Development of ductile green flame retardant poly(lactic acid) composites using hydromagnesite&huntite and bio-based plasticizer

Turning brittle poly(lactic acid) (PLA) to ductile form via plasticizer inclusion is an effective option in the case of processing with high amounts of additives. Additionally, the integration of natural flame retardants to PLA involving bio-based plasticizer enables to use of environmentally friendly composites in conditions where fire resistance performance is required. In the current study, ductile green fire retardant PLA composites were manufactured using hydromagnesite&huntite (HH) as a natural fire retardant additive and acetyl tributyl citrate as a bio-based plasticizer. The influences of plasticizer and HH contents on the fire retardant, thermal and mechanical performances of the composites were explored. According to test results, the limiting oxygen index (LOI) value of PLA reduced from 29.2 to 28.0 and the UL-94 V rating changed from V2 to BC with the addition of 20 wt% plasticizer owing to the reduction in melt viscosity. The peak heat release rate (pHRR) and average heat release rate (avHRR) values increased steadily as the concentration of plasticizer increased due to the formation of a more porous residue structure stemming from the increased transportation rate of gases. In order to produce ductile flame retardant material, the plasticizer content was required to 20 wt% of HH. The highest LOI value (36.2) and UL-94 rating of V0 were achieved with the inclusion of 70 wt% HH in the presence of 20 wt% plasticizer. Improvement in impact resistance and reduction in tensile strength were observed as the added amount of plasticizer increased.     

Determination of the quality and purity characteristics of olive oils obtained from different regions of Turkey,depending on climatic changes

Virgin olive oils (VOOs) obtained from olives grown in different regions of Turkey under changing climatic conditions sometimes show different sensory and chemical properties. This study was planned to determine whether these deviations are due to climatic changes or not. For this purpose, five different olive varieties (Ayvalık, Memecik, Gemlik, Nizip Yağlık, Kilis Yağlık) of commercial importance were harvested from the provinces/districts (four different region) where cultivation is intense during the 2017/2018–2020/2021 harvest years. Every year, olive samples were collected from 3 orchards from 13 provinces/districts. One hundred and fifty-six samples were subjected to the purity, quality and sensory analysis. Basic climatic values (average, minimum and maximum temperature, humidity and precipitation) were examined for four consecutive years. All of the examined olive oil samples were determined within the legal limits in terms of fatty acid composition and fatty acid ethyl ester values. However, delta-7-stigmastenol value from the sterol composition was found to be above 0.5% in some samples in all the years studied (total 21 samples). Delta-7-stigmastenol values of olive oil samples varied between 0.16% and 1.14%. Multiple linear regression analysis was applied using a genetic algorithm-based inverse least squares method to determine whether there is a relationship between climate data and delta-7-stigmastenol values. According to this result, it has been determined that the delta-7-stigmastenol value is high when the annual average relative humidity is low and the annual average temperature is high. There is an urgent need to make forward-looking plans due to climate change.     

Effect of roasting on the physico-chemical properties,fatty acids,polyphenols and mineral contents of tobacco (Nicotiana tabacum L.) seed and oils

The physico-chemical properties, phytochemicals, mineral contents of tobacco (Nicotiana tabacum L.) seeds grown at Samsun province in Turkey were evaluated. The oil contents of tobacco seeds ranged from 20.6% (control) to 29.0% (microwave-roasted). L*, a* and b* values of tobacco seeds ranged from 32.38 to 35.61; from 6.32 to 6.78; from 13.72 to 14.27, respectively. Total phenolic contents of tobacco seed extract and oils were reported between 31.02 (oven-roasted) and 34.42 mg GAE/100 g (microwave-roasted) to 4.60 (microwave-roasted) and 6.45 mg GAE/100 g (oven-roasted), respectively. Total flavonoid values of raw and roasted tobacco seed extract and oils were determined between 26.62 (oven) and 67.10 mg/100 g (control) to 21.57 (control) and 44.71 mg/100 g (microwave-roasted), respectively. Gallic acid, 3,4-dihydroxybenzoic acid and catechin are the predominant phenolic components of raw and roasted tobacco seed oils. The amounts of oleic and linoleic acid in raw and roasted tobacco seed oils ranged from 10.23% (oven-roasted) to 12.48% (control) and 73.72% (control) to 76.63% (oven-roasted), respectively. The abundant elements found in seeds were K, P, Ca, Mg, S and Fe. The mineral amounts of the roasted seeds were found higher than that of the control. The highest increase was detected in oven roasted tobacco seeds.     

Improvement of Interfacial Adhesion of Glass Fiber/Epoxy Composite by Using Plasma Polymerized Glass Fibers

This study intends to produce plasma polymer thin films of γ-glycidoxypropyltrimethoxysilane (γ-GPS) on glass fibers in order to improve interfacial adhesion of glass fiber-reinforced epoxy composites. A low frequency (LF) plasma generator was used for the plasma polymerization of γ-GPS on the surface of glass fibers at different plasma powers and exposure times. X-ray photoelectron spectroscopy (XPS) and SEM analyses of plasma polymerized glass fibers were conducted to obtain some information about surface properties of glass fibers. Interlaminar shear strength (ILSS) values and interfacial shear strength (IFSS) of composites reinforced with plasma polymerized glass fiber were evaluated. The ILSS and IFSS values of non-plasma polymerized glass fiber-reinforced epoxy composite were increased 110 and 53%, respectively, after plasma polymerization of γ-GPS at a plasma power of 60 W for 30 min. The improvement of interfacial adhesion was also confirmed by SEM observations of fractured surface of the composites.     

Dehydration,Water Vapor Adsorption and Desorption Behavior of Zn[B3O3(OH)5] · H2O and Zn[B3O4(OH)3]

The dehydration behaviors of two different hydrated zinc borate species, Zn[B₃O₃(OH)₅] · H₂O and Zn[B₃O₄(OH)₃], which are industrially important flame retardants, were studied by thermal gravimetric(TG) analysis and in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. Dehydration onset temperatures of Zn[B₃O₃(OH)₅] · H₂O and Zn[B₃O₄(OH)₃] were 129 and 320°C, respectively, at a 10°C/min ramp rate. A very small amount of boric acid was volatilized in addition to water vapor when both samples were heated at 250°C. A significant amount of water vapor was adsorbed by Zn[B₃O₃(OH)₅] · H₂O from air at 25°C. However, Zn[B₃O₄(OH)₃] adsorbed a very small amount of water under the same conditions. Both zinc borates did not have a tendency to cake during storage.     

Recovery of Zinc by LIX 984N‐C from Electroplating Rinse Bath Solution

The development of a complete solvent extraction process at the laboratory scale for recovering zinc from the zinc electroplating first rinse bath solution (alkali solution) containing ～1.9 g/L zinc (ZEFRBS) by a solvent extraction route using LIX 984N‐C, which is a new SX reagent developed by Cognis, and dissolved in commercial kerosene was investigated. By using LIX 984N‐C, an electrolyte from ZEFRBS with ～12 g/L zinc content, which was addable to the alkali zinc electroplating bath, was generated by 10 vol.% LIX 984N‐C in commercial kerosene at the O/A ratio of 1/4 and equilibrium pH value of 8.00 ± 0.05 with a two‐stage countercurrent extraction, and stripping of the loaded organic by a strip solution with 150 g/L sulfuric acid and with the O/A ratio of 1.5 at a two‐stage countercurrent stripping process. A new complete flow sheet of 10 vol.% LIX 984N‐C process for the recovery of zinc from ZEFRBS has been demonstrated.     

Kinetic Investigation of Reaction Between Colemanite Ore and Methanol

In the field of industry, it is very important that boron compounds are produced from boron ores. The aim of this study was to investigate the dissolution kinetics with carbon dioxide of colemanite in methanol medium in a pressure reactor and to derive an alternative process for producing boron compounds. Reaction temperature, stirring speed, solid/liquid ratio, pressure, and particle size were selected as parameters for the dissolution rate of colemanite. It was found that the dissolution rate increased with increase in pressure and reaction temperature, and with decrease in particle size and solid/liquid ratio. No effect of stirring speed was observed on conversion. The dissolution kinetics of colemanite were examined using both heterogeneous and homogeneous reaction models, and it was determined that the reaction rate can be described by a second-order pseudo-homogeneous reaction model. The activation energy was found to be 51.4 kJ/mol.     

Recent advances in the preparation of functionalized polysulfones

This review summarizes the studies related to chemical functionalization of polysulfones used in many different applications such as membranes with special functions, nanocomposites, biofilm formation, fuel cells etc. reported in recent years from the literature since 2000. Various strategies have been applied for the functionalization of polysulfones. One strategy is to add desired functionality into starting monomers in the solution containing the main components of commercial polysulfones, the aromatic dihalide sulfone and bisphenol monomers, or to functionalize the related monomers before the condensation. Another approach is to form difunctional polysulfone oligomers. Then, functional groups can be utilized to react with monomers or other polymers to obtain functional polymers or block copolymers. The most applied method is post‐modification of commercially available polysulfones by incorporation of functional groups to their aromatic groups and their use in the formation of graft polymers or polysulfone‐based networks. © 2013 Society of Chemical Industry     

OBTAINING SCARLET SAGE (SALVIA COCCINEA) EXTRACT THROUGH HOMOGENIZER- AND ULTRASOUND-ASSISTED EXTRACTION METHODS

Scarlet sage (Salvia coccinea) leaves were extracted with water, ethanol, methanol, and aqueous mixtures of those solvents by homogenizer-assisted extraction (HAE) and ultrasound-assisted extraction (UAE) methods, which are novel technologies used for this purpose. The best results were compared with those obtained by the conventional Soxhlet method (SM). Total phenolic content was expressed in gallic acid equivalent (GAE) per g of dried leaf. Free radical scavenging activity for the antioxidant capacity was tested by 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical. The greatest amount of extraction was achieved by pure water with the value of 368.87 mg/g dried matter and the highest total phenolic content was observed by 100% methanol as 43.18 mg-GAE/g dried matter, both obtained by the HAE method. The mint leaves extracted by SM exhibited the highest antioxidant capacity, with a value of 90.55% for inhibition of DPPH radical.     

Evaluation of antibacterial effects of contemporary orthodontic bonding materials

Aim: The aim of this study was to evaluate the antibacterial effects of five orthodontic bonding materials commonly used in orthodontics. Materials and Methods: The antibacterial effects of five orthodontic bonding materials were evaluated against Streptococcus mutans and Streptococcus salivarius by direct contact test (DCT). Using the DCT technique, quintet specimens of Transbond XT, Blugloo, Grengloo, Light Bond, and Opal Bond were applied to the bottom and the walls of the five wells of a 96-microtiter plate with a height of 2 mm. Samples were prepared in two sets: 1-day samples and 7-day samples. Ten microliters of bacterial suspension were added to each well for direct contact with each material for 1h at 37 °C. Bacterial growth was then measured in a microplate spectrophotometer hourly at 600 nm for 24 h. Five uncoated wells with identical inoculum sizes served as positive controls. The data obtained at the end of 24 h was statistically analyzed with one-way ANOVA, and post hoc comparisons were done using Tamhane’s T2 test. Results: Blugloo generally showed better antibacterial activity than the other materials. Transbond XT did not show any antibacterial activity. There was a statistically significant difference between Transbond XT and Light Bond in the 1-day sample against S. mutans (p < 0.05). No statistically significant differences were found among the other groups (p > 0.05). Conclusion: Blugloo had the most potent antibacterial activity against S. salivarious.