Gustavo Cervi - Academia.edu (original) (raw)

Papers by Gustavo Cervi

Research paper thumbnail of Evaluation of the functionalization process of reinforced glass powder utilized in dental composites Materials and Methods Figure 1: 3-methacryloxypropyltrimetoxi-silane (MEMO)

Evaluation of the functionalization process of reinforced glass powder utilized in dental composites Materials and Methods Figure 1: 3-methacryloxypropyltrimetoxi-silane (MEMO)

ABSTRACT The interfacial properties between methacrylate polymers/reinforced glass powder (filler... more ABSTRACT The interfacial properties between methacrylate polymers/reinforced glass powder (filler) used in dental composites affects the physical, chemical and mechanical characteristics of these materials. The compatibility of these hydrophobic and hydrophilic interfaces is improved by silanisation. In this research project, we have studied the effect of different conditions on the silanisation process and its effects on the implementation of the functionalized glass into the polymer matrix in order to create composites. The following processes variables were analysed: the solvent (ethanol, acetone and hexane); the presence of moisture (humid and anhydrous); agitation (occasional or continuous). We used physicochemical methods of analysis to characterize both the glass powder and the final composite, such as SEM (scan electron microscopy), TGA (termogravimetric analysis), Raman spectroscopy and measurement of contact angle (CA), microhardness Vickers, flexural strength. and water absorption (WA).

Research paper thumbnail of Desenvolvimento e validação da espectroscopia vibracional de íons em fase gasosa

Cervi, Gustavo. Development and validation of gas-phase ion spectroscopy 2019. 145p. Masters Thes... more Cervi, Gustavo. Development and validation of gas-phase ion spectroscopy 2019. 145p. Masters Thesis-Graduate Program in Chemistry.

Research paper thumbnail of Development of a Photoinduced Fragmentation Ion Trap for Infrared Multiple Photon Dissociation Spectroscopy

Development of a Photoinduced Fragmentation Ion Trap for Infrared Multiple Photon Dissociation Spectroscopy

Rapid Communications in Mass Spectrometry

Research paper thumbnail of Evaluation of Common Theoretical Methods for Predicting Infrared Multiphotonic Dissociation Vibrational Spectra of Intramolecular Hydrogen-Bonded Ions

ACS Omega

Infrared photodissociation analyses are supported by theoretical calculations that allow a trustw... more Infrared photodissociation analyses are supported by theoretical calculations that allow a trustworthy interpretation of experimental spectra of gaseous ions. B3LYP calculations are the most prominent method used to model IR spectra, as detailed in our bibliographic survey. However, this and other commonly used methods are known to provide inaccurate energy values and geometries, especially when it comes to long-range interactions, such as intramolecular Hbonds, which show increased anharmonicity. Therefore, we evaluated some of the most commonly used density functional theory methods (B3LYP, CAM-B3LYP, and M06-2X) and basis sets (6-31+G(d,p), 6-311++G(d,p), 6-311++G(3df,2pd), aug-cc-pVDZ, and aug-cc-pVTZ), including anharmonicity and dispersion corrections. The results were compared to MP2 calculations and to experimental high-frequency (2000−4000 cm −1) IR multiphotonic dissociation (IRMPD) spectra of two protonated model molecules containing intramolecular hydrogen bonds: biotin and tryptophan. M06-2X/6-31+G(d,p) was shown to be the most cost-effective level of theory, whereas CAM-B3LYP was the most efficient method to describe the van der Waals interactions. The use of the dispersion correction D3, proposed by Grimme, improved the description of O−H vibrations involved in H-bonding but worsened the description of N− H stretches. Anharmonic calculations were shown to be extremely expensive when compared to other approaches. The efficiencies of well-established scaling factors (SFs) in opposition to sample-dependent SFs were also discussed and the use of fitted SFs were shown to be the most cost-effective approach to predict IRMPD spectra. M06-2X/6-31+G(d,p) and CAM-B3LYP/aug-cc-pVDZ were also tested against the fingerprint region. Our results suggest that these methods can also be used for analysis in this lower frequency range and should be regarded as the methods of choice for cost-effective IRMPD simulations rather than the ubiquitous B3LYP method, especially when further molecular properties are needed.

Research paper thumbnail of Differential Scanning Calorimetry study on curing kinetics of diglycidyl ether of bisphenol A with amine curing agents for self-healing systems

Matéria (Rio de Janeiro)

Epoxy resin is one of the most important polymeric matrixes for diverse uses, such as aeronautica... more Epoxy resin is one of the most important polymeric matrixes for diverse uses, such as aeronautical, mobile, electronics and others. Providing a material capable of self-healing microcracks will allow it to have a more reliable and longer use. In order to study this new property of self-healing to an epoxy resin, a Differential Scanning Calorimetry (DSC) study was carried out to measure physical chemical properties such as activation energy, enthalpy of polymerization, order of reaction and pre-exponential factor based on an Arrhenius equation modelling. The materials used are diglycidyl ether of bisphenol A (DGBA) as the core material, triethylenetetramine (TETA) and an aminated polydimethylsiloxane (ADM), as curing agent and poly(urea-formaldehyde) (PUF) as microcapsule wall. Tests were done by dynamic and isothermal DSC of systems containing the resin and microencapsulated curing agent and also the resin with the free curing agent. The results showed the necessity of heating for the cure and the self-healing to be initiated.

Research paper thumbnail of Evaluation of the functionalization process of reinforced glass powder utilized in dental composites Materials and Methods Figure 1: 3-methacryloxypropyltrimetoxi-silane (MEMO)

The interfacial properties between methacrylate polymers/reinforced glass powder (filler) used in... more The interfacial properties between methacrylate polymers/reinforced glass powder (filler) used in dental composites affects the physical, chemical and mechanical characteristics of these materials. The compatibility of these hydrophobic and hydrophilic interfaces is improved by silanisation. In this research project, we have studied the effect of different conditions on the silanisation process and its effects on the implementation of the functionalized glass into the polymer matrix in order to create composites. The following processes variables were analysed: the solvent (ethanol, acetone and hexane); the presence of moisture (humid and anhydrous); agitation (occasional or continuous). We used physicochemical methods of analysis to characterize both the glass powder and the final composite, such as SEM (scan electron microscopy), TGA (termogravimetric analysis), Raman spectroscopy and measurement of contact angle (CA), microhardness Vickers, flexural strength. and water absorption...

Research paper thumbnail of Multiplexed FBG Optical Instrumentation Using an FPGA-Based System

Latin America Optics and Photonics Conference, 2012

An FBG interrogation system was developed. Data processing algorithms were implemented by FPGA. I... more An FBG interrogation system was developed. Data processing algorithms were implemented by FPGA. It was tested by monitoring the fabrication of an evanescent-field sensor, which is then applied in an refractive index sensing experiment.

Research paper thumbnail of DSC STUDY ON CURING KINETICS OF DIGLYCIDYL ETHER OF BISPHENOL A WITH MICROENCAPSULATED TRIETHYLENETETRAMINE AS CURING AGENT

Epoxy resin is one of the most important polymeric matrix for diverse uses, such as aeronautical,... more Epoxy resin is one of the most important polymeric matrix for diverse uses, such as aeronautical, mobile, electronics and others. Providing a material capable of self healing microcracks will allow it to have a more reliable and longer use. In order to study this new property of self healing to an epoxy resin, a DSC study was carried out to measure physical chemical properties such as activation energy, enthalpy of polymerization, order of reaction and pre-exponential factor based on an Arrhenius equation modelling. The materials used are diglycidyl ether of bisphenol A (DGBA) as the core material, triethylenetetramine (TETA) and an aminated polydimethylsiloxane (ADM), as curing agent and poly(urea-formaldehyde) (PUF) as microcapsule wall. Tests were done by dynamic and isothermal DSC of systems containing the resin and microencapsulated curing agent and also the resin with the free curing agent. The results showed the necessity of heating for the cure and the self healing to be initiated.

Research paper thumbnail of Evaluation of the functionalization process of reinforced glass powder utilized in dental composites Materials and Methods Figure 1: 3-methacryloxypropyltrimetoxi-silane (MEMO)

Evaluation of the functionalization process of reinforced glass powder utilized in dental composites Materials and Methods Figure 1: 3-methacryloxypropyltrimetoxi-silane (MEMO)

ABSTRACT The interfacial properties between methacrylate polymers/reinforced glass powder (filler... more ABSTRACT The interfacial properties between methacrylate polymers/reinforced glass powder (filler) used in dental composites affects the physical, chemical and mechanical characteristics of these materials. The compatibility of these hydrophobic and hydrophilic interfaces is improved by silanisation. In this research project, we have studied the effect of different conditions on the silanisation process and its effects on the implementation of the functionalized glass into the polymer matrix in order to create composites. The following processes variables were analysed: the solvent (ethanol, acetone and hexane); the presence of moisture (humid and anhydrous); agitation (occasional or continuous). We used physicochemical methods of analysis to characterize both the glass powder and the final composite, such as SEM (scan electron microscopy), TGA (termogravimetric analysis), Raman spectroscopy and measurement of contact angle (CA), microhardness Vickers, flexural strength. and water absorption (WA).

Research paper thumbnail of Desenvolvimento e validação da espectroscopia vibracional de íons em fase gasosa

Cervi, Gustavo. Development and validation of gas-phase ion spectroscopy 2019. 145p. Masters Thes... more Cervi, Gustavo. Development and validation of gas-phase ion spectroscopy 2019. 145p. Masters Thesis-Graduate Program in Chemistry.

Research paper thumbnail of Development of a Photoinduced Fragmentation Ion Trap for Infrared Multiple Photon Dissociation Spectroscopy

Development of a Photoinduced Fragmentation Ion Trap for Infrared Multiple Photon Dissociation Spectroscopy

Rapid Communications in Mass Spectrometry

Research paper thumbnail of Evaluation of Common Theoretical Methods for Predicting Infrared Multiphotonic Dissociation Vibrational Spectra of Intramolecular Hydrogen-Bonded Ions

ACS Omega

Infrared photodissociation analyses are supported by theoretical calculations that allow a trustw... more Infrared photodissociation analyses are supported by theoretical calculations that allow a trustworthy interpretation of experimental spectra of gaseous ions. B3LYP calculations are the most prominent method used to model IR spectra, as detailed in our bibliographic survey. However, this and other commonly used methods are known to provide inaccurate energy values and geometries, especially when it comes to long-range interactions, such as intramolecular Hbonds, which show increased anharmonicity. Therefore, we evaluated some of the most commonly used density functional theory methods (B3LYP, CAM-B3LYP, and M06-2X) and basis sets (6-31+G(d,p), 6-311++G(d,p), 6-311++G(3df,2pd), aug-cc-pVDZ, and aug-cc-pVTZ), including anharmonicity and dispersion corrections. The results were compared to MP2 calculations and to experimental high-frequency (2000−4000 cm −1) IR multiphotonic dissociation (IRMPD) spectra of two protonated model molecules containing intramolecular hydrogen bonds: biotin and tryptophan. M06-2X/6-31+G(d,p) was shown to be the most cost-effective level of theory, whereas CAM-B3LYP was the most efficient method to describe the van der Waals interactions. The use of the dispersion correction D3, proposed by Grimme, improved the description of O−H vibrations involved in H-bonding but worsened the description of N− H stretches. Anharmonic calculations were shown to be extremely expensive when compared to other approaches. The efficiencies of well-established scaling factors (SFs) in opposition to sample-dependent SFs were also discussed and the use of fitted SFs were shown to be the most cost-effective approach to predict IRMPD spectra. M06-2X/6-31+G(d,p) and CAM-B3LYP/aug-cc-pVDZ were also tested against the fingerprint region. Our results suggest that these methods can also be used for analysis in this lower frequency range and should be regarded as the methods of choice for cost-effective IRMPD simulations rather than the ubiquitous B3LYP method, especially when further molecular properties are needed.

Research paper thumbnail of Differential Scanning Calorimetry study on curing kinetics of diglycidyl ether of bisphenol A with amine curing agents for self-healing systems

Matéria (Rio de Janeiro)

Epoxy resin is one of the most important polymeric matrixes for diverse uses, such as aeronautica... more Epoxy resin is one of the most important polymeric matrixes for diverse uses, such as aeronautical, mobile, electronics and others. Providing a material capable of self-healing microcracks will allow it to have a more reliable and longer use. In order to study this new property of self-healing to an epoxy resin, a Differential Scanning Calorimetry (DSC) study was carried out to measure physical chemical properties such as activation energy, enthalpy of polymerization, order of reaction and pre-exponential factor based on an Arrhenius equation modelling. The materials used are diglycidyl ether of bisphenol A (DGBA) as the core material, triethylenetetramine (TETA) and an aminated polydimethylsiloxane (ADM), as curing agent and poly(urea-formaldehyde) (PUF) as microcapsule wall. Tests were done by dynamic and isothermal DSC of systems containing the resin and microencapsulated curing agent and also the resin with the free curing agent. The results showed the necessity of heating for the cure and the self-healing to be initiated.

Research paper thumbnail of Evaluation of the functionalization process of reinforced glass powder utilized in dental composites Materials and Methods Figure 1: 3-methacryloxypropyltrimetoxi-silane (MEMO)

The interfacial properties between methacrylate polymers/reinforced glass powder (filler) used in... more The interfacial properties between methacrylate polymers/reinforced glass powder (filler) used in dental composites affects the physical, chemical and mechanical characteristics of these materials. The compatibility of these hydrophobic and hydrophilic interfaces is improved by silanisation. In this research project, we have studied the effect of different conditions on the silanisation process and its effects on the implementation of the functionalized glass into the polymer matrix in order to create composites. The following processes variables were analysed: the solvent (ethanol, acetone and hexane); the presence of moisture (humid and anhydrous); agitation (occasional or continuous). We used physicochemical methods of analysis to characterize both the glass powder and the final composite, such as SEM (scan electron microscopy), TGA (termogravimetric analysis), Raman spectroscopy and measurement of contact angle (CA), microhardness Vickers, flexural strength. and water absorption...

Research paper thumbnail of Multiplexed FBG Optical Instrumentation Using an FPGA-Based System

Latin America Optics and Photonics Conference, 2012

An FBG interrogation system was developed. Data processing algorithms were implemented by FPGA. I... more An FBG interrogation system was developed. Data processing algorithms were implemented by FPGA. It was tested by monitoring the fabrication of an evanescent-field sensor, which is then applied in an refractive index sensing experiment.

Research paper thumbnail of DSC STUDY ON CURING KINETICS OF DIGLYCIDYL ETHER OF BISPHENOL A WITH MICROENCAPSULATED TRIETHYLENETETRAMINE AS CURING AGENT

Epoxy resin is one of the most important polymeric matrix for diverse uses, such as aeronautical,... more Epoxy resin is one of the most important polymeric matrix for diverse uses, such as aeronautical, mobile, electronics and others. Providing a material capable of self healing microcracks will allow it to have a more reliable and longer use. In order to study this new property of self healing to an epoxy resin, a DSC study was carried out to measure physical chemical properties such as activation energy, enthalpy of polymerization, order of reaction and pre-exponential factor based on an Arrhenius equation modelling. The materials used are diglycidyl ether of bisphenol A (DGBA) as the core material, triethylenetetramine (TETA) and an aminated polydimethylsiloxane (ADM), as curing agent and poly(urea-formaldehyde) (PUF) as microcapsule wall. Tests were done by dynamic and isothermal DSC of systems containing the resin and microencapsulated curing agent and also the resin with the free curing agent. The results showed the necessity of heating for the cure and the self healing to be initiated.