Mechanochemical block copolymerization in heterogeneous systems of the solid poly(vinyl chloride) with styrene by ultrasonic irradiation

Summary Mechanochemical block copolymerization in heterogeneous systems of the solid poly(vinyl chloride)-styrene-sodium dodecyl sulfate aqueous solutions has been studied by ultrasonic irradiation at 65 °C. The block copolymerization of styrene was initiated by free radicals produced from the poly(vinyl chloride) particles by ultrasonic waves. The initial rate of the block copolymerization Rp was given by Rp α [Styrene] [Sodium dodecyl sulfate]^1/2. Both copolymer and homopolymer were obtained. For example, when 2.506 g of the poly(vinyl chloride) particles, 24.23 g of styrene, and 54.00 g of sodium dodecyl sulfate aqueous solution (0.500 wt%) were added in the reaction system, the weight proportions of the block copolymer and polystyrene after 60 min were approximately 50 and 20%.     

Mechanochemical block copolymerization in heterogeneous systems of the solid poly(vinyl chloride) with styrene by ultrasonic irradiation

Summary The effect of several forms of suspension polymerized poly(vinyl chloride) particles on mechanochemical block copolymerization in the solid poly(vinyl chloride)-styrene-sodium dodecyl sulfate solutions has been studied by ultrasonic irradiation at 60 °C. The block copolymerization of styrene was initiated by free radicals produced from the poly(vinyl chloride) particles by ultrasonic waves. The rates of copolymerization increased with increasing the additional amount of the solid poly(vinyl chloride), the porosity, and the average diameter of the grain particles. In particular, the influence of the average diameter was much larger than that of the porosity. When the porosity and the average diameter were increased, the rates of decrease in the viscosity-average degree of polymerization of the degraded poly(vinyl chloride) were much increased. In addition, the changes in the composition of the block copolymer and homopolymers in the reaction products were obtained.     

Mechanochemical block copolymerization of poly(vinyl chloride) with methyl methacrylate by ultrasonic irradiation

Summary Mechanical degradation and mechanochemical block copolymerization in systems of poly(vinyl chloride)-methyl methacrylate-solvents have been studied by ultrasonic irradiation at 60°C. The effect of the concentrations of poly(vinyl chloride) on mechanical degradation was investigated. In addition, the effects of poly(vinyl chloride) and methyl methacrylate concentrations on mechanochemical block copolymerization were investigated. The rate equation for mechanochemical block copolymerization has been deduced, and the experimental results were in fairly good agreement with the equation. The changes in the composition of the block copolymer and homopolymers in the reaction products were followed by turbidimetric titration.     

Mechanochemical polymerization in mixtures of diallyl terephthalate and distilled water by ultrasonic irradiation

Summary Mechanochemical polymerization in systems of diallyl terephthalate-distilled water has been studied by ultrasonic irradiation at 90°C. An additional effect of distilled water on mechanochemical polymerization of diallyl terephthalate was investigated. When a 1.2 wt % distilled water solution, the conversion of poly(diallyl terephthalate) was the greatest and the initial rate of the polymerization R _p was 1.3x10^-5 mol/l sec. This polymerization proceeded by a radical mechanism and the primary radicals produced from water molecules by ultrasonic waves. In addition, changes in the iodine value and the weight-average molecular weight of the resulting polymers were proved.     

Synthesis of amphiphilic block copolymer of acrylamide with styrene using free radical interfacial copolymerization

A novel free radical interfacial copolymerization was proposed and used to prepare the amphiphilic block copolymer of acrylamide (AM) with styrene (S). In this copolymerization, a synthesized new kind of initiator, namely, amphiphilic bifunctional initiator, which has not only a hydrophilic and a hydrophobic group but also two functional groups generating radicals in both ends of its molecule, was used to initiate the interfacial copolymerization. The generated amphiphilic block copolymer was characterized by infrared analysis, differential scanning calorimetry, elemental analysis, and dissolution behavior. The migration of generated copolymer from interface to water phase was discussed. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 443–449, 1998     

Interpolymerization of acrylamide with ammonium and sodium acrylates in concentrated aqueous solutions

The effect of cation nature on the kinetics of the process and molecular characteristics of the formed interpolymers during homogeneous radical interpolymerization of acrylamide with ammonium and sodium acrylates in concentrated aqueous solutions at 60°C in the presence of an initiator (potassium peroxysulphate) has been evaluated.     

Mechanochemical synthesis of nanosize products in heterogeneous systems: Macroscopic kinetics

Suggested is a mathematical model (in a macroscopic approximation) for mechanochemical synthesis of nanopowders. The model involves the equations for heat balance in a reactor, for the dynamics of excess energy in processed powders (defining the effect of mechanoactivation on the reaction rate), for the chemical kinetics, and for powdering and changes in the state of reactive interface. Investigated is the effect of inert diluent on the process under study.      

Gelcasting of ceramic suspension in acrylamide/polyethylene glycol systems

A new polyethylene glycol/acrylamide-based gelcasting system has been developed. The new system performs at least as well as, and in some cases better than, the original acrylamide-based system. The development of this system is for the sake of eliminating the surface-exfoliation phenomenon of green bodies gelcast in air. This study concentrates attention on dispersion, rheological and gelation behavior in the new system and flexural strength of green body.     

Surface modification of polyethylene terephthalate film by CO2 laser‐induced graft copolymerization of acrylamide

Graft copolymerization of acrylamide onto polyethylene terephthalate (PET) using a CO₂ pulsed laser was performed to improve water wettability. After laser irradiation in air, the films were placed in the aqueous solution of monomer and then heated to decompose peroxides formed onto the irradiated PET film. Peroxide density was determined spectrophotometrically by means of the iodide method. The grafted PET surfaces were characterized by attenuated total reflectance infrared spectroscopy, scanning electron microscopy, and contact angle measurements. The electron micrographs showed that the grafting changed the surface morphology of the PET film, which is consistent with the infrared spectra of the grafted films. To evaluate the surface hydrophilicity, water drop contact angle was determined. The contact angle decreased as a result of graft polymerization. It was also found that the hydrophilicity is related to the surface morphology and grafting level. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 401–407, 2000     

Synthesis of cationic flocculant by radiation-induced copolymerization of methyl chloride salt of N,N-dimethylaminoethyl methacrylate with acrylamide in aqueous solution

The radiation-induced copolymerization of the methyl chloride salt of N,N-dimethylaminoethyl methacrylate (DMAEM·MC) with acrylamide (AAm) was used to prepare a cationic polymer flocculant. The polymerization rate increased with increasing dose rate, polymerization temperature, monomer concentration and mole fraction of AAm in the monomer mixture. The molecular weight of the copolymer was also found to increase with monomer concentration and mole fraction of AAm, but at high concentration and fraction of AAm, intermolecular crosslinking tends to occur during the polymerization to form water-insoluble copolymer. A water-soluble copolymer having various molecular weights and cationic strengths can be synthesized by selecting suitable reaction conditions; i.e., this radiation process can provide a much higher molecular weight copolymer with a wide range of cationic strength. The flocculation effect was evaluated using sludge from wastewater of sugar manufacture. It was found that the radiation-polymerized copolymer DMAEM·MC–AAm has an excellent flocculation effect.     

Dispersion copolymerization of acrylamide with acrylic acid in an aqueous solution of ammonium sulfate: Synthesis and characterization

Dispersion copolymerization of acrylamide with acrylic acid in an aqueous solution of ammonium sulfate using poly(2‐acrylamido‐2‐methylpropanesulfonic acid sodium) as the stabilizer and ammonium persulfate (APS) as the initiator was investigated. The influence of initiator concentration, stabilizer concentration, ammonium sulfate concentration, chain‐transfer agent concentration, and polymerization temperature on the copolymerization was discussed. The results showed that varying the ammonium sulfate concentration could affect the particle size and the intrinsic viscosity of the copolymer significantly. With increasing the stabilizer concentration, the particle size of the copolymer decreased first, and then increased, meanwhile the intrinsic viscosity of the copolymer decreased. The increase of initiator concentration, chain‐transfer agent concentration, and polymerization temperature resulted in the increase in the particle size. Polydisperse spherical particles were formed in the system, and the kinetics for the dispersion copolymerization were discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3685–3690, 2006     

玉米淀粉/丙烯酰胺接枝型高吸水性树脂的合成

本文以硝酸铈铵为引发剂 ,研究了单体浓度、引发剂浓度、反应温度和反应时间等因素对玉米淀粉与丙烯酰胺接枝共聚制备高吸水性树脂的影响 ,通过反应条件和正交试验 ,确定了最适宜的反应条件和工艺路线 ,制备出了吸水率在 4 5 0～ 70 0g·g-1的玉米淀粉接枝型高吸水性树脂。     

Graft copolymerization of acrylamide on cotton cellulose in a limited aqueous system following pretreatment technique

Graft copolymerization of acrylamide on cotton (dialdelyde cellulose, DAC) fibers and fabrics was studied in a limited aqueous system using K₂S₂O₈ as the initiator. Grafting parameters under different sets of conditions were determined and the mechanism of graft copolymerization discussed. Optimum conditions for grafting were established and the effect of polyacrylamide grafting on tenacity, modulus, breaking elongation, and stiffness of the cotton (DAC) fabrics and on their dyeability and moisture regain properties were also studied; 9–10% grafting of polyacrylamide on (DAC) fabric at _pH 7–10 imparts an improved balance in its mechanical and other properties. © 1995 John Wiley & Sons, Inc.     

Graft copolymerization of acrylamide onto carboxymethylcellulose with the xanthate method

Acrylamide was grafted to an xanthate mixture of carboxymethylcellulose with a sodium bisulfate/ammonium persulfate redox initiator system in water, sodium hydroxide, potassium hydroxide, and dioxane at 40, 50, 60, 70, and 80°C during a reaction period of 2 h. The grafted polymer and homopolymer were isolated with diethyl ether from the reaction mixture, dried, and weighed. The grafted polymer was characterized with IR and mass spectrometry methods, and the microscopic morphology was detected with electron scanning microscopy. The graft level percentage distinctly increased with the use of sodium hydroxide, potassium hydroxide, and dioxane over that of a reaction carried out completely in an aqueous medium. Also, the graft level decreased as the reaction temperature increased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 271–278, 2004     

Degradation of C.I. Acid Orange 7 by heterogeneous Fenton oxidation in combination with ultrasonic irradiation

BACKGROUND: A mesoporous alumina supported nanosized Fe₂O₃ was prepared through an original synthesis procedure and used as a heterogeneous catalyst for the Fenton process degradation of the model azo dye C.I. Acid Orange 7 enhanced by ultrasound irradiation (US/Fe₂O₃‐Al₂O₃‐meso/H₂O₂ system). The effect of various operating conditions was investigated, namely hydrogen peroxide concentration, initial pH, ultrasonic power and catalyst loading. RESULTS: The results indicated that the degradation of C.I. Acid Orange 7 followed a pseudo‐first‐order kinetic model. There exists an optimal hydrogen peroxide concentration, initial pH, ultrasonic power and catalyst loading for decolorization. The aggregate size of the spent catalyst was reduced after dispersion in water by ultrasonic irradiation. A very low level of iron leaching was observed ranging from < 0.1 to 0.23 mg L^?1. The intermediate products of C.I. Acid Orange 7 degradation were identified using gas chromatography–mass spectrometry (GC‐MS). CONCLUSION: The optimal conditions for efficient C.I. Acid Orange 7 degradation were pH close to 3, hydrogen peroxide concentration 4 mmol L^?1, catalyst loading 0.3 g L^?1, and ultrasonic power 80 W. Copyright © 2011 Society of Chemical Industry     

The surface characterization of mulberry silk grafted with acrylamide by plasma copolymerization

The effects of plasma-induced graft copolymerization and simultaneous plasma-treated graft copolymerization with acrylamide (AAm) on the structure of mulberry silk are investigated. Through scanning electron microscopy, transmission infrared (IR), and attenuated total reflectance-IR and x-ray photoelectron spectroscopy (XPS) studies, changes of the surface morphology, structure, and composition are observed. The results show that plasma-induced graft copolymerization has more influence on the original structure of silk than does simultaneous plasma-treated graft copolymerization. The former brings the AAm branch polymer into the main chain of silk by the initiation of some kind of oxygen and nitrogen groups formed by the plasma, but the latter directly forms the AAm branch or cross-linking polymers with oxygen and nitrogen groups on the silk surface. This is the reason for the high elastic recovery angle of silk fabric modified by the two plasma graft copolymerizations. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1713–1717, 1997     

Mechanochemical copolymerization of methyl methacrylate and styrene initiated by the grinding of quartz

The copolymerization of methyl methacrylate and styrene mechanochemically initiated by the grinding of quartz in the monomer mixture was investigated by using a vibrating ball mill. The effect of the grinding of quartz on the copolymerization was investigated by characterizing both the polymer formed and the ground quartz. The copolymerization proceeds apparently from the quartz grindings and was closely related to the total surface area of the ground quartz. The molecular weight distributions of the copolymers formed were unimodal as found in a homopolymer of only methyl methacrylate. It was clear from the composition analysis of the copolymer that the mechanochemical copolymerization of methyl methacrylate and styrene proceeded with a radical polymerization mechanism because of radicals on the quartz surface produced by the grinding. The monomer reactivity ratios obtained by the Fineman‐Ross method suggested that the copolymers formed were alternating copolymers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2011–2017, 2002; DOI 10.1002/app.10544     

Synthesis of solid solutions in double metallic systems by the iodine-transport method

The paper is devoted to investigating the formation of solid solutions of metals from elements by the iodine-transport method. The possibility for the synthesis of a continuous series of solutions of Cu-Ni, as well as solutions of aluminum and silicon in copper, without the formation of liquid metallic phases is shown.     

Mechanochemical synthesis and characterization of poly(vinyl chloride)-block-poly(ethylene-co-propylene) copolymers by ultrasonic irradiation

Mechanical degradation and mechanochemical reaction in heterogeneous and homogeneous systems of poly(vinyl chloride) and poly(ethylene-co-propylene) polymer have been studied by ultrasonic irradiation at 30 °C. The rates of decrease in the number-average molecular weights of the degraded poly(vinyl chloride) and poly(ethylene-co-propylene) polymer were much faster in order of the solid poly(vinyl chloride)—poly(ethylene-co-propylene) polymer solution, the swelled poly(vinyl chloride)—poly(ethylene-co-propylene) polymer solution, and the homogeneous solution systems. On the other hand, mechanochemical reaction occurred by free radicals produced from the chain scissions of both polymers by ultrasonic waves. The changes in the composition of the total block copolymer, the unreacted poly(vinyl chloride), and the unreacted poly(ethylene-co-propylene) polymer in individual reaction systems were obtained. In addition, the microscopic observation of the surfaces of the polymers on before and after mechanochemical reaction is carried out. Received: 10 May 2000/Revised version: 1 August 2000/Accepted: 3 August 2000