Nilgün Kızılcan

Modification of acetophenone–formaldehyde and cyclohexanone–formaldehyde resins

Cyclohexanone–formaldehyde and acetophenone–formaldehyde resin were in situ modified with phenol, Bisphenols, and substituted acetophenones. Furthermore, acetophenone–formaldehyde, cyclohexanon–formaldehyde, and in situ-modified resins were modified with anhydrides such as acetic anhydride, maleic anhydride, dodecenylsuccinic anhydride, 3,4,3′,4′-biphenyltetracarboxylic dianhydride, and 4,4′-oxydiphtalic anhydride. Modification of these resins with hydroxyl amine, semicarbazide, and phenyl hydrazine were also studied. Melting points, solubilities in organic solvents, FTIR, and NMR spectrum of the modified resins were determined.

In situ modified reactive cyclohexanone‐formaldehyde resins

The preparation of cyclohexanone-formaldehyde resins containing functional groups such as carboxylic acid, ester, phenol and vinyl is described. These resins were obtained by in situ modification of a cyclohexanone-formaldehyde resin. Modifier compounds were 1,4-cyclohexanedione, salicylic acid, o-cresol, p-cresol, citric acid, glyoxal, benzaldehyde, acetaldehyde, and acrylamide. Conductivities of the resin modified with glyoxal and acetaldehyde were 10–4 and 3·10–3 S cm–1, respectively. Durch in-situ-Modifikation eines Cyclohexanon-Formaldehyd-Harzes wurden Harze mit funktionellen Gruppen (Carbonsaure, Ester, phenolisches OH und Vinyl) hergestellt. Als Modifikatoren wurden 1,4-Cyclohexandion, Salicylsaure, o-Kresol, p-Kresol, Zitronensaure, Glyoxal, Benzaldehyd, Acetaldehyd und Acrylamid verwendet. Die Leitfahigkeiten der mit Glyoxal bzw. Acetaldehyd modifizierten Harze betragen 10–4 bzw. 3·10–3 S cm–1.

Effect of post-polymerization heat-treatments on degree of conversion, leaching residual MMA and in vitro cytotoxicity of autopolymerizing acrylic repair resin

OBJECTIVES This study evaluated the effect of post-polymerization heat-treatments on degree of conversion (DC), residual methyl methacrylate concentration (MMA(r)) and in vitro cytotoxicity of autopolymerizing acrylic repair resin. METHODS A total of 336 specimens were prepared by bench- and hydroflask-curing and subjected to post-polymerization heat-treatments: a) water immersion at 60°C for 30 min, b) microwaving at 500 W for 3 min, c) combined use of water immersion and microwaving d) no treatment (as control). Specimens were eluted in cell culture medium for 1, 2, 5 and 7 days. DC and MMA(r) in eluates were measured by FTIR spectrometry and HPLC, respectively. In vitro cytotoxicity of eluates on L-929 fibroblasts was determined by XTT assay. Data were statistically analyzed with Dunns multiple comparison and Pearson correlation tests (p≤0.05). RESULTS DC was highest (99.9%) in bench- and hydroflask-cured groups which were subjected to water immersion. At all elution periods, MMA(r) was detected in eluates of all treatment groups and were higher in bench-cured groups than hydro-flask cured groups. Cell proliferation values indicated slightly cytotoxic effect throughout 7 days; regardless of the curing method or post-polymerization treatment. The correlation between MMA(r) and cell proliferation was negative after elution of 1, 2, 5 days and was only statistically significant (p<0.05) at 5 days. At elution of 7 days, the correlation was positive with no significance. SIGNIFICANCE Post-polymerization heat-treatment of autopolymerizing acrylic repair resin by immersion in water at 60°C for 30 min is clinically recommended to improve the DC while reducing the leaching residual MMA.

Block copolymers of styrene containing oligomeric esters of terephthalic acids

A new generation of block copolymers were synthesized starting with depolymerized PET by glycolysis with some oligomeric diols. α,ω-Dihydroxy poly(dimethyl siloxane)s, hexylene glycol, poly(ethylene oxide)glycols, and ethylene glycol were used as diols. The dihydroxy-terminated depolymerization products containing a terephthalyl group and oligomeric diols were used to prepare a diradicalic macroinitiator (MI). These MIs were used to polymerize the styrene monomer. The new block copolymers obtained were characterized by physical and chemical methods and mechanical and thermal analyses.

Aniline and oligoaniline modified cyclohexanone‐formaldehyde resins

Purpose – Cyclohexanone‐formaldehyde resins (CF‐Rs) were in situ modified with aniline, 4‐aminodiphenylamine, and N‐N′‐diphenyl‐1,4‐phenylene diamine in presence of sodium hydroxide. The purpose of this paper is to report the synthesis of conducting resins with aniline, dimer and trimer aniline, with a one‐step method of in situ modification of ketonic resin. The roles of ketone, aniline concentration, the conductivity of the product are investigated.Design/methodology/approach – Ketone, formalin (37 per cent aqueous solution), aniline or oligoaniline were mixed and 20 per cent aqueous NaOH solution was added to produce the resin.Findings – The aniline‐modified (CF‐Rs) were found to have conductivity values of 10−3‐10−5 S/cm and may be considered as conductive ketonic resin.Research limitations/implications – The reaction mixture must be stirred continuously. Amount of aniline and oligoaniline is limited. Subsequently, 37 per cent formalin was added dropwise in total while refluxing. The amount of aniline...

Carbazole modified ketonic resins

Purpose – The purpose of this paper is to report the synthesis of resins having conducting and fluorescence properties, with carbazole and oligocarbazole with a one step method of in situ modification of ketonic resin. Cyclohexanone‐formaldehyde (CFR), and acetophenone‐formaldehyde (AFR) resins were in situ modified with carbazole in the presence of sodium hydroxide.Design/methodology/approach – Carbazole modified ketonic resins were synthesised by the condensation reaction of Cz, formaldehyde and ketone. Oligo carbazole was synthesised by redox reaction of carbazole and ceric ammonium nitrate (CAN). Then, for the in situ modification of oligo carbazole modified ketonic resin, reaction mixture of oligocarbazole carbazole was added to the cyclohexanone/formaldehyde solution.Findings – The carbazole modified cyclohexanone‐formaldehyde and acetophenone formaldehyde resins have conductivity values of 10−5‐10−6 S/cm and may be considered as semi‐conductive ketonic resins. These new carbazole modified ketonic r...

Polymerization of cyclohexanone formaldehyde resin modified with carbazole‐9‐carbonyl chloride

Purpose – The purpose of this paper is to synthesise cyclohexanone formaldehyde resin (CFR)‐modified carbazole‐9‐carbonyl chloride (CzCl) via hydroxyl groups of CFR. This carbazole‐modified resin (Cz‐CFR) comonomer was characterised by common techniques such as UV, NMR, FTIR, fluorescence spectrophotometer, and scanning electron microscopy. The oxidative and electrochemical polymerisation of CzCl‐modified cyclohexanone formaldehyde resin (Cz‐CFR) were carried out.Design/methodology/approach – Cz‐CFR comonomer was synthesised by the esterification reaction of CzCl and hydroxyl groups of CFR. Then, for the chemical polymerisation, ceric ammonium nitrate (CAN)/DMF solution was added to the comonomer/DMF solution. The precipitate was filtered, washed with chloroform and dried. For the electrochemical polymerisation, potentiodynamic electrodeposition of Cz‐CFR comonomer in dichloromethane on to Pt was carried out.Findings – The concentration effect of CAN and Cz‐CFR on the conductivity, yield, solubility and T...

Chain extended cyclohexanone-formaldehyde and acetophenone-formaldehyde resins

The preparation of chain extended cyclohexanone–formaldehyde and acetophenone–formaldehyde resins and their physical properties were studied. The chain extension was regulated by the ratio of the hydroxyl groups of the ketonic resin/reactive reagents. Both resins were chain extended with dimethyl dichlorosilane, phosphorus oxychloride, phenylphosphonic dichloride, toluene-2,4-diisocyanate, prepolymers (prepared from trimethylolpropane and toluene-2,4-diisocyanate), phthalic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, 4,4′-oxydiphthalic anhydride, and maleic anhydride. Solubilities, melting point, molecular weight, and flammability of the chain extended resins were affected by the extender reagent.

Polymerisation of methyl ethyl ketone formaldehyde resin modified with carbazole‐9‐carbonyl chloride

Purpose – The purpose of this paper is to obtain a conductive polymer by using a fluorescence comonomer which is an insulator. In this study, methyl ethyl ketone formaldehyde resin (MEKFR) modified with carbazole‐9‐carbonyl chloride (CzCl) was synthesised via hydroxyl groups of MEKFR. Electrochemical polymerisation of Cz‐MEKFR comonomer was carried out potentiostatically and a green, conductive polymer P(Cz‐MEKFR) was obtained. The advantages of obtaining alternative structure of P(Cz‐MEKFR) to the random copolymer were reported.Design/methodology/approach – Cz‐MEKFR comonomer was synthesised by the esterification reaction of CzCl and hydroxyl groups of MEKFR. Then, for the electrochemical polymerisation, potentiodynamic electrodeposition of Cz‐MEKFR comonomer in dichloromethane on to Pt was carried out. Electrochemical activities of polymers were tested by electrochemical methods (i.e. polarization curves and cyclovoltammetry). UV‐visible, NMR, polarization curves, cyclovoltammetric, solid‐state conducti...

Electrochemical Copolymerization of Pyrrole and Methyl Ethyl Ketone Formaldehyde Resin

ABSTRACT Electrochemical polymerization of pyrrole in the presence of methyl ethyl ketone formaldehyde resin (MEKF-R) was accomplished. Characterization of insoluble free-standing films was carried out via FTIR spectrum, cyclic voltammogram (CV), UV-visible spectrum, and four-point probe conductivity measurements. The effect of pyrrole and the resin concentrations on the conductivity of the resulting products was investigated. The copolymers obtained as free-standing films have conductivity value of 10−6–10−2 S/cm and they are insoluble in organic solvents.