STUDY ON SYNTHESIS OF AMPHOTERIC POLYACRYLAMIDE IN INVERSE EMULSION

Amphoteric polyacrylamide was prepared first by the copolymerization of acrylamide with sodium acrylate and then through Mannich reaction.The copolymerization was carried out with a redox initiation system using the method of inverse emulsion polymerization.In this paper the reaction conditions and factors that affect emulsion stability were studied.Experiments show that a stable latex can be obtained under the following conditions:anionic degree is five percent,the ratio among acrylamide,formaldehyde and dimethylamine is 1∶1∶1.2,reaction temperature is 45 ℃,reaction time lasts four hours,and pH equals 5.0.The amphoteric copolymer has a higher molecular weight and cationic degree,so it is an ideal filler retention and drainage aid in paper making.

PHOTOINITIATED INVERSE EMULSION POLYMERIZATION OF SODIUM ACRYLATE

Photoinitiated inverse emulsion polymerization of sodium acrylate(AANa)in kerosene was carried out at room orlower temperature,using 2,2-dimethoxy-2-phenylacetophenone(DMPA)as the initiator.Kinetic investigations indicated thatthe polymerization could be completed in about 30 min and produce polymer with high molecular weight(10~6～10~7).It wasfound that monomer droplets are the main sites for the polymerization(nucleation).With the increase of DMPAconcentration,polymerization rate(R_p)reaches a maximum value while molecular weight of the produced polymer has anadverse result,but the dependence of R_p on incident light intensity is similar.Influences of other parameters such asmonomer concentration,emulsifier content and reaction temperature,etc.were also studied.At lower pH values of waterphase,R_p depends strongly on the pH due to the electrostatic interaction between the ionized radicals and the monomer.Athigher pH,R_p shows a slight dependence on pH.

Synthesis, adsorption and selectivity of inverse emulsion Cd(Ⅱ) imprinted polymers

Inverse emulsion polymerization was employed to synthesize inverse emulsion Cd（Ⅱ） imprinted polymers （IEⅡ P）. The morphology and functional groups of IEⅡP were characterized by SEM,FTIR and TG. Static adsorption experiments and competitive adsorption test were used to evaluate the adsorption ability of IEⅡP. The adsorption capacity of polymers could reach 86.7 mg·g^-1 under the optimal adsorption conditions. The pseudo second order kinetic model and Langmuir isotherm model could be used to analyze the experimental data well. The adsorption process of IEⅡP was chemical adsorption process and monomolecular type. Thermodynamic parameters showed that the adsorption process was endothermic and could occur spontaneously. The selectivity coefficients k of Cd^2＋/v, Cd^2＋/Zn^2＋ and Cd^2＋/Cu^2＋ were 2.4998, 1.2437 and 4.6882, respectively. The proposed method provides a new thought for removing Cd（Ⅱ） in water samples.

INFLUENCES OF WATER-SOLUBLE CATIONIC MONOMERS ON THE POLYMERIZATION RATE IN THE INVERSE EMULSION

This investigation deals with the free radical polymerization both of (2-methacryloyloxyethyl) trimethyl ammonium chloride (QACEMA) and of diallyldimethyl ammonium chloride (DADMAC) in inverse emulsion. The influences of some factors, such as the concentration of monomers, initiator and emulsifier are discussed. The polymerization rate equations of above two monomers can be written as follows: R(p) = k[M](1.21)[I](0.82)[E](0.57) (for QACEMA) R(p) = k'[M](1.34)[I](0.90)[E](0.62) (for DADMAC)

Preparation of Chitosan-g-PAM PS in H_2O/scCO_2 Inverse Emulsion

Chitosan （CS） was successfully modified in supercritical carbon dioxide （ scCOz ） by grafting method to enhance its water solubility. In this work, a three.arm star-like fluorinated polymer was synthesized by atom transfer radical polymerization （ ATRP ） method and applied as a surfactant in supereriticul carbon dioxide （scCO2 ）. Then 2-acrylamido-2-methyl propane sulfonie acid （AMPS） was grafted onto CS （CS-g-PAMPS） in H2O/scCO2 inverse emulsion. The effects of mass ratio of water and surfactants （Rw/s ） and pressure of scCO2 on the grafting reaction were investigated. The grafting rate, partide size, and dispersity in water of CS-g-PAMPS varied greatly as Rw/s and pressure of scCO2 changed. It could be found that the value of Rw/s at 12 and the pressure of scCO2 at 30 MPa were the optimum conditions for the grafting reaction. CS-g-PAMPS prepared in this reaction system has higher grafting rate, smaller particle sizes, and better dispersity in water than those prepared via conventional methods.

THE PREPARATION OF DOXORUBICIN-POLYVINYLPYRROLIDONE-NANOPARTICLES BY INVERSE EMULSION POLYMERIZATION

Doxorubicin-loaded nanoparticles, using doxorubicin （ADM） as model drug and vinylpyrrolidone as matrix, were prepared by inverse emulsion polymerization in the paper. The nanoparticles were characterized by telescope electron microscopy （TEM）, laser light scattering technique （LLS） and infrared spectrum （IR）. LLS test showed that the optimal prepared ADM-loaded nanoparticles had an average size 18.8nm and a narrow size distribution between 15nm and 32nm, which was consistent with the result obtained by TEM. And 1R results indicated that the nanoparticles consisted of ADM and polyvinylpyrrolidone （PVP）.

Investigation on the Inverse Emulsion Polymerization of Acrylic Acid

Polyacrylic acid particles in nano-scale were synthesized using an inverse (W/O) emulsion polymerization method. The particle size and size change of inverse micelles which solubilize a part of monomer solution was monitored by PCS (photon correlation spectroscopy) and the particles of polyacrylic acid were viewed in scanning electron microscope for the first time. It was concluded that the inverse micelles were primarily the polymerization reaction sites.

Microstructure and Properties of PET Fabric Grafted by Polyacrylic Acid with Inverse Microemulsion Polymerization

Annual production output of poly(ethylene terephthalate)(PET) fiber has been over 15 million tons in China due to its good mechanical properties and processability,but the shortage of hydrophilic group of PET has imposed many limitations to further extend its application.The PET fabrics were grafted with polyacrylic acid in inverse microemulsion after low pressure plasma treatment,and the microstructure and properties of the grafted fabrics were investigated with infrared spectroscopy,scanning electron microscope(SEM),hydrophilic and mechanical tests.The grafting yield was increased with the grafting time.The grafting polymer was in the granular form with its particle size ranging from a few micrometers to a dozen of micrometers,normally smaller than the fiber diameter.The moisture regain and water uptake increased while the air permeability of the grafted fabrics decreased with the increase of grafting yield.The bending rigidity and tensile properties show slightly complicated behaviors with grafting yield.The inverse emulsion grafting technique can be used to control the grafting polymer architecture.

Carbon dioxide/calcium oxide responsive behavior and application potential of amine emulsion

Green and low cost CO_(2) and CaO were used to stimulate amine emulsions to reveal the responsive behavior of amine emulsions.On this basis,oil-based drilling fluids responsive to CO_(2) and CaO were formulated and their properties were evaluated.The results showed that the amine emulsions inversed from water-in-oil state to oil-in-water state readily and their rheological behavior underwent transitions of decreasing,rising again and decreasing again via induction by CO_(2).These CO_(2) responsive behaviors could be reversed by CaO.Oil-based drilling fluids prepared based on the amine emulsions with oil-water volume ratios of 50:50 to 70:30,densities of 1.4-2.0 g/cm^(3) had good rheological and filtration properties at 160℃;and be readily cleaned up using CO_(2) bubbling.The useless solid phase with low density could be removed efficiently via reducing the viscosity of emulsion by CO_(2) and the residual liquid phase could be restored to the original state by CaO and reused to prepare drilling fluid.The mechanisms analysis indicated that CO_(2)/CaO induced the reversible conversion between amine emulsifiers and their salts,which enabled the reversible regulation of both the hydrophilic-lipophilic balance of amine emulsifiers and the emulsion particles’size and finally caused the controllable-reversion of the form and rheology of amine emulsion.

DMC-grafted cellulose as green-based flocculants for agglomerating fine kaolin particles

Novel cellulose based flocculants C-g-P(DMC) with various chain architectures are synthesized through a situ graft copolymerization. The cationic ammonium chloride group(DMC) is grafted onto cellulose by two separate inverse emulsion polymerization with γ-methacryloxypropyl trimethoxy silane(KH-570) and double bond addition reactions, which is a new and simple method to employ KH-570 as a bridge for the connection of cellulose matrix and DMC group. The effects of pH, flocculant dose, standing time on turbidity of kaolin suspensions and particle sizes have been studied systematically. In addition, the response surface methodology(RSM) study confirms that PAC and C-g-P(DMC)have synergy in turbidity removal with a higher removal efficiency of 98.32%. Moreover, C-g-P(DMC) 1 has higher removal efficiency with 96.5% at a low dosage of 0.6 mg L^(-1) and better floc properties than C-g-P(DMC) 2 and C-g-P(DMC) 3, suggesting that the length and quantity of cationic branch chains play a crucial role in Kaolin flocculation due to their dramatically enhanced bridging effects.

PREPARATION AND CHARACTERIZATION OF DOXORUBICIN-LOADED MAGNETIC ANTICANCER NANOPARTICLES

Doxorubicin（ADM）-loaded magnetic anticancer nanoparticles, using Fe3O4 as core, doxorubicin as model drug and polyvinylpyrrolidone （PVP） as matrix, were prepared by inverse emulsion polymerization. The experimental results showed that the average diameter of Fe3O4 particles was 19.8nm. The X-ray diffraction itzdicated that the prepared Fe3O4 particle was pure cubic Fe3O4, The results obtained by SEM showed the magnetic nanoparticles under optimal operating condition had a smooth spherical surface, LLS showed an average size of 78. 7nm. And IR results demonstrated that they consisted of ADM, PVP and Fe3O4.

Preparation of polyacrylamide/silica composite capsules by inverse Pickering emulsion polymerization

Polyacrylamide/silica （PAM/SiO2） composite capsules were synthesized by inverse Pickering emulsion polymerization. Silica nanoparticles modified with methacryloxypropyltrimethoxysilane （MPS） were used as a stabilizer. Transmission electron microscopy （TEM）, scanning electron microscopy （SEM）. Fourier transform infrared （FTIR） spectroscopy, and thermal gravimetric analysis （TGA） were used to characterize the morphology and composition of the composite capsules. SEM and TEM images showed that capsules consisted of a particle shell and a polymer inner layer. The capsule size depends on the nanoparticle concentration in the continuous phase. The composite rigidity largely depends on the acrylamide concentration. FTIR and TGA results indicated the existence of polyacrylamide and SiO2 in the composite particles. Aqueous Hg（ll） removal testing by the PAM/SiO2 composite capsules indicated promising potential for removing heavy metal ions from wastewater.