Elaine C. Ramires
University of São Paulo
Izod impact strength testComposite numberUltimate tensile strengthElectrospinningNanoparticleComposite materialAbsorption of waterThermosetting polymerFlexural strengthChemistryPolymer chemistryMaterials scienceRaw materialScanning electron microscopeSISALCastor oilCelluloseSodium lignosulfonateMicrocrystalline celluloseCoirContext (language use)LigninThermogravimetryChemical engineeringFiberPolymerThermal stabilityDynamic mechanical analysisNanofiberNanocomposite
26Publications
13H-index
813Citations
Publications 25
Newest
#1Elaine C. RamiresH-Index: 13
#2Jackson D. MegiattoH-Index: 22
Last. Elisabete FrolliniH-Index: 9
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Cellulose nanocrystals (CNC) exhibit remarkable properties such as being lightweight, renewability, nanoscale dimension, raw material availability, and a unique morphology. They have been widely used in film-forming composites, but the literature is scarce concerning bulky-composites (i.e., non-filmogenic). Microcrystalline cellulose (MCC) is widely available and has emerged as an important material for the reinforcement of composites. This investigation focuses on the preparation of non-filmoge...
5 CitationsSource
#1Elisabete FrolliniH-Index: 38
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The goals of our studies have been the use of renewable raw materials in the preparation of polymeric materials with diversified properties. In this context, lignosulfonate, which is produced in large scale around the world, but not widely used in the production of polymeric materials, was used to replace phenol and polyols in the preparation of phenolic- (Ligno-PH) and polyurethane-type (Ligno-PU) polymers, respectively. These polymers were used to prepare composites reinforced with sisal ligno...
2 CitationsSource
#1Rachel Passos de Oliveira Santos (USP: University of São Paulo)H-Index: 6
#2Bruno V.M. Rodrigues (USP: University of São Paulo)H-Index: 12
Last. Elisabete Frollini (USP: University of São Paulo)H-Index: 9
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Abstract Mats of ultrathin and nanoscale fibers were prepared via room temperature electrospinning of lignocellulosic sisal fibers (S) and recycled PET trifluoroacetic acid solutions. The properties of the resulting mats (S/PET ratios from 0.1 to 0.4) were examined by infrared spectroscopy, scanning electronic microscopy (SEM), contact angle measurements (CA), thermogravimetry and dynamic mechanical analysis (DMA). SEM images confirmed that the electrospinning led to ultrathin and nanofibers. Th...
43 CitationsSource
#1Fernando de Oliveira (USP: University of São Paulo)H-Index: 9
#2Elaine C. Ramires (USP: University of São Paulo)H-Index: 13
Last. Mohamed Naceur Belgacem (CNRS: Centre national de la recherche scientifique)H-Index: 69
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Abstract The rational valorization of lignin and its derivatives is a challenge in biorefinery because this biopolymer is one of the major source of aromatic moieties. Lignosulfonates are used to a lesser extent than lignin to prepare macromolecular materials. In the current study, sodium lignosulfonate (NaLS), which was either blended or not blended with OH-containing vegetable oil (i.e., castor oil (CO)), was reacted with diphenylmethane diisocyanate (MDI) to prepare polyurethane-type material...
39 CitationsSource
#1Bruno V.M. Rodrigues (USP: University of São Paulo)H-Index: 12
#2Elaine C. Ramires (USP: University of São Paulo)H-Index: 13
Last. Elisabete Frollini (USP: University of São Paulo)H-Index: 9
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Lignocellulosic sisal fiber (LSF) and sisal pulp (SP) were electrospun at room temperature from solutions in trifluoroacetic acid (TFA) prepared at concentrations of 2 × 10−2 g mL−1 and 3 × 10−2 g mL−1, respectively. Scanning electron microscopy images of the electrospun LSF showed fibers with diameters ranging from 120 to 510 nm. The presence of defects decreased along with increasing the flow rate of the SP solution, which generated nanofibers and ultrathin fibers with diameters in the range o...
14 CitationsSource
Enzymatic activities are important to be quantified in products as enzymatic cleaners, which are used in medical and surgical devices reprocessing. Enzymatic activities are critical for the proper chemical cleaning that intends to remove solid organic dirt from inaccessible sites. The most important enzyme for this purpose is the protease, which is able to dissolve the main dirt attached to medical and surgical instruments. In this context, this study contributes to the development of a new prot...
Source
#1Elaine C. Ramires (USP: University of São Paulo)H-Index: 13
#2Fernando de Oliveira (USP: University of São Paulo)H-Index: 9
Last. Elisabete Frollini (USP: University of São Paulo)H-Index: 38
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The use of products and byproducts from the agro-industry and forest biorefinery is essential for the development of value-added and low environmental-impact materials. In this study, polyurethanes were prepared using sodium lignosulfonate (NaLS) and castor oil (CO) as reagents and were used to prepare composites reinforced with lignocellulosic fibers, namely, curaua and coir fibers (30 wt %, 3 cm length, and randomly oriented). The SEM images of fractured surfaces of the composites revealed exc...
21 CitationsSource
#2Elaine C. RamiresH-Index: 13
Last. Elisabete FrolliniH-Index: 38
view all 3 authors...
#1Elisabete Frollini (USP: University of São Paulo)H-Index: 38
#2Cristina Gomes da Silva (USP: University of São Paulo)H-Index: 7
Last. Elaine C. Ramires (USP: University of São Paulo)H-Index: 13
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Abstract: Thermosets such as phenolic thermosets are brittle at room temperature. Thus, in applications where good mechanical properties are required thermosets must be combined with reinforcements to improve these properties. Composites based on thermoset matrices can substitute for steel and concrete in some applications of civil construction structures because of their higher resistance to oxidation than steel and better freeze–thaw resistance than concrete. Furthermore, phenolic composites c...
14 CitationsSource
#1Elaine C. Ramires (USP: University of São Paulo)H-Index: 13
#2Elisabete Frollini (USP: University of São Paulo)H-Index: 38
Abstract A tannin–phenolic resin (40 wt% of tannin, characterized by 1 H nuclear magnetic resonance (NMR) and 13 C NMR, Fourier transform infrared, thermogravimetry, differential scanning calorimetry) was used to prepare composites reinforced with sisal fibers (30–70 wt%). Inverse gas chromatography results showed that the sisal fibers and the tannin–phenolic thermoset have close values of the dispersive component and also have predominance of acid sites (acid character) at the surface, confirmi...
50 CitationsSource