Investigating the electrical percolation threshold of ternary composite films with different compatibility between polymer blends

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Huagen Xu ◽  
Muchao Qu ◽  
Qiancheng Yang ◽  
Dirk W. Schubert

Abstract Electrical conductive of polystyrene (PS)/poly(butyl methacrylate) (PBMA)/carbon black (CB) and PS/poly (cyclohexyl methacrylate) (PChMA)/CB ternary composite films with different polymer blend ratios are prepared through solution casting. The percolation thresholds (ϕ c ) of all the composite films before and after thermal annealing have been determined through the McLachlan GEM equation. Moreover, the PS/poly (methyl methacrylate) (PMMA)/CB and PS/poly (ethyl methacrylate) (PEMA)/CB films obtained from the same method while only considering conductivity after thermal annealing as well in this work for comparison. Though the CB particles are revealed to be located at only one polymer phase of all four different polymer blends, with compatibility between polymer blends increasing, the ternary composite films show different ϕ c behaviors by changing polymer blend ratios. In PS/PChMA/CB case, the phase separation between PChMA and PS cannot be observed under scanning electron microscope (SEM). After thermal annealing, all the ϕ c of PS/PChMA/CB films with different PS/PChMA ratios almost show a linear behavior instead of the double percolation behavior with PChMA content increasing. Suppose both ϕ c of binary systems (polymer A/filler and polymer B/filler) is determined. In that case, a linear behavior relationship between the ϕ c of the ternary composites (A + B + fillers) with the ratio of two polymers can be revealed when polymer A and B are miscible.

1979 ◽  
Vol 44 (12) ◽  
pp. 3632-3643 ◽  
Author(s):  
Karel Mach ◽  
Igor Janovský ◽  
Karel Vacek

Total yields of paramagnetic species, their optical bleaching and thermal annealing in acetic, propionic, a-butyric, isobutyric, and pivalic acid γ-irradiated at 77 K were followed by ESR spectroscopy. Radical anions, always found after irradiation, disappear during optical bleaching without formation of any paramagnetic product. During thermal annealing they are converted almost quantitatively into the α-radicals of the respective acid, with the exception of pivalic acid. Amounts of radical anions were estimated from the difference of integrated ESR spectra taken before and after optical bleaching. The results show that approximately equal amounts of the reduction and oxidation paramagnetic products of the γ-irradiation can be detected.


2007 ◽  
Vol 62 (10-11) ◽  
pp. 609-619 ◽  
Author(s):  
Zivayi Chiguvare ◽  
Jürgen Parisi ◽  
Vladimir Dyakonov

The effects of thermal annealing on the bulk transport properties of poly(3-hexylthiophene) (P3HT) were studied by analyzing room temperature current-voltage characteristics of polymer thin films sandwiched between indium tin oxide/poly[ethylene dioxythiophene]:poly[styrene sulfonate] (ITO/PEDOT:PSS) and aluminum electrodes, before and after a thermal annealing step. It was observed that annealing takes place in two steps: (1) Dedoping of the polymer of impurities such as oxygen, remnant solvent, water, leading to a decrease in the conductivity of the film, and (2) thermally induced motion of the polymer chains leading to closer packing, thus, stronger inter-chain interaction and, consequently, increase in conductivity. It was also observed that the ITO/PEDOT:PSS/P3HT hole injection barrier increases on annealing the ITO/PEDOT:PSS/P3HT/Al thin film devices. The implications of impurity dedoping and closer packing on the output characteristics of bulk heterojunction polymer-fullerene thin film solar cells are discussed.


Author(s):  
Yunlong Li ◽  
Ivan Ciofi ◽  
Laureen Carbonell ◽  
Guido Groeseneken ◽  
Karen Maex ◽  
...  

2020 ◽  
Vol 635 ◽  
pp. A167 ◽  
Author(s):  
◽  
H. Abdalla ◽  
R. Adam ◽  
F. Aharonian ◽  
F. Ait Benkhali ◽  
...  

Aims. Colliding wind binary systems have long been suspected to be high-energy (HE; 100 MeV < E < 100 GeV) γ-ray emitters. η Car is the most prominent member of this object class and is confirmed to emit phase-locked HE γ rays from hundreds of MeV to ~100 GeV energies. This work aims to search for and characterise the very-high-energy (VHE; E >100 GeV) γ-ray emission from η Car around the last periastron passage in 2014 with the ground-based High Energy Stereoscopic System (H.E.S.S.). Methods. The region around η Car was observed with H.E.S.S. between orbital phase p = 0.78−1.10, with a closer sampling at p ≈ 0.95 and p ≈ 1.10 (assuming a period of 2023 days). Optimised hardware settings as well as adjustments to the data reduction, reconstruction, and signal selection were needed to suppress and take into account the strong, extended, and inhomogeneous night sky background (NSB) in the η Car field of view. Tailored run-wise Monte-Carlo simulations (RWS) were required to accurately treat the additional noise from NSB photons in the instrument response functions. Results. H.E.S.S. detected VHE γ-ray emission from the direction of η Car shortly before and after the minimum in the X-ray light-curve close to periastron. Using the point spread function provided by RWS, the reconstructed signal is point-like and the spectrum is best described by a power law. The overall flux and spectral index in VHE γ rays agree within statistical and systematic errors before and after periastron. The γ-ray spectrum extends up to at least ~400 GeV. This implies a maximum magnetic field in a leptonic scenario in the emission region of 0.5 Gauss. No indication for phase-locked flux variations is detected in the H.E.S.S. data.


2020 ◽  
Vol 492 (4) ◽  
pp. 5271-5279 ◽  
Author(s):  
Nick Higginbottom ◽  
Christian Knigge ◽  
Stuart A Sim ◽  
Knox S Long ◽  
James H Matthews ◽  
...  

ABSTRACT X-ray signatures of outflowing gas have been detected in several accreting black hole binaries, always in the soft state. A key question raised by these observations is whether these winds might also exist in the hard state. Here, we carry out the first full-frequency radiation hydrodynamic simulations of luminous (${L = 0.5 \, L_{\mathrm{\mathrm{ Edd}}}}$) black hole X-ray binary systems in both the hard and the soft state, with realistic spectral energy distributions (SEDs). Our simulations are designed to describe X-ray transients near the peak of their outburst, just before and after the hard-to-soft state transition. At these luminosities, it is essential to include radiation driving, and we include not only electron scattering, but also photoelectric and line interactions. We find powerful outflows with ${\dot{M}_{\mathrm{ wind}} \simeq 2 \, \dot{M}_{\mathrm{ acc}}}$ are driven by thermal and radiation pressure in both hard and soft states. The hard-state wind is significantly faster and carries approximately 20 times as much kinetic energy as the soft-state wind. However, in the hard state the wind is more ionized, and so weaker X-ray absorption lines are seen over a narrower range of viewing angles. Nevertheless, for inclinations ≳80°, blueshifted wind-formed Fe xxv and Fe xxvi features should be observable even in the hard state. Given that the data required to detect these lines currently exist for only a single system in a luminous hard state – the peculiar GRS 1915+105 – we urge the acquisition of new observations to test this prediction. The new generation of X-ray spectrometers should be able to resolve the velocity structure.


2018 ◽  
Vol 34 (4) ◽  
pp. 2043-2050 ◽  
Author(s):  
Buhani Buhani ◽  
Megafhit Puspitarini ◽  
Rahmawaty Rahmawaty ◽  
Suharso Suharso ◽  
Mita Rilyanti ◽  
...  

In this research, it has been performed carbon activation of oil palm shells (CAC) prepared by chemical treatment as adsorbents of phenol and methylene blue (MB) in solution either in the form of single or in pair solution. The activation of carbon from the oil palm shells was done physically at a temperature of 700°C for 1 hour continued with chemical activation using 10% H3PO4 for 24 hours. Identification of functional groups on the carbon from oil palm shell before and after chemically activated was performed using infrared spectrophotometer (IR) and analysis of its surface morphology was carried out using scanning electron microscope (SEM). The phenol and MB adsorption process was performed in single and binary systems using the batch method. The adsorption of phenol on CAC is optimum at pH 8 while MB at pH 11 with optimum contact time of 90 min for phenol and 120 min for MB respectively. The phenol and MB adsorption data on the CAC in the single system follow the pseudo-second-order kinetics model with the adsorption rate constant of 0.399 and 0.769 g mmol-1 min-1 respectively. The adsorption isotherms of phenol and MB in CAC tend to follow Freundlich adsorption isotherm pattern with the adsorption intensity factor (n) for phenol, MB, phenol/MB, and MB/phenol: 1.739, 1.341, 1.334, and 1.293 respectively. The adsorbent of CAC is effective to remove phenol and MB in solution, either in single or paired condition.


2017 ◽  
Vol 885 ◽  
pp. 36-41 ◽  
Author(s):  
Károly Dobrovszky ◽  
Ferenc Ronkay

Blending polymers is an effective method to develop novel materials, tailoring the properties of the components. However, different morphology structures can be formed during the preparation, which could result in a wide diversity of mechanical and physical properties. The properties of polymer blends are most significantly influenced by the emerging range of phase inversion, which depends on the composition ratio and the viscosity ratio. In this paper various blends were prepared, utilizing polyethylene terephthalate (PET), polystyrene (PS) and two high density polyethylenes (HDPE), which differ in flowability. After preliminary homogenization by twin screw extruder, standard injection moulded specimen were prepared in order to present the effects of phase inversion on tensile properties, shrinkage and burning characteristics in binary polymer blends.


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