Abstract:Resumo: Neste trabalho foi estudada a influência da adição de nano-argila nas propriedades reológicas de suspensões de plastisol de poli(cloreto de vinila). Foram utilizados dois tipos de nano-argila, montmorilonita sódica e a organicamente modificada com sal quaternário de amônio, contemplando a avaliação tanto do método de inchamento da argila, quanto da influência da concentração. A nano-argila, na concentração de 2,5, 5, e 10 pcr, foi previamente inchada em plastificante, sob ação de cisalhamento e tempera… Show more
“…6 For those systems containing the same amount of clay (Figure 2(a)), viscosity was higher for the samples prepared with lower amplitude of sonication, indicating better clay dispersion. 12,13 For higher clay content (Figure 2(b)), viscosity increased, as expected, due to the increase in alkyl ammonium cation concentration, which increased the electrostatic repulsion of these cations with the molecules of the polymer surface, thereby increasing viscosity. 13 Figure 2.Viscosity values for the resin/30B-Mt clay system: (a) for different amplitudes of sonication and (b) for different clay content.…”
The aim of this work is to evaluate the effect of sonication and clay content on the crosslinking and curing characteristics and the final properties of unsaturated polyester/montmorillonite nanocomposites. The Cloisite 30B clay (1, 3 or 5 wt.%) was dispersed in the resin by mechanical stirring and sonication at different ultrasonic amplitudes (20% and 30%). Amplitude is one of the most important parameter when reproducing sonication results. An increase in viscosity with clay incorporation, at 20% amplitude, was related to the better dispersion, corroborating differential scanning calorimetry results. The sequential diffractograms confirmed the influence of the clay on resin crosslinking and the curing process. An intercalated structure was observed for samples up to 3 wt.% of clay and an amplitude of 20% during sonication, corroborating the increase in flexural strength and lower values of coefficient of thermal expansion. Modulus increased with the incorporation of clay, whereas impact strength and linear burning rate declined.
“…6 For those systems containing the same amount of clay (Figure 2(a)), viscosity was higher for the samples prepared with lower amplitude of sonication, indicating better clay dispersion. 12,13 For higher clay content (Figure 2(b)), viscosity increased, as expected, due to the increase in alkyl ammonium cation concentration, which increased the electrostatic repulsion of these cations with the molecules of the polymer surface, thereby increasing viscosity. 13 Figure 2.Viscosity values for the resin/30B-Mt clay system: (a) for different amplitudes of sonication and (b) for different clay content.…”
The aim of this work is to evaluate the effect of sonication and clay content on the crosslinking and curing characteristics and the final properties of unsaturated polyester/montmorillonite nanocomposites. The Cloisite 30B clay (1, 3 or 5 wt.%) was dispersed in the resin by mechanical stirring and sonication at different ultrasonic amplitudes (20% and 30%). Amplitude is one of the most important parameter when reproducing sonication results. An increase in viscosity with clay incorporation, at 20% amplitude, was related to the better dispersion, corroborating differential scanning calorimetry results. The sequential diffractograms confirmed the influence of the clay on resin crosslinking and the curing process. An intercalated structure was observed for samples up to 3 wt.% of clay and an amplitude of 20% during sonication, corroborating the increase in flexural strength and lower values of coefficient of thermal expansion. Modulus increased with the incorporation of clay, whereas impact strength and linear burning rate declined.
“…Composites using nanoparticulate organophilic clays that interact at the nanometric scale with the polymeric matrix are materials that normally generate products with high mechanical, thermal and barrier properties, at low loading levels. Therefore, the development and use of nanocomposites having biodegradable polymers as a matrix, stable during processing, is one of the ways to expand the applications of these materials and contribute to their use in a more environmentally correct way (Fukushima et al, 2012;Almeida et al, 2016;Falcão et al, 2017;Bettio et al, 2012).…”
The packaging industry requires permeable materials capable of offering freshness of the packaging content. The use of fillers can enhance these permeable properties to the polymeric material. This work investigates the effect of incorporating different fillers (organophilic clay and corn straw) on the rheological, mechanical, permeability, water absorption and biodegradability characteristics of poly (butylene adipate co-terephthalate) (PBAT) processed in an internal laboratory mixer. Extruded films and specimens injection molded were produced. The results of torque rheometry suggest polymer matrix degradation during processing slightly increase, also evidenced by MFR results. Composite films showed a drop in tensile strength, higher stiffness and lower elongation. Incorporation of the fillers in the PBAT matrix enhanced the permeability to oxygen gas of the produced films. The presence of fillers significantly increased the capacity of water absorption. The incorporation of C20A and, mainly, CS tends to accelerate the biodegradation of PBAT. Adding small amounts of organoclay C20A and CS to PBAT leads to a material that combines maintenance or improvement of biodegradation combined with higher permeability to oxygen, which indicates the potential use of these systems in packaging industry for maintenance of freshness of content.
“…The formation of composites using montmorillonite clays as reinforcing material for polymers, due, among other factors, to the possibility of intercalation/exfoliation of the silicate layers in the polymer matrix, as well as the natural fiber, has promoted improvements in the properties of the final material, including with the improvement in the barrier properties of polymeric films (Bettio & Pessan, 2012;Luna et al, 2022).…”
The packaging industry requires materials capable of offering barriers to the entry of microorganisms, with the ability to protect and maintain the characteristics of the packaging content. The use of fillers can enhance these barrier properties to the polymeric material. This work investigates the effect of incorporating different fillers (organophilic clay and corn straw) on the rheological, thermal, mechanical and permeability characteristics of polycaprolactone (PCL) processed in an internal laboratory mixer. The results of torque rheometry suggest polymer matrix degradation during processing did not increase, nor the thermal stability of the matrix. Composite films showed higher tensile strength, higher stiffness and lower elongation. Incorporation of the fillers in the PCL matrix reduced the permeability to oxygen and carbon dioxide gases of the produced films. Adding up to 1% of organoclay C20A or corn straw to PCL leads to a material that combines maintenance or improvement of properties combined with lower permeability to oxygen and carbon dioxide, which confirms the potential use of these systems in packaging industry.
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