In this work, an investigation was carried out on the effect of ultraviolet light on different films. Polystyrene (PS), poly (caprolactone) (PCL), and blended films of PS/PCL were produced. Ethyl acetate (AE) was used as a solvent, and PS and PCL solutions were prepared by dissolving 250 mg in 2.5mL of AE under mechanical stirring at room temperature. The blended solutions of PS/PCL (PS:PCL) were prepared with different mass proportions, such as 90:10, 80:20, 70:30, and 60:40 into 2.5 mL of EA. The solutions were dripped with 500 µL on a glass substrate, and the films were produced with mechanical rotation of N=2000 RPM for 15 seconds using a Spin coater. The films were submitted to ultraviolet light for t=60 minutes and morphologically analyzed by optical microscopy, chemically by IR spectroscopy, and superficially by contact angle and wettability; this last analysis also investigated the effect of ultraviolet light at t=0, t=30, and t=60 minutes. The exposure of ultraviolet light on the films affected its morphologies. IR spectra showed that the photodegradation increased for larger PCL amounts into the blend. The contact angle measurements showed that after exposure to ultraviolet light, the hydrophobicity of the films increased. Therefore, the presence of PCL in the polymer mixture promoted the photodegradation of the PS/PCL films, making it attractive for developing new packaging.
In this work, an investigation was carried out on the effect of ultraviolet light on different films. Polystyrene (PS), poly (caprolactone) (PCL), and blended films of PS/PCL were produced. Ethyl acetate (AE) was used as a solvent, and PS and PCL solutions were prepared by dissolving 250 mg in 2.5mL of AE under mechanical stirring at room temperature. The blended solutions of PS/PCL (PS:PCL) were prepared with different mass proportions, such as 90:10, 80:20, 70:30, and 60:40 into 2.5 mL of EA. The solutions were dripped with 500 µL on a glass substrate, and the films were produced with mechanical rotation of N=2000 RPM for 15 seconds using a Spin coater. The films were submitted to ultraviolet light for t=60 minutes and morphologically analyzed by optical microscopy, chemically by IR spectroscopy, and superficially by contact angle and wettability; this last analysis also investigated the effect of ultraviolet light at t=0, t=30, and t=60 minutes. The exposure of ultraviolet light on the films affected its morphologies. IR spectra showed that the photodegradation increased for larger PCL amounts into the blend. The contact angle measurements showed that after exposure to ultraviolet light, the hydrophobicity of the films increased. Therefore, the presence of PCL in the polymer mixture promoted the photodegradation of the PS/PCL films, making it attractive for developing new packaging.
In this work, 3D extrusion-based printing head was used to produce 3D geometry of hydrogel containing caffeic acid (CA). The hydrogel was prepared with 10wt.% polyvinylpyrrolidone (PVP) and 3wt.% sodium carboxymethylcellulose (CMC) using deionized water as solvent (PVP-CMC hydrogel), likewise the PVP-CMC hydrogel containing CA was prepared but was added 2wt.% CA (PVP-CA-CMC hydrogel). The rheological properties of the hydrogels were obtained using a modular rheometer with plate-plate geometry. The PVP-CMC hydrogel presented shear-thinning flow behavior and the adding of CA did not affect its rheological behavior. The power-law model described the shear-thinning curves of the hydrogels. Frequency sweep tests demonstrated that the PVP-CMC and PVP-CA-CMC hydrogels presented a physical gelation characteristic of the solid behaviors. The IR spectroscopy chemically characterized the hydrogel, indicating by carbonyl peaks a good intermolecular interaction between the functional groups. Therefore, we demonstrated the printing capacity of the PVP-CMC inks with caffeic acid, which makes it interesting to additive manufacture field. I. is linked to cell biology and materials science [5].Compared with other manufacturing techniques where João de Deus Pereira et al.
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Revisão: Os Autores O conteúdo dos artigos e seus dados em sua forma, correção e confiabilidade são de responsabilidade exclusiva dos autores. Permitido o download da obra e o compartilhamento desde que sejam atribuídos créditos aos autores, mas sem a possibilidade de alterá-la de nenhuma forma ou utilizá-la para fins comerciais.
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