Concentration Of Ceric Ammonium Nitrate Research Articles

Optimization of preparation process for allylamine-bacterial cellulose via graft copolymerization by response surface methodology

In order to improve the efficiency of new adsorbent, grafting-allylamine bacterial cellulose(al-BC), response surface methodology(RSM) was used for the optimization of preparation process. Three factors affecting the yield of grafting reaction are the amount of allylamine, the concentration of ceric ammonium nitrate(CAN) and the concentration of nitric acid. Based on the regression coefficient analysis in the Box-Behnken design, a relationship between the preparation variable and grafting yield was obtained. Square error analysis on main factors, and multi-variable interactions were employed for studying grafting yield. The results show that at the conditions of CAN of 23.00 mmol/L CAN, 0.17 mol/L nitric acid, adding an amount of grafting-allylamine bacterial cellulose of 26.49 mL/L made grafting rate reach maximum of 24.25% at 40 °C after the reaction for 4 h. The experimental results are in good agreement with the calculation values via proposed regression equation, indicating that the equation could be used to predict and optimizate the preparation of grafting al-BC.

CO sensor based on thick films of 3D hierarchical CeO2 architectures

Hollow CeO2 microspheres, having 3D architectures on their surface, were prepared by a microwave-assisted coprecipitation method. By this method, ceric ammonium nitrate was diluted in formic acid. The application of microwave irradiation produced the precipitation of a white powder, with the simultaneous emission of NO2. At low temperature, cerium formate was formed; whereas from 400°C, CeO2 with cubic crystal structure was identified. The morphology of the samples calcined from 170 to 600°C was of hollow microspheres, with size between 1.5 and 10μm. Their surface displayed unique 3D architectures, which consisted of ramifications formed by the assembly of nanograins and nanoporous. Microwave irradiation played a key role in the formation of 3D hollow architectures. The effect of the concentration of ceric ammonium nitrate on the particle morphology was also investigated. Thick films were prepared by depositing a suspension of the CeO2 powder on alumina substrates. The electrical characterization in gases was performed in alternating current (AC). The films exhibited a reliable and quantitative detection of carbon monoxide from 250°C. The effect of the applied frequency and the operating temperature was analyzed.

Graft Polymerization of Acrylic Acid onto Polypropylene Film: Immobilization of Chitosan Nanoparticles onto Grafted Films

In this paper the aim is to immobilize chitosan nanoparticles on the surface of the polypropylene film, aqueous phase thermal decomposition characteristics of ammonium persulfate is used. The PP film is first hydroxylation pretreated in the protection of the high-purity nitrogen. And then ceric ammonium nitrate acting as an initiator, induce graft polymerization of acrylic acid on the hydroxylated treated PP film. Thus, carboxyl functional groups are grafted on the surface of PP film. Finally chitason namoparticles are fixed on PP film by the reaction of carboxyl group and the amino group of chitosan. Experimental results show that: when the reaction temperature is 60 ° C, the concentration of acrylic acid is 8% (w/w), the reaction time reaches 4h, the concentration of ceric ammonium nitrate is 2mM, the optimum grafting ratio is obtained, which is up to 0.6008×10-7mol/cm2. Total reflection Fourier transform infrared spectroscopy absorption peaks appear at 1712cm-1, indicating that the-COOH has been successfully grafted to the film surface; the SEM scanning the film surface shows that the chitosan nanoparticles were perfectly immobilized on the modified film. Key words: Acrylic acid, Polypropylene film, Chitosan nanoparticles, Graft polymerization

Synthesization, characterization and adsorption properties of sulfonic cellulose

The synthesization and characterization of a new environmental functional material-sulfonic cellulose - were studied in this paper. The preparation conditions were optimized through an orthogonal experiment. The modified cellulose was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The adsorption rules of cationic organic pollutants and heavy metal ions by this new material were discussed. Regeneration and recycling performances of the sulfonic cellulose were also investigated. At the temperature of 323 K, sulfonic cellulose was prepared by grafting 2-acrylamido-2-methylpropane sulfonic acid (AMPS) onto alkali-treated cellulose for 4 h with the employing of ceric ammonium nitrate as initiator. The mass ratio of AMPS to cellulose was 3:1 and the concentration of ceric ammonium nitrate was 63.8 mmol/L. The sulfur content of sulfonic cellulose was 7.32 wt%. The peaks of 1,303 and 1,159 cm⁻¹ in IR suggested the existence of the sulfonic group in sulfonic cellulose. The XRD and SEM results showed that the crystallinity decreased while the specific surface area increased after modification. Batch adsorption results showed that sulfonic cellulose had a favorable adsorption capacity for model contaminants at pH 6.0-7.0. The adsorption process was endothermic and reached equilibrium in 180 min. The adsorption rules of cationic organic pollutants and heavy metal ions indicated that sulfonic cellulose had high adsorption capacity for the cationic dyes with a coplanar macromolecule structure and organic compounds carrying the amino group. Under room temperature, 1.0 mol/L HCl can be used as a desorption solution and the equilibrium adsorption capacity had little decrease (less than 7%) after six adsorption-desorption cycles.

Characterization of cationic polyacrylamide-grafted starch flocculant synthesized by one-step reaction

Cationic polyacrylamide-grafted starch (St-g-CPAM) flocculant was prepared by using corn starch and acrylamide (AM) as monomers, dimethyl diallyl ammonium chloride (DMDAAC) as cationic monomer through solution polymerization. The effects of initiator, reaction temperature, and monomer concentration on flocculation, the efficiency of grafting, and the yield of grafting were investigated. The results show that the optimal conditions of the polymerization are as follows: the concentration of ceric ammonium nitrate is 0.5%, the reaction temperature is 60°C, the concentration of total monomer is 20%, and the monomer ratio between AM and DMDAAC is 7 : 3. The flocculation capability was characterized by turbidity reduction. The thermal behavior, chemical structure, and microstructure of St-g-CPAM were also investigated by thermal gravimetric, IR, and SEM analyses. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Microwave assisted synthesis and characterization of Phaseolus aconitifolius starch-g-acrylamide

Moth bean starch was modified through microwave assisted synthesis using a very low concentration of free radical initiator. Grafted copolymer was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Swelling study was also performed at various temperatures to access its suitability in diverse industrial application. Starch-grafted-acrylamide could be efficiently synthesized using a small concentration of ceric ammonium nitrate (CAN) in aqueous medium under microwave irradiation. The FT-IR spectral analysis confirms group attachment on starch backbone. XRD and SEM studies confirmed more crystalline structure, while TGA confirmed high thermal stability as compared to native starch. Starch-g acrylamide was successfully grafted and this novel biomaterial could be used in various industrial applications like food, textile paper, petroleum and pharmaceutical.

Optimization of reaction conditions for grafting of α-cellulose isolated from Lantana camara with acrylamide

Lantana camara, a noxious weed is a serious threat to the ecosystems and demands concerted efforts for its management. Though a number of approaches have been adopted for effective management of L. camara, however each approach has inbuilt limitation and satisfactory approach is yet to be seen. Utilisation of abundantly available cellulosic biomass derived from Lantana could be a practical proposition for the management of the weed. Therefore, chemical analysis of the raw material was done to isolate α-cellulose followed by its characterization. Graft copolymerization of acrylamide onto α-cellulose was studied with ceric ammonium nitrate as a redox initiator in an aqueous medium. The reaction conditions were optimized by varying concentration of ceric ammonium nitrate, nitric acid, acrylamide, time and temperature. The products were characterized by IR, SEM and thermal analysis. Grafting of acrylamide chains onto the α-cellulose enhances its thermal stability. A reaction mechanism is also proposed.

Modified katira gum for colon targeted drug delivery

AbstractThe aim of the this study is to develop colon targeted drug delivery systems for Ibuprofen using grafted katira gum as a carrier. Polyacrylamide‐grafted katira gum was synthesized by grafting acrylamide onto katira gum in presence of varying concentration of ceric ammonium nitrate (CAN) as initiator. Elemental analysis, FTIR, TGA, DTA, DSC, and SEM were used to characterize the grafting of acrylamide onto katira gum. Matrix tablets containing various proportions of grafted katira gum were prepared by wet granulation method. All the formulations were evaluated for hardness, drug content, swelling index, and in vitro release studies in simulated gastric fluid, small intestinal fluid, and simulated colonic fluid with and without enzymes. Ibuprofen was used for controlled release study. The drug release mechanism was studied by fitting into Peppas model and was found to be supercase‐II transport. Matrix tablets containing 0.3 g of CAN/gm of acrylamide showed optimum value and retained its physical integrity in simulated gastric, small intestinal and colonic fluid, where as other composition disintegrated within 2 h of dissolution testing in pH 1.2 buffer, simulated gastric fluid. The results of this study indicates that Ibuprofen matrix tablet containing 60 wt % composition of the above grafted katira gum would be potential formulations in delivering the drug to the colon and the more susceptible for enzymatic degradation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Response Surface Methodology for the Optimization and Characterization of Cassava Starch‐graft‐Poly(acrylamide)

AbstractResponse surface methodology (RSM) was employed for the synthesis of cassava starch‐graft‐poly(acrylamide) using ceric ammonium nitrate as free radical initiator. Concentration of acrylamide, concentration of ceric ammonium nitrate, reaction temperature and duration of reaction were optimized using a 4‐factor 3‐level Box‐Behnken design. The dependent variables were percentage grafting (%G) and grafting efficiency (GE). Second order polynomial relationships were obtained for %G and GE, which explained the main, quadratic and interaction effects of factors. The highest%G and GE obtained were 174.8% and 90.7%, respectively. The optimum values of parameters predicted through RSM were 20 g acrylamide/10 g dry starch, 3.3 g/L ceric ammonium nitrate, 180 min reaction duration and 45ºC temperature with a %G of 190.0. For GE, the predicted levels of factors for the optimum value of 90.8% were 17.5 g acrylamide/10 g dry starch, 4.1 g/L ceric ammonium nitrate, 180 min reaction duration and 55ºC temperature. The graft reaction was confirmed by FTIR analysis, where the absorption bands corresponding to the C=O stretching and N‐H bending of the –CONH2 group were observed. Scanning electron microscopic studies on grafted starches revealed that the granular structure of the starch was affected by the reaction. X‐ray diffraction analysis showed that the crystallinity of starch was decreased as a result of grafting and the reduction was higher for the grafted starches with higher percentage grafting.

Grafting of acrylonitrile onto cellulosic material derived from bamboo (Dendrocalamus strictus)

Bamboo, a lignocellulosic biopolymer material, is of interest as feedstock for production of cellulose derivatives by chemical functionalization. Optimization of grafting of acrylonitrile onto cellulosic material (average Degree of Poly- merization 816), isolated from bamboo (Dendrocalamus stictus) was performed by varying the process parameters such as duration of soaking of cellulosic material in ceric ammonium nitrate solution, ceric ammonium nitrate concentration, poly- merization time, temperature of reaction and acrylonitrile concentration to study their influence on percent grafting and grafting efficiency. Graft copolymerization of acrylonitrile onto cellulosic material derived from bamboo (Dendrocalamus strictus) in het- erogenous medium can be initiated effectively with ceric ammonium nitrate. The optimum reaction conditions obtained for grafting of acrylonitrile onto cellulosic material were: duration of dipping cellulosic material in ceric ammonium nitrate solution 1 hr, ceric ammonium nitrate concentration 0.02 M, acrylonitrile concentration 24.6 mol/anhydroglucose unit, temperature of reaction 40°C and polymerization time 4 hrs. The percent grafting for optimized samples is 210.3% and grafting efficiency is 97%. The characterization of the grafted products by means of FTIR and Scanning Electron Microscopy furnished the evidence of grafting of acrylonitrile onto the cellulosic material.

Graft Copolymerization on to Cellulose Using Binary Mixture of Monomers

The graft copolymerization of acrylonitrile (AN) and ethyl acrylate (EA) comonomers onto cellulose has been carried out using ceric ammonium nitrate (CAN) as an initiator in the presence of nitric acid at 35±0.1°C. The addition of ethyl acrylate as comonomer has shown a significant effect on overall and individual graft copolymerization of acrylonitrile on cellulose. The graft yield (%GY) and other grafting parameters viz. true grafting (%GT), graft conversion (%CG), cellulose number (Ng) and frequency of grafting (GF) were evaluated on varying the concentration of comonomers from 6.0–30.0×10−1 mol dm−3 and ceric (IV) ions concentration from 2.5–25×10−3 mol dm−3 at constant feed composition (fAN 0.6) and constant concentration of nitric acid (7.5×10−2 mol dm−3) in the reaction mixture. The graft yield (%GY) and other grafting parameters were optimal at 15×10−1 mol dm−3 concentration of comonomers and at 10×10−3 mol dm−3 concentration of ceric ammonium nitrate. The graft yield (%GY) and composition of grafted chains (FAN) was optimal at a feed composition (fAN) of 0.6. The energy of activation (Ea) for graft copolymerization has been found to be 16 kJ mol−1. The molecular weight (Mw) and molecular weight distribution (Mw/Mn) of grafted chains was determined by GPC and found to be optimum at 15×10−1 mol dm−3 concentration of comonomer in the reaction mixture. The composition of grafted chains (FAN) determined by IR method was used to calculate the reactivity ratios of monomers, which has been found to be 0.62 (r1) and 1.52 (r2), respectively for acrylonitrile (AN) and ethyl acrylate (EA) monomers used for graft copolymerization. The energy of activation for decomposition of cellulose and grafted cellulose was determining by using different models based on constant and different rate (β) of heating. Considering experimental observations, the reaction steps for graft copolymerization were proposed.

Ceric(IV) ion‐induced graft copolymerization of acrylamide and ethyl acrylate onto cellulose

AbstractGraft copolymerization of acrylamide (AAm) and ethyl acrylate (EA) onto cellulose has been carried out from their binary mixtures using ceric ammonium nitrate (CAN) as an initiator in the presence of nitric acid at 25 ± 1 °C. The extent of acrylamide grafting increased in the presence of the EA comonomer. The composition of the grafted chains (FAAm = 0.52) was found to be constant during the feed molarity variation from 7.5 × 10−2 to 60.0 × 10−2 mol L−1, whereas the composition of the grafted chains (FAAm) was found to be dependent on feed composition (fAAm) and reaction temperature. The effects of ceric(IV) ion concentration, reaction time and temperature on the grafting parameters have been studied. The grafting parameters showed an increasing trend up to 6.0 × 10−3 mol L−1 concentration of CAN at a feed molarity of 30.0 × 10−2 mol L−1 and showed a decreasing trend on further increasing the concentration of CAN (>6.0 × 10−3 mol L−1) at a constant concentration of nitric acid (5.0 × 10−2 mol L−1). The composition of the grafted chains (FAAm) was determined by IR spectroscopy and nitrogen content and the data obtained then used to determine the reactivity ratios of the acrylamide (r1) and ethyl acrylate (r2) comonomers by using a Mayo and Lewis plot. The reactivity ratios of acrylamide and ethyl acrylate were found to be r1 = 0.54 and r2 = 1.10, respectively, and hence the sequence lengths of acrylamide (m̄M1) and ethyl acrylate (m̄M2) in the grafted chains are arranged in an alternating form, as the product of the reactivity ratios of acrylamide and ethyl acrylate (r1 × r2) is less than unity. The rate of graft copolymerization of the comonomers onto cellulose was found to be dependant on the ‘squares’ of the concentrations of the comonomers and on the ‘square root’ of the concentration of ceric ammonium nitrate. The energy of activation (ΔEa) of graft copolymerzation was found to be 5.57 kJ mol−1 within the temperature range from 15 to 50 °C. On the basis of the results, suitable reaction steps have been proposed for the graft copolymerzation of acrylamide and ethyl acrylate comonomers from their mixtures. Copyright © 2005 Society of Chemical Industry

Acrylamide–Methylmethacrylate Graft Copolymerization onto Cellulose Using Ceric Ammonium Nitrate

The graft copolymerization of acrylamide (AAm) and methylmethacrylate (MMA) onto cellulose has been carried out from their mixtures using ceric ammonium nitrate (CAN) as initiator in the presence of nitric acid at 25.0±0.1°C. The extent of graft copolymerization of acrylamide onto cellulose has shown a substantial increasing trend in the presence of methylmethacrylate comonomer. On varying the feed molarity from 7.5×10−2 mol dm−3 to 60×10−2 mol dm−3, the graft yield has shown a linear increase with grafted chains of almost constant composition (FAAm=0.57). The composition of the grafted chains (FAAm) has been found to be dependent on the feed composition (fAAm) and temperature of reaction mixture. The effect of ceric (IV) ions concentration, reaction time and temperature was also studied and grafting parameters were determined to evaluate the effect of these reaction variables. The grafting parameters have shown an increasing trend up to 8.0×10−3 mol dm−3 concentration of ceric ammonium nitrate at a feed morality of 45.0×10−2 mol dm−3 and shown a decreasing trend on further increasing the concentration of ceric ammonium nitrate (>8.0×10−3 mol dm−3) while keeping fixed concentrations of nitric acid (9.0×10−2 mol dm−3). The IR and nitrogen percent data were used to determine the composition of the grafted chains (FAAM), which was further used to determine reactivity ratios of acrylamide (r1) and methylmethacrylate (r2) using the Mayo and Lewis plot. The reactivity ratios of acrylamide (r1) and methylmethacrylate (r2) were found to be 0.82 and 1.10 respectively. This indicated an alternate arrangement of average sequence lengths of acrylamide (m¯M1) and methylmethacrylate (m¯M2) in the grafted chains as the product of reactivity ratios (r1r2) was less then unity. The rate of graft copolymerization of comonomers onto cellulose has been found to be dependent on the square concentration of comonomers and square root of the ceric ammonium nitrate concentration. The activation energy (ΔEa) of graft copolymerization was found to be low (14.36 kJ mol−1) within the temperature range of 20°C to 45°C. On the basis of experimental observations, suitable reaction steps for graft copolymerization of acrylamide and methylmethacrylate have been proposed to explain the grafting of these comonomers onto cellulose.

Ce(IV)-Ion Initiated Graft Copolymerization of Methyl Methacrylate onto Guar Gum

Graft copolymerization of methyl methacrylate onto guar gum was carried out in an aqueous medium using a ceric ammonium nitrate–nitric acid initiation system. The percent grafting (%G) and percent grafting efficiency (%GE) were determined as functions of the concentrations of ceric ammonium nitrate, nitric acid, methyl methacrylate, guar gum, polymerization temperature and time. Results are discussed and a reaction mechanism is proposed.

Modification of sago starch by graft copolymerization. Effect of reaction conditions on grafting parameters

Graft copolymerization of acrylonitrile onto sago starch was carried out by a free radical initiating process in which the ceric ion (Ce 4+ ) was used as an initiator. The reaction conditions significantly influence the graft copolymerization. The percentage of grafting, grafting efficiency and rate of grafting were all dependent on the concentration of ceric ammonium nitrate (CAN), acrylonitrile (AN), sago starch (AGU, anhydro glucose unit), mineral acid (H 2 SO 4 ) and the reaction temperature and period. The optimum yield was obtained when the concentrations of CAN, AN, AGU and H 2 SO 4 were used at 9.61×10 −3 , 0.653, 0.152 and 0.187 mol L −1 , respectively. The optimum temperature and reaction period were 50°C and 90 min, respectively. The rate of graft copolymerization was examined using the experimental results and the reaction mechanism. The polya1crylonitrile grafted sago starch was characterized by using FT-IR spectroscopy, DSC and SEM analysis.

Graft copolymerization of acrylamide–methylacrylate comonomers onto cellulose using ceric ammonium nitrate

AbstractThe graft copolymerization of acrylamide–methylacrylate comonomers was carried out using ceric ammonium nitrate as initiator in the presence of nitric acid at 25 ± 1°C. The effects of feed molarity, feed composition, reaction time, and temperature on graft yield (%G) and other grafting parameters were investigated. The determination of rate of ceric (IV) ions disappearance as a function of feed molarity and reaction time was useful in the determination of the rate of ceric (IV) ions consumption during graft copolymerization. The graft yield (%G) in the presence of acrylamide increases because of the synergistic effect of acrylamide comonomer. The composition of the grafted chains (FAAm) varies on varying the feed composition and reaction temperature but is almost constant during feed molarity variation. The Mayo and Lewis method was used to determine the reactivity ratios of acrylamide (r1) and methylacrylate (r2), which are 0.65 and 1.07, respectively. The product of reactivity ratio (r1 r2) is less then unity; hence, an alternate arrangement of comonomer blocks in the grafted copolymer chain is proposed. The rate of graft copolymerization of comonomers onto cellulose is second power to the concentration of comonomers and square root to the concentration of ceric ammonium nitrate. Suitable reaction steps for graft copolymerization of comonomers onto cellulose are proposed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2631–2642, 2002

Graft copolymerization of acrylic acid onto cellulose: Effects of pretreatments and crosslinking agent

AbstractThe graft copolymerization of acrylic acid (AA) and 2‐acrylamido 2‐methylpropane sulfonic acid (AASO3H) onto cellulose, in the presence or absence of crosslinking agent N,N′‐methylene bisacrylamide (NMBA), by using different concentrations of ceric ammonium nitrate (CAN) initiator in aqueous nitric acid solution at either 5 or 30°C was investigated. To investigate the effect of pretreatment of cellulose on the copolymerization, before some grafting reactions cellulose was pretreated with either 2 or 20 wt % NaOH solutions or heated in distilled water/aqueous nitric acid (2.5 × 10−3 M) at 55°C. To determine how the excess of initiator affects the grafting and homopolymerization, separate reactions were carried out by removing the excess of ceric ions by filtration of the mixture of initiator solution and cellulose before the monomer addition. Extraction‐purified products were characterized by grafting percentage and equilibrium swelling capacity. Pretreatment of cellulose with NaOH solutions decreased the grafting percentage of copolymers. In the case of AA–AASO3H mixtures, nonpretreated cellulose gave a higher grafting percentage than NaOH‐pretreated cellulose. Filtration also lowered the grafting of AA on the cellulose in the cases of pretreatment with either water or nitric acid. Copolymers with the highest grafting percentage (64.8%) and equilibrium swelling value (105 g H2O/g copolymer) were obtained in grafting reactions carried out in the presence of NMBA at 5°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2267–2272, 2001

Kinetics of graft copolymerization of acrylonitrile onto sago starch using free radicals initiated by ceric ammonium nitrate

This article reports an experimental investigation on the graft copolymerization of acrylonitrile monomer onto sago starch in which ceric ammonium nitrate was an initiator. The grafting reactions were initiated by the known free radical method. It was observed that the rate of graft polymerization and the grafting efficiency were dependent on the concentration of ceric ammonium nitrate (CAN), acrylonitrile (AN), sago starch (AGU, anhydro glucose unit), and the reaction period. The equation for the rate of polymerization (R p) is a first-order dependence of the monomer (AN) concentration and the square root of the CAN concentration. The experimental results were used to verify the kinetic equation relating the graft fraction of poly(acrylonitrile) on sago starch.

Metal ions binding by chelating ligands from new polymer bearing amidoxime functional groups

Chelating polymer materials are mainly used in analytical, industrial and radiochemical laboratories, but only to a limited extent in solving environmental problems. Metal pollution of the environment presents a unique problem, since metals are not subjected to biodegradation. The chelating resins containing amidoxime groups have been playing a vital role in environmental monitoring of toxic trace metals. The amidoxime chelating resins can be used for extraction of toxic metals in the environment and sewage waters. The possibility of uranium recovery from seawater has been studied in many countries, a particularly high number of publications come from Japanese scientists, which contain the synthesis of macroreticular resins bearing amidoxime groups, because of their use in extraction of uranium from seawater. 1‐4 Most of these papers involve the incorporation of a nitrile group into a polymer matrix, followed by the conversion of the nitrile group into an amidoxime group using the alkaline solution of hydroxylamine. Egawa et al. 5 prepared a macroreticular chelating resin containing amidoxime by reacting acrylonitrile-divinyl benzene copolymer with hydroxylamine. Kubota and Shigehisa 6 proposed a new route in which amidoxime groups were prepared by the reaction of cyanoethylcellulose and acrylonitrile grafted cellulose with hydroxylamine. Fetscher 7 described the extraction of metals from dilute solutions by poly(amidoxime) resin derived from fibrous homopolymers and copolymers of acrylonitrile. Divinylbenzene cross-linked poly(acryloamidoxime) resins were obtained and successfully used in the determination of trace metals in natural waters. 8,9 Most of the work centralised on the uranium extraction in sea water by poly(amidoxime) resin. There are very few articles published for transition metal uptake by poly(amidoxime) resin. This may first be introduced by the preparation of poly(amidoxime) chelating resin from polyacrylonitrile (PAN) grafted sago starch. In this report, the PAN grafted copolymer was used as a cheapest starting material to obtain the poly(amidoxime) resin and the binding property of the chelating resin was examined with a series of metal ions. The PAN grafted sago starch was prepared from acrylonitrile monomer and sago starch using the free radical initiating process according to the reaction mechanism suggested by Ceresa. 10 The grafting procedure was described elsewhere. 11 The optimum yield of PAN grafted copolymer at the concentration of ceric ammonium nitrate, acylonitrile, sago starch (AGU, anhydroglucose unit) and sulfuric acid were 9.52 〈 10 ‐3 , 0.506, 0.146 and 0.190 mol/l respectively, as well the reaction temperature and period were 50°C and 90 min, respectively. The conversion of the nitrile group into amidoxime was carried out by the treatment of hydroxylamine in an alkaline medium. According to the mechanism suggested by Schouteden, 12 the reaction of PAN with hydroxylamine is shown in Scheme 1, where P is the backbone polymer.

Kinetics and mechanism of free radical grafting of methyl acrylate onto sago starch

The graft copolymerization was carried out by methyl acrylate with sago starch in which ceric ammonium nitrate was used as an initiator. It has been found that the rates of graft polymerization and grafting efficiency were dependent upon the concentration of ceric ammonium nitrate (CAN), methyl acrylate (MA), sago starch (AGU, anhydro glucose unit), mineral acid (H2SO4), and as well as reaction temperature and period. A rate equation of polymerization was established from the proposed reaction mechanism, and the rate of polymerization (Rp) was the first-order dependence of the MA monomer concentration and square root of the CAN concentration. A new kinetic model of the grafting reaction has been proposed, and a normal kinetics of methyl acrylate polymerization was observed. An equation of a predicted model relating the graft fraction of poly(methyl acrylate) with the sago starch has been derived, and validity of the predicted model was verified by the experimental results. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 784–791, 2000