A strategy for the preparation of closed‐cell and crosslinked polypropylene foam by supercritical <scp>CO</scp><sub>2</sub> foaming

Yang, Chenguang; Xing, Zhe; Zhao, Qianqian; Wang, Mouhua; Wang, Guozhong

doi:10.1002/app.45809

Cited by 28 publications

(35 citation statements)

References 38 publications

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“…The outstanding structural parameters of PP/MS foams indicate good mechanical properties for many applications. 8,10,27 It can be clearly seen in Fig. 2 that the cell-size distribution of the PP/MS foam becomes narrower than that of the pure PP foam, which indicates that the presence of MS particles improves the cellular structure of PP/MS foams greatly, resulting in a uniform cell size in the obtained foams.…”

Section: Ms Particle Dispersion In Pp Matrixmentioning

confidence: 88%

“…10,32 According to the results mentioned above, the addition of MS improved the morphology of the PP/MS foams greatly. Therefore, the resultant good mechanical properties further proved that better microstructure signicantly increases the tensile stress and tensile strain at break, which is preferred for potential applications.…”

Section: Inuence Of Cellular Structure Of Foams On Their Mechanical mentioning

confidence: 99%

“…The cell wall thickness and foam bulk density (Table 2) increased as the loading of MS particles increased. In previous studies, 8,10,27,35,36 thick cell walls and large bulk density of the foam indicated better mechanical properties. Therefore, these results cannot explain this behavior.…”

Section: 34mentioning

confidence: 99%

“…[7][8][9][10]24,25 The system was kept at 154 C and 20 MPa for 2 h. Then the vessel was depressurized to vent CO 2 in less than 10 s. Aer that, the sample was removed from the vessel and allowed to cool to room temperature.…”

Section: Foaming Processmentioning

confidence: 99%

“…[1][2][3] Polypropylene (PP) foam is one of the most promising materials because of its outstanding overall performance, such as high toughness, low electrical conductivity, excellent chemical resistance, easy recycling, and high thermal stability for a variety of applications. [4][5][6][7][8][9][10] However, owing to its weak melt strength and melt elasticity, the properties of the resulting PP foams are poor. The reason for this is that the foam structure (cell walls) is not sufficiently strong to bear the extensional force applied during cell growth and the cells are prone to coalescing and collapsing during CO 2 release from the melt PP matrix.…”

Section: Introductionmentioning

confidence: 99%

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A new promising nucleating agent for polymer foaming: effects of hollow molecular-sieve particles on polypropylene supercritical CO₂ microcellular foaming

et al. 2018

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Because polypropylene (PP) foam normally exhibits nonuniform cell size and cracked cellular structure, a narrow cell-size distribution and a well-defined morphology are always the focus of PP foaming technology. In this work, hollow molecular-sieve (MS) particles were applied as a potential nucleating agent in supercritical carbon dioxide (scCO 2 ) foaming of PP. It was observed that the addition of MS particles largely narrowed the cell-size distribution. The resultant PP/MS foams exhibited significant concurrent enhancement in their cell density and mechanical properties: the cell density increased remarkably, by approximately 10 times, and the tensile strength increased from 6.1 MPa to 12.6 MPa. The hollow-structure MS particles resulted in a higher heterogeneous nucleation efficiency in the PP foaming process. We believe that the trapping of CO 2 in the hollow holes of MS particles largely increased the solubility CO 2 in PP and a number of gas cavities were formed. The existence of gas cavities reduced the energy barrier of heterogeneous nucleation, favoring the formation of a well-defined cellular structure.Additionally, the regular-hexagon shape of the cells might endow the PP foam with better mechanical properties compared with a circular cell shape.

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Section: Ms Particle Dispersion In Pp Matrixmentioning

confidence: 88%

Section: Inuence Of Cellular Structure Of Foams On Their Mechanical mentioning

confidence: 99%

Section: 34mentioning

confidence: 99%

Section: Foaming Processmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A new promising nucleating agent for polymer foaming: effects of hollow molecular-sieve particles on polypropylene supercritical CO₂ microcellular foaming

et al. 2018

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Strategy for the preparation of lightweight polypropylene/polyethylene‐octene elastomer composite foams with different phase morphologies using supercritical carbon dioxide

Wang

2019

J of Applied Polymer Sci

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Polypropylene (PP)/polyethylene-octene elastomer (POE) composites with a "sea-island" structure and a cocontinuous structure were prepared. With the selection of a suitable foaming temperature, the supercritical carbon dioxide foaming of PP/POE composites with different phase morphologies occurred only in the POE phase. The effects of the POE content, foaming temperature, pressure, and number of layers on the cell size, cell density, apparent density, foaming layer density, and foaming ratio under different phase morphologies were investigated by scanning electron microscopy, polarized optical microscopy, differential scanning calorimetry, and dynamic thermomechanical analysis. This article provides a novel approach for foaming PP at a low temperature. For PP/POE-blended composites with a "sea-island" structure, the foaming temperature is as low as 80 C, and for PP/POE alternating multilayered composites with a cocontinuous structure, foaming can occur at 40 C. Compared with the conventional methods for foaming PP, this method avoids the problems of a high foaming temperature, a narrow range of the foaming temperature, and a low melt strength of the PP. Thus, the PP foaming method was successfully improved, yielding a new technique for the preparation of lightweight PP.

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Preparation and properties of foamed cellulose acetate/polylactic acid blends

Zhang

Wan

et al. 2021

Polymer Engineering & Sci

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In order to improve the foaming performance of pure cellulose acetate (CA), blends were prepared by mixing polylactic acid (PLA) in CA and foamed by supercritical CO2 (ScCO2) in this study. The effect of PLA content (percentage by mass of blend) on structure, thermal properties, rheological properties, foaming properties and mechanical properties of the blends was investigated. The results showed that the addition of PLA destroyed the original hydrogen bonds of CA, while the blends had good crystallization properties. At the same time, compared with pure CA, the glass transition temperature (Tg) of the blends decreased, and the initial decomposition temperature (T0) was reduced from 349.41°C (pure CA) to 334.68°C (CA/20%PLA). In addition, the rheological properties of the blends were improved, and the viscosity was reduced, which was obviously beneficial to foaming process. The pore size and density of the foamed blends both reached the maximum value at 20%PLA. The presence of PLA could degrade the mechanical properties of the blends. However, the overall drop (1.01 KJ/m2) of impact strength of the blends after foaming is much smaller than that before foaming (12.11 KJ/m2), indicating that the improvement of foaming performance was beneficial to improve its impact strength.

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A strategy for the preparation of closed‐cell and crosslinked polypropylene foam by supercritical CO₂ foaming

Cited by 28 publications

References 38 publications

A new promising nucleating agent for polymer foaming: effects of hollow molecular-sieve particles on polypropylene supercritical CO₂ microcellular foaming

A new promising nucleating agent for polymer foaming: effects of hollow molecular-sieve particles on polypropylene supercritical CO₂ microcellular foaming

Strategy for the preparation of lightweight polypropylene/polyethylene‐octene elastomer composite foams with different phase morphologies using supercritical carbon dioxide

Preparation and properties of foamed cellulose acetate/polylactic acid blends

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A strategy for the preparation of closed‐cell and crosslinked polypropylene foam by supercritical CO2 foaming

Cited by 28 publications

References 38 publications

A new promising nucleating agent for polymer foaming: effects of hollow molecular-sieve particles on polypropylene supercritical CO2 microcellular foaming

A new promising nucleating agent for polymer foaming: effects of hollow molecular-sieve particles on polypropylene supercritical CO2 microcellular foaming

Strategy for the preparation of lightweight polypropylene/polyethylene‐octene elastomer composite foams with different phase morphologies using supercritical carbon dioxide

Preparation and properties of foamed cellulose acetate/polylactic acid blends

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Product

Resources

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A strategy for the preparation of closed‐cell and crosslinked polypropylene foam by supercritical CO₂ foaming

A new promising nucleating agent for polymer foaming: effects of hollow molecular-sieve particles on polypropylene supercritical CO₂ microcellular foaming

A new promising nucleating agent for polymer foaming: effects of hollow molecular-sieve particles on polypropylene supercritical CO₂ microcellular foaming