A new photochemical approach for the synthesis of metal-free three-dimensional hollow spherical conjugated polymers is described. Irradiation of solutions containing specially designed monomer, namely 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) possessing both carbazole and...

Abstract The main goal of this study is to prepare antibacterial poly(lactic acid) (PLA) containing cinnamaldehyde and geraniol and to evaluate the antibacterial activity and assess the changes of physical properties of the PLA films. Cinnamaldehyde- and geraniol-incorporated (10%, 20%, 30%, and 50% v/w) PLA films were prepared via solution-casting. While preparing these films, plasticizers were not added to the matrix. Antibacterial activities of these films against Escherichia coli and Staphylococcus aureus were investigated by the disk diffusion method. Thermal degradation characteristics were analyzed via thermogravimetric analysis (TGA), glass transition, crystallization, and melting temperatures, and enthalpies of the films were determined from differential scanning calorimetry (DSC) scans. Tensile strength and elongation-at-break values of neat PLA and antibacterial-compound-containing films were evaluated and compared after the mechanical tests. Moreover, the changes in the polymer morphology were observed by SEM analysis, and opacity of the films was determined by UV-vis spectroscopy. Our results showed that both compounds provided antibacterial effect to the PLA, with cinnamaldehyde being more effective than geraniol. Moreover, plasticization effects of the compounds were confirmed by DSC analysis.

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Physicochemical properties as well as antioxidant and antimicrobial capabilities of Rhododendron honey and pollen produced in Turkey were determined. Monofloral honey samples from three different Rhododendron species (R. ponticum L., R. luteum L., and R. caucasicum L.) were collected from the mountains of the Eastern Black Sea Region of Turkey. The experimental results revealed that each crude extract of honey and pollen exhibited significant antibacterial and antifungal capacity in the bacteria and fungus. The pollen samples and SEM images have been analysed and recorded. The total phenolic contents and antioxidative activities of the samples were investigated based on DPPH free radical scavenging activities and ferric reducing antioxidative power potentials, and higher phenolic content and antioxidant activities were observed for pollen samples with respect to honey. Furthermore, the potential to inhibit Acetyl- and Butrylcholinesterase activity and lipid peroxidation were evaluated. The potential to inhibit DNA damage were also studied, and R. ponticum honey was observed to influence most positively damaged DNA.

Currently, 90% of all packaging films are composed of non‐renewable, petroleum‐based materials. However, these materials have a significant environmental footprint. Polylactic acid (PLA) is a well‐known biodegradable thermoplastic polymer. However, the use of PLA poses some inherent challenges, like the brittleness of PLA films. For this study, with the objective of overcoming the shortcomings of PLA films, mastic gum (MG), which is an under‐utilized hydrophobic polymer, was incorporated into PLA, and the resultant films were characterized for their chemical (x‐ray diffraction [XRD], Fourier‐transform infrared [FTIR]), thermal (thermogravimetric analysis [TGA], dynamic mechanical analysis [DMA]), optical (optical microscope, color, and opacity), and barrier properties (water vapor permeability [WVP]). MG addition yielded films with much higher opacities and decreased WVPs up to 80%. Optical microscope images revealed the presence of some defects for films with MG concentrations above 1% g/g solvent, which also decreased the film's tear resistance. Glass transition temperature (Tg) values are reduced with MG addition, resulting in less rigid films at room temperature. In the end, MG incorporation yielded more flexible films with much better water barrier properties. In addition, all other properties of the films were drastically modified with MG addition. Hence, MG/PLA is demonstrated to be a promising biopolymer combination for the preparation of biodegradable films as a food packaging material.