Poly(aminomethoxypropylacrylamide)

In this study, a temperature sensitive polymer was obtained by the solution polymerization of 2-amino-1-methoxypropylacrylamide. The monomer, 2-amino-1-methoxypropylacrylamide was synthesized by the nucleophilic substitution reaction of N-2-amino-1-methoxypropane and acryloyl chloride. The solution polymerization was performed in ethanol at 70 degrees C by using azobisisobutyronitrile as the initiator. Poly(2-amino-1-methoxypropylacrylamide). PAMPA, exhibited a reversible phase transition behavior by the temperature in the aqueous medium. The effects of polymer and salt concentrations on the lower critical solution temperature and critical flocculation temperature were investigated. The lower critical solution temperature values were 56.5, 46.5, 43.5 and 35.0 degrees C for 0.1, 0.5, 1.0 and 5.0 wt.% PAMPA solutions in aqueous media, respectively. These results indicated that lower critical solution temperature is dependent on the polymer concentration. It was also found that critical flocculation temperature for 0.1 wt.% PAMPA concentration decreased from 52.5 degrees C to 35.0 degrees C and for 1.0 wt.% PAMPA from 47.5 degrees C to 28.5 degrees C in salt concentrations. The effect of salt concentration on the critical flocculation temperature of poly(2-amino-1-methoxypropylacrylamide) was reasonably similar to that of poly(isopropylacrylamide). In ethanol-water media, the reversible phase transition behavior was observed up to the ethanol concentration of 30% (v/v). This study indicated that poly(2-amino-1-methoxypropylacrylamide) was an alternative thermally reversible material for poly(isopropylacrylamide). (C) 2010 Elsevier B.V. All rights reserved

Brewed black tea waste (Camellia sinensis L.) as alternative pectin source

The novelty of this study is the use of brewed black tea waste (BBTW) for pectin extraction. For this purpose, the effects of extraction conditions including extraction temperature, particle size, extraction duration and solid-liquid ratio (w/v) (SLR), on the yields (PY) and physicochemical properties of the extracted pectins were investigated. In the study, pectin extractions were accomplished using solutions of citric acid (CA) as organic acid and hydrochloric acid (HCl) as inorganic acid. Extracted pectin yields from BBTW were varied between 3.18 and 10.75% depending on the extraction conditions. Galacturonic acid values were observed between 29.39 and 73.99% for the extracted pectins. Obtained pectins showed 30.87-62.50% of degree of esterification, 5.31-10.49% of methoxyl content and equivalent weight values varied between 429 and 1238 g/mol. These values for the commercial pectin (CP) were found to be respectively 69.31%, 11.57% and 1250 g/mol. These results showed that brewed black tea waste can be considered as an alternative resource for pectin production. [GRAPHICS]

Pectin extraction from garlic waste under dual acid condition

A novel approach for the extraction of pectin from garlic waste (peel, stem, and straw) was accomplished under dual acid solution conditions including two organic (citric acid [CA] and acetic acid [AA]), two inorganic (hydrochloric acid [HCl] and sulfuric acid [H2SO4]) and six different mixtures of these acids (CA-HCl, CA-H2SO4, CA-AA, AA-H2SO4, AA-HCl, and HCl-H2SO4) with 1/30 (v/w) solid-liquid ratio at 90 degrees C in 90 min extraction duration. The effects of acid mixture on the yields and physicochemical properties of the extracted pectins from garlic waste were investigated. Applying different acid mixtures during the extraction process allowed to obtain pectin samples with controlled physicochemical properties and higher yields. The maximum pectin yield of 22.4% was observed in the extraction condition carried out HCl-H2SO4 (1/3 v/v) mixture. Extractions carried out under dual acid mixtures showed higher Gal-A contents compared with the conditions where organic or inorganic acids were used alone. The extracted pectin samples were generally composed of high methoxyl pectin and their methoxyl contents are observed to be close to that of commercial citrus pectin. FT-IR spectra results of the extracted samples from garlic waste confirmed the pectin structure compared with the FT-IR spectrum of commercial citrus pectin. Results indicate that organic-inorganic dual acid mixtures could be used as an efficient extraction media for the controlled physicochemical properties and higher yields of pectin extraction. Considering that about 3.7 million tons of garlic waste is annually produced worldwide, it could be very beneficial to obtain pectin from these wastes as a useful product for the industry. Practical applications Garlic waste was converted into a valuable product for the industry and used as an alternative pectin source. Applying organic-inorganic dual acid mixtures during the pectin extraction process from garlic waste allowed to obtain pectin samples with controlled physicochemical properties and higher yields. Extracted pectin samples showed higher Gal-A contents compared with the conditions where organic or inorganic acids used alone. Obtained pectins were generally composed of high methoxyl pectins and their methoxyl contents are observed to be close to that of the commercial citrus pectin.Pamukkale UniversitesiPamukkale Universites

The use of polyethyleneglycolmethacrylate-co-vinylimidazole (PEGMA-co-VI) microspheres for the removal of nickel(II) and chromium(VI) ions

The polyethyleneglycolmethacrylate-co-vinylimidazole (PEGMA-VI) copolymers, that can be used in heavy metal removal applications, were synthesized and characterized; and their use as sorbents in heavy metal removal was investigated. It was determined that the ligand vinylimidazole was successfully inserted into the polymer structure. Then, chromium (Cr(VI)) and nickel (Ni(II)) ions were used as model species to investigate the usability of the obtained microspheres in heavy metal removal. The effects of pH of the adsorption medium, initial concentration of the metal ions and VI content of PEGMA-VI microspheres were investigated as the effective parameters on the adsorption capacities of the microspheres. The adsorption rate of the microspheres was also investigated for determination of the optimum adsorption time which is the required time for maximum adsorption capacity. The adsorption capacities under optimum conditions were also determined. The order of adsorption affinities of PEGMA-VI microspheres with respect to the used metals was determined by competitive adsorption studies. According to the obtained results, the highest adsorption affinity of the PEGMA-VI microspheres was towards Cr(VI) ions, the adsorption affinity was less for Ni(II) and the least affinity was towards Cu(II) ions. The adsorption-desorption studies showed that the microspheres were reusable without a significant decrease in the ion adsorption capacities. © 2009 Elsevier B.V

Extraction and characterization of pectin from waste of fruit peels

In this study; pectin was extracted using traditional acid extraction method using fruit peel waste such as mandarin, pomegranate and pumpkin peels. The pectins obtained by using different fruit peels and changing the extraction conditions were characterized and compared with commercial pectin. Pectin extractions were carried out with varying parameters such as three different fruit peels as raw materials, two different acid types (citric acid and hydrochloric acid) for the extraction medium and two different extraction temperatures (80 degrees C and 90 degrees C). The effects of these parameters on the pectin yield and properties of pectin were investigated. Moisture and ash content, FTIR analysis, esterification degree, equivalent weight, methoxyl content and anhydrouronic acid content were determined for the characterisation of the extracted pectin samples. The pectin yields were found to be; 4.70-14.50% for mandarin peel, 4.40-9.25% for pomegranate peel and 2.10-4.80% for pumpkin peel. Among the fruit peels used in the study for pectin extraction, the highest pectin yield was obtained as 14.50% from the mandarin peel, which is a citrus fruit. The results of the analysis and characterization show that the samples are mainly composed of high methoxy pectins. Considering the yields of extracted pectins from different fruit peels, their properties and environmental effects, it was concluded that it is more appropriate to use citric acid as the extraction medium and to select the extraction temperature of 90 degrees C

Synthesis of monodisperse glycerol dimethacrylate-based microgel particles by precipitation polymerization

A new, single-stage precipitation polymerization was proposed for the synthesis of monodisperse crosslinked glycerol dimethacrylate (GDMA)-based microgel particles carrying hydroxyl and carboxyl functionalities, from nanometer to micrometer size range. The synthesis of monodisperse microgel spheres in the size range of 30-1500 nm was possible by the proposed method. In the polymerizations, glycerol dimethacrylate was copolymerized with methacrylic acid (MAA) in the medium containing toluene and acetonitrile without using a stabilizing agent. The effects of polymerization conditions on the final monomer conversion, polymerization kinetics, and MAA distribution in the microgel particles were investigated. The hydrodynamic size, the size distribution characteristics, and the mass charge density of microgel particles were also determined. Highly monodisperse and spherical microgel particles were obtained particularly with low GDMA feed concentrations. A marked increase in the hydrodynamic size was observed with the decreasing polarity (i.e., increasing toluene concentration) in the continuous medium. The distribution of MAA in the particles and the effect of pH on the swelling behavior in the aqueous medium indicated that the microgel particles contained a swellable shell and a nonswellable core. Most of the MAA charged was buried within the core part of the microgel particles. The swelling of microgel was controlled by the ionization of the carboxyl groups located on the shell layer. The swellable character, the presence of functional groups for surface derivatization, and the similarity of microgel to a biocompatible structure, poly(hydroxyethyl methacrylate), make the new microgel a promising material for biomedical applications. © 2009 American Chemical Society