Synthesis and properties of alkoxysilane-functionalized styrenated oil based polyester

Alkoxysilane-functionalized styrenated oil based polyester hybrid films were prepared by using vinyl trimethoxysilane (VTMS) as an inorganic source. For this purpose, an oil based polyester (PGMA) was first synthesized by the esterification of partial glyceride (PG) mixture with maleic anhydride (MA). Then, PGMA was further reacted with both styrene (St) and the mixture of St and VTMS yielding St–PGMA and St–PGMA–VTMS samples, respectively. The synthesis was carried out by changing VTMS content in the range of 5–15 wt.% in order to investigate the effect of inorganic domains on the film properties. While the films of St–PGMA–VTMS were formed on the appropriate substrates by moisture curing and oxidative polymerization, St–PGMA films were only cured by oxidative polymerization. The characterization of the polymers was done by FTIR, ¹H NMR, DSC, TGA and SEM. FTIR and DSC analyses indicated the completion of the moisture curing process. Film properties such as flexibility, adhesion, water, alkali and acid resistances were determined. All samples showed good film properties. Moreover, in comparison, St–PGMA–VTMS samples exhibited better alkali resistance than St–PGMA due to the contribution of the inorganic domains.     

Determination of Physicochemical Properties,Fatty Acid,Tocopherol, Sterol,and Phenolic Profiles of Expeller–Pressed Poppy Seed Oils from Turkey

In this study, the aim was to characterize the physicochemical properties and some bioactive compounds of expeller-pressed oils of five registered poppy seed varieties (TMO–1, Ofis–8, Ofis–96, Ofis–95, Ofis–3) grown in Turkey. The amounts of total carotenoids, chlorophylls, phenols, and antioxidant activities of oils ranged between 0.08–0.24 mg 100 g⁻¹, 0.03–9.04 mg pheophytin a kg⁻¹, 3.41–8.57 mg gallic acid equivalent 100 g⁻¹, and 5.60–7.33 mM Trolox equivalent 100 g⁻¹, respectively. The most abundant fatty acid in poppy seed oils was linoleic acid (69.85–74.02%), followed by oleic acid (13.98–16.99%), and palmitic acid (8.51–9.75%). In addition, poppy seed oils were rich in β–sitosterol (133.47–153.42 mg 100 g⁻¹), campesterol (45.36–58.60 mg 100 g⁻¹), and δ–5–avenasterol (28.21–39.40 mg 100 g⁻¹). High amounts of γ–tocopherol and α–tocopherol were detected. This research is the first study, which identified and quantified the polyphenol, β–carotene, and lutein compounds of expeller–pressed poppy seed oils by HPLC. Tyrosol, apigenin, syringic acid, 3–hydroxytyrosol, luteolin, p–coumaric acid, quercetin, ferulic acid, sinapic acid, and veratric acid were detected in expeller-pressed poppy seed oils.     

The evaluation of low‐cost biosorbents for removal of an azo dye from aqueous solution

There is a need to develop innovative and alternative technologies that can remove dyes from wastewater. In this study, low‐cost and locally available two renewable biosorbents (cotton stalk and apricot seed) were investigated to remove of Astrazone Black from aqueous solution. The effects of various experimental parameters such as dye concentration, adsorbent amount, adsorbent particle size and initial pH were tested, and optimal experimental conditions were examined. The results showed that as the amount of adsorbent was increased, the percentage of dye removal increased accordingly. The ratios of dye sorbed increased as the adsorbent particle size decreased. In addition, antibacterial effect of untreated and treated (decolourized) dye on a soil bacterium, Pseudomonas aeruginosa, was determined. The removal of this dye with agricultural wastes reduced the toxic effect on P. aeruginosa. This reduction in toxic effect is important both in respect of environmental biotechnology and waste detoxification.     

Dual-responsive hydrogels based on maleilated curdlan-graft-poly(N-isopropylacrylamide)

The esterification reaction between curdlan and maleic anhydride was performed to provide polymerizable double bonds and pH-sensitive carboxylic groups for the curdlan chains. The new derivative was used as macromolecular cross-linker in the polymerization of N-isopropylacrylamide, when thermo and pH-sensitive networks were obtained in the form of microparticles. The loading and releasing profiles of a model macromolecular drug, lysozyme, were evaluated. The protein release rate was influenced by the pH and temperature. The pulsatile release of the lysozyme was also observed, the pulse being the swelling of the microparticles due to the decrease of the temperature under the volume phase transition temperature.     

Effects of Tungsten and Boron Contents on Crystallization Temperature and Microhardness of Tungsten Based Metallic Glasses

Effects of tungsten and boron contents on the thermal properties and microhardness of W-Fe-B metallic glass system were studied. Thin foils, with thicknesses of 20 and 100 μm, of the alloys were produced by piston and anvil method in an arc furnace. The structures of the foils were investigated by X-ray diffraction. Thermal stabilities of the alloys were examined by using differential scanning calorimetry. 20-μm- thick foils of all the alloys were determined to be fully amorphous, but crystalline phases were detected in the 100-μm-thick foils. It was found that crystallization temperatures of the alloys are between 1060 and 1177 K. Tungsten and boron content increases improve the crystallization temperature and microhardness of the alloys significantly, but deteriorate the glass forming ability of the alloys. It was also observed that for constant Fe content, increasing tungsten content to the level higher than that of boron content does not result in any further improvement in crystallization temperature, but improves glass forming ability significantly. The alloy containing highest total amount of tungsten and boron, W₃₅Fe₃₅B₃₀, has the highest crystallization temperature, 1177 K, and microhardness, 1634 HV.     

Iron‐encapsulated cold‐set whey protein isolate gel powder ‐ Part 2: Effect of iron fortification on sensory and storage qualities of Yoghurt

Iron was incorporated at 20–60 mg/kg of yoghurt using iron‐encapsulated cold‐set whey protein isolate gel powder (WPI‐Fe) and by direct addition of ferrous sulphate solution. The changes in physicochemical and sensory qualities of the yoghurt samples were determined over 14 days of storage. Quality attributes of the yoghurt fortified using WPI‐Fe particles at up to 60 mg iron/kg were similar to those of unfortified control samples, especially in terms of colour and flavour, while the samples fortified by direct addition of ferrous sulphate exhibited noticeable adverse effects even at 20 mg iron/kg.     

Improvement of SO2 adsorption capacity of fiber web surface produced from continous graphene oxide fiber

Sulphur dioxide (SO₂) is an important atmospheric pollutant, and capture of SO₂ is of great importance for the environment, human health and market. Carbon based materials, especially activated carbon, are mostly used for adsorption purposes. However, there is a notable lack on adsorption of SO₂ on graphene oxide (GO) fibers and fiber web surface. In this study, the effect of addition of activated carbon, pH of GO dispersions, hydrazine reduction and oxygen/argon plasma treatment on SO₂ adsorption of GO fiber web surface were evaluated. It was seen that GO fiber web surface with activated carbon provides high SO₂ adsorption (896 mg SO₂/g) which is very higher than many of carbon based materials presented in the literatures. Single coagulation bath increases surface roughness of fiber and provides higher functional group than three coagulation baths leading to higher SO₂ adsorption capacity.     

Identification of bioactive compounds and total phenol contents of cold pressed oils from safflower and camelina seeds

The compositions of fatty acids, tocopherols, polyphenols, sterols, and the total phenol contents of cold pressed oils obtained from five varieties of safflower seeds and ten varieties of camelina seeds cultivated in Turkey were determined. Total phenol contents of safflower oils were higher (272.20–525.30 mg GAE/kg) than camelina seed oils (25.90–63.70 mg GAE/kg). Apigenin, luteolin, tyrosol, syringic acid, 3-hydroxytyrosol, p-coumaric acid and sinapic acid were detected in seed oils. Camelina seed oils were rich in tocopherol (144.11–168.69 mg/100 g). γ-Tocopherol was the predominant tocopherol in camelina seed oils consisting of averagely 80% of total tocopherol, while α-tocopherol was the main compound of safflower seed oils, representing 97.85–98.53% of total tocopherols. β-Sitosterol was the major sterol in both type of seed oils. Its concentration ranged between 92.51–121.83 mg/100 g and 80.52–25.54 mg/100 g in safflower seed and camelina oils, respectively. Camelina seed oils contained 22.31–26.57% linolenic acid, 21.25–24.05% linoleic acid and 19.46–21.47% oleic acid, whereas safflower seed oils mainly consisted of linoleic (28.03–76.85%) and oleic (13.01–62.61%) acids.     

Aqueous solubility and alkaline hydrolysis of the novel high explosive hexanitrohexaazaisowurtzitane (CL-20)

The recently developed polycyclic nitramine CL-20 is considered as a possible replacement for the monocyclic nitramines RDX and HMX. The present study reports aqueous solubility data for CL-20, as well as the kinetic parameters for its alkaline hydrolysis with sodium hydroxide below and above its solubility limits. Aqueous solubility of CL-20 was measured in the temperature range of 4–69 °C and the data were fitted to a generalized solubility model. Alkaline hydrolysis experiments were conducted at 15, 20, 30 and 40 °C, with hydroxide concentrations ranging from 0.25 to 300 mM. Like RDX and HMX, alkaline hydrolysis of CL-20 follows second-order kinetics. CL-20 alkaline hydrolysis was found to proceed at a significantly faster rate than RDX. The temperature dependency of the second-order rate constants was evaluated using the Arrhenius model. The activation energy for CL-20 was found to be within close range of the activation energies reported for RDX and HMX.     

Development and properties of advanced composites based on cork and nanometric silicon carbide-filled phenolic resin

This paper presents the obtaining of advanced materials based on cork powder as reinforcement and phenolic resin (PR) with silicon carbide (nSiC) nanofiller as matrix with potential applications in aerospace industry. Three formulations were obtained: one control sample PR/cork with no nanofiller, two nanofilled samples with 1 and 2 wt% nSiC loadings into the resin. The materials were tested by flexural and compressive mechanical tests to determine their strength and stiffness, to determine their friction coefficient by tribological tests, to determine their thermal decomposition behaviour by TG-DSC analysis and to evaluate their thermal behaviour by thermal shock tests when subjected to extreme temperature directly from room temperature. The material structure was analysed by SEM visualizing the fracture cross-section after mechanical testing. The test results illustrate that silicon carbide nanoparticles improve flexural and compressive strength, but also stiffness and friction coefficient, delay thermal decomposition onset and improve thermal shock resistance. All these sustain the PR/nSiC/cork materials as potential advanced materials candidates for thermal protection applications.