Demet Topaloğlu Yazıcı

Packaging refers to the process applied to protect materials against environmental factors such as oxygen, moisture, light, and microorganisms, thereby preserving product quality and extending shelf life. Petroleum-based plastics, which are commonly used in packaging applications, are not biodegradable and can persist in the environment for long periods. This has led to an increasing demand for environmentally friendly and sustainable packaging materials. However, many biodegradable packaging materials exhibit limited mechanical strength, restricting their practical applicability in protective packaging systems. In this study, bio-based biocomposite films were prepared and characterized using chitosan, polyethylene glycol (PEG), and polyvinyl alcohol (PVA) biopolymers, reinforced with locally sourced hawthorn (Crataegus spp.) and pomegranate (Punica granatum L.), with the aim of developing potential biodegradable packaging films with both sufficient mechanical strength and antibacterial functionality. The results demonstrated that the biocomposite films exhibited resistance to solvents with different characteristics. Optical microscopy and SEM analyses confirmed the homogeneous dispersion of the reinforcing materials within the polymer matrix. Compared to similar materials reported in the literature, the developed biocomposite films displayed superior mechanical performance. Soil burial tests further verified that the biocomposite films exhibited significantly higher biodegradability than conventional plastics. Among the developed formulations, the 3BP film containing pomegranate peel exhibited promising characteristics for sustainable packaging applications due to its strong mechanical and antibacterial performance.

Son yıllarda hayatımızı önemli ölçüde etkileyen COVID-19 ve influenza gibi yaygın viral hastalıklar, ortak temas edilen yüzeylerden hızlı bir şekilde yayılmakta ve çeşitli enfeksiyonlara neden olmaktadırlar. Bu nedenle, halka açık alanlardaki yüzeylerin antimikrobiyal özellik göstermesi viral ve bakteriyel yayılımın engellenmesi açısından oldukça önemlidir. Antimikrobiyal uygulamalarda, kitosan gibi doğal polimerlerin ve metal nanoparçacıkların kullanımlarına yönelik çalışmalar mevcuttur. Bu çalışmanın amacı, yeşil sentez yöntemi ile metal nanoparçacıkların hazırlanması ve hijyenik alan uygulamalarında yüzey kaplaması olarak kullanılabilecek, çevreye duyarlı yeşil kompozit filmlerin geliştirilmesi ve karakterize edilmesidir. Kaplama filmlerinin; sudaki, asidik ve bazik ortamlardaki davranışları ultraviyole (UV) spektroskopi kullanılarak incelenmiş, nem tutma kapasiteleri değerlendirilmiş ve yüzey temas açısı ölçümleri yapılmıştır. Taramalı Elektron Mikroskobu (SEM) analizi ile kompozit filmlerin yüzey morfolojileri incelenmiş ve Geçirimli Elektron Mikroskobu (TEM) görüntüleri ile nanoparçacıkların parçacık boyutu özellikleri ve dağılımları değerlendirilmiştir. Ek olarak, hazırlanan yeşil kompozit filmlerin antimikrobiyal özellikleri, E. Coli ve S. Aureus bakterilerine karşı değerlendirilmiştir. TEM görüntüleri, nano gümüş ve bakır parçacık boyutlarının literatür verileriyle eşleştiğini göstermiştir. Hazırlanan kompozit filmlere uygulanan antimikrobiyal testler ise gümüş nanoparçacık içeren kompozit filmlerin test edilen bakterilere karşı antimikrobiyal bölge oluşturduğunu göstermiştir.

Çözelti polimerizasyonu yöntemiyle sentezlenen Morfolino etil metakrilamid polimerinin (PMoEMA), camsı geçiş sıcaklığının (Tg) üstündeki sıcaklıklarda termodinamik özellikleri Ters Gaz Kromatografisi (TGK) yöntemiyle incelenmiştir. Bu amaçla, aromatik hidrokarbonlar ve alkollerin sorpsiyonuna ait termodinamik parametreler (kısmi molar entalpi, kısmi molar serbest enerji, ve kısmi molar entropi), ağırlık kesri aktiflik katsayıları, Flory-Huggins etkileşim parametreleri ve polimer ile çözücü için çözünürlük parametreleri hesaplanmıştır.

There is a strong linkage between the waste tea fibre and chitosan, because of being used as wound treating materials separately for years. The waste tea fibre and chitosan including biomaterials were developed due to being renewable sources, biodegradable, hygienic and harmless materials. Waste natural fibres were pre-treated with different chemicals in order to improve the compatibility of the fibre and the polymer. The effect of treatment type and additives were examined by using X-ray diffraction patterns and SEM images. Drug delivery behaviours were determined by calculating the diffusion coefficients of biomaterial-drug systems with a selected model drug, ciprofloxacin. The diffusion phenomenon was affected by both the treatment type and the additives. The findings of the structural and morphological examinations indicated that the association of the tea waste fibre and chitosan may be a promising biomaterial for wound dressing applications.

The aim of this study is to analyze the effect of natural additive incorporation on processing nanocomposites and their effect on the functional characteristics of nanocomposites such as water uptake characteristics, drug adsorption and dissolution behaviors. Chitosan and montmorillonite were processed with olive oil and glycerin natural additives. In order to compare the processing results, the structure and the morphology of the polymer nanocomposites were examined by using infrared spectra, X-ray diffractograms and electron microscope images. Processing with nontoxic and healthful olive oil as a hydrophobizing agent overcame the high water uptake properties of the polymer nanocomposites and eliminated the use of other expensive chemicals. The nanocomposites without additives adsorbed the highest amounts of methylene blue at equilibrium. In vitamin B12 dissolution studies, not only the additives but also the reinforcement affected the results. Obviously, it can be seen that both the natural additive types and the reinforcement modification effects governed the drug adsorption and dissolution behaviors of the new tailored polymer nanocomposites. Moreover, the additives also improved the processing and handling abilities of these polymer nanocomposites. According to the results, these nanocomposites are promising candidates for medical applications like as a carrier for drug delivery and for skin treatment studies.

The surface properties of newly synthesized N-methoxy isopropyl acrylamide, N-methoxy isopropyl methacrylamide, cyclo propyl acrylamide, and cyclo propyl methacrylamide polymers were investigated using inverse gas chromatography. The highest dispersive component of the surface energy value was obtained for cyclo propyl methacrylamide at 30°C. The values obtained for all polymers were decreasing with the increasing temperature. The values obtained for the acidic and the basic parameters revealed strong basic characters for the surface of N-methoxy isopropyl methacrylamide and cyclo propyl methacrylamide polymers and weak basic characters for the surface of N-methoxy isopropyl acrylamide and cyclo propyl acrylamide polymers.

Boron industrial solid waste is used as reinforcement for preparing composite materials. This waste has boron trioxide which holds unique properties may affect the surface or interface of the composite. The prepared composites are characterized in order to determine the dispersion and the structure by means of inverse gas chromatography (IGC), Fourier transform infrared spectroscopy, thermal gravimetric analysis, scanning electron microscopy (SEM) and X-ray diffraction (XRD). There is a strong relation between the dispersion of reinforcement and the properties of newly formed composite. The dispersive component of the surface energies of the composites and components are determined by IGC. This parameter is difficult to measure by other methods and it is related to the wettability and adhesive characters of solid materials. The effect of compounding ratios of reinforcement is also examined. Furthermore, XRD diffractograms and SEM images of composites showed well dispersion. Thermal analysis revealed that the addition of the boron industrial solid waste to the polymer increased the thermal stability of pure polymer. Infrared spectra of the composites indicated that the composites were formed from the waste reinforcement and the polymer matrix. Graphical Abstract