Characterization of additives in NR formulations by TLC-IR (UATR)

Murakami, Lídia Mattos Silva; Azevedo, Joyce Baracho; Diniz, Milton Faria; Silva, Leandro Mattos; Dutra, Rita de Cássia Lazzarini

doi:10.1590/0104-1428.06317

Cited by 9 publications

(5 citation statements)

References 11 publications

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“…72 The peak at 502 cm −1 in the FTIR spectrum of the CLCE S−S film (Figure S3c) evidenced successful −S−S− bond formation in the CLCE S−S photonic film. 76,77 The −S−S− bonds can be exchanged with other nearby −S−S− bonds by heating at high temperature or through UV irradiation. The prepared CLCE S−S film exhibited a low glass-transition temperature (T g ) of −19 °C and a CLC- to-isotropic transition temperature (T ChI ) of 62 °C based on the DSC thermogram (Figure S5).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Photonic Cholesteric Liquid-Crystal Elastomers with Reprogrammable Helical Pitch and Handedness

Hussain

Park

2021

ACS Appl. Mater. Interfaces

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The unique combination of the rubber-like property and the photonic helicoidal structure of cholesteric liquid-crystal elastomers (CLCEs) results in one-handed circular polarized light reflection, the wavelength of which is dictated by the Bragg relationship. Herein, a highly stretchable mechanochromic photonic CLCE film was fabricated by cross-linking mesogenic oligomers having thiol terminal groups, which further reacted to form disulfide (−S−S−) linkages. The mechanically stretched photonic CLCE film reflected both right-and left-handed circular polarized lights with a blue-shifted color. The helicoidal pitch and handedness controlled by the applied strain were programmed through a dynamic exchange reaction between the −S−S− linkages, thus realizing the patterning at selective regions. The pattern almost vanished under unpolarized daylight but was visible under circularly polarized light when the patterned photonic CLCE film had been heated above its isotropic temperature. The hidden patterns of the heat-treated CLCE film reappeared under unpolarized daylight when stretched, demonstrating a data encryption ability. These patterned photonic elastomers can be uniquely used in sensors, actuators, soft robotics, flexible displays, data encryption, and anticounterfeiting applications with a mechanochromic camouflage response.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Photonic Cholesteric Liquid-Crystal Elastomers with Reprogrammable Helical Pitch and Handedness

Hussain

Park

2021

ACS Appl. Mater. Interfaces

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“…Additional typical PLA peaks can be found at 1452 cm -1 (-CH 3 bending), 1268 cm -1 (-C=O bending), 1038 cm -1 (-OH bending) as well as 872 cm -1 and 754 cm -1 (-C-C-stretching of amorphous and crystalline phases, respectively) (all marked by dashed lines) [25]. Finally, the small peaks around 1358 cm -1 and 1384 cm -1 can be attributed to -CH vibration and symmetric -CH 3 bending, respectively (dotted lines) ( [26] and [27]).…”

Section: Resultsmentioning

confidence: 96%

Quality of the Surface Texture and Mechanical Properties of FDM Printed Samples after Thermal and Chemical Treatment

2020

SV-JME

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Additive manufacturing technologies are nowadays used in various industries. In most cases, however, the surface texture of the produced models is unsatisfactory and requires further processing, aiming to reduce surface roughness and waviness. The quality of the surface layer in many cases plays not only an aesthetic role but also affects, for example, the process of wear and tribological properties. In the presented work, samples prepared by fused deposition modelling technology from polylactic acid (PLA) material were subjected to tests. The samples were subjected to heat or chemical treatment through the use of acetone. The quality of the surface texture was tested both before and after the treatments. In addition, tests were carried out to determine the effect of the presented finishing treatment on the tensile strength of the tested sample models. The test results showed that both thermal treatment and acetone treatment influence the surface texture quality, especially the waviness, and that the acetone treatment can improve some mechanical properties.

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“…Next, Figure 6b shows FTIR measurements of PAN nanofiber mats on 3D printed PLA. Figure 6a gives an overview of typical peaks of PLA [51,52,53,54] (grey lines) and PAN [55] (red lines), respectively.…”

Section: Resultsmentioning

confidence: 99%

Stabilization of Electrospun Nanofiber Mats Used for Filters by 3D Printing

et al. 2019

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Electrospinning is a well-known technology used to create nanofiber mats from diverse polymers and other materials. Due to their large surface-to-volume ratio, such nanofiber mats are often applied as air or water filters. Especially the latter, however, have to be mechanically highly stable, which is challenging for common nanofiber mats. One of the approaches to overcome this problem is gluing them on top of more rigid objects, integrating them in composites, or reinforcing them using other technologies to avoid damage due to the water pressure. Here, we suggest another solution. While direct 3D printing with the fused deposition modeling (FDM) technique on macroscopic textile fabrics has been under examination by several research groups for years, here we report on direct FDM printing on nanofiber mats for the first time. We show that by choosing the proper height of the printing nozzle above the nanofiber mat, printing is possible for raw polyacrylonitrile (PAN) nanofiber mats, as well as for stabilized and even more brittle carbonized material. Under these conditions, the adhesion between both parts of the composite is high enough to prevent the nanofiber mat from being peeled off the 3D printed polymer. Abrasion tests emphasize the significantly increased mechanical properties, while contact angle examinations reveal a hydrophilicity between the original values of the electrospun and the 3D printed materials.

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Characterization of additives in NR formulations by TLC-IR (UATR)

Cited by 9 publications

References 11 publications

Photonic Cholesteric Liquid-Crystal Elastomers with Reprogrammable Helical Pitch and Handedness

Photonic Cholesteric Liquid-Crystal Elastomers with Reprogrammable Helical Pitch and Handedness

Quality of the Surface Texture and Mechanical Properties of FDM Printed Samples after Thermal and Chemical Treatment

Stabilization of Electrospun Nanofiber Mats Used for Filters by 3D Printing

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