA) was widely used in the biomedical field for its good biocompatibility, especially in the field of controlled drug release. In this study, polyethylene glycol (PEG) was used to modify PLA to improve the hydrophilicity of the material. The synthesis of the block copolymers was proven by infrared and nuclear magnetic characterization and the hydrophilicity was tested. Vancomycin was immobilized by coaxial electrospray, and PLA-PEG 6000 -PLA was used as the shell layer. The parameters of coaxial electrospray under this material were explored, and the effects of concentration, voltage and temperature on the formation of microspheres were systematically studied. The optimum parameters were determined as follows: concentration 20 wt%, temperature 35 °C and voltage 14 kV. The maximum encapsulation rate and drug loading were calculated to be 89.54 ± 1.22 % and 15.33 ± 0.97 %, respectively, and the cumulative release of drug-loaded microspheres was less than 45 % in 24 h with a slow releasing time of more than one month. The drug loaded microspheres showed good sustained release and good control of burst release.

The development of stable carrageenan nanoparticles connected to the sulfate functional group of carrageenan and barium ion for the use of selectively targeting cancer cell and imaging contrast to help with diagnosis (tracing/imaging) is the concern of the present research. This study provides an overview of ion substitution chemistry, highlighting the role of ions and how they affect the applicability of carrageenan. The characteristic of barium sulfate, which is widely used as radiopaque to provide contrast for diagnostic radiographic examinations in the gastrointestinal mucosa, is provided by its linkage with the barium ion despite K + ’s natural binding with carrageenan. The additional role of the Ba ion linked carrageenan was found highly selective for cancer cell through the in vitro cell line assay; however, the nonattachability to the normal cell makes useful to trace and treat the cancer cell. The tracing is possible because of the barium sulfate functional group and its nanosize molecule, which shows precision medicine, fluorescence, and X-ray/CT imaging character, to be utilized as the diagnostic purpose, especially to tumor cell. The apoptosis from the Ba 2+ ion by the inhibition of outflux of K + to disturb the osmosis of cell and selectivity of the molecules because of high pKa (Logarithms of acid dissociation constant) value, which makes the drug more active anionic (nonpolar) form in the cancer cell and ionic form (polar) in the normal cell, which avoids the interaction with normal cell and facilitate the interaction with cancer cell. In conclusion, the cancer cell selectivity with fluorescence and radiopaque properties of Ba ion linked carrageenan makes the molecule useful for tracing, imaging, and treating cancer cell with high selectivity.

In this study, superoleophobic and superhydrophilic fabrics with self-healing property have been prepared by the use of chitosan (CS), sodium tripolyphosphate (TPP), Capstone FS-60 (FS-60), and dopamine hydrochloride as coating materials. The coated fabrics show oil contact angle of 154° for soybean oil, and water droplets can be spread on the surface in 1 s. Notably, it is further demonstrated that the coating has self-healing property. After undergoing home laundering, Martindale abrasion, or acid/base etching, the fabrics lose their superoleophobic and superhydrophilic property, while they can restore the superoleophobic and superhydrophilic property by just being wetted with distilled water and then heated in an oven. Additionally, the coated fabrics prove effective in separating oil/water mixtures. These fabrics, endowed with superoleophobic and superhydrophilic property along with self-healing capability, present innovative features and applications across diverse fields.

This study presents the synthesis of a magnetic sodium alginate hydrogel for efficient adsorption of heavy metal ions. The hydrogel, composed of sodium alginate, demonstrates a network structure that facilitates effective metal ion adsorption. Utilizing magnetic forces, the hydrogel can be easily separated and regenerated, exhibiting excellent recyclability. Compared to traditional adsorbents, the magnetic sodium alginate hydrogel shows significantly improved adsorption capacity, particularly for Pb 2+ ions. At pH ca. 4 and an adsorption time of 120 min, the hydrogel achieves a maximum adsorption capacity of 137 mg/g for Pb 2+ , with an adsorption rate of 83 %. The adsorption kinetics follow a pseudo-second-order equation, while thermodynamically, the process adheres to the Freundlich adsorption model, with capacity positively correlated with temperature and concentration. The negative Δ H value indicates an exothermic and spontaneous adsorption process. In competitive adsorption experiments, the hydrogel demonstrates strong selective adsorption towards Pb 2+ . It also exhibits excellent reusability, maintaining 80 % adsorption capacity after 10 cycles. The magnetic sodium alginate composite material possesses favorable recyclability and convenient magnetic separation properties, offering significant potential in various applications.