Evaluation of Nanoparticle Effect on Bubble Nucleation in Polymer Foaming

Wang, Linyan; Zhou, Hongfu; Wang, Xiangdong; Mi, Jianguo

doi:10.1021/acs.jpcc.6b08723

Cited by 23 publications

(19 citation statements)

References 53 publications

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“…The critical bubble radius for our CO 2 PMMA-saturated system is on the order of 3 nm for a saturation pressure of 55 bar (see also eq 10 ). 64 In addition, from high-resolution SEM images, the CO 2 swollen polymer–particle contact angles of bare and PDMS-grafted particles with a silica core of 80 nm were determined to be ∼79 and ∼28°, respectively (see Figure S3 ). The lower contact angle for the 80 nm SiO 2 -PDMS particles compared to that of the bare NPs is ascribed to the high affinity of the grafted NPs to the CO 2 phase, and it explains also the higher nucleation efficiency.…”

Section: Results and Discussionmentioning

confidence: 99%

Silica-Assisted Nucleation of Polymer Foam Cells with Nanoscopic Dimensions: Impact of Particle Size, Line Tension, and Surface Functionality

Liu

Eijkelenkamp

Duvigneau

et al. 2017

ACS Appl. Mater. Interfaces

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Core–shell nanoparticles consisting of silica as core and surface-grafted poly(dimethylsiloxane) (PDMS) as shell with different diameters were prepared and used as heterogeneous nucleation agents to obtain CO2-blown poly(methyl methacrylate) (PMMA) nanocomposite foams. PDMS was selected as the shell material as it possesses a low surface energy and high CO2-philicity. The successful synthesis of core–shell nanoparticles was confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis, and transmission electron microscopy. The cell size and cell density of the PMMA micro- and nanocellular materials were determined by scanning electron microscopy. The cell nucleation efficiency using core–shell nanoparticles was significantly enhanced when compared to that of unmodified silica. The highest nucleation efficiency observed had a value of ∼0.5 for nanoparticles with a core diameter of 80 nm. The particle size dependence of cell nucleation efficiency is discussed taking into account line tension effects. Complete engulfment by the polymer matrix of particles with a core diameter below 40 nm at the cell wall interface was observed corresponding to line tension values of approximately 0.42 nN. This line tension significantly increases the energy barrier of heterogeneous nucleation and thus reduces the nucleation efficiency. The increase of the CO2 saturation pressure to 300 bar prior to batch foaming resulted in an increased line tension length. We observed a decrease of the heterogeneous nucleation efficiency for foaming after saturation with CO2 at 300 bar, which we attribute to homogenous nucleation becoming more favorable at the expense of heterogeneous nucleation in this case. Overall, it is shown that the contribution of line tension to the free energy barrier of heterogeneous foam cell nucleation must be considered to understand foaming of viscoelastic materials. This finding emphasizes the need for new strategies including the use of designer nucleating particles to enhance the foam cell nucleation efficiency.

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Section: Results and Discussionmentioning

confidence: 99%

Silica-Assisted Nucleation of Polymer Foam Cells with Nanoscopic Dimensions: Impact of Particle Size, Line Tension, and Surface Functionality

Liu

Eijkelenkamp

Duvigneau

et al. 2017

ACS Appl. Mater. Interfaces

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“…24,25 The schematic representation and corresponding SEM images of these nano-fillers are shown in Figure 1(a). TPU is a polymer with glass transition temperature of −40 C and softening point of 109 C. 28 The density of TPU is about 1.20 g/cm 3 . The schematic of segmented thermoplastic polyurethane is shown in the Figure S1 of the supporting information showing the aligned hard segment and soft segment.…”

Section: Methodsmentioning

confidence: 99%

“…18,19 Low dimensional nanofiller helps as nucleating agent to initiate heterogeneous nucleation for polymer having lower degree of crystallinity. 28 The higher active area and surface curvature of fullerenol 62 and functionalized graphene are responsible for the controlled orientation of polymer chains which leads to the formation spherulites. Fullerenol incorporated composites did not show any enhancement in tensile strength and modulus but elongation at break was found to increase.…”

Section: Morphology and Its Effect On The Tensile Propertiesmentioning

confidence: 99%

Interfacial interactions and properties of cellular structured polyurethane nanocomposite based on carbonaceous nano‐fillers

Mandal

Roy

Prasad

et al. 2020

J of Applied Polymer Sci

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In this article, we have studied the effect of carbonaceous nanofillers viz. fullerenol (0D), carboxylated multi-wall carbon nanotube (MWCNT, 1D), hydroxylated graphene (2D) and combination of carboxylated CNT and hydroxylated graphene as 3D in thermoplastic polyurethane on the tensile properties of the fabricated cellular structures. The concentration of nano-fillers was varied as 0.1, 1, and 5 wt%. Tensile properties of the nanocomposite cellular structures were measured as per ASTM D882 at 20 C (below glass transition temperature, T g) and 40 C (above T g). The results have shown that the tensile strength was found to increase by 200%-300% and the tensile modulus was found to increase by 150%-300% for 2D and 3D nano-fillers while significantly poor results were observed for 0D. However, the test data tensile strength and modulus showed marginal increase at 20 C and marginally low at 40 C for 1D filler. The interfacial adhesion was calculated by using experimental tensile data and the predictive models. The interfacial adhesion parameter (B σ) calculated using Pukanszky equation was found significantly higher value for 2D (B σ20 = 195.8) and 3D (B σ20 = 192.0) fillers while poor adhesion was observed for 0D (B σ20 = −81.6) fillers. The developed cellular structured materials were also evaluated by attenuated total reflection Fourier transform IR spectra, differential scanning calorimetry, X-ray diffraction, scanning electron microscope, and transmission electron microscope. K E Y W O R D S foams, graphene and fullerenes, mechanical properties, microscopy, nanotubes, surfaces and interfaces 1 | INTRODUCTION Polyurethane (PU) is an elastic and flexible polymer and is used in adhesives, coatings, medical devices, sealants, and thermoplastic elastomers. 1 Polymer foams which are made of skeleton of more or less regular closed or open cells are popularly used in the industry. They have high energy shock absorption capacity, acoustic and thermal insulating properties, filtering applications, 2 and so forth. They are also widely used in automobile, aircraft industry, buildings and packaging. 2 The foams of PUs are used as insulating and core materials for cooling, furniture, and freezing systems, shipbuilding, in house building, 3 and so forth. The use of rigid foams is due to their low

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“…Consequently, the resultant PP foam usually To improve the melt strength, considerable efforts have been made to optimize the PP foaming process, enhance PP foam ability as well as improve cellular structure [11,[13][14][15][16][17][18][19][20][21][22][23], such as long-chain branching [24,25], crosslinking [10,20,[26][27][28], polymer blending [11,29], and compounding [30,31]. In recent years, it was found nanoparticles such as graphene, carbon nanotubes, and carbon nanofibers added in PP could provide heterogeneous nucleation sites to increase cell density, minish cell size, improve cell uniformity, and at the same time reinforce the polymeric matrix [11,22,[32][33][34]. But the cost of these nanoparticles are high, making it difficult to use them for the high-volume production of polymer foams [11].…”

Section: Introductionmentioning

confidence: 99%

Improving the Supercritical CO<sub>2</sub> Foaming of Polypropylene by the Addition of Fluoroelastomer as a Nucleation Agent

Yang¹,

Zhao²,

Xing³

et al. 2018

Preprint

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Polypropylene (PP) foam has a great deal of application since it normally exhibits non-uniform cell size distribution, low cell density, and cracked cells. In this study, a small amount of fluoroelastomer (FKM) was used as a nucleating agent to prepare well-defined microporous PP foam by supercritical CO2. It was observed that solid FKM was present as the nanoscale independent phase in PP matrix and the FKM could induce a mass of CO2 aggregation, which significantly enhanced the diffusion rate of CO2 in PP. The resultant PP/FKM foams exhibited much smaller cell size (～24 μm), and more than 16 times cell density (3.2×108 cells/cm3) as well as a much more uniform cell size distribution than that of the neat PP foam. PP/FKM foams possessed major concurrent enhancement in their tensile stress and compressive stress compared to neat PP foam. We believed that the added FKM played a key role in enhancing the heterogeneous nucleation, combined with the local strain field variation in the multiple-phase system, which was responsible for the considerably improved cell morphology of PP foaming. This paper provides a deep understanding of the scCO2 foaming behavior of PP in the presence of FKM.

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Evaluation of Nanoparticle Effect on Bubble Nucleation in Polymer Foaming

Cited by 23 publications

References 53 publications

Silica-Assisted Nucleation of Polymer Foam Cells with Nanoscopic Dimensions: Impact of Particle Size, Line Tension, and Surface Functionality

Silica-Assisted Nucleation of Polymer Foam Cells with Nanoscopic Dimensions: Impact of Particle Size, Line Tension, and Surface Functionality

Interfacial interactions and properties of cellular structured polyurethane nanocomposite based on carbonaceous nano‐fillers

Improving the Supercritical CO<sub>2</sub> Foaming of Polypropylene by the Addition of Fluoroelastomer as a Nucleation Agent

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