Influence of the characteristics of a water-in-CO2 microemulsion on the separation of metal species

In this study, AOT [sodium bis(2-ethylhexyl) sulfosuccinate] combined with fluorinated cosurfactant or alcohol was used to form a water-in-CO₂ (W/C) microemulsion. The amount of water uptake in the microemulsion was closely related to the PFPE-PO₄/AOT (P/A) ratio. The stability of the microemulsion decreased with the amount of water. Lower temperature and higher pressure stabilize W/C microemulsions. The extraction efficiencies of metals (Cd, Co, Cu, Pb, Zn), when this W/C microemulsion method was used, exceeded 90% (AOT + octanol). The efficiencies for the extraction of Eu, La, and Sr could exceed 94% (AOT + PFPE-PO₄) in sc-CO_2.     

Toughening of syndiotactic polypropylene with chalk

We hypothesized that polymer crystal anisotropy is advantageous for toughening of polymer composites involving easy slip network of oriented crystalline layers around filler particles. To this end, composites of syndiotactic polypropylene (sPP) with high concentration of submicrometer calcium carbonate particles were prepared and examined because usual sPP crystals exhibit high packing anisotropy. The specific orientation of sPP lamellae around chalk grains was found, which is supposed to facilitate the plastic deformation of polymer matrices. The compression molded bars of the composite exhibited markedly higher Izod impact strength than those of neat sPP. Toughening was even enhanced in the injection molded composite, for which 4.5‐fold increase in the impact strength was achieved. Injection‐induced orientation of the disordered form I sPP crystals was enhanced in the composite. The injection molded tensile specimens exhibited also a good drawability. Debonding at chalk–sPP interface occurred both during the impact and tensile tests facilitating the plastic deformation of sPP matrix. Chalk did not have any significant influence on the thermal properties of the composites but it affected the rheological behavior, increasing the loss and storage moduli, and the viscosity. Highly filled sPP composite exhibited solid‐like behavior in a molten state with the storage modulus exceeding the loss modulus in the entire frequency range. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43651.     

The influence of electron beam irradiation,plastic deformation,and re‐irradiation on crystallinity degree,mechanical and sclerometric properties of GUR 1050 used for arthroplasty

The article describes the influence of an electron beam irradiation (I), plastic deformation (D), and re‐irradiation (R) on the properties of ultrahigh molecular weight polyethylene (GUR 1050). It was found that the modification through irradiation entailed a gradual increase in the degree of crystallinity (after irradiation–I). After plastic deformation and re‐irradiation (IDR) the degree of crystallinity decreases which had a direct influence on the mechanical properties. The polymer irradiation only (technique I) resulted in an increase in the maximum stress as compared with the material in the initial state. The application of deformation and re‐irradiation (technique IDR) allowed increasing the deformation resistance by more than 40%. Moreover, the irradiation with an electron beam resulted in the increase in hardness (H) and Young's modulus (E) proportionally to the applied irradiation dose and in the reduction of total indentation work (W_tot) and its components. After deformation and re‐irradiation the polyethylene hardness went down. The application of technique (I) caused an improvement to the material abrasion resistance (reduction of parameter PD–working scratch depth) with the increasing irradiation dose. The introduction of deformation and re‐irradiation did not have a material impact on parameter (PD) increasing at the same time elastic properties of UHMWPE (increase in parameter NPS–elastic recovery). Modification IDR has changed the wear mechanism (β) toward ploughing and has increased the abrasion‐resistance index (W_β) and also significantly reduced the coefficient of friction (μ) of GUR 1050. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43683.     

Polydimethylsiloxane Fluidic Device with Polydopamine‐Coated Inner Channel for Production of Uniform Droplets

A polydimethylsiloxane (PDMS)‐based fluidic device with two flow channels is fabricated by using a rapid prototyping method. The PDMS‐based fluidic device is used to produce water‐in‐oil emulsion (W/O) droplets due to its intrinsic hydrophobicity. To produce uniform oil‐in‐water (O/W) emulsion droplets, the inner channel of the PDMS fluidic device is coated with polydopamine (PDA) by flowing a dopamine precursor in the water channel of the fluidic device. The PDA coating is confirmed by an increase in morphological roughness and nitrogen content. In addition, the contact angle of the PDMS surface decreases from 95° to 30° during PDA coating, suggesting that the inner surface of the fluidic device is hydrophilic. Uniform W/O and O/W emulsion droplets are produced by the pristine PDMS and PDA‐coated PDMS fluidic devices, respectively.

     

Optimization of subtractive-transformative hybrid processes supported by the technological heredity concept

This paper presents the optimization procedure of a hybrid removal-forming type process based on the minimum energy consumption and demanded surface roughness which is supported by the analysis of transformation of the surface and sublayer properties termed as the technological heredity. The experimental investigation covers an alloy steel hardened to 35 HRC and 55 HRC which was initially turned using coated carbide and CBN tools and subsequently burnished to produce surfaces with Ra roughness parameter of about 0.15 μm. The modifications of the initial surface profiles, microstructure and microhardness of the sublayer were determined and relevant technological limits are selected.     

Use of FIB to Study ZDDP Tribofilms

Focussed ion beam milling (FIB) followed by TEM has been used to study ZDDP tribofilms on rubbed steel surfaces. It has been found that the impact of high energy platinum and gallium ions during FIB causes significant morphological and structural changes to the uppermost 30–50 nm of a ZDDP tribofilm. This can be prevented by the low energy deposition of a quite thick gold layer prior to installation of the sample in the FIB facility. This problem, and its solution, have been quite widely reported in the non-tribology literature but have not previously been highlighted in the application of FIB to study tribological surfaces. It has also been found, using this gold pre-deposition method, that the bulk of the ZDDP tribofilm studied has a polycrystalline structure.     

The Influence of Betulin and Its Derivatives EB5 and ECH147 on the Antioxidant Status of Human Renal Proximal Tubule Epithelial Cells

Betulin and its derivatives, 28-propyne derivative EB5 and 29-diethyl phosphonate analog ECH147, are promising compounds in anti-tumor activity studies. However, their effect on kidney cells has not yet been studied. The study aimed to determine whether betulin and its derivatives—EB5 and ECH147—influence the viability and oxidative status of human renal proximal tubule epithelial cells (RPTECs). The total antioxidant capacity of cells (TEAC), lipid peroxidation product malondialdehyde (MDA) level, and activity of antioxidant enzymes (SOD, CAT, and GPX) were evaluated. Additionally, the mRNA level of genes encoding antioxidant enzymes was assessed. Cisplatin and 5-fluorouracil were used as reference substances. Betulin and its derivatives affected the viability and antioxidant systems of RPTECs. Betulin strongly reduced TEAC in a concentration-dependent manner. All tested compounds caused an increase in MDA levels. The activity of SOD, CAT, and GPX, and the mRNA profiles of genes encoding antioxidant enzymes depended on the tested compound and its concentration. Betulin showed an cisplatin-like effect, indicating its nephrotoxic potential. Betulin derivatives EB5 and ECH147 showed different impacts on the antioxidant system, which gives hope that these compounds will not cause severe consequences for the kidneys in vivo.