31 research outputs found
ABERRANT COLOR PATTERNS IN THE PAPILIO AND AN UPDATE ON THE SEMI-MELANIC "FLETCHERI" VARIANTS, INCLUDING FEMALES (LEPIDOPTERA: PAPILIONIDAE)
No full textVolume: 63Start Page: 118End Page: 12
GPC−MALS Characterization of Fluoropolymers in a α,α,α-Trifluorotoluene Mobile Phase: An Enabling Step in the Syntheses of Well-Defined Fluoropolymer-Based Self-Assembling Materials
No full text
GMA-functionalized reactive stabilizer for polymerization of methyl methacrylate in supercritical CO2: effect of stabilizer, initiator and monomer concentrations
No full textPolymerizations of Tetrafluoroethylene in Homogeneous Supercritical Fluoroform and in Detergent-Free Heterogeneous Emulsion of Supercritical Fluoroform/Water
No full textEmulsion polymerization in a hybrid carbon dioxide aqueous medium
No full textThe development of a new reaction medium is reported, based on a biphasic mixture of carbon dioxide and water for emulsion polymerizations: a surfactant-free aqueous emulsion polymerization of methyl methacrylate using potassium persulfate under a varying head pressure of CO2 (0-350 bar) at 75 degrees C. The resulting polymer is a stable latex with. particles of submicron size. The Effect of CO2 on polymerization is relatively small, until there is a significant change at high CO2 pressure. This is seen by examining the molecular weight distribution in the form of the log(number distribution), P(M) (readily obtained by GPC). At pressures of 140 bar and below, the P(I) show the form expected for chain-stopping events dominated by transfer and by diffusion-controlled termination. At 280 bar, In P(M) is significantly steeper than its lower-pressure counterpart at relatively low conversion(45%). This is attributed to swelling by supercritical CO2 reducing the viscosity of the particles, allowing more rapid termination
