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Faraday tomography of a field centred on the extragalactic point source 3C 196 with the LOw Frequency ARray (LOFAR) revealed an intertwined structure of diffuse polarised emission with straight depolarisation canals and tracers of the magnetized and multi-phase interstellar medium (ISM), such as dust and line emission from atomic hydrogen (HI). This study aims at extending the multi-tracer analysis of LOFAR data to three additional fields in the surroundings of the 3C 196 field. For the first time, we study the three-dimensional structure of the LOFAR emission by determining the distance to the depolarisation canals. We use the Rolling Hough Transform to compare the orientation of the depolarisation canals with that of the filamentary structure seen in HI and, based on starlight and dust polarisation data, with that of the plane-of-the-sky magnetic field. Stellar parallaxes from $Gaia$ complement the starlight polarisation with the corresponding distances. Faraday tomography of the three fields shows a rich network of diffuse polarised emission at Faraday depths between $-10~{\rm rad~m^{-2}}$ and $+15~{\rm rad~m^{-2}}$. A complex system of straight depolarisation canals resembles that of the 3C 196 field. The depolarisation canals align both with the HI filaments and with the magnetic field probed by dust. The observed alignment suggests that an ordered magnetic field organises the multiphase ISM over a large area ($\sim$20$^{\circ}$). In one field, two groups of stars at distances below and above 200 pc, respectively, show distinct magnetic-field orientations. These are both comparable with the orientations of the depolarisation canals in the same field. We conclude that the depolarisation canals likely trace the same change of the magnetic field as probed by the stars, which corresponds to the edge of the Local Bubble., Comment: 14 pages, 11 figures, accepted for publication in A&A

Faraday tomography of radio polarimetric data below 200 MHz from LOFAR are providing us with a new perspective on the diffuse and magnetized interstellar medium (ISM). Of particular interest is the discovery of Faraday-rotated synchrotron polarization associated with neutral gas, as traced by atomic hydrogen (HI) and dust. Here we present the first in-depth numerical study of these LOFAR results. We produce and analyze comprehensive synthetic observations of low-frequency synchrotron polarization from MHD simulations of colliding super shells in the multiphase ISM. We define five distinct gas phases over more than four orders of magnitude in gas temperature and density, ranging from hot, and warm, fully ionized gas to cold neutral medium. We focus on the contribution of each gas phase to synthetic observations of both rotation measure and synchrotron polarized intensity below 200 MHz. We also investigate the link between the latter and synthetic observations of optically thin HI gas. We find that, not only the fully ionized gas but also the warm partially ionized and neutral phases strongly contribute to the total rotation measure and polarized intensity. However, the contribution of each phase to the observables strongly depends on the choice of integration axis and the orientation of the mean magnetic field with respect to the shell-collision axis. Strong correlation between HI synthetic data and synchrotron polarized intensity, reminiscent of LOFAR results, is obtained with lines of sight perpendicular to the mean magnetic field direction. Our study suggests that multiphase modelling of MHD processes is needed in order to interpret observations of the radio sky at low frequency. This work is a first step toward understanding the complexity of low-frequency synchrotron emission that will be soon revolutionized by large-scale surveys with LOFAR and the SKA., Comment: 17 pages, 20 figures, accepted by A&A, in press

N‐tert‐butylacrylamide (NtBA) was copolymerized with ethylene glycol dimethacrylate (EDMA) in butanone solution over a wide composition and conversion range, using dibenzoyl peroxide (Bz2O2) as a free‐radical initiator. The copolymer composition was determined from the nitrogen content. Using only low conversion (≤20%) collected for the copolymerization reactions, monomer reactivity ratios were estimated using the Kelen‐Tudos graphical method and were found to be r1=0.26 (NtBA) and r2=7.05 (EDMA). In order to get a better insight into the mechanism of nanoporous copolymers of NtBA with EDMA preparation by thermal degradation of copolymers of N‐acryl‐N,N′‐di‐tert‐butylurea (A‐DitBuU) with EDMA, nonporous copolymers (model compound), of the same chemical structure and composition, were prepared by performing copolymerization of NtBA with EDMA up to the high conversion of 97–100%. Thermal behavior of nanoporous and nonporous copolymers of NtBA with EDMA was studied.

Synthesis and free‐radical initiated copolymerization of N‐acryl‐N,N′‐di‐tert‐butylurea (A‐DitBuU) with ethylene glycol dimethacrylate (EDMA) are described. The A‐DitBuU monomer was prepared by the condensation of acrylic acid to the N,N′‐di‐tert‐butylcarbodiimide (DitBuC) at room temperature. Copolymers of A‐DitBuU with EDMA of different monomer to monomer ratios in the feed were prepared in the presence of dibenzoyl peroxide (Bz2O2) in butanone at 70°C for 48 h up to a high conversion. The obtained crosslinked copolymers are insoluble in organic solvents. Copolymers thermal decomposition resulted in separation of tert‐butylisocyanate (C4H9NCO) in the temperature range between 180 and 280°C and by the formation of the thermally stable molecularly imprinted copolymers of N‐acryl‐N‐terc‐butylamide (A‐tBuA) with EDMA.

Copolymers of methacryl‐N,N′‐diisopropylurea (MA‐DiPrU) with ethylene glycol dimethacrylate (EDMA) at monomer‐to‐monomer ratios in the feed: 0.3/0.7; 0.5/0.5; 0.7/0.3; 0.8/0.2 were prepared in butanone in the presence of 2% of dibenzoyl peroxide (Bz2O2) at 70°C for 48 hr. Copolymers regardless of the ratio of comonomers in the feed decompose thermally at 200–250°C under the separation of isopropylisocyanate (iPrNCO). Residues after the removal of iPrNCO are thermally stable nanoporous crosslinked copolymers of methacryl‐isopropylamide (MA‐iPrA) with EDMA which decompose by a one‐step mechanism between 280°C and 450°C. Nonporous model copolymers poly(MA‐iPrA‐co‐EDMA) of similar composition, prepared by copolymerization of MA‐iPrA with EDMA, also decomposed by a one‐step mechanism as shown by TGA measurements.

Copolymers of methacryl‐dicyclohexylurea (MA‐DCU) with ethylene glycol dimethacrylate (EDMA) at monomer‐to‐monomer ratios in the feed: 0.3/0.7, 0.5/0.5, 0.7/0.3, 0.8/0.2 were prepared in butanone in the presence of 2% of dibenzoyl peroxide at 70°C for 48 hr. Copolymers, regardless of the ratio of comonomers in the feed, decompose thermally at 200–250°C under the separation of cyclohexylisocyanate (C6H11NCO). Residues after the removal of C6H11NCO are thermally stable nanoporous crosslinked copolymers of methacryl‐cyclohexylamide (MA‐CHA) with EDMA, which decompose by a one‐step mechanism between 300°C and 480°C.

Copolymerization of N-acryl-N,N′-dicyclohexylurea with ethylene glycol dimethacrylate or divinyl benzene in the presence of dibenzoyl peroxide as initiator gave corresponding crosslinked copolymers. Both copolymers thermally decompose by two-step mechanism. The first step separates cyclohexylisocyanate, thus forming the thermostable residue, which contains molecular imprints of cyclohexylisocyanates.

N-Acryl-N,N′-dicyclohexylurea (A-DCU) homopolymers and copolymers with styrene (St) are prepared under the standard free-radical-initiated polymerization. Copolymers of A-DCU with St prepared under different monomer-to-monomer ratios in the feed, have random composition with an azeotropic point at a ratio of 0.73 (A-DCU) to 0.27 (St). N-Methacryl-N,N′-dicyclohexylurea (MA-DCU) does not homopolymerize, but copolymerizes with St to randomly composed copolymers. Reactivity ratios determined by the Kelen-Tudos method are: r1 (A-DCU) = 0.80; r2 (St) = 0.50, and r1 (MADCU) = 0.18; r2 (St) = 4.84. All copolymers decompose under TGA conditions by a two step mechanism. In the first step, at a temperature of about 200°C separates cyclohexylisocyanate (C6 H11 NCO) under the formation of thermally stable poly(C6 H11 -acrylamido-co-St) and poly(C6 H11-methacrylamido-co-St) which decompose at a temperature of 450°C without the residue.

The title copolymers have been prepared by the free-radical-initiated copolymerization of 2-chlorostyrene (2-ClSt), 4-chlorostyrene (4-ClSt) and 2, 6-dichlorostyrene (2, 6-DClSt) with maleic anhydride (MAn) in toluene at 650C. Copolymers of chlorinated styrenes with MAn prepared under different monomer-to-monomer ratios in the feed have alternating composition. In all cases the mixture of comonomers forms charge-transfer complex monomers (CTC). Initial rate of copolymerization increases with the increase of electron donors in the comonomer feed, and the highest rates were at the equimolar ratios of comonomers in the feed. The thermal stability of the polymers was measured by thermogravimetric analysis in nitrogen. Homopolymers decompose by one-step mechanism while copolymers are more thermostable and decompose by two-step mechanism. Tg’s of homopolymers are lower than Tg’s of copolymers. The number and weight average molecular weights of chlorinated copolymers are higher than those of the corresponding homopolymers.

The free-radical-initiated copolymerization of 2,6-dichloro-styrene (2,6-DClSt), with maleimide (MI), N-methylmaleimide (NMeMI) and N-phenylmaleimide (NPhMI) was carried out in butanone or in toluene at 65°C with different monomer-to-monomer ratios in the feed. The copolymer composition was evaluated by chlorine content in polymers. The reactivity ratios determined by Kelen-Tudos method indicate the random arrangement of monomers in copolymer chains. In all studied systems, azeotropic points were observed at ratios of: 0.5 (2,6-DClSt) to 0.5 (MI) and 0.4 (2,6-DClSt) to 0.6 (NMeMI and NPhMI). Molecular weights of copolymer, which contain equimolar ratio of 2,6-DClSt-co-MI, NMeMI, and NPhMI are: Mw· 10−3 = 46.1; 90.4; 81.4. Mn 10−3 = 27.1; 46.0; 37.0. The copolymers are thermostable, film forming materials, which decompose by one-step mechanism between 400°C, and 500°C. The Tg's are linearly distributed between Tg's of homopolymers and in all cases, single well defined Tg's are obtained.

N(p-Phenoxy-phenyl)methacrylamide (PhOPhMAA) prepared by condensation of methacrylic acid anhydride with p-phenoxy-phe-nylamine readily homopolymerizes and copolymerizes with styrene (St) in the presence of azobisisobutyronitrile as initiator. The copolymers prepared under different monomer-to-monomer ratios in the feed have random composition with an azeotropic point at ratio f 0.65 (St) to 0.35 (PhOPhMAA). Reactivity ratios determined by Kelen-Tudos method are r 1 (St) = 0.61; r 2 (PhOPhMAA) = 0.55. Activation energy determined by Arrhenius method is 71.2 kJ mol -1 . Poly-PhOPhMAA and poly(PhOPhMAA-co-St) are thermally stable up to 350°C under TGA conditions. Tgs and higher transition temperatures are within the thermally stable region.

Synthesis and free-radical-initiated homopolymerization of phenoxy-phenylmaleimide (PhOPhMI) and copolymerization with styrene (St), (α-methylstyrene (αMeSt) and β–methylstyrene (β-MeSt) are described. It was found that alternating copolymers are formed under different monomer-to-monomer ratios in the feed and that the mechanism based on the participation of CT-complex best explains the formation of alternating copolymers. Equilibrium constants of CT-complexes are: K PhOPhMI/St = 0.20 Lmol−1; KPhOPhMI/αMeSt = 0.05 Lmol−1; KPhOPhMI/βMeSt = 0.02 Lmol−1. Homopolymer and co-polymers are film-forming materials, stable up to 350°C under TGA conditions. Tg s and higher transition temperatures are within the thermally stable region.

The title compounds have been prepared by the addition of acrylic acid and methacrylic acid to dicyclohexylcarbodiimide (DCC). N-Acryl-N,N′-dicyclohexylurea (Acryl-DCU) homo-polymerizes and copolymerizes with α-methylstyrene (αMeSt), while Methacryl-DCU does not polymerize under the standard free-radical-initiated polymerization. Copolymers of Acryl-DCU with αMeSt prepared under different monomer-to-monomer ratios in the feed have random composition with an azeotropic point at ratio of 0.75 (Acryl-DCU) to 0.25 (αMeSt). Reactivity ratios determined by the Kelen-Tudos method are r1 (Acryl-DCU) = 0.72 and r2 (αMeSt) = 0.07. Poly(Acryl-DCU) and copolymers with αMeSt decompose under the TGA conditions by a two step mechanism. In the first step between 180 and 250°C, cyclohexylisocyanate separates by degradation of dicyclohexylurea in the side chain, while the thermally stable residue represents the poly(cyclohexylacrylamide) and copolymers with αMeSt.