Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 52 for “"propylene oxide"”.
-
Electrochemical Synthesis of Propylene Oxide With Alternating and Direct Current
Electro-organic processes typically contain complex reaction sequences which couple the heterogeneous electrode reactions with an extended homogeneous reaction pathway. An experimental - theoretical approach was applied to understand the coupled diffusion-reaction processes and establish general …
-
Synthesis and characterization of poly(propylene oxide) and its copolymers
The synthesis of molecularly designed poly(propylene oxide) was accomplished by using aluminum porphyrin initiator/catalysts to prepare controlled molecular weights, narrow molecular weight distributions, topologies, and functionalities. Poly(propylene oxide) has been an important intermediate in …
-
Polymer Stabilized Magnetite Nanoparticles and Poly(propylene oxide) Modified Styrene-Dimethacrylate Networks
… chloride salts in the presence of ammonium hydroxide at pH 9-10. One goal of this work has been to develop a generalized methodology for stabilizing nanomagnetite dispersions using well-defined, non-toxic, block copolymers, so that the resultant magnetite-polymer complexes can be used in a range …
-
Inactivation Of Salmonella And Surrogate Bacteria On Cashews And Macadamia Nuts Exposed To Saturated Steam And Propylene Oxide Treatments
Saturated steam (SS) and propylene oxide (PPO) fumigation are two common methods to improve microbiological quality and safety of tree nuts. Validation of these processes is needed to ensure adequate control of bacterial pathogens. Since pathogens cannot be studied in food processing environments, …
-
Hydroxypropylation of lignin and lignin-like model compounds
Copolymerization reaction of propylene oxide and Kraft lignin with various catalysts, catalyst concentrations, at several temperature levels were studied. The reaction rate of propylene oxide was estimated from the pressure vs time diagram of the reaction and the copolymerization extent was …
-
Electrochemical synthesis of polyesters and polyamides. A study of the polymerisation of lactams, lactones and the anhydride/propylene oxide system by direct electrolysis of their conducting solutions
… polymerisation of phthalic anhydride/propylene oxide, maleic anhydride/propylene oxide, caprolactam, laurolactam and E-caprolactone in N,N-dimethylformamide (DMF), acetonitrile and tetrahydrofuran (THF) using alkali metal salts or quaternary ammonium salts as supporting electrolytes. …
-
Star-like macromers from lignin
… from hydroxypropyl lignin by reaction with propylene oxide. The average number of arms per macromer was controlled by partial capping with diethylsulfate, and the average arm length by the degree of chain extension with propylene oxide. Six methods of analysis were applied for characterizing …
-
Hybrid Inorganic-Organic Materials: Novel Poly(Propylene Oxide) Based Ceramers, Abrasion Resistant Sol-Gel Coatings for Metals, and Epoxy-Clay Nanocomposites. With an Additional Chapter On: Metallocene Catalyzed Linear Polyethylene
… functionalized soft organic oligomer, poly(propylene oxide) (PPO), and tetramethoxysilane (TMOS). Despite the formation of covalent bonds between the inorganic and organic constituents, the resulting network materials were phase separated, composed of a silicate rich phase embedded in a …
-
Synthesis, properties, and morphology of lignin based epoxy resins
Star-like lignin-poly(propylene oxide) copolymers were prepared by chain-extending steam exploded lignins (tulipifera liriodendron) with propylene oxide and by subsequent endcapping with ethylene oxide. Epoxidation of these copolymers was carried out with epichlorohydrin at room temperature, using …
-
Enabling Synthesis Toward the Production of Biocompatible Magnetic Nanoparticles With Tailored Surface Properties
… nanoparticles in biological media. A benzyl alkoxide initiator was utilized to prepare poly(ethylene oxide) (BzO-PEO-OH), poly(propylene oxide) (BzO-PPO-OH) and poly(ethylene oxide-b-propylene oxide) (poly(BzO-EO-b-PO-OH)) oligomeric tail blocks with varying lengths of PEO and PPO. The oligomers …
-
Synthesis and Characterization of Novel Magnetite Nanoparticle Block Copolymer Complexes
… dispersants possessed either poly(ethylene oxide), poly(ethylene oxide-co-propylene oxide), or poly(ethylene oxide-b-propylene oxide) outer blocks, and all contained a polyurethane center block with pendant carboxylate functional groups. The complexes were formed through interactions of the …
-
Gas-Phase Epoxidation of Ethylene and Propylene
… direct oxidation of ethylene to ethylene oxide. For this study, which used no promoters, ethylene oxidation selectivity of SiC-supported catalysts ranged from 10 to 60% and conversion from 0-4.5%. Silicon carbide supported catalysts exhibited poor performance except for a surface-modified …
-
ASYMMETRIC REDUCTIONS BY CHIRAL LITHIUM-ALUMINUM HYDRIDE AND POTASSIUM-BOROHYDRIDE REAGENTS
… from ammonia and three equivalents of (S)-propylene oxide. The triol was allowed to condense with boric acid to form a bicyclic borate {(S,S,S)-triisopropanolamine borate, 2} which was allowed to react with a suspension of potassium hydride in tetrahydrofuran to form a borate hydride …
-
Incorporation of lignin copolymers into polyurethane materials
… (HPLs) from several sources were reacted with propylene oxide to produce chain-extended ) hydroxypropyl lignin (CEHPL) copolymers with molar substitutions (MS) between 1 and 7 propylene oxide units. Isolated copolymers were characterized with respect to their chemical composition, molecular …
-
Multicomponent network and linear polymer systems: thermal and morphological characterization
… in the presence of low molecular weight poly (propylene oxide). The resulting morphology of these polymers has been studied with the help of scanning electron microscopy.
-
Synthesis and characterization of high Tg nanofoams based on pyromellitic dianhydride and 1,1-bis(4-aminophenyl)-1-phenyl-2,2,2-trifluoroethane polyimide block and graft copolymers
… with labile con1ponents (especially polypropylene oxide), have been prepared and investigated as low dielectric materials that afford desirable thermal, mechanical and electrical properties. Polyimide nanofoams based upon the controlled pyrolysis of the labile component were prepared. The …
-
Nanostructured thermoset resins and nanocomposites containing hyperbranched blockcopolyether liquid rubbers and organophilic layered silicates
… were added together with modified liquid poly(propylene oxide) starpolymers to epoxy resins. The resulting epoxy “hybrid nanocomposites” afforded improved toughness showing no reduction in stiffness and glass temperature. An optimized hybrid system was employed in a resin transfer moulding …
-
Application of PEO-PPO-PEO Triblock Copolymers in Synthesis of Silica and Organosilica Nanomaterials
… of Pluronic triblock copolymers, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO), in the synthesis of mesoporous material, such as double-helical silica nanotube structures as well as bridged organosilica nanotubes by using swollen micelles of Pluronic surfactants …
-
The oxidation chemistry of the xylenes and related aromatic hydrocarbons
… isomeric tolualdehydes, toluene and a-xylylcne oxide (from a-xylene). These were found to be similar to the products formed from the oxidation of toluene at 753K. From examination of the products available it was also possible to obtain more detailed rate constants for the attack of H radicals …
-
PEO-PPO-PEO Surfactant Mixtures as Templates for Silicas With Very Large Cylindrical Mesopores at Ambient Temperature and With Helical Mesopores at Sub-Ambient Temperature
… a mixed surfactant system of two poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) surfactants, with one of the copolymers containing a much larger percentage of hydrophobic (PPO) blocks than the employed co-surfactant. Systematic adjustments of experimental parameters initially …
Page 1 of 3