γ-radiation-induced telomerization of vinyl acetate,styrene, and methyl methacrylate

Vinyl acetate (VAc), styrene (St), and methyl methacrylate (MMA) were irradiated in dilute solution at an absorbed dose rate of 0.5 Mrad/hr in the absence of oxygen at room temperature. In homogeneous systems, telomers are formed with a rate ∝ [M]¹ at monomer concentrations [M] > ca. 0.4M. The chain length (D.P. .n) increases with increasing [M]. (D.P. .n)^?1 depends over large ranges of [M] linearly on the ratio [S]/[M] (S = solvent) in accordance with the Mayo equation. These findings were obtained with VAc in methanol and with St in cyclohexane. In heterogeneous systems, telomer is formed at all monomer concentrations. The 100-eV yield for telomer formation passes a maximum of G_T(–M) = 40 (MMA in 2-propanol) and G_T(–M) = 27 (MMA in cyclohexane) at the onset of polymer formation ([M] ～ 3 vol-%). With the system St/2-propanol, G_T(–M) ～ 15 was found being independent of [M]. The molecular weight M _n (telomer) increased from ca. 600 to ca. 1200 by increasing [M] up to 100 vol-% (MMA/2-propanol). M _n (telomer) does not depend on [M] in the other two cases (M _n ～ 500, MMA/cyclohexane; M _n ～ 700, St/2-propanol).     

UNIFAC model for ionic liquid‐CO2 systems

The new group binary interaction parameters of UNIFAC model (a_nm and a_mn) between CO₂ and 22 ionic liquid (IL) groups were obtained by means of correlating the solubility data of CO₂ in pure ILs at different temperatures (>273.2 K). We measured the CO₂ solubility at low temperatures down to 243.2 K in pure ILs, i.e., [OMIM]⁺[BF₄]^? and [OMIM]⁺[Tf₂N]^?, and their equimolar amount of mixture, in order to fill the blank of solubility data at low temperatures and also to justify the applicability of UNIFAC model over a wider temperature range. It was verified that UNIFAC model can be used for predicting the CO₂ solubility in pure ILs and in the binary mixture of ILs both at high (>273.2 K) and low temperatures (<273.2 K) effectively, as well as identifying the new structure–property relation. This is the first work to extend the UNIFAC model to IL‐CO₂ systems. © 2013 American Institute of Chemical Engineers AIChE J 60: 716–729, 2014     

Kinetics of azo‐initiated 1‐vinyl‐2‐pyrrolidone polymerizations at low conversions in aqueous media

The free‐radical polymerization behavior of 1‐vinyl,2‐pyrrolidone (NVP) was studied at low conversions, using capillary dilatometry. The aqueous media were kept at neutral pH and the studies were conducted isothermally, at 40 or 45°C. The azo‐type initiators used were 4,4′‐azobis‐4‐cyanopentanoic acid (ACPA), 2,2′‐azobisisobutyronitrile (AZBN), and 2,2′‐azobis[2‐(2‐imidazolin‐2‐yl)propane dihydrochloride] (ABDH). The monomer concentration and initiator concentration ranges were 1.17–2.34 mol L⁻¹ and 1–8 mmol L⁻¹, respectively. The rates of polymerization (R_p) and orders of reaction with respect to NVP and the initiator were evaluated and the kinetic equations were found to be R_p ∝ [NVP] [ACPA]^1.2; R_p ∝ [NVP] [AZBN]^1.1; and R_p ∝ [NVP]^2.2 [ABDH]^1.1. The polymers obtained were characterized by their viscosity numbers and correlation of the viscosity average molecular weights made with the type and amount of the azo initiator. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 239–246, 2000     

The association constant of macrocyclic ether–cation interactions in 1,4-dioxane/water mixtures. III. Effect of temperature on the binding

The association constant, K_a of Na⁺ with [12]crown-4, [15]crown-5 and [18]crown-6 crown ethers were determined in a binary mixture, 1,4-dioxane/water (50/50) using a Na⁺ ion selective electrode at different temperatures. K_a values were determined with the relationship, 1/K_a [L_o]^n+m–1 = (1–nP′)ⁿ(1–mP′)^m/P′, for various stoichiometries, (n:m), where P′ is the mole fraction of the complexed cation. The exothermic association constants and the thermodynamic data for cation–macrocycle complexes explained in terms of Eigen–Winkler binding mechanism are given. The binding power found for Na⁺, however, was the highest with [18] crown-6.     

Orientation dependence of electric field induced phase transitions in lead-free (Na0.5Bi0.5)TiO3-based single crystals

The orientation dependence of the electric field induced strain and phase transitions in 0.92(Na_0.5Bi_0.5)TiO₃–0.06BaTiO₃–0.02(K_0.5Na_0.5)NbO₃ (NBT–6BT–2KNN) single crystals has been investigated. The evolution of Raman spectra with electric field reveals that a tetragonal ferroelectric phase is initially induced at E = 14 kV/cm and completed above E = 25 kV/cm for [001] oriented single crystals. When the electric field is applied along [111] direction, a partial phase transition from pseudocubic to rhombohedral structure is triggered at E = 19 kV/cm, which is higher than that for inducing tetragonal ferroelectric phase along [001] direction. Both field-induced phase structures and stability of NBT–6BT–2KNN single crystal are strongly associated with the crystallographic orientations. These results provide a better understanding to the field-induced macroscopic strain in lead-free NBT-based ferroelectrics.     

Effect of raster angle on the fracture properties of additively manufactured ABS via essential work of fracture

The increasing application of additive manufacturing (AM) technology across various sectors has sparked significant interest in characterizing 3D-printed components. An essential aspect of achieving fracture-resistant designs is gaining a comprehensive understanding of the fracture behavior exhibited by these components. While most studies have focused on linear-elastic fracture mechanics (LEFM), there is a lack of comprehensive studies on the post-yield fracture behavior (PYFM) of 3D-printed components. As a result, this study aims to fill this gap by investigating the impact of raster angle, a critical parameter influencing fracture properties and often leading to premature failures, on the fracture properties of fused deposition modeling (FDM) 3D printed acrylonitrile butadiene styrene (ABS) using essential work of fracture (EWF). Outcomes showed that by changing lay-ups from [90]₅ to [0]₅, the value of w_e or elastic work increased by nearly 306%. Further, the maximum and minimum values of the plastic work (βw_p) were for [45/−45/45/−45/45] and [90]₅ lay-ups, in order. By changing lay-ups from [90]₅ to [45/−45/45/−45/45], the value of βw_p increased by approximately 216%. In addition, the fractured surfaces of tested samples are also analyzed to provide insights into the dominant failure mechanisms for different raster angles.     

Reactive extrusion of acrylic acid grafted polypropylene with hexadecylamine

To study the possibility of the production of branched polypropylene (PP) by a reactive extrusion (REX) route, side chains were introduced on the backbone of a polypropylene material by reacting hexadecylamine with acrylic acid grafted PP. Experiments were carried out both in solution and in the melt, and the products were analyzed by FTIR, elemental analysis, dynamic mechanical, and rheological techniques. Analysis of the FTIR spectra of the samples produced in the solution reactions, at an equal molar ratio of [ –NH₂]/[–COOH] without catalyst addition and without removal of the by-product, revealed that the formation of imide was increased with increasing the reaction time up to 10 h, while a further increase in reaction time resulted in a reversal of the reaction. In the REX experiments, FTIR analysis showed that the imide formation increased with the [–NH₂]/[–COOH] molar ratio. At a molar ratio of one, more imide was present in the REX product than the in-solution one. Elemental analysis suggested that the nitrogen content in the products initially increased with [–NH₂]/[–COOH] molar ratio and then reached an almost constant value at molar ratio values of about unity. The glass transition temperature (T_g) was measured by dynamic mechanical analysis (DMA), and it was found that the attachment of the alkyl chains caused a reduction in T_g of the products. Finally, rheological measurements showed that the shear viscosity of the products increased with the amine/carboxyl molar ratio at low shear rates and that their moduli were enhanced as a result of the attachment of the alkyl side chains.     

Copolymerization of butadiene with styrene using a rare‐earth metal compound – dialkylmagnesium – halohydrocarbon catalytic system

Copolymerizations of butadiene (Bd) with styrene (St) were carried out with catalytic systems composed of a rare‐earth compound, Mg(n‐Bu)₂ (di‐n‐butyl magnesium) and halohydrocarbon. Of all the rare earth catalysts examined, Nd(P₅₀₇)₃–Mg(n‐Bu)₂–CHCl₃ showed a high activity in the copolymerization under certain conditions: [Bd] = [St] = 1.8 mol l^?1, [Nd] = 6.0 × 10^?3 mol l^?1, Mg/Nd = 10, Cl/Nd = 10 (molar ratio), ageing for 2 h, copolymerization at 50 °C for 6–20 h. The copolymer of butadiene and styrene obtained has a relatively high styrene content (10–30 mol%), cis‐1,4 content in butadiene unit (85–90%), and molecular weight ([η] = 0.8–1 dL g^?1). Monomer reactivity ratios were estimated to be r_Bd = 36 and r_St = 0.36 in the copolymerization. © 2002 Society of Chemical Industry     

Ozone Generation with Narrow–Band UV Radiation

Ozone formation in oxygen at atmospheric pressure following the photodissociation of O₂ molecules in the vacuum UV range is tudied. A new VUV source based on incoherent xenon excimer radiation from a dielectric–barrier discharge provided narrow–band UV radiation at 172 nm with a half–width of 14 nm. The formation of ozone from the initial photodissociation fragments O(³P) and O(¹D) is treated theoretically and compared to measurements.     

Density-dependent photochemical branching ratio in supercritical CO2: Photodissociation and isomerization of diiodomethane

The photodissociation of diiodomethane following excitation at 305 nm in supercritical CO₂ was investigated by femtosecond pump-probe absorption spectroscopy at pressures between 10 and 100 MPa. As in liquid solution, transient absorption signals in the wavelength range from 350 to 450 nm generally show an instantaneous peak, followed by a fast initial decay (200–300 fs) and a subsequent rise on a 10-ps timescale. The initial fast decay time is found to be linearly dependent on viscosity, suggesting that dissociative motion on the repulsive surface is damped by solvent friction. Both amplitude and formation rate of the rising component, which is assigned to formation of iso-diiodomethane within the solvent cage, increase with increasing pressure. Spectral narrowing of the transient absorption band indicates vibrational cooling of hot isomer by energy transfer to CO₂ in about 20–40 ps. Immediately after excitation, this band shows absorption anisotropy for about 3 ps. The anisotropy decay rate increases from 3·10¹¹ s⁻¹ to 2·10¹² s⁻¹ as the pressure is lowered from 80 to 10 MPa. It is tentatively assigned to rotational relaxation of “hot” CH₂I radicals generated in ultrafast photodissociation of the parent molecule. The observed density dependence of formation rate and relative yield of iso-diiodomethane are described in terms of a simple kinetic model.     

Functional copolymer of geraniol and acrylonitrile: Synthesis and characterization

The radical copolymerization of acyclic terpene namely geraniol [GER] with acrylonitrile [AN] in DMF at (70 ± 0.1)°C for 1 h, using benzoylperoxide (BPO) as an initiator has been carried out under inert atmosphere of nitrogen. The kinetic expression for reaction is R_p ∝ [BPO]^0.5 [AN]^1.0 [GER]^1.0. The IR spectrum of the copolymer shows bands at 3432 and at 2244 cm^?1 due to ? OH group of GER and ? CN group of AN, respectively. The ¹³C‐NMR spectrum shows peaks at 73–75 δ ppm and 116–120 δ ppm due to ? OH group of GER and ? CN group of AN, respectively. The thermogravimetric analysis and differential scanning calorimetry study shows that copolymer is thermally stable up to 407°C and has glass transition temperatures (T_g) 56°C. The reactivity ratios r₁ (AN) and r₂ (GER) have been calculated as 0.05 and 0.005, respectively. The Alfrey‐Price Q‐e parameter for GER has been calculated as 0.094 and ?2.0, respectively. The molecular weights of the copolymers have been evaluated by gel‐permeation chromatography. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of a terpolymer of limonene,styrene, and methyl methacrylate via a free‐radical route

The free‐radical terpolymerization of a monocyclic terpene, namely, limonene (Lim), with styrene (Sty) and methyl methacrylate (MMA) in xylene at 80 ± 0.1°C for 2 h, with benzoyl peroxide (BPO) as an initiator under an inert atmosphere of nitrogen was extensively studied. The kinetic expression was R_pα[BPO]^0.5[Sty]^1.0[MMA]^1.0[Lim]^?1.0, where R_p is the rate of polymerization. The overall energy of activation was calculated as 26 kJ/mol. R_p decreased as [Lim] increased. This was due to a penultimate unit effect. The Fourier transform infrared spectra of the terpolymer showed bands at 3025–3082, 1728, and 2851–2984 cm^?1 due to C? H stretching of phenyl (? C₆H₅) protons of Sty, ? OCH₃ of MMA, and trisubstituted olefinic protons of Lim, respectively. The ¹H‐NMR spectra showed peaks at 7.3–8.1, 3.9–4.4, and 5.0–5.5 δ due to the phenyl, methoxy, and trisubstituted olefinic protons of Sty, MMA and Lim, respectively. The values of the reactivity ratios r₁ (MMA; 0.33) and r₂ (Sty + Lim; 0.06) were calculated with the Kelen–T?udos method. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2343–2347, 2004     

Mixed modifier effects on structural,mechanical, chemical,and mechanochemical properties of sodium calcium aluminosilicate glass

Glass properties are governed by the interplay between network formers and network modifiers; for a given composition of network formers, the ratio of different cationic modifiers compensating the anionic species in the network has a profound effect, which is often nonlinear, called a mixed modifier effect (MME). We have investigated the MME of sodium (Na) and calcium (Ca) in an aluminosilicate (NCAS) glass series following the formula [Na₂O]_30−x [CaO]_x [Al₂O₃]₁₀ [SiO₂]₆₀, where x = 0, 7.5, 15, 22.5, and 30. A nonadditive trend was observed in hardness and indentation toughness, with aqueous corrosion resistance exhibiting a shift from incongruent to congruent corrosion, whereas the network structure determined by molecular dynamics simulations revealed no significant trend with composition. Additionally, the NCAS glass containing both [Na₂O] and [CaO] within an intermediate range exhibited superior resistance to wear at high humidity, a clear MME phenomenon previously only observed in soda–lime silica.     

Ionic liquid-based extraction and separation trends of bioactive compounds from plant biomass

Ionic liquids have been projected as the best solvent for extraction and separation of bioactive compounds from various origins. This review offers a collection of the published results, using ionic liquids for the extraction and purification of biomolecules. Ionic liquids have been studied as solvents, co-solvents and supported materials for separation of bioactive compounds. The ionic liquids-based extraction procedures were previously reported, such as ionic liquids-based solid-liquid extraction, liquid-liquid extraction and ionic liquids-modified materials are reviewed and compared to their performance. In this review, the main activities and future challenges are discussed, with major gaps identified using ionic liquids in extraction procedures and by advancing few steps to overcome these drawbacks.

Abbreviation: [(HSO₃)C₄MIM]⁺: 1-(4-sulfonylbutyl)-3-methylimidazolium; [(C₆H₃OCH₂)₂im]⁺: 1,3-dihexyloxymethylimidazolium; [C_nC₁MIM]⁺: 1-alkyl-2,3-dimethylimidazolium; [C_nMIM]^{+; [Cn, 2, 3, 4, 6, 8, 10, 12]}: 1-alkyl-3-methylimidazolium; [C_nC₁pyr]⁺: 1-alkyl-3-methylpyridinium; [C_nim]⁺: 1-alkylimidazolium; [C_npyr]⁺: 1-alkylpyridinium; [aC_nim]⁺: 1-allyl-3-alkylimidazolium; [C₇H₇MIM]⁺: 1-benzyl-3-methylimidazolium; [C₄(C₁C₁C₁Si)im]⁺: 1-butyl-3-trimethylsilylimidazolium; [(HOOC)C₂MIM]⁺: 1-carboxyethyl-3-methylimidazolium; [(OH)C_nMIM]⁺: 1-hydroxyalkyl-3-methylimidazolium; [(C₂H₅O)₃SiC₃MIM]⁺: 1-methyl-3-(triethoxy)silypropyl imidazolium; [(NH₂)C₃MIM]⁺: 1-propylamine-3-methylimidazolium; [C_wH_xN_yO_z]⁺: Chirally functionalized methylimidazolium; [P_{10(3OH)(3OH)(3OH)}]⁺: Decyltris(3-hydrox- ypropyl) phosphonium; [N_111(2OH)]⁺: N,N,N-trimethyl-N-(2-hydroxyethyl) ammonium (cholinium); [N_00nn]⁺: N,N-dialkylammonium; [N_0nn(2OH)]⁺: N,N-dialkyl-N-(2-hydroxyethyl) ammonium; [C₁₀C₁₀C₁gluc]⁺: N,N-didecyl-N-methyl-d-glucaminium; [N_11(2(O)1)0]⁺: N,N-dimethyl(2-methoxyethyl) ammonium; [N_{11(2OH)(C7H7)}]⁺: N-benzyl-N,N-dimethyl-N-(2-hydroxyethyl) ammonium; [P₆₆₆₁₄]⁺: Trihexyltetradecylph- osphonium; [P_i(444)1]⁺: Triisobutyl (methyl) phosphonium; P.minus: Polygonum minus; NPs: Nanoparticle; ZnO : Zinc oxide nanoparticles ; Ni NPs: Nickel nanoparticles; MO: Methyl orange; UAE: Ultrasonic-assisted extraction; LLE: Liquid-liquid extraction; ABS: Aqueous biphasic system ; [Ace]^?: Acesulfamate; [Ala]^?: alalinate; [TMPP]^?: bis(2,4,4-trimethylpentyl)phosphinate; : ; [NTf₂]^?: bis(trifluoromethylsulfonyl)imide; [[Br]^–]: [Br]omide; [Calc]: calkanoate; [Cl]^–: chloride; [Bz]^?: benzoate; [PF₆]^?: hexafluorophosphate; [HSO₄]^?: hydrogenosulfate; [OH]^?: hydroxide; I^–: iodide; [Lac]^?: lactate; [NO₃]^?: nitrate; [[Cl]O₄]^?: perchlorate; [Phe]^?: phenilalaninate; [BF₄]^?: tetrafluoroborate; [SCN]^?: thiocyanate; [C(CN)₃]^?: tricyanomethanide; [CF₃CO₂]^?: trifluoroacetate; [CF₃SO₃]^?: trifluoromethanesulfonate; [FAP]^?: tris(pentafluoroethyl)trifluorophosphate; ILs: Ionic liquids; Ag NPs: Silver nanoparticle; Cu NPs: Copper nanoparticle; MB: Methylene blue; MR: Methyl red ; MAE: Microwave-assisted extraction; SLE: solid-liquid extraction.     

Synthesis and spectroelectrochemistry of dithieno(3,2‐b:2′,3′‐d)pyrrole derivatives

New π‐conjugated polymers containing dithieno(3,2‐b:2′,3′‐d)pyrrole (DTP) were successfully synthesized via electropolymerization. The effect of structural differences on the electrochemical and optoelectronic properties of the 4‐[4H‐dithieno(3,2‐b:2′,3′‐d)pyrrol‐4‐yl]aniline (DTP–aryl–NH₂), 10‐[4H‐dithiyeno(3,2‐b:2′,3′‐d)pirol‐4‐il]dekan‐1‐amine (DTP–alkyl–NH₂), and 1,10‐bis[4H‐dithieno(3,2‐b:2′,3′‐d)pyrrol‐4‐yl] decane (DTP–alkyl–DTP) were investigated. The corresponding polymers were characterized by cyclic voltammetry, NMR (¹H‐NMR and ¹³C‐NMR), and ultraviolet–visible spectroscopy. Changes in the electronic nature of the functional groups led to variations in the electrochemical properties of the π‐conjugated systems. The electroactive polymer films revealed redox couples and exhibited electrochromic behavior. The replacement of the DTP–alkyl–DTP unit with DTP–aryl–NH₂ and DTP–alkyl–NH₂ resulted in a lower oxidation potential. Both the poly(10‐(4H‐Dithiyeno[3,2‐b:2′,3′‐d]pirol‐4‐il)dekan‐1‐amin) (poly(DTP–alkyl–NH₂)) and poly(1,10‐bis(4H‐dithieno[3,2‐b:2′,3′‐d]pyrrol‐4‐yl) decane) (poly(DTP–alkyl–DTP)) films showed multicolor electrochromism and also fast switching times (<1 s) in the visible and near infrared regions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40701.     

Reusable ionic liquid-functionalized polystyrene for the highly efficient removal of sulfadiazine sodium

The extensive use of sulfonamides has caused serious ecotoxicological effects, sulfonamide antibiotics are difficult to remove when they are in their anionic form. In this work, a novel polystyrene supported ionic liquid (PS-CH₂-[TSiIm][Cl]) material was prepared for the effective removal of sulfadiazine sodium (SDS). Results showed that the adsorption efficiency maintained relatively stable and high in a wide pH (6–10) and temperature (25–70 °C) ranges. SDS adsorbed onto the PS-CH₂-[TSiIm][Cl] could be well evaluated by Langmuir model and the maximum adsorption capacity could be reached as high as 438.2 mg g⁻¹. Simultaneously, the PS-CH₂-[TSiIm][Cl] exhibited excellent removal performance toward trace SDS at ppb level (0.005 mg L⁻¹). Common inorganic ions such as K⁺, Na⁺, Ca²⁺, and Cl⁻ had no effect of on the removal of SDS even if their concentrations were 20 000 times higher than that of SDS. And the PS-CH₂-[TSiIm][Cl] was easy to regenerate without loss in adsorption performance. Additionally, the PS-CH₂-[TSiIm][Cl] was applied to remove the SDS from environmental water samples. The possible adsorption mechanism was also investigated. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47981.     

Synthesis of star‐shaped poly(ϵ‐caprolactone) by samarium‐based tetrafunctional initiator and its dilute‐solution properties

An in situ–generated tetrafunctional samarium enolate from the reduction of 1,1,1,1‐tetra(2‐bromoisobutyryloxymethyl)methane with divalent samarium complexes [Sm(PPh₂)₂ and SmI₂] in tetrahydrofuran has proven to initiate the ring‐opening polymerization of ?‐caprolactone (CL) giving star‐shaped aliphatic polyesters. The polymerization proceeded with quantitative conversions at room temperature in 2 h and exhibited good controllability of the molecular weight of polymer. The resulting four‐armed poly(?‐caprolactone) (PCL) was fractionated, and the dilute‐solution properties of the fractions were studied in tetrahydrofuran and toluene at 30°C. The Mark–Houwink relations for these solvents were [η] = 2.73 × 10^?2M_w^0.74 and [η] = 1.97 × 10^?2M_w^0.75, respectively. In addition, the unperturbed dimensions of the star‐shaped PCL systems were also evaluated, and a significant solvent effect was observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 175–182, 2006     

Antistatic effects and mechanism of ionic liquids for methyl vinyl silicone rubber

The effect of two ionic liquids (ILs), namely, 1‐allyl‐3‐methyl imidazolium chloride ([AMIM]Cl) and 1‐ethyl‐3‐methyl imidazolium tetrafluoroborate ([EMIM]BF₄), on the surface and volume resistivities, mechanical properties, transparency, and water contact angle of methyl vinyl silicone rubber (MVQ) were investigated. The chemical structures of the two ILs before and after heat treatment were characterized by Fourier transform infrared spectroscopy. The morphology and fluorine and chlorine elemental dispersion were characterized by field emission scanning electron microscopy and energy‐dispersive X‐ray spectroscopy mapping, respectively. The antistatic mechanism was revealed. The results show that the MVQ–[EMIM]BF₄ composites had lower surface and volume resistivities than the MVQ–[AMIM]Cl composites. The mechanical properties of the MVQ–[EMIM]BF₄ and MVQ–[AMIM]Cl composites were slightly lower than those of the pristine MVQ. With increasing [EMIM]BF₄ content, the surface and volume resistivities and water contact angle of the MVQ–[EMIM]BF₄ composites decreased. When the content of [EMIM]BF₄ was 2.0 phr, the MVQ–[EMIM]BF₄ composites showed better antistatic performance with lower surface and volume resistivities of 9.6 × 10⁹ Ω and 1.2 × 10¹¹ Ω cm, respectively. The antistatic mechanism of the MVQ–IL composites was ascribed to the synergistic effect of ionic migration and moisture absorption. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45180.     

Characterization of block copolymers based on poly[3,3-bis(ethoxymethyl)oxetane] and other novel polyethers

Diblock, triblock, and alternating block copolymers based on poly[3,3-bis(ethoxymethyl) oxetane] [poly(BEMO)] and a random copolymer center block poly(BMMO-co-THF) composed of poly[3,3-bis(methoxymethyl)oxetane] [poly(BMMO)], and poly(tetrahydrofuran) [poly(THF)] were synthesized and characterized with respect to molecular weight. Glass transition temperatures T_g and melting temperatures T_m were characterized via DSC, modulus–temperature, and dynamic mechanical spectroscopy (DMS). These polyethers had T_m between 70°C and 90°C, and T_g between ?55°C and ?30°C. The degree of crystallinity of poly(BEMO) was found to be 65% by X-ray powder diffraction. Tensile properties of the triblock copolymer, poly(BEMO-block-BMMO-co-THF-block-BEMO) were also studied. A yield point was found at 4.1 × 10⁷ dyn/cm² and 10% elongation and failure at 3.8 × 10⁷ dyn/cm² and 760 % elongation. Morphological features were examined by reflected light microscopy and the kinetics of crystallization were studied. Poly(BEMO) and its block copolymers were found to form spherulites of 2–10 μm in diameter. Crystallization was complete after 2–5 min.     

Selective Extraction of Fe3+ Cation by Calixarene-Based Cyclic Ligands

Abstract

The selective liquid-liquid extraction of Fe³⁺ cation from the aqueous phase to the organic phase was carried out by using p-tert-butylcalix[4]arene [L₁], ca-lix[4]arene [L₂], p-nitro-calix[4]arene [L₃], calix[4]arene p-sulfonic acid [L₄], p-(diethylamino)methylcalixt4]arene [L₅], tetramethyl-p-tert-butylcalix[4]arene tet-raketone [L₆], 25,27-dimethyl-26,28-dihydroxy-p-tert-butylcalix[4]arene diketone [L₇], calix[4]arene-bearing dioxime group on the lower rim [L₈], and a monooxime [L₉]. The effect of varying pH upon the extraction ability of calixarenes substituted with electron-donating and electron-withdrawing groups at their p-position was examined. Observed results were compared with those found for unsubstituted calix[4]arene.