Marcus Giotto

This study reports the synthesis, physicochemical characterization by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and solid-state MAS NMR (¹H, ²³Na, ²⁹Si and ¹¹⁹Sn MAS NMR) of a metallo-stannosilicate and its application as a heterogeneous catalyst for biodiesel production via ethanolysis and methanolysis routes using edible,...

Aerogels of SnO2 were synthesized by an epoxide-initiated sol-gel method. Using ammonium fluoride in the precursor solution allowed for tunability of the aerogel morphology while no change in the conductivity was measured. In particular, aerogel shrinkage was decreased dramatically by the addition of the fluoride precursor. Unfluorinated aerogels s...

Formation of coke during biomass catalytic pyrolysis deteriorates the selectivity to valuable liquid products and deactivates the catalyst, due to pore blocking and active site poisoning. In this work we investigate reaction mechanisms of coke formation and the structure of coke, formed from model compounds of relevance to biomass catalytic pyrolys...

An exfoliated clay−polymer nanocomposite was prepared by surface-initiated ring opening metathesis polymerization (SI-ROMP) of norbornene on a montmorillonite (MMT) clay with a modified surface. Utilizing the hydrothermal-silylation reaction between a norbornenyl-bearing chlorosilane agent and silanol groups of the MMT clay, we were able to bind a...

Polyvinyl alcohol (PVA) microspheres with different degree of crystallinity were used as solid supports for Rhizomucor miehei lipase immobilization, and the enzyme-PVA complexes were used as biocatalysts for the transesterification of soybean oil to fatty acid ethyl esters (FAEE). The amounts of immobilized enzyme on the polymeric supports were sim...

Electrospun nanofibers of highly sulfonated polystyrene (IEC ∼4.8 mequiv/g) might be good candidates for use in ion exchange applications because of their ability to form continuous, highly conducting pathways for cation transport. However, such fibers suffer in terms of dimensional stability due to high water uptake at elevated humidity. To improv...

Vanadosilicates with the structures of ETS-10 and AM-6 microporous materials have been hydrothermally synthesized using organic directing structures agent (SDAs) derivatives of decahydroquinoline, 3,5-dimethyl-piperidine, 2,6-dimethyl-piperidine and (S)-Sparteine. Derivatives of these chiral amines have not been explored before in the sot gel chemi...

Recent experimental research into the adsorption of various cations on zeolite minerals has shown that nanopore channels of approximately 0.5 nm or less can create an effect whereby the adsorption of ions, especially those that are weakly hydrated, can be significantly enhanced. This enhanced adsorption occurs due to the removal of hydrating water...

Typically, phenylethynyl (PE) end-capped oligomides require a temperature of 370 �C for 1 h to develop a crosslinked system. A published method using poly(ethylene glycol)s (DM-PEG-250 and PEG-400) as cosolvents with NMP was effective in crosslinking the ethynyl end-caps at 250 �C/3h in nonsulfonated oligomides. The application of this novel crossl...

A relatively low-temperature crosslinking method for phenylethynyl (PE) end-capped oligomides was developed. PE end-capped oligomides are typically cured into crosslinked polyimides at 370 �C for about 1 h. The addition of a low viscosity mixed-solvent of N-methylpyrrolidinone (NMP)/dimethyl ether of polyethylene glycol (M ¼ 250 g/mol), NMP/DM-PEG-...

We have synthesized a catalytically active polymer inspired by the naturally occurring protein silicatein R and have shown it to catalyze the formation of silica from tetraethoxysilane under near-neutral pH and ambient temperatures. We based the composition of the polymer on the functionalities found in silicatein R, specifically those essential co...

The structural influence on translational diffusion of 2,2,4-trimethylpentane (TMP) through SEBS triblock polymer (poly(styrene)-block-poly(ethene-co-but-1-ene)-block-poly(styrene)) was studied using pulse field gradient (PFG) NMR coupled with lattice model simulation. Two types of PFG experiments were performed:  one observing the time-dependent a...

The three versions of poly-styrene-ethylene/butylene-styrene (SEBS) triblock copolymers under investigation have different micro-scale morphologies: polystyrene (PS) spheres in poly-ethylene/butylene (EB) matrix, PS cylinders in EB matrix and EB cylinders in PS matrix. The diffusion phenomena of 2,2,4-trimethyl pentane (TMP) in SEBS probed with pul...

Proton and sodium-23 spectra are reported on acid and sodium neutralized forms of the perfluorosulfonate ionomer (Nafion), respectively. This local structural view is compared with pulse field gradient diffusion measurements of water, methanol and dimethyl methylphosphonate (DMMP) in several Nafion films. Both the proton and sodium-23 spectra indic...

Solid triblock copolymers can serve as the basis for membranes in such applications as separations and fuel cells. Diffusion of a low molecular weight penetrant in such a membrane is strongly affected by the morphology. The effect of the morphology on the translational motion of the penetrant can be directly assessed by pulse field gradient NMR mea...

Pulse field gradient (PFG) Proton (H-1) NMR measurements of diffusion in heterogeneous solid polymer systems provide a measure of the structure influencing translational motion. The influence of structure leads to a dependence of the apparent diffusion constant on the time over which diffusion is observed. The penetrant selected for this study is 2...

A novel porous silica matrix has been prepared from Pyrex glass, using hydrothermal treatment under saturated-steam condition. This process makes it possible to obtain, in one step, a silica support formed of a homogeneously distributed and interconnected macropore microstructure. The new matrix contains silanol groups that can be used in reactions...

Fluorine-19 NMR was used to study the structure and mobility of the perfluorosulfonate ionomer Nafion (Dupont trademark) in the presence of dimethyl methylphosphonate (DMMP). Fluorine-19 resonances arising from the ionomeric side chain narrowed rapidly with increasing DMMP content while the resonances arising from the perfluoroethylene backbone uni...

Miscible blends of poly(ethylene oxide) (PEO) and poly(methyl methacrylate) (PMMA) were studied using pulse field gradient (PFG) diffusion experiments in the concentration range 10 to 30 wt measurements of diethyl ether or low molecular weight PEO in the blends were made as a function of the time allowed for diffusion to occur in a three-pulse diff...

In this work MAPO-11 molecular sieve was prepared with several degrees of magnesium substitution. The syntheses were carried by using phosphoric acid, pseudo-boehmite and magnesium acetate as sources of structural elements and diisopropylamine as the structure-directing agent. The samples were characterized by powder X-ray diffraction, thermogravim...

The ABA triblock copolymer poly(ethylene glycol) distearate (PEGD), average Mn ca. 930, complexed with lithium and sodium perchlorates has been studied by 1H, 7Li, 13C, and 23Na solid-state nuclear magnetic resonance (NMR), SAXS, DSC, and polarized-light optical microscopy. Unlike other solid polymer electrolytes, highly Li+-doped PEGD samples exhi...

Poly(ethylene glycol) distearate (PEGD) complexed with lithium perchlorate has been studied by NMR, SAXS, DSC, and Polarized-Light Optical Microscopy (PLOM). Unlike other polymer electrolytes, highly Lithium-doped PEGD samples exhibit sharp Li-7 NMR quadrupolar powder patterns even at temperatures well above the melting point, indicating that this...

Nuclear magnetic resonance spectroscopy was used to characterize dynamics and structure in the swollen perfluorosulfonate ionomer Nafion (DuPont ®) in the acid form. Translational diffusion was determined for water, ethanol and dimethyl methylphosphonate (DMMP) by Pulse Field Gradient H-1 NMR. Measurements of the self-diffusion constants were made...

Samples of MAPO-36 (ATS structure) and MAPO-5 (AFI structure) prepared with different magnesium contents and high crystallinity were characterized by several physical chemical techniques and catalytically evaluated using the isomerization of m-xylene as a reaction model. Chemical analysis of the solids indicated a greater incorporation of Mg into M...

Carbon-13 spin–lattice relaxation times are measured for poly(octadecyl acrylate) above and below the melting point of the crystalline side chains. The chain backbone has long spin–lattice relaxation times below the melting point that shorten by more than an order of magnitude as the melting point range is traversed. Below the melting point, the ba...

Na-Y zeolites ion exchanged with rare earth cations (Nd3+, Sm3+, Gd3+, Dy3+) were studied by X-ray diffraction in order to locate the rare earth cations in the zeolite framework and the resulting changes in its structural properties. The results indicate that the rare earth cations dealuminate the framework differently. This is observed as a decrea...

Ru/HY and Ru/NaY catalysts were prepared by ion-exchange from an aqueous solution of [Ru(NH3)6]Cl3. The catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and nuclear magnetic resonance (NMR). The results showed that Si/Al ratio of the zeolite framework after use depends on the catalyst preparation proce...

The aim of this work was to study the hydrothermal synthesis of Si and SiAlMCM-41 performed under both autogenic pressure and refluxing conditions. XRD data showed that the MCM-41 phase may be formed by both processes and that the synthesized material in the presence of Al and/or under reflux presents the hexagonally arrangement of less ordered mes...

This work reports on the study of polyaniline, doped with LiClO4 via pseudoprotonalion, by Nuclear Magnetic Resonance and morphology analysis. The 7Li NMR spin-lattice relaxation and linewidth investigations were performed for two different salt concentrations as a function of the temperature. The increase of ion concentration strongly affects the...

A comparative study of the electrical conductivity, electron spin density and 13C high-resolution solid-state NMR linewidth of FeCl3-doped poly(para-phenylene) (PPP) was made as a function of Fe3+ concentration. It is concluded that the NMR linewidth changes are related to the interaction between bipolarons in the polymeric chain.