Belkis Ustamehmetoğlu, Nesrin Köken, Nilgun Kizilcan, Ahmet Akar and Şebnem Tayyar
The purpose of this paper is to produce non-conductive copolymers of N-vinyl carbazole (NVCz) and methyl ethyl ketone formaldehyde resin (MEKFR) by the electroinduced Ce (IV…
Abstract
Purpose
The purpose of this paper is to produce non-conductive copolymers of N-vinyl carbazole (NVCz) and methyl ethyl ketone formaldehyde resin (MEKFR) by the electroinduced Ce (IV) polymerization method and the electrochemical oxidization of the formed copolymer to produce their conductive green form. The non-conductive and conductive copolymers were characterized by using Fourier transform infrared, solid-state conductivity and spectroelectrochemical, chronoamperometric, cyclovoltammetric and electrochemical impedance spectroscopic measurements.
Design/methodology/approach
The chronoamperometric electropolymerization of white, insulator form of the copolymer of NVCz and MEKFR (copolymer 1) on to Pt electrode was carried out and the green coloured film of the MEKFR-ox-NVCz copolymer (copolymer 11) was produced in the doped and conductive form. All reactions were performed in dichloromethane containing 0.1 M BU4NClO4. Copolymer 11 films obtained on the surface of the working electrode were removed and washed in acetonitrile and dried at room temperature before characterization. The results were compared with the copolymer obtained by electrochemical oxidation of MEKF-R and NVCz (copolymer 2).
Findings
The insulating copolymer of NVCz and MEKFR (copolymer 1) was produced by the electroinduced Ce (IV) polymerization method and converted into the conductive form electrochemically on the surface of the Pt electrode (copolymer 11). The polymers were characterized by electrochemical, spectrophotometric and conductivity measurements. The ionization potentials, optical band gap, peak potentials Ep, doping degree and specific capacitance of the copolymer 11 were obtained. The conductivity of the copolymer 11 is lower than the PNVCz and higher than the copolymer obtained by electrochemical oxidation of MEKF-R and NVCz (copolymer 2). The copolymer 11 has a lower onset potential than PNVCz and the copolymer 1 and slightly higher band gap than PNVCz. The capacitive behaviours of the copolymer 11 were very close to PNVCz.
Research limitations/implications
This study focuses on obtaining a green and conductive form of the copolymer of NVCz and MEKFR with the electrochemical method by using a white and insulator form of the same copolymer.
Practical implications
This work provides technical information for the synthesis of conducting copolymer of NVCz and MEKFR.
Social implications
These copolymers may be in the field of PNVCz applications such as photoconductivity and corrosion inhibition.
Originality/value
Electroinduced Ce (IV) MEKFR redox system was applied for the polymerization of NVCz monomer to produce the copolymer 1. The conductive copolymer 11 was synthesized through electrochemical oxidative coupling of the carbazole groups of the copolymer 1.
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Yusuf Yivlik, Nilgun Kizilcan and Ahmet Akar
Cyclohexanone–formaldehyde resin (CFR) was in situ modified with isocyanuric acid (ICA) in the presence of hydrochloric acid or p-toluenesulfonic acid by condensation…
Abstract
Purpose
Cyclohexanone–formaldehyde resin (CFR) was in situ modified with isocyanuric acid (ICA) in the presence of hydrochloric acid or p-toluenesulfonic acid by condensation polymerization. The purpose of this study is to produce isocyanuric acid-modified ketonic resins that have higher melting and decomposition temperature, and to use the produced resin in the production of fire-retardant polyurethane.
Design/methodology/approach
Two methods were used for in situ preparation of ICA-modified CFR in the presence of an acid catalyst. Method I: cyclohexanone, paraformaldehyde and ICA were mixed, and then an acid catalyst was added to form the modified CFR. Method II: ICA and formalin were mixed to produce N, N, N-trihydroxymethyl isocyanurate, and then water was removed under vacuum. The produced N, N, N-trihydroxymethyl isocyanurate solution was mixed with cyclohexanone and paraformaldehyde, then an acid catalyst was slowly added to this mixture to obtain ICA-modified CFR.
Findings
CFR was prepared in the presence of an acid catalyst. The product, CFR, has a dark red colour. The resulting resins have similar physical properties with the resin prepared in the presence of a basic catalyst. The solubility of ICA-modified CFR is much different than CFR in organic solvents.
Research limitations/implications
This study focuses on obtaining an ICA-modified ketonic resin. Cyanuric acid has the form of an enolic structure under a basic condition; therefore, it cannot give a product with formaldehyde under basic conditions. The modification experiments were carried out in acidic conditions.
Practical implications
This study provides technical information for in situ modification of ketonic resin in the presence of acid catalysts. The resins may also promote the adhesive strength of the coating and provide corrosion inhibition on metal surfaces for a coating. The modified resins may also be used in the field of fire-retardant polyurethane applications.
Social implications
These resins may be used for the preparation of non-toxic fire-retardant polyurethane foam. Polyurethane containing ICA-modified resin may exhibit better fire-retardant performance because of the incorporation of ICA molecule into the polyurethane structure.
Originality/value
ICA-modified CFRs have been synthesized in the presence of an acid catalyst, and the ICA-modified resin was used to produce fire-retardant polyurethane.
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Ahmet Akar, Berrin Değirmenci and Nesrin Köken
The purpose of this paper is the production of fire retardant and smoke suppressant rigid polyurethane foam (RPUF) with lower toxicity by using several fire-retardant combinations.
Abstract
Purpose
The purpose of this paper is the production of fire retardant and smoke suppressant rigid polyurethane foam (RPUF) with lower toxicity by using several fire-retardant combinations.
Design/methodology/approach
Fire-retardant additives with cooling effect, barrier ash formation effect, gas-phase inhibition effect and smoke suppressant effect combined to produce an optimum outcome on RPUF. The additive amount and burning time correlation were studied to find out the minimum amount of fire-retardant to obtain fire-retardant polyurethane foam.
Findings
Zinc borate powder was coated with 1.5 wt % of stearic acid and hydroxy stearic acid. Polyammonium diborates (PABs) were synthesized and used as a fire-retardant and smoke suppressant for rigid PU foam. Fire-retardant rigid polyurethane foams (FR-RPUF) composites formed by using several combinations of zinc borate, aluminum trihydroxide, trischloroisopropyl phosphate (TCPP), PABs, zinc borate coated with stearic acid and hydroxy stearic acid. Produced FR-RPUF were horizontal burning grade, and burning time was in the range of 1–10 s.
Research limitations/implications
There were limitations during the mixing of fire-retardant powders with polyol due to the high viscosity of the mixture.
Practical implications
FR-RPUF foam with lower toxicity can be produced industrially with these fire-retardant combinations.
Social implications
FR-RPUF could be produced by using non-toxic additives. During a fire, these additives do not evolve toxic gases. The TCPP content of RPUF foam was reduced, and fire-retardant PU with lower toxicity was produced.
Originality/value
Coated zinc borate and the combinations of the fire-retardants were successful in producing non-toxic fire-retardant and smoke suppressant PU foam.
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Belkis Ustamehmetoğlu, Ahmet Akar, Nilgun Kizilcan and Eda Kelleboz
The purpose of this paper is to develop the soluble and processable conducting copolymers of carbazole (Cz), ethylcarbazole (ECz), N‐vinylcarbazole (NVCz) by oxidatively…
Abstract
Purpose
The purpose of this paper is to develop the soluble and processable conducting copolymers of carbazole (Cz), ethylcarbazole (ECz), N‐vinylcarbazole (NVCz) by oxidatively polymerising carbazoles by ceric ammonium nitrate (CAN) in the presence of methyl ethyl ketone formaldehyde resin (MEKF‐R); and to report the advantages of obtaining copolymer structure.
Design/methodology/approach
A new class of soluble and conductive P(Cz/MEKF‐R), P(NVCz/MEKF‐R) and P(ECz/MEKF‐R) copolymers were synthesised by the method of oxidative polymerisation with ceric ammonium nitrate. MEKF‐R, CAN and carbazole monomers (Cz, NVCz and ECz) were dissolved in acetonitrile separately. Then, the CAN solution was added dropwise into the mixture of MEKF‐R and Cz, NVCz or ECz solutions while stirring and a green powder was formed almost instantaneously. After one hour stirring at 25°C, the powder was filtered, washed with acetonitrile and dried at room temperature. A green coloured product was obtained. The colourless insulator copolymer present in this product was separated by selectively dissolving with toluene. The insoluble green copolymer was filtered off and dried at room temperature under vacuum. The products were characterised by FTIR, DSC thermograms, 1H‐NMR, four‐point probe conductivity and atomic absorption measurements.
Findings
The solubility and conductivity of the Cz/MEKF‐R copolymer P(Cz/MEKF‐R), the NVCz/MEKF‐R copolymer P(NVCz/MEKF‐R) and the ECz/MEKF‐R copolymer P(ECz/MEKF‐R) were regulated by the ratios of (Cz, NVCz, ECz)/CAN/MEKF‐R. By inclusion of the ketonic resin segments to the polycarbazole chains, thermally processable copolymers have been obtained with a melting point of about 80°C. FT‐IR results in different reaction time and the presence of metal in copolymers show together a complex between monomer‐metal and resin.
Research limitations/implications
This study focuses on obtaining conductive, soluble and processable copolymers. Since the ketonic resin is an insulator, in order to obtain both conductive and totally soluble polymer, successively regulating the ratios of (Cz, NVCz, ECz)/CAN/MEKF‐R is necessary.
Practical implications
This work provides technical information for the synthesis of conducting and totally soluble copolymer.
Originality/value
The conductive P(Cz/MEKF‐R), P(NVCz/MEKF‐R) and P(ECz/MEKF‐R) copolymers obtained by the method of oxidative polymerisation with ceric ammonium nitrate, which are totally soluble in DMF, could only be produced with this method and may increase the area of application of the carbazole polymers.
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The purpose of this paper is to prepare poly[allyl amino bis(methylene phosphonic acid)-ran-acrylic acid]s by two different routes. In the first route, poly(allyl…
Abstract
Purpose
The purpose of this paper is to prepare poly[allyl amino bis(methylene phosphonic acid)-ran-acrylic acid]s by two different routes. In the first route, poly(allyl amine-ran-acrylic acid)s were produced by radical copolymerization of a mixture of ally amine and acrylic acid, then converted into poly[allyl amino bis(methylene phosphonic acid)-ran-acrylic acid]s by the Mannich reaction with a mixture of formaldehyde and phosphonic acid. In the second route, allyl amino bis(methylene phosphonic acid) monomer was synthesized and copolymerised with acrylic acid. The aim of this work is to produce low-molecular-weight copolymer with the low amount of nitrogen and phosphorous having better scale inhibiting performance than commercial low-molecular-weight poly(acrylic acid)s.
Design/methodology/approach
Poly(allyl amine-ran-acrylic acid)s were prepared by radical copolymerisation of a mixture of ally amine and acrylic acid, and the molecular weight of copolymers was regulated by using an effective chain transfer compound and the formed copolymer was reacted with a mixture of formaldehyde and phosphorous acid. Allyl amino bis(methylene phosphonic acid) monomer was prepared and then copolymerised with acrylic acid using radical initiators.
Findings
Poly[allyl amino bis(methylene phosphonic acid)-ran-acrylic acid] produced with both routes, especially low-molecular weight ones have better anti-scaling performance than low-molecular-weight commercial poly(acrylic acid).
Research limitations/implications
By using an excess of formaldehyde and phosphonic acid, a limited increase in the conversion of amine groups of poly(allyl amine-ran-acrylic acid) to amino methylene phosphonic acid groups was achieved, so unreacted amine groups were always present in the structure of the final copolymers.
Practical implications
The low-molecular-weight poly[allyl amino bis(methylene phosphonic acid)-ran-acrylic acid] may be used as a better anti-scaling polymer in industry.
Social implications
The low-molecular-weight poly[allyl amino bis(methylene phosphonic acid)-ran-acrylic acid] is an alternative polymer for scale inhibition in the water boilers.
Originality/value
The low-molecular-weight poly[allyl amino bis(methylene phosphonic acid)-ran-acrylic acid] copolymers containing both carboxylic acid and amino bis(methylene phosphonic acid) are more effective anti-scaling additives than poly(acrylic acid)s in water boilers.
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Conventional wisdom tells us that mediation without ripeness is a fool’s errand (Zartman and Touval, 1985). What, then, is Türkiye’s motivation for mediating the war in Ukraine in…
Abstract
Purpose
Conventional wisdom tells us that mediation without ripeness is a fool’s errand (Zartman and Touval, 1985). What, then, is Türkiye’s motivation for mediating the war in Ukraine in lieu of ripeness – and what can its behavior as a mediator tell us about that motivation? In pursuit of this question, this paper inductively analyzes Turkish mediation in the Ukraine war to unpack the relationship between a contextual (ripeness) and actor-level (motivation) variable. Of particular interest is the decision-making and behavior of third parties (like Türkiye in Ukraine) who elect to mediate highly complex conflicts in which ripeness is indiscernible. The purpose of this research is not to propose or test a causal relationship between obscured ripeness and mediation, but rather to examine mediation behavior in situations where ripeness is obscured.
Design/methodology/approach
The impact of weaponized information on ripeness and third-party mediation is evaluated through an original, systematic and inductive case study analysis of Turkish mediation in the Russia–Ukraine war. As an intense theater of operations for information warfare for well over a decade, the war in Ukraine serves as an especially apt choice for an analysis of “obscured ripeness.” Likewise, Türkiye’s anomalous position as the only substantive source of mediation in the conflict lends significance to an empirical examination of its motivation and behavior as a mediator.
Findings
This research reveals that the pervasive use of weaponized information in the Russia–Ukraine war has distorted and disordered the information environment, thereby obscuring the ability of third parties to determine if the conflict is or could be ripe for mediation. However, the condition of obscured ripeness that prevails in the conflict has not proven a deterrent for mediation by Türkiye, which, as the only mediator in the conflict, has used a transactional approach to mediation motivated by self-regarding interests and animated by a manipulative mediation strategy. In sum, this inductive analysis of Turkish mediation in Ukraine reveals that the use of weaponized information in a conflict indirectly selects on transactional mediation (and mediators). The significance of this finding is magnified by the widespread use of weaponized information in contemporary conflicts as well as the declining frequency of third-party mediation.
Originality/value
There have been few, if any, systematic assessments in Turkish mediation of the Russia–Ukraine war, and none specifically concerned with the effects of weaponized information. Additionally, the paper proposes a typology of mediator motivation that is used to structure that assessment, while also introducing a new concept (“obscured ripeness”) and linking that concept both to the existing literature on ripeness and to the use of weaponized information in contemporary armed conflicts. As such, this manuscript represents an important contribution both to the empirical and theoretical landscape with respect to the study of mediation and international conflict management.