Polystyrene/MCM–41 nanocomposites were synthesized by atom transfer radical polymerization (ATRP) at 110°C. Activators generated by electron transfer (AGET) and activators regenerated by electron transfer (ARGET), as two novel initiation techniques, for ATRP were used. Specific structure, surface area, particles size and their distribution and spongy and porous structure of the synthesized MCM–41 nanoparticles were evaluated using X–ray diffraction, nitrogen adsorption/desorption isotherm analysis, scanning and transmission electron microscopy images, respectively. The final monomer conversion was determined using gas chromatography. Number and weight average molecular weights (Mn and Mw) and polydispersity index (PDI) were also evaluated by gel permeation chromatography. According to the results, addition of 3 wt% MCM–41 nanoparticles into the polymerization media resulted in lowering conversion from 81 to 58% in the AGET ATRP system. Moreover, a reduction in the molecular weight of the products from 17116 to 12798 g/mol was also occurred, although, the polydispersity index increased from 1.24 to 1.58. The similar results were also obtained by ARGET ATRP system; lowering conversion from 69 to 43% and molecular weight from 14892 to 9297 g/mol, and an increase of PDI from 1.14 to 1.41. The improvement in thermal stability of the nanocomposites, as a result of higher MCM–41 nanoparticles loading, was confirmed by thermogravimetric analysis. In addition, according to the analytical results of differential scanning calorimetry, a decrease in glass transition temperature, due to the addition of 3 wt% of MCM–41 nanoparticles (from 100.1 to 91.5oC in AGET ATRP system and from 100.3 to 85.8oC in ARGET ATRP), was achieved.

To better control the gelation time of in situ polymerization of gel system in reservoir, an activator regenerated by AGET (activator generated by electron transfer) ATRP (atom transfer radical polymerization) initiating system was developed. The AGET ATRP initiating system was composed of an initiator 1, 2-dibromoethane, a catalyst ferric chloride and a reducing agent vitamin C, and the effects of these three component proportions on the gelation time and gel viscosity were systematically investigated. Results of bottle tests indicated that the gelation time can even be more than 20 h at 60 °, C at optimal concentration ratios. Moreover, the viscosity decreased and the gelation time increased with the increase of salinity and temperature. The gelation time of the core test was 1. 5 times or even longer in comparison with that of the bottle test owing to the influences of dilution, adsorption, and rock skeleton isolation. It was also confirmed that the AGET ATRP initiating system can initiate the cross-link gelation of monomers in the core. The enhanced oil recovery result indicated that the oil recovery increased by 9. 17% after the gelation of the gelling solutions, and final oil recovery was 40. 05%. This research provided a brand-new method to control the gelation time of the in situ polymerization of gel system.

The first example of N -tetradecyl-N -methyl-2-pyrrolidonium was synthesized by using bromide as both an ionic liquid and a surfactant in ionic liquid-based microemulsion polymerization of methyl methacrylate under atom transfer radical polymerization at activator generated electron transfer conditions. The polymerization was carried out at room temperature using copper (II) chloride (CuCl2) /hexamethylene tetramine (HMTA) as a catalyst and CCl4 as an initiator in the absence of surfactant. Ascorbic acid was used as reducing agent. A pseudoternary phase diagram was constructed at 25oC using the water titration method in the presence and absence of hexadecyltrimethylammonium bromide (CTAB). Kinetics experimental results showed that the polymerization proceeded in a controlled/‘living’ process as evidenced by a linear increase of molecular weights of polymers with monomer conversion with a relatively narrow polydispersity (<1.35) in all cases and Mn, GPC values of the resulting polymer were in excellent agreement with the theoretical values Mn, th. The polymerization rate increased with the amount of surfactant. However, the polydispersity became broader. The polymerization rate increased with the amount of ligand and decreased with the amount of monomer. In this system, particles of nanoscale (33-51 nm) were prepared. The average particle diameter was found to be affected by the amount of surfactant. The AGET- ATRP of MMA retained the characteristic of living polymerization when the ionic liquid C14MPnBr and catalyst complex were recovered and reused. Living nature of the polymerization was confirmed by the successful homo chain extension experiment. The resultant PMMA was characterized by 1H NMR spectroscopy and gel permeation chromatography techniques.

Poly (styrene-co-butyl acrylate) /clay nanocomposites were synthesized via in situ atom transfer radical polymerization using activators generated by electron transfer in the presence of a montmorillonite ion-exchanged with mixed surfactants of dodecyl trimethyl ammonium bromide and vinyl trimethyl ammonium chloride. The living nature of polymerization is confirmed by occurrence of narrow molecular weight distribution of the nanocomposites in which copolymers with polydispersity index of about 1.13-1.15 were obtained. Partial exfoliation of clay layers in the copolymer matrix was demonstrated by XRD patterns and further studies of TEM images. Thermogravimetric analysis (TGA) results demonstrated a slight increase in the thermal stability of nanocomposites in comparison with the neat copolymer. DSC results indicated a decrease in the glass transition temperature (Tg) of nanocomposites by the addition of clay content which are attributed to low molecular weights of the copolymers and weaker interactions between polymer chains. The chemical structure and composition of copolymers was identified by 1H NMR analysis.

Atom transfer radical polymerization (ATRP) provides a robust route to synthesize well-defined polymers with predetermined molecular weight and low polydispersity index. ATRP as a popular member of controlled radical polymerization (CRP) family provides some advantages over others among which the usage of different initiation techniques are unique features of ATRP. Although Reverse ATRP (RATRP) is an appropriate technique for overcoming oxidation problem, synthesis of block copolymer is impossible by this procedure. Despite RATRP, simultaneous reverse and normal initiation techniques (SR&NI) can be used to synthesize various block copolymers. Activators generated by electron transfer (AGET) and activators regenerated by electron transfer (ARGET) employ environmentally friendly reducing agents to activate a metal complex in its higher oxidation state. However, initiators for continuous activator regeneration (ICAR) initiation techniques use conventional radical initiator. Moreover, ARGET and ICAR ATRP are designed to decrease the metal catalyst concentration to ppm level, which is an important goal to industrial applications.

A well-defined poly (n-butyl acrylate) (PBA) homopolymer was prepared by activators generated by electron transfer (AGET) ATRP at 90°C in N, N -dimethylformamide using ferric chloride hexahydrate (FeCl3.6H2O) /succinic acid (SA) as a catalyst and ethyl 2-bromoisobutyrate as an initiator. Ascorbic acid was selected as a reducing agent. The kinetic results showed that a linear increase of molecular weights of polymers with monomer conversion and a relatively narrow polydispersity (<1.25), when the conversion is beyond 40%, is an indication of a polymerization controlled by AGET ATRP of n-butyl acrylate (nBA). That is to say, (FeCl3.6H2O) /SA catalyst complex is demonstrated to be highly efficient for the AGET ATRP of nBA. The effects of different molar ratios of [FeCl3.6H2O] / [SA] and the concentration of ascorbic acid on polymerization rate were investigated. The maximum polymerization rate was obtained at molar ratio of [FeCl3.6H2O] / [SA] =1:2 and gave the best control of molecular weight and the distribution of polymer molecular weight. The polymerization reaction rate decreased when the higher or lower molar ratio of [FeCl3.6H2O] / [SA] was employed.The polymerization rate increased with higher content of ascorbic acid. The effects of different solvents on the polymerization were investigated. The experimental results showed that the polymerization rate was faster in polar solvent (such as DMF) than that in non-polar solvent (such as benzene). The obtained polymers had higher molecular weights with narrow distribution of molecular weight in DMF than that in benzene.Moreover, the obtained PBA was used as a macroinitiator in the chain extension experiment via AGET ATRP. The molecular weight of polymer increased after chain extension experiment.The chain extension experiment confirmed the living character of the polymerization system. The resultant PBA was characterized by 1H NMR, FTIR and gel permeation chromatography.

Poly (styrene-butyl acrylate)/clay nanocomposite was synthesized by activators generated by electron transfer (AGET) for atom transfer radical polymerization (ATRP). The chemical composition of the samples was studied by infra-red-Furier transformation (FT-IR) spectroscopy. Number- and weight-average molecular weights of the resultant copolymer nanocomposites and their molecular weight distributions were determined by gel permeation chromatography (GPC). The polydispersity index of the Nano composites were lower than 1.2. The effect of the nanoclay layers on the kinetics of ATRP was investigated by using a plot of ln ([M0]/[M]) versus time of the reaction and also control over the polymerization was investigated by linear relation between number-average molecular weight and monomer conversion. All of the studies confirmed the controlled/living characteristics of the AGET ATRP in the miniemulsion medium. Because of the hindrance effect of the nanoclay layers on the diffusion of the monomers toward the growing macro radicals, the rate of the polymerization decreased.