Weathering performance of waterborne acrylic coating systems on flat-pressed wood–plastic composites

This study applied coating systems containing two different waterborne acrylic resins with an ultraviolet (UV) absorber on the surfaces of polyvinyl chloride-based flat-pressed wood–plastic composites (WPCs) evaluated and the effects of waterborne acrylic coating on the performance of WPCs in outdoor conditions. The results showed that waterborne acrylic coating systems enhanced the surface quality of WPC. The decrease in flexural strength was found to reach up to 22%, while it was about 25% for modulus. The color changes on the surface decreased by 55% as a result of the UV absorbability of the coating systems. Moreover, the chemical changes in the composites were found to be almost nonexistent in the attenuated total reflection–Fourier transform infrared spectroscopy for WPCs coated with both formulations. The light microscopy images revealed that the coating systems minimized deformation on the surface. In comparison to the control samples, it was seen that the surface roughness of the WPC was also improved by using waterborne acrylic coating systems. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48518.     

Sustainable Membrane Production through Polyelectrolyte Complexation Induced Aqueous Phase Separation

Nonsolvent induced phase separation (NIPS) is the most common approach to produce polymeric membranes. Unfortunately, NIPS relies heavily on aprotic organic solvents like N‐methyl‐pyrrolidone. These solvents are unsustainable, repro‐toxic for humans and are therefore becoming increasingly restricted within the European Union. A new and sustainable method, aqueous phase separation (APS), is reported that eliminates the use of organic solvents. A homogeneous solution of two polyelectrolytes, the strong polyanion poly(sodium 4‐styrenesulfonate) (PSS) and the weak polycation poly(allylamine hydrochloride) (PAH), is prepared at high pH, where PAH is uncharged. Immersing a film of this solution in a low pH bath charges the PAH and results in a controlled precipitation, forming a porous water‐insoluble polyelectrolyte complex, a membrane. Pore sizes can be tuned from micrometers to just a few nanometers, and even to dense films, simply by tuning the polyelectrolyte concentrations, molecular weights, and by changing the salinity of the bath. This leads to excellent examples of microfiltration, ultrafiltration, and nanofiltration membranes. Polyelectrolyte complexation induced APS is a viable and sustainable approach to membrane production that provides excellent control over membrane properties and even allows new types of separations.     

The kinetic analysis of optimization and selective transportation of Cu(Ⅱ) ions with TNOA as carrier by MDLM system

This study covers the transportation of Cu(Ⅱ) ions by multi-dropped liquid membrane(MDLM) system and tri-noctylamine(TNOA) as carrier in kerosene. Batch experiments are held to obtain optimum conditions for the transportation of Cu(Ⅱ) ions such as volume of donor, organic, and acceptor phase 100 ml, p H of donor phase9.00, temperature 298.15 K, concentration of H_2SO_4 in acceptor phase 1.00 mol·L~(-1), concentration of TNOA in organic phase 5.00 × 10~(-3)mol·L~(-1)and rate of peristaltic pump 50 ml·min~(-1). Optimum circumstances of this extraction are as follows: p H of donor phase is 9.00, concentration of TNOA is 5.00 × 10~(-3)mol·L~(-1),1.00 mol·L~(-1)H_2SO_4 as acceptor phase, and flux rate is 50 ml·min~(-1). Cu(Ⅱ) ion transportation is consecutive first order irreversible reaction. Activation energy is found as 5.22 kcal·mol-1(21.82 k J·mol~(-1), this process is called as diffusion controlled system. Selective transportation of Cu(Ⅱ) ions with alkaline, alkaline earth, and different heavy metal ions at optimum conditions of single Cu(Ⅱ) extraction was conducted. According to the selective transportation Cu(Ⅱ) ions with alkaline and alkaline earth metal ions, Na~+, K~+, and Ba~(2+)ions are not detected in the acceptor phase, but 12.00% of Ca~(2+)ions is transported from donor phase to acceptor phase. At the end of the simultaneous extraction of Zn(Ⅱ), Fe(ⅡI), and Mo(VI) with Cu(Ⅱ) ions, 2.20% of Mo(VI), 0.80% of Fe(Ⅲ) and 3.60% of Zn(Ⅱ) are detected in the acceptor phase.     

Peculiarities of δ- and α-relaxations in thermotropic side chain liquid crystalline polymers with and without nematic reentrant phase

We have performed a dielectric spectroscopy study of four homologous cyanobiphenyl polyacrylates with long side chains. The α- and δ-relaxation times were found to be sensitive to the sequential transformations between mesophases. The τ^δ in the isotropic phase exhibits the characteristics that obeys VFT relation and depend strongly on spacer length. The relaxation times, τ^δ, for the crossover from short range intermolecular interactions to long range LC ordering, decreases with increasing side chain length, implying that the cooperative motions of mesogenic dipoles arrange long range order at shorter time scales, as the spacer length is increased. In the SmA mesophases of CBPAn compounds with n = 8, 9 and 11 α-relaxation times were found to be nearly temperature independent at high temperatures. Thus, segmental motions take place in the state of diminished dynamical constraints of backbones, which can be attributed to the plasticization effects of polymeric layers in the case of long methylene spacers. In CBPA6 and CBPA8, with even numbers of methylene groups, anomalies of δ-relaxation processes were observed at the nematic reentrant (N_re) transitions. The anomalies of α-relaxation processes in the SmA mesophases were found to be precursors of N_re transitions as temperature decreases. The changes in backbone conformations of the SmA layers with decreasing temperature create the conditions for molecular corrugations of the side chains leading to the formation of the nematic order of N_re phases.     

Data processing of absorption spectra from photoionized plasma experiments at Z

We discuss the processing of x-ray absorption spectra from photoionized plasma experiments at Z. The data was recorded with an imaging spectrometer equipped with two elliptically bent potassium acid phthalate (KAP) crystals. Both time-integrated and time-resolved data were recorded. In both cases, the goal is to obtain the transmission spectra for quantitative analysis of plasma conditions.     

Approximate solutions for nonlinear oscillation of a mass attached to a stretched elastic wire

In this paper, the approximate solutions of the mathematical model of a mass attached to a stretched elastic wire are presented. At the beginning of the study, the equation of motion is derived in a detailed way. He’s max–min approach, He’s frequency–amplitude method and the parameter-expansion method are implemented to solve the established model. The numerical results are further compared with the approximate analytical solutions for both a small and large amplitude of oscillations, and a very good agreement is observed. The relative errors are computed to illustrate the strength of agreement between the numerical and approximate analytical results.     

Scrubbing of SO2 with trona solution in a spray drier

Effect of operating variables on the scrubbing efficiency of SO₂ in a spray drier was investigated using trona (Na₂ CO₃ · NaHCO₃ · 2H₂ O) solutions of different compositions. Results indicated that for a Na/S mole ratio of two (stoichiometric ratio) about 80% of the SO₂ was removed. For higher Na/S ratios, SO₂ removal efficiency increased by up to 100%. Increased SO₂ concentration in the feed gas and decreased outlet temperature caused an increase in the overall conversion. At low temperatures and low SO₂ concentration, the reaction takes place mainly between SO₂ and Na₂ CO₃ As the temperature is increased, decomposition of NaHCO₃ to Na₂ CO₃ and sorption reactions take place simultaneously.     

Antioxidant properties of roasted apricot (Prunus armeniaca L.) kernel

The antioxidant properties of peeled, defatted and roasted apricot kernel flours were evaluated by determining radical scavenging power (RSP), anti-lipid peroxidative activity (ALPA), reducing power (RP), total phenolic content (TPC), assessed by DPPH test, β-carotene bleaching method, iron (III to II) reducing test and Folin method, respectively. Browning degree of the samples was also measured and found to increase almost linearly with the roasting time. Contrary to browning degree, RSP, RP and TPC did not increase linearly but showed a maximum for 10 min of roasting. Roasting reduced the ALPA values, thus unroasted sample showed the highest ALPA value. RSP, RP and TPC measurements of all samples, were in high correlation (at least, r = 0.92).     

Zeolite-filled regenerated cellulose membranes for pervaporative dehydration of glycerol

Regenerated cellulosic membranes were prepared by dissolving linter pulp in N-methylmorpholine-N-oxide (NMMO) solution with four different cellulose concentrations (3, 5, 8 and 10 wt. % cellulose) at three different coagulation temperatures (5, 25 and 50 °C). Zeolite 13 X with an average particle size of 310 nm and Zeolite 4A with an average particle size of 270 nm were added during dissolution. The resulting composite membranes were characterized by Fourier Transform Infrared (FTIR), Thermogravimetric Analyzer (TGA), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). Pervaporation performances of the zeolite filled and unfilled regenerated cellulose membranes were tested for glycerol/water mixture.Chemically and thermally stable regenerated cellulose membranes could be prepared by using submicron sized zeolite loading maximum of 50%. The SEM pictures showed that the zeolite particles in polymer phase were uniformly distributed. It was concluded that the zeolite filled regenerated cellulose membranes have minimum degradation during membrane preparation obtained from NMMO and could be used as pervaporation membranes. At 30 °C and with the addition of 20 wt. % Zeolite 13 X to the cellulose membrane, the flux and selectivity was obtained 65 gm⁻²h⁻¹ and 1681 for 90 wt% glycerol aqueous solution, respectively.