Transparent nanocellular PMMA: Characterization and modeling of the optical properties

León, Judith Martín‐de; Pura, José Luis; Bernardo, Victoria; Rodríguez‐Pérez, Miguel Ángel

doi:10.1016/j.polymer.2019.03.010

Cited by 45 publications

(28 citation statements)

References 18 publications

(23 reference statements)

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“…[17][18][19][20] Enhanced mechanical performance was also demonstrated in some nanocellular polymers. [21,22] Further, it is possible to produce semi-transparent nanocellular polymers, [23,24] among other interesting properties and applications. [25][26][27] The challenge in the production of these systems is currently in the reduction of the density while keeping the cell size in the nanometric range.…”

Section: Introductionmentioning

confidence: 99%

Nanocellular Polymers with a Gradient Cellular Structure Based on Poly(methyl methacrylate)/Thermoplastic Polyurethane Blends Produced by Gas Dissolution Foaming

Bernardo

León

Sánchez-Calderón

et al. 2019

Macro Materials & Eng

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Graded structures and nanocellular polymers are two examples of advanced cellular morphologies. In this work, a methodology to obtain low‐density graded nanocellular polymers based on poly(methyl methacrylate) (PMMA)/thermoplastic polyurethane (TPU) blends produced by gas dissolution foaming is reported. A systematic study of the effect of the processing condition is presented. Results show that the melt‐blending results in a solid nanostructured material formed by nanometric TPU domains. The PMMA/TPU foamed samples show a gradient cellular structure, with a homogeneous nanocellular core. In the core, the TPU domains act as nucleating sites, enhancing nucleation compared to pure PMMA and allowing the change from a microcellular to a nanocellular structure. Nonetheless, the outer region shows a gradient of cell sizes from nano‐ to micron‐sized cells. This gradient structure is attributed to a non‐constant pressure profile in the samples due to gas desorption before foaming. The nucleation in the PMMA/TPU increases as the saturation pressure increases. Regarding the effect of the foaming conditions, it is proved that it is necessary to have a fine control to avoid degeneration of the cellular materials. Graded nanocellular polymers with relative densities of 0.16–0.30 and cell sizes ranging 310–480 nm (in the nanocellular core) are obtained.

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Section: Introductionmentioning

confidence: 99%

Nanocellular Polymers with a Gradient Cellular Structure Based on Poly(methyl methacrylate)/Thermoplastic Polyurethane Blends Produced by Gas Dissolution Foaming

Bernardo

León

Sánchez-Calderón

et al. 2019

Macro Materials & Eng

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“…4,7 On the other hand, when referring to the transparency of these cellular materials, more demanding requirements are needed, cell sizes smaller than 50 nm are needed, and it also expected that this property would strongly depend on the cellular material density. 8 Therefore, it is mandatory to acquire a fine control of the process of the design of nanocellular polymers with the right density and cell size, and, in this sense, it is also needed to find simple approaches to obtain that control. In particular, it has been proven that the viscosity of the polymer matrix is crucial for all the steps in the production of cellular and microcellular materials; that is, nucleation, growth, degeneration mechanisms of the cellular structure and stabilization are affected by this property of the solid material.…”

Section: Introductionmentioning

confidence: 99%

Influence of the viscosity of poly(methyl methacrylate) on the cellular structure of nanocellular materials

León

Bernardo

Laguna‐Gutiérrez³

et al. 2019

Polymer International

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Three different grades of poly(methyl methacrylate) (PMMA) with different rheological properties are used for the production of nanocellular materials using gas dissolution foaming. The influences of both the viscosity of the different polymers and the processing parameters on the final cellular structure are studied using a wide range of saturation and foaming conditions. Foaming conditions affect similarly all cellular materials. It is found that an increase of the foaming temperature results in less dense nanocellular materials, with higher cell nucleation densities. In addition, it is demonstrated that a lower viscosity leads to cellular polymers with a lower relative density but larger cell sizes and smaller cell nucleation densities, these differences being more noticeable for the conditions in which low solubilities are reached. It is possible to produce nanocellular materials with relative densities of 0.24 combined with cell sizes of 75 nm and cell nucleation densities of 10 15 nuclei cm −3 using the PMMA with the lowest viscosity. In contrast, minimum cell sizes of around 14 nm and maximum cell nucleation densities of 3.5 × 10 16 nuclei cm −3 with relative densities of 0.4 are obtained with the most viscous one.

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“…Moreover, enhanced mechanical performance has been demonstrated in nanocellular polymers [ 5 , 6 , 7 ]. Furthermore, it is possible to produce semi-transparent nanocellular polymers [ 8 , 9 ], among other interesting properties [ 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of the Molecular Structure of TPU on the Cellular Structure of Nanocellular Polymers Based on PMMA/TPU Blends

Sánchez-Calderón

Bernardo²,

Santiago‐Calvo

et al. 2021

Polymers

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In this work, the effects of thermoplastic polyurethane (TPU) chemistry and concentration on the cellular structure of nanocellular polymers based on poly(methyl-methacrylate) (PMMA) are presented. Three grades of TPU with different fractions of hard segments (HS) (60%, 70%, and 80%) have been synthesized by the prepolymer method. Nanocellular polymers based on PMMA have been produced by gas dissolution foaming using TPU as a nucleating agent in different contents (0.5 wt%, 2 wt%, and 5 wt%). TPU characterization shows that as the content of HS increases, the density, hardness, and molecular weight of the TPU are higher. PMMA/TPU cellular materials show a gradient cell size distribution from the edge of the sample towards the nanocellular core. In the core region, the addition of TPU has a strong nucleating effect in PMMA. Core structure depends on the HS content and the TPU content. As the HS or TPU content increases, the cell nucleation density increases, and the cell size is reduced. Then, the use of TPUs with different characteristics allows controlling the cellular structure. Nanocellular polymers have been obtained with a core relative density between 0.15 and 0.20 and cell sizes between 220 and 640 nm.

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Transparent nanocellular PMMA: Characterization and modeling of the optical properties

Cited by 45 publications

References 18 publications

Nanocellular Polymers with a Gradient Cellular Structure Based on Poly(methyl methacrylate)/Thermoplastic Polyurethane Blends Produced by Gas Dissolution Foaming

Nanocellular Polymers with a Gradient Cellular Structure Based on Poly(methyl methacrylate)/Thermoplastic Polyurethane Blends Produced by Gas Dissolution Foaming

Influence of the viscosity of poly(methyl methacrylate) on the cellular structure of nanocellular materials

Effect of the Molecular Structure of TPU on the Cellular Structure of Nanocellular Polymers Based on PMMA/TPU Blends

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