Ayça Bal

Effects of Nanoparticles on Film Properties of Waterborne Acrylic Emulsions

Waterborne acrylic emulsion was obtained by using methyl methacrylate, ethyl and butyl acrylate monomers. Emulsions containing nanoparticles were prepared by blending the stable dispersions containing SiO2 or MMT nanoparticles. The films were prepared from emulsions and coating tests were applied. The physical properties of prepared emulsions are better than the commercial emulsions. The addition of the nanoparticles especially SiO2 have positive effect on the resistance to environmental conditions of emulsions. Waterborne acrylic emulsions containing nanoparticles prepared in this study can be used in the manufacturing of the semi-lustrous emulsion type nano paint with low cost, high performance and environmentally friendly.

Study on adsorption, regeneration, and reuse of crosslinked chitosan graft copolymers for Cu(II) ion removal from aqueous solutions

AbstractThis study deals with the adsorption, regeneration, and reuse of chitosan-graft-itaconic acid and chitosan-graft-crotonic acid beads for Cu(II) ion removal from aqueous solutions. For this aim, adsorption capacities, adsorption kinetics, and adsorption isotherms of these crosslinked chitosan-graft-copolymeric beads were investigated in detail. The maximum adsorption capacities of chitosan-graft-itaconic acid and chitosan-graft-crotonic acid beads were found to be 0.31 and 0.25 mmol/g, respectively. In addition, it was found that the pseudo-second-order kinetic model is more suitable than pseudo-first-order model for the adsorption of Cu(II) ions onto the beads according to adsorption kinetics data. Adsorption isotherm data were evaluated using Freundlich, Langmuir, Brauner–Emmet–Teller, Dubinin–Radushkevich and Temkin isotherm models. The results revealed that the adsorption of Cu(II) ions onto the beads fits very well Freundlich isotherm model. Then, the beads were regenerated with an acid soluti...

A Novel Type of Organo Clay Containing Alkyd-Melamine Formaldehyde Resins

In this study, organo clay-modified alkyd resins were synthesized and these modified alkyd resins were cured with different ratios of melamine formaldehyde resin for the first time. Alkyd resins were blended with 30% and 40% of a commercial melamine-formaldehyde resin. Alkyd-melamine formaldehyde resin films were cured at 140°C for 2 h in an oven. The effect of organo clay addition on the physical and chemical film properties was investigated. These surface coating properties of the resins enhanced with amount of organo clay up to 2–3%. These resins are suitable for manufacturing of high-performance industrial baking enamels.

Effects of organo clay on film properties of alkyd‐phenol formaldehyde resins

Purpose – In this study, organo clay modified alkyd resins were synthesised and these modified alkyd resins were cured with different ratios of phenol formaldehyde resin. The purpose of this paper is to investigate the physical and chemical properties of the films and thermal behaviours of the resins.Design/methodology/approach – Alkyds formulated to have an oil content of 40 percent were prepared with phthalic anhydride (PA), glycerine (G), coconut oil fatty acid (COFA), dipropylene glycol (DPG) and organo clay. “K alkyd constant system” was used for the formulation calculations of the alkyd resins. Alkyd resins were blended with 30 percent of a phenol–formaldehyde. The films of the alkyd–phenol formaldehyde (A‐PF) resins were prepared from 60 percent solid content xylene solutions by using 50 μm applicators. After the films were cured at 150°C for 2 h in an oven, properties of the films were determined.Findings – The effect of organo clay addition on the film properties such as drying degree, hardness, ...

THERMAL OXIDATIVE DEGRADATION KINETICS OF NANOCOMPOSITE ALKYD-MELAMINE FORMALDEHYDE RESIN CONTAINING MODIFIED SILICA

□ Thermal oxidative degradation kinetics of a nanocomposite alkyd-melamine formaldehyde resin containing surface-modified silica were investigated by thermogravimetric analysis. For this goal, the surface of the silica nanoparticles was modified with glycidoxypropyl trimethoxysilane. Afterwards, a nanocomposite alkyd-melamine formaldehyde resin containing 3% (wt.) ratio of surface modified silica was prepared by an in situ polymerization method. The degradation kinetics of this resin were investigated using different methods. The activation energies of different mechanism models were determined by the Coats-Redfern method. It was concluded that the actual reaction mechanism obeyed three-dimensional diffusion compared with the values obtained from the Kissinger and Flynn-Wall-Ozawa methods.

Characterization of the thermal oxidative degradation kinetics of thermoplastics

ABSTRACT Thermal oxidative degradation kinetics of polyethylene, poly(ethylene terephthalate), and polystyrene were investigated by thermogravimetric analysis. The samples included low-density polyethylene, medium-density polyethylene, high-density polyethylene, a starch-based biodegradable thermoplastic polyester, polyethylene natural gas pipe, a poly(ethylene terephthalate) water bottle, and a polystyrene drinking cup. The kinetics were conducted under dynamic conditions at heating rates of 10, 20, 30, and 40°C min−1 between 25 and 650°C in air. The Kissinger, Flynn–Wall–Ozawa, and Coats–Redfern methods were used for investigation of degradation of these polymers. Thermal oxidative degradation of the polymers was compared. Low-density polyethylene, medium-density polyethylene, high-density polyethylene, and polyethylene pipe obeyed a diffusion mechanism for oxidative thermal degradation. The starch-based biodegradable thermoplastic polyester, polystyrene cup, and poly(ethylene terephthalate) bottle followed random nucleation, diffusion, and phase boundary-controlled reaction mechanisms, respectively.

Sodyum Akrilat Esaslı Hidrojel ve Kriyojellerin Şişme, Adsorpsiyon ve Mekanik Özelliklerinin İncelenmesi

Bu calismada, sodyum akrilat esasli hidrojel ve kriyojellerin sisme davranislari (sisme kapasitesi, denge sisme degeri ve sisme kinetigi), boyar madde (metilen mavisi) adsorpsiyonu ve mekanik ozellikleri karsilastirmali olarak incelenmistir. Kinetik paramatreler, dogrusal ve dogrusal olmayan metotlar kullanilarak belirlenmistir. Buna ek olarak, kriyojel ve hidrojel yapilarin yuzey morfolojileri, taramali elektron mikroskobu (SEM) kullanilarak karakterize edilmistir. Analizlerden elde edilen tum sonuclar karsilastirmali olarak degerlendirilmistir. In this study, swelling behavior (swelling capacity, equilibrium swelling ratio and swelling kinetics), basic dye (methylene blue) adsorption and mechanical properties of sodium acrylate based hydrogel and cryogels were comparatively investigated. Kinetic parameters were determined using linear and non-linear methods. In addition, the surface morphologies of cryogel and hydrogel structures were characterized using by Scanning Electron Microscopy (SEM). All results obtained from analyses were comparatively evaluated. Anahtar kelimeler: Hidrojel, Kriyojel, Adsorpsiyon, Sodyum akrilat, Dogrusal ve dogrusal olmayan analiz yontemleri.