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We propose a new strategy for preparing high solid content, surfactant-free charge stabilized monodisperse latex particles via alcoholic dispersion polymerization by means of a mixed inoic/nonionic initiator system, which produces hundreds of nanometer up to several micrometer sized latex particles with a clean surface in a single batch process. Two criteria should be met to produce these electrostatically stabilized uniform size latexes: (1) The ionic initiator chosen should have a greater or comparable decomposition rate to the nonionic initiator. (2) A relatively small amount of ionic initiator to the nonionic initiator should be employed in the polymerization. The electrostatic stabilization is solely provided by the ionic fragments arising form the ionic initiator in the absence of any stabilizer, and the addition of nonionic initiator has increased the latex uniformity through the enhancement of particle seeds formation at the nucleation stage also the perferred particle phase polymerization after nucleation. The ultimate particle sizes are predominantly controlled by the medium solvency, the polymerization temperature, the concentration of nonionic initiator, and the types of mixed initiator pairs empolyed. A perlonged particle number (N p) variation to the conversion before it reaches a constant is observed, which would be the most stricking difference between the nucleation characteristics in classical dispersion polymerization (usually has unchanged N p below 1% monomer conversion) or soapless polymerization. It is shown that highly monodisperse latex can be formed in wide range of monomer and initiator concentrations also a considerable temperature range. The effect of various factors on this new approach is investigated, and a sepcific mechanism is also presented.

In this research, poly(methyl methacrylate)-b-poly(butyl acrylate) (PMMA-b-PBA) block copolymers were prepared by 1,1-diphenylethene (DPE) controlled radical polymerization in homogeneous and miniemulsion systems. First, monomer methyl methacrylate (MMA), initiator 2,2 0 -azobisisobutyronitrile (AIBN) and a control agent DPE were bulk polymerized to form the DPE-containing PMMA macroinitiator. Then the DPE-containing PMMA was heated in the presence of a second monomer BA, the block copolymer was synthesized successfully. The effects of solvent and polymerization methods (homogeneous polymerization or miniemulsion polymerization) on the reaction rate, controlled living character, molecular weight (M n ) and molecular weight distribution (PDI) of polymers throughout the polymerization were studied and discussed. The results showed that, increasing the amounts of solvent reduced the reaction rate and viscosity of the polymerization system. It allowed more activation-deactivation cycles to occur at a given conversion thus better controlled living character and narrower molecular weight distribution of polymers were demonstrated throughout the polymerization. Furthermore, the polymerization carried out in miniemulsion system exhibited higher reaction rate and better controlled living character than those in homogeneous system. It was attributed to the compartmentalization of growing radicals and the enhanced deactivation reaction of DPE controlled radical polymerization in miniemulsified droplets. V V C 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: [4435][4436][4437][4438][4439][4440][4441][4442][4443][4444][4445] 2009

In this work, we present the first Pickering emulsion polymerization with a controlled/living character. Pickering emulsion polymerization in the presence of a novel suspension of zinc oxide/poly(sodium 4‐styrenesulfonate) (ZnO/PSS−) nanocomposite particles was applied to prepare ZnO/living block copolymer latexes. In the emulsion system, 1,1‐diphenylethene (DPE)‐controlled radical polymerization of poly(methyl methacrylate)‐b‐poly(butyl acrylate) (PMMA‐b‐PBA) was proceeded in oil phase. The nanocomposite particles of ZnO/PSS− with an average diameter of 20 nm and negatively charged zeta potential around −30 mV were synthesized via hydrothermal method then served as an effective emulsion stabilizer at the oil/water interface. Living polymerization was carried out using DPE‐capped PMMA as the macroinitiator and PMMA‐b‐PBA block copolymer latex was successfully prepared with coverage of ZnO/PSS− nanoparticles. Narrow size distributions of the droplets as well as latex particles were obtained, and the livingness of block copolymers was comparable to that of emulsions stabilized by conventional surfactants. The controlled/living character in Pickering emulsion polymerization was slightly influenced by the amount of PSS− immobilized into the ZnO/PSS− nanoparticles, whereas it was significantly influenced by the weight ratios between ZnO/PSS− and oil phase. The Pickering latexes showed excellent long term stability against either coalescence or sedimentation over several months. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

The IPI‐POSS‐modified epoxy resin (IPEP) was prepared from isocyanato‐propyldinethylsilyl‐isobutyl‐POSS (IPI‐POSS) and diglycidyl ether of bisphenol A epoxy resin. The steric hindrance of the IPEP bulky POSS side chain improved the curing activation energies. The POSS particles sizes were about 2–3 nm and dispersed uniformly. At lower IPEP concentration (POSS < 12 wt %), the glass transition temperatures (Tgs) of the IPEP nanocomposites increased from 118 to 170 °C. The char yield increased from 15 to 20 wt %, and the LOI values increased from 22 to 28. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 643–652, 2010

The side-chain polyhedral oligomeric silsesquioxane (POSS)-type epoxy (IPEP) hybrid material was synthesized, and the particle sizes of the POSS segment were less than 5 nm and which particles dispersed uniformly. The 3D AFM microphotograph of the IPEP/ DGEBA (diglycidyl ether of bisphenol A) hybrid material exhibited the unique ''island'' shape, and their XRD pattern displayed amorphous halo structure. The POSS segments of the IPEP could improve the thermal degradation activation energies. Additionally, introduction of the IPEP into the DGEBA could improve the char yield and provide the antioxidation property in the air atmosphere. The char yields of the IPEP/DGEBA hybrid materials could improve from 14.48 to 19.21% and from 0.18 to 1.17% in the nitrogen and air atmospheres, respectively. The IPEP segments could also improve the hardness when the IPEP contents of the IPEP/DGEBA hybrid materials were less than 50 wt %.

The thiodiphenyl epoxy (THEP) was prepared by the 4,4 0 -thiodiphenol (THDOL) and the epichlorohydrin (ECH) without using any NaOH or KOH catalysts. The THEP possessed weak hydrogen bonding in the cured THEP/DGEBA system. The intermolecular motion parameters k and q were 0.26 and À168.5, respectively, which determined by the Gordon-Taylor and Kwei equations. The soft sulfide linkage (ASA) of the THEP degraded at lower temperature than cured DGEBA material, and further to form various thermal stable sulfate derivative chars. The char yields increased from 11.43 to 25.94 wt % and from 0.65 to 1.04 wt % in the nitrogen and air, respectively. Introduction of the THEP into the DGEBA could provide the antioxidation thermal property and improve the thermal stability of the DGEBA epoxy in the air. In the air atmosphere, the activation energies of the second thermal degradation were increased from 66.67 to 103.42 kJ/mol. V C 2010 Wiley Periodicals, Inc. J Appl Polym