Mechanical and Microstructural Properties of Redispersible Polymer-Gypsum Composites

Gomes, Carlos Eduardo Marmorato; Sousa, Almir; Araujo, M.E. da Silva Oliveira; Ferreira, Sindynara; Fontanini, Patrícia Stella Pucharelli

doi:10.1590/1980-5373-mr-2018-0119

Cited by 10 publications

(4 citation statements)

References 15 publications

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“…Therefore, the CMC as a polymer can be a strong inhibitor of dihydrate formation, resulting retardation of crystal growth and increase of setting time. 35 The extended time for the material for setting in the clinical scenario might be favorable for dentine remineralization. Kim et al stated that prolonged application time using remineralization agents can promote remineralization of the early carious lesion.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Novel Cement-Based Carboxymethyl Chitosan/Amorphous Calcium Phosphate

et al. 2022

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Objective This study aimed to analyze, evaluate, and characterize novel cement-based carboxymethyl chitosan/amorphous calcium phosphate (CMC/ACP). Materials and Methods The three cement groups studied were gypsum (Gyp), and CMC/ACP—gypsum cement-based 5% (5% CAG) and 10% (10% CAG). The groups were characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), setting time, and scanning electron microscopy (SEM) data. The characterization results were analyzed qualitatively, but the data for setting time were analyzed using SPSS (p < 0.05). Statistical Analysis Data were statistically analyzed. One-way analysis of variance was used to compare numerical (parametric) data between more than two separate groups followed by post hoc Tukey. Results FTIR showed phosphate groups indicate the presence of calcium phosphate in the form of amorphous (ACP) in the CMC/ACP, CMC/ACP post-milled powder, and CMC/ACP cement-based (5% CAG and 10% CAG). XRD showed no difference in the diffraction spectra among the Gyp, 5% CAG, and 10% CAG groups. SEM images revealed that the CMC/ACP cement-based groups (5% CAG and 10% CAG) showed CMC/ACP cluster filled with hollow spaces between the gypsum crystals and aggregations surrounding the gypsum crystals. The CMC/ACP showed envelopes and attached to the crystalline structures of the gypsum. Setting times of 5% CAG and 10% CAG showed significant differences compared with Gyp (p < 0.05). Conclusion The result of our study showed that CMC/ACP cement-based (5% CAG and 10% CAG) demonstrated amorphous characteristic, which can stabilize calcium ions and phosphate group (ACP). In addition, the modification of gypsum using CMC/ACP as cement-based extended the time of setting.

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Section: Discussionmentioning

confidence: 99%

Characterization of Novel Cement-Based Carboxymethyl Chitosan/Amorphous Calcium Phosphate

et al. 2022

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“…The reinforcement of gypsum compositions is often carried out by the introduction of fibrous fillers [10] or polymeric additives such as PVA [11][12][13], latex [14,15], plastic waste [16].…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Strength and chemical resistance of composites based on epoxy resins, filled with gypsum in the original and waterhardened forms

Starokadomsky¹,

Rassokhin²,

Ishchenko³

et al. 2020

EEJET

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This paper reports the results of studying epoxy compositions with gypsum taken in the form of dispersed powders in the original and water-hardened form. The exact pattern has been shown in the way the introduction of a gypsum additive in the amount of 50 % by weight affects the strength, chemical stability, and morphology of the composites. Under conventional heat treatment (60-110 °C) of the hardened composites, the maximum stress at compression σ m and the elasticity module at compression Е с , as well as wear resistance, decrease after the introduction of gypsums (of both types). At the same time, after a hard (destructive) heating at 250-260 °C, the elasticity module Ес of the hardened composites increases. The maximum stress at compression σ m is also increased. The same applies to the wear resistance, which grows especially noticeably after 250 °C. The micro-hardness after filling is prone to increase but the fragility of epoxy-gypsum composites does not make it possible to measure it when a punch (a steel hemisphere) penetrates it deeper than 20 μm. However, after the heat treatment at 250-260 °C, the unfilled polymer, on the contrary, is embrittled while the filled ones are plasticized, thus showing a high micro-hardness at significant (30-50 μm) immersion. The composites with gypsum, in contrast to the unfilled ones, do not disintegrate in acetone and retain integrity at any aging duration (up to 75 days and beyond). In this case, the original gypsum produces a composite with less swelling in acetone than the hardened gypsum. Based on the data from atomic-strength microscopy (ASM) microscopy, the morphologies of the non-filled composite, the composites with the hardened gypsum and original gypsum are different. The original gypsum forms a composite with a more pronounced (possibly crystalline) filler structure; the morphology for the hardened composite reflects the distribution of inert particles; for the unfilled composite (H-composite), only pores are visible against the background of a relatively smooth relief

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“…2 Despite the hydrophilic character of MCC, 20 the aqueous emulsion form of the terpolymer matrix enables its adhesion and its uniform dispersion by using an environmentally friendly method described in the works of Zyane et al 21 Vast industrial applications of commercial and biodegradable polymers used as matrices have been shown recently. 22,23 Ethylene vinyl acetate (EVA) copolymer with a high percentage of vinyl acetate exhibits softness, flexibility, and physicochemical stability. 24 It has a wide range of applications such as component packaging, petroleum industry and cable insulators.…”

Section: Introductionmentioning

confidence: 99%

“…Vast industrial applications of commercial and biodegradable polymers used as matrices have been shown recently. 22,23 Ethylene vinyl acetate (EVA) copolymer with a high percentage of vinyl acetate exhibits softness, flexibility, and physicochemical stability. 24 It has a wide range of applications such as component packaging, petroleum industry and cable insulators.…”

Section: Introductionmentioning

confidence: 99%

Dielectric properties of microcrystalline cellulose/multi-wall carbon nanotubes multi-scale reinforced EVA/VeoVa terpolymer

Larguech

Kreit

Zyane

et al. 2022

Journal of Composite Materials

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Dielectric analyses were investigated on vinyl resin emulsion based on ethylene vinyl acetate/vinyl ester of versatic acid terpolymer (EVA/VeoVa) and its composites reinforced with microcrystalline cellulose and multi-wall carbon nanotubes. Dielectric spectra were measured in the frequency range from 10-1 Hz to 107 Hz and the temperature interval from -35°C to 130°C. Three dielectric relaxations were identified for the matrix. The first one, appearing at lower temperatures and higher frequencies, was associated with secondary β relaxation. The second one appearing above the glass transition temperature was attributed to the α relaxation due to the main glass transition of the terpolymer. The third dielectric relaxation appearing at higher temperatures and lower frequencies was attributed to α’ relaxation originating from the motion of more repeat units compared to the α one. The addition of the reinforcements into the matrix gave rise to three additional dielectric phenomena originating either from microcrystalline cellulose or matrix/reinforcement interfaces. Analyses of secondary dielectric relaxations at low temperatures by using the Havriliak-Negami model and those at high temperatures according to an adequate equivalent circuit model allowed probing reinforcement/matrix interactions. This dielectric study was complemented by the thermal, structural and morphological analyses based on differential scanning calorimeter (DSC), X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively

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Mechanical and Microstructural Properties of Redispersible Polymer-Gypsum Composites

Cited by 10 publications

References 15 publications

Characterization of Novel Cement-Based Carboxymethyl Chitosan/Amorphous Calcium Phosphate

Characterization of Novel Cement-Based Carboxymethyl Chitosan/Amorphous Calcium Phosphate

Strength and chemical resistance of composites based on epoxy resins, filled with gypsum in the original and waterhardened forms

Dielectric properties of microcrystalline cellulose/multi-wall carbon nanotubes multi-scale reinforced EVA/VeoVa terpolymer

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Mechanical and Microstructural Properties of Redispersible Polymer-Gypsum Composites

Cited by 10 publications

References 15 publications

Characterization of Novel Cement-Based Carboxymethyl Chitosan/Amorphous Calcium Phosphate

Characterization of Novel Cement-Based Carboxymethyl Chitosan/Amorphous Calcium Phosphate

Strength and chemical resistance of composites based on epoxy resins, filled with gypsum in the original and water­hardened forms

Dielectric properties of microcrystalline cellulose/multi-wall carbon nanotubes multi-scale reinforced EVA/VeoVa terpolymer

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Strength and chemical resistance of composites based on epoxy resins, filled with gypsum in the original and waterhardened forms