The influence of carbon-containing, magnetic and nano-dispersed additions on structure and electrophysical properties of polypropylene-based composite monofibers

There were PP- and iron-containing, fibrous, carbon- and nanodispersed-addition-based composite fibers prepared. There were addition content equals of 5.0%mass. There were blend of isotactic PP and addition homogenized in melt with one-screw lab extruder. There were zonal temperature on extruder equals of 230-250 o C. There were strangs receiving in bath of water and threated with knife granulation. Then, there were granules drying on air during 5h, and, then in thermal vacuum oven at 80±5 o C during 3h. Then, there are monofiber of 1 mm’s diameter formed on lab stand. Then, from one formed those others monofibers of different values of spinneret drawing (Фв, %). There were Фв for monofibers equals of 300 and 500%. Then, there were formed monofibers threated with thermoorientational drawing process at 150 oC. Then, there were monofibers of Фв value, which equals of 300%, drawn till draw degree λ=6, but, those others of Фв value, which equals of 500% - to λ=4. It is succeed, for composite monofibers, that orientational drawing process has had realized, until to the same value, as well as for one of virgin PP. But, when at formation and thermoorientational drawing processes, there were placing much number of breaks, as compared with monofiber of pure PP. When studying the structure with SEM technique, there was revealed microfibrillar structure of composite monofiber. When using optical microscopy, then there was determined irregularity for distribution of addition’s particles, leading to disproportional distribution of tension values at loading. It is revealed, for composite monofiber, at given value for content of addition, that electrical conductivity phenomenon is absent here. There are real ε’and imaginal ε’’ parts of complex dielectrical permittivity phenomenon, on frequency of 9 GHz, equals of 2.1 and 0.2, accordingly. It is established, that pure, non-drawn and composite monofiber itrinsically have satisfactory magnetic properties (σs=0.5 Gs∙cm3/g, Hc= 695 E). There are real μ’ and imaginal μ’’ parts of complex magnetical permittivity phenomenon equals of 1.1 and 0.02, accordingly.

Determination of the Best Working Conditions for the Recycling of Solar Modules

The work describes experiments conducted on ethylene vinyl acetate layer in samples of photovoltaic module, where it functions as insulation and binder. The degradation was achieved by thermal vacuum oven, in which degradation by heat in common air and nitrogen atmosphere was conducted. The aim of the work was to find the lowest workable temperature and melting conditions for a laminated EVA material and thus to minimize the energy requirements of PV module recycling.

Vitrimerization of Poly(butylene succinate) By Reactive Melt Mixing Using Zn(II) Epoxy-Vitrimer Chemistry

Vitrimers constitute a new class of covalent adaptable networks (CANs), in which thermally stimulated associative exchange reactions allow the topological rearrangement of the dynamic network while keeping the number of bonds and the crosslink density constant. The current study proposed a solvent-free method to synthesize vitrimers by reactive melt mixing using a commercial biobased/biodegradable polyester, poly(butylene succinate), PBS. More specifically, a two-step process was followed; the first step involved reactive mixing of PBS with the crosslinker (diglycidyl ether of bisphenol A, DGEBA) and the transesterification catalyst (Zinc(II) acetylacetonate hydrate, Zn(acac)2) in a twin-screw mini-compounder, in order to incorporate the epoxy groups in the polymer backbone. The second step (vitrimerization) comprised a crosslinking process of the homogenous mixtures in a vacuum oven at 170 °C, resulting in the formation of a dynamic crosslinked network with epoxy moieties serving as the crosslinkers. By tuning the crosslinker content (0–10% mol with respect to PBS repeating unit) and the Zinc(II) catalyst to crosslinker ratio (0 to 1), tailor-made vitrimers were prepared with high insolubility and improved melt strength. Moreover, PBS vitrimers could still be reprocessed by compression molding after the crosslinking, which enables the recycling process. This work was made possible by the “Basic Research Programme, NTUA, PEVE 2020 NTUA” [PEVE0050] of the National Technical University of Athens and is gratefully acknowledged.

Preparation and characterization of liquid natural rubber through oxidative degradation with phenyl hydrazine and benzoyl peroxide-oxygen

The aim of this research was to synthesize liquid natural rubber (LNR) from Natural rubber (SIR-20) by chain scission method in the presence of oxygen gas and difference of peroxides, phenyl hydrazine and benzoyl peroxide. The chain scission reaction was conducted in solution of xylene in close system. SIR-20 was diluted xylene before flushing with oxygen and the addition of the peroxide. The degradation oxidation by the oxygen and the peroxides was processed at 60°C for 24 hours. The degradative oxidation product was re-precipitated by adding the excess of methanol and filtrated before dried in vacuum oven 60°C for 24 hours. The dried product was characterized by Fourier Transform Infra Red (FTIR). It was found that the liquid natural rubber product successfully degraded by chain scission process as shown the change of the peak area intensity of infrared absorption. It was showed the peaks area intensity of O-H and carbonyl group of liquid natural rubber spectra increased.

Determination of myo-inositol content in milk by high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD)

A method to determine inositol content in milk using high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) was developed and validated. Samples were hydrolyzed with 10 mL HCl in a vacuum oven at 120oC, prolonging 6 h. Hydrolyzed samples were neutralized to a pH from 6 to 7.5 before analysing in an HPAEC-PAD system. The analytical program used Dionex CarboPacTM MA1 column (4 × 250 mm) with a mobile phase of a gradient program including NaOH 50 mM and NaOH 1M. The method was validated following AOAC guidelines: selectivity, linear range from 0,01 to 20 mg/L with a coefficient (R) 0.9998, the recoveries in the range of 99 - 102%, and repeatability with RSD under 1.8%. The limit of detection (LOD) and the limit of quantification (LOQ) of inositol were 0.047 µg/g and 0.155 µg/g, respectively. The method has been applied to determine of inositol content in milk samples with content ranging from 22.5 mg/100g to 64.7 mg/100g.

Proximate Analysis of Goat Milk Yogurt Powder Produced by Freeze Drying and Vacuum-Oven Drying and in Comparing with Freeze-Dried Yogurt Powder Prepared with Tualang Honey

This study was carried out to produce powdered yogurt from goat milk with longer shelf life.Two methods of drying process of yogurt were used which are vacuum-oven drying (VD) and freezedrying (FD). Goat milk yogurt powder prepared with added Tualang honey (TH) was produced by freeze-drying method. In this study, four formulations of yogurt were prepared with the addition of commercial yogurt containingas starter culture.Granulated sugar was added about 8% into the yogurt as control sample. While other three yogurts were prepared with 8% of Tualang honey, 6% of Tualang honey with 2% of sugar and 4% of Tualang honey with 4% of sugar. The proximateanalysis was used in order to identify the proximate composition and pH value of the yogurt. The moisture content of goat milk yogurt, VD goat yogurt powder and FD goat yogurt powder were 79.20%, 8.22% and 9.66% respectively. While, the moisture content for FD goat yogurt powder with addition of 4%, 6% and 8% Tualang honey were 15.12%,15.92% and 13.53% respectively.While the value of ash content for FD goat milk yogurt powder with addition of 4%, 6% and 8% Tualang honey were 0.37%, 0.35% and 0.50% respectively. The total protein content for goat milk yogurt was 4.61% whilein VD goat yogurt powder and FD goat yogurt powder were 15.04% and 15.07% respectively. The value of protein content for FD goat milk yogurt powder with addition of 8% of Tualang honey was 15.38%. The pH value ofgoat milk sample and fresh yogurt goat milk were 6.52 and 3.82. The pH values for fresh yogurt with addition of 4%, 6% and 8% of Tualang honey were 4.64, 4.68 and 4.73.Vacuum-oven drying method and freeze-drying method did not show any significant different in moisture, ash and protein content but showed significant different in pH value.

Vacuum oven drying of mussels: mathematical modeling, drying characteristics and kinetics study

PurposeThe aim of this work was to study the effect of the different temperatures on drying kinetics and quality parameters of vacuum oven-dried mediterranean or black mussel (Mytilus galloprovincialis) specimens.Design/methodology/approachDrying process was performed at 50, 60 and 70 °C and a vacuum drying pressure of 0.1 kPa. The proximate composition analysis was done. Drying rates of the mussels were computed. Mathematical modeling was carried out. Effective moisture diffusivity, activation energy and total energy consumption were calculated. Color measurement was conducted.FindingsDrying took place entirely in the falling rate period. The obtained results indicated that the drying air temperature has a remarkable influence on the moisture content and drying rate. Drying resulted in a significant increasing of protein and fat content. The Deff values ranged from 1.44 × 10−9–3.23 × 10−9 m2/s, with the activation energy 4.47 kW kg−1. The Alibas model is the most proper model to define the drying curves. This method provided high energy efficiency and quality in dried products.Research limitations/implicationsFresh mussels grown in Eceabat location were used as the study sample. In the drying process, 50, 60, 70 °C temperatures and 0.1 kPa pressure was used. These are the limitations of the research.Originality/valueThis work is the first to report the influence of vacuum oven drying on the color changes and drying kinetics of black mussels.

Study on the Chemistry Identification and Assessment of Antioxidant and Antibacterial Activity of the Biologically Active Constituents from the Roots of Arnebia Euchroma for Promising Application in Nanomedicine and Pharmaceutical

The recent work aims to investigate different extracts of A. euchroma as a medicinal plant and evaluate their phytochemicals screening, chemical compositions, total phenols content, antioxidant and antimicrobial activities. The plant's roots were extracted with various solvents: ethanol, n-Hexane, and chloroform through the maceration method at ambient temperature for several days. All extracts were filtered and evaporated to dryness using a rotary evaporator and vacuum oven. The chemical compositions, spectroscopy analysis, total phenols, antioxidant and antimicrobial activities of three prepared extracts were evaluated by Liquid Chromatography-Mass Spectrometry (LC-MS), UV-vis, High-performance thin-layer chromatography (HPTLC), Folin-Ciocalteu reagent (FCR), 2,2-diphenyl- 1-picrylhydrazyl (DPPH), and MIC and MBC methods, as well as the structure and surface morphologies of the bacteria after and before treatment, were imaged by Scanning Electron Microscopy (SEM). The phytochemical screening demonstrated that the extracts contain tannins, saponin, alkaloid, and anthraquinone. This result was supported via LC-MS analysis, which confirmed the existence of several components. The highest amount of phenols was detected in n-hexane extract, and the lowest was in chloroform. All extracts had good antioxidant activity, with IC50 values of 3.9 µg/ml for ethanol and chloroform extract and 7.8 µg/ml for n-hexane in the DPPH assay. The extracts inhibited both Gram-positive and Gram-negative bacteria's growth at a 300-700 µg/ml MIC. LC-MS analysis showed the presence of phenolic compounds, which had high antioxidant activity. It could be used as a potent antioxidant and antibacterial agent with remarkable prospects in pharmaceutical and nanoformulation.