We investigated the influence of anion type (salicylate, [(MOB)MIm][Sal], vs chloride, [(MOB)MIm][Cl]) of imidazolium-based ionic liquid (IL) and its content on the curing kinetics of bisphenol A diglicydyl ether (DGEBA of molecular weight M_n = 340 g/mol). Further physicochemical properties (i.e., glass transition temperature, T_g, and conductivity, σ_dc) of produced polymers were investigated. The polymerization of the studied systems was examined at various molar ratios (1:1, 10:1, and 20:1) at different reaction temperatures (T_reaction = 353–383 K) by using differential scanning calorimetry (DSC). Interestingly, both DGEBA/IL compositions studied herein revealed significantly different reaction kinetics and yielded materials of completely distinct physical properties. Surprisingly, in contrast to [(MOB)MIm][Cl], for the low concentration of [(MOB)MIm][Sal] in the reaction mixture, an additional step in the kinetic curves, likely due to the combined enhanced initiation activity of anion (salicylate)–cation (imidazolium-based), was noted. To thoroughly analyze the kinetics of all studied systems, including the two-step kinetics of DGEBA/[(MOB)MIm][Sal], we applied a new approach that relies on the combination of the two phenomenological Avrami equations. Analysis of the determined constant rates revealed that the reaction occurring in the presence of the salicylate anion is characterized by higher activation energy with respect to those with the chloride. Moreover, DGEBA/[(MOB)MIm][Sal] cured materials have higher T_g in comparison to DGEBA polymerized with [(MOB)MIm][Cl] independent of the IL concentration. This fact might indicate that, most likely, the products of hardening are highly cross-linked (high T_g) or oligomeric linear polymers (low T_g) in the former and latter cases, respectively. Such a change in the chemical structure of the polymer is also reflected in the dc conductivity measured at the glass transition temperature, which is much higher for DGEBA cured with [(MOB)MIm][Cl]. Herein, we have clearly demonstrated that the type of anion has a crucial impact on the polymerization mechanism, kinetics, and properties of produced materials.

This review concerns the interpretation of the signal provided by SQUID magnetometers designed for measurements of magnetization and magnetic susceptibility. ‘‘Image effect’’ refers to the influence of superconducting elements in the vicinity of the sample and detection coil. Several exact and approximate methods are presented for calculation of how the device sensitivity G(r) varies with position r of a unit dipole sample in the presence of a superconducting shielding tube. In particular, the relative decrease of G(r) is approximately given by the third power of the ratio of the detection coil and shield diameters, and the effect of the shield’s finite length is found to be negligible in practical situations. A survey of complex detection coils (Helmholtz, saddle‐type, gradiometer, and second derivative coil) includes calculation of the optimum spacing of the Helmholtz pair in the presence of a superconducting cylinder. The image effects due to the properties of the SQUID circuit and the field‐dependent effects in high‐field SQUID magnetometers are also discussed. Change in the instrument calibration due to sample size, shape, and location is considered for arbitrary samples as well as for specific cases of small, medium, and very long samples. A spherical harmonic expansion of G(r) makes it possible to derive simple formulas describing sample geometry effects for medium‐sized samples with regular geometries (thin rod, cylinder, and rectangular parallelepiped). The results are compared to published experimental data.

Novel method of N-dealkylating quinobenzothiazinium salts 2, promoted by reaction with benzimidazole, led to a series of new azaphenothiazine derivatives having 12(H)-quino[3,4-b][1,4] benzothiazine 4 structure. Reaction of compounds 4 in an alkaline milieu with alkylating agents occur as N-alkylation of the thiazine nitrogen and yields quinobenzothiazine derivatives 7. In vitro antiproliferative activity of compounds 4 and 7 was tested using two cancer cell lines (SNB-19 and C-32) and cisplatin as a reference. Most of the studied azaphenothiazine derivatives showed activity against both cell lines investigated (5.6–12.4 μg/ml concentration range tested). Compounds 4(b–e) containing a halogen atom or methyl group at the 9-position of the quinobenzothiazine ring show activity in the tested concentration range only against C-32 cell line. Compound 4f with methyl group in 11-position of quinobenzothiazine ring lacked activity against either cell line. The presence of additional aminoalkyl substituents at the thiazine nitrogen atom in compounds 7 increases their activity against both examined cell lines, when compared to compounds 4.

In this paper, catalyzed and non-catalyzed water-initiated Ring-Opening Polymerization (ROP) of ε-caprolactone (ε-CL) under various thermodynamic conditions (T = 293–393 K and p = 0.1–500 MPa) was carried out. As organocatalysts, two non-nucleophilic bases characterized by different modes of action, i.e. 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), were used. High-pressure experiments revealed that polymerization proceeded much faster with respect to the reactions performed at ambient pressure (a limiting example of t = 168 h vs. t = 6 h) and the synthesized PCLs were characterized by molar masses, M_n, up to 16.7 kg mol⁻¹ and low/moderate dispersity, Đ = 1.03–1.56. Moreover, as revealed by MALDI-TOF studies, polymers with telechelic characters were obtained. In each case the varying content of cyclic polyesters was detected as well. Their presence had a strong influence on the discrepancy between theoretically and experimentally determined M_n. Collected data surprisingly also revealed the enhanced catalytic activity of DBU over TBD at high pressure. One can add that for the ROP catalyzed by the latter compound, the termination process was still observed, while for a selected monomer to catalyst ratio a “pseudo-living” character of polymerization was warranted for the former catalyst. Further investigations with the use of FT-IR allowed us to hypothesize that TBD is fully protonated by water that is followed by cluster formation limiting its catalytic activity. On the other hand, the enhanced activity of DBU results from the presence of both forms (protonated and non-protonated) in reaction media acting as a Brønsted acid/base system. Our studies offer a new, more eco-friendly way to synthesize well-defined telechelic PCLs of moderate molecular weights in very short times and a better understanding of the role of intermolecular interactions in the catalytic activity of organocatalysts and generally the progress of ROP.

The synthesis of well-defined imidazolium-based poly(ionic liquid)s (PILs) by reversible addition–fragmentation chain transfer (RAFT) polymerization is demonstrated. Two specially designed monomeric ionic liquids (MILs), such as 1-methyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide [MVIM][NTf₂] and 1-ethyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide [EVIM][NTf₂] were polymerized with the 2,2′-azobisisobutyronitrile (AIBN) initiator in the presence of a trithiocarbonate RAFT agent. Depending on the varied ratios of the monomer to CTA ([monomer]/[CTA] = 100/1; 400/1; 1000/1) we obtained P[MVIM][NTf₂] and P[EVIM][NTf₂] homopolymers with the number-average molecular weights (M_n) in a broad range M_n = 2.5–340.0 kDa and M_n = 2.1–450.0 kDa, respectively. The controlled character of the polymerization of each ionic monomer was confirmed by the pseudo-first order kinetic, a linear increase in the M_n with conversion and relatively narrow dispersity indices (Đ = 1.09–1.37 for P[MVIM][NTf₂] and Đ = 1.10–1.41 for P[EVIM][NTf₂]). Additionally, the obtained macromolecules are characterized by the enhanced/or comparable conductivity in comparison with those reported in the literature [Wojnarowska et al., Macromolecules, 2014, 47, 4056–4065 and Fan et al., Macromolecules, 2016, 49, 4557–4570], indicating that we are able to produce polymers of high molecular weights characterized by relatively high conductivity (σ_dc ∼ 10⁻⁹ at T_g). Finally, we found quite unexpected evolution of T_gvs. M_n of the produced polymers in the limit of low molecular weight, which seems to correspond to those observed in the case of van der Waals polymers such as polystyrene or polyisobutylene.