Extrusion of linear polypropylene–clay nanocomposite foams

Chaudhary, Amit; Jayaraman, K.

doi:10.1002/pen.21961

Cited by 53 publications

(49 citation statements)

References 37 publications

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“…In the case of PP foams with nano‐fillers, Chaudhary and Jayaraman were able to correlate the observed improvements in the regularity of the foam microstructure to the improved extensional strain hardening behaviour of the PP nanocomposite melts through incorporation of specially functionalized nano‐clay which resulted in an intercalated microstructure.…”

Section: Introductionmentioning

confidence: 99%

Polypropylene–nano‐silica nanocomposite foams: mechanisms underlying foamability, and foam microstructure, crystallinity and mechanical properties

Anish

Patham²,

Mohanty

et al. 2020

Polymer International

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We investigate the production and characterization of foams prepared from polypropylene (PP) as well as PP–silica nanocomposites containing different loadings of nano‐silica. This study was carried out to investigate the mechanisms underlying the production of foams with a regular cell structure through the use of nano‐scale fillers. Foaming was carried out in batch mode using an autoclave with CO2 as the physical blowing agent; high pressures of the order of 14 MPa were achieved through a combination of active pressurization and the use of high foaming temperatures. The resulting PP nanocomposite foams were characterized in detail to quantify the effect of the nano‐silica loading on the foam density and mechanical, morphological and thermal properties. The addition of nano‐silica in PP resulted in the improvement of foam quality – as assessed from the well‐defined and regular cell structures with absence of cell coalescence – as well as an increase in expansion ratio and decrease in foam density. Careful analyses of trends in cell size, cell density and expansion ratio of the foams were correlated with measurements of melt rheology and nano‐filler morphology of the unfoamed specimens in order to identify subtle details regarding the role of silica nanoparticles in improving foam quality. © 2019 Society of Chemical Industry

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Section: Introductionmentioning

confidence: 99%

Polypropylene–nano‐silica nanocomposite foams: mechanisms underlying foamability, and foam microstructure, crystallinity and mechanical properties

Anish

Patham²,

Mohanty

et al. 2020

Polymer International

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“…The cell nucleation, bubble growth and the final cell morphology of extruded PP foams have been studied extensively (2)(3)(4)(5)(6). Earlier studies attempted to enhance the melt strength by partial crosslinking of PP (7).…”

Section: Introductionmentioning

confidence: 99%

The simultaneous effect of nucleating and blowing agents on the cellular structure of polypropylene foamed via the extrusion process

2016

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Abstract:The current work presents the preparation of polypropylene (PP) foams by the extrusion process, focusing on the influence of the foaming agent and nucleating agent on the microstructure of the foams. Sodium bicarbonate alone and also its mixture with citric acid were used as the chemical blowing agents. Expanded graphite nanoparticle and talc were also used as the nucleating agents. Great differences were found in terms of the foam structure depending on the type of nucleating and blowing agents. Using expanded graphite nucleating agent instead of talc resulted in foams with higher cell densities and more uniform cellular structures. Moreover, the foams including the mixed blowing agents exhibited higher cell densities and upper expansion ratio.

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“…Furthermore, the cell density N was calculated using N = (n/A) 3/2 [42] where n is the number of cells and A is a defined area of the SEM micrograph.…”

Section: Preparation and Characterisation Of Diblock Copolymer Foamsmentioning

confidence: 99%

“…Viscosity measurements in elongational flows were performed by Wang et al [41]. In the work of Chaudhary and Jayaraman [42] rheological experiments in melt elongation and foaming of polypropylene clay nanocomposites were performed. The authors showed that an increasing degree of strain-hardening along with slower crystallization of polypropylene was associated with a smaller cell size and a larger cell density.…”

Section: Introductionmentioning

confidence: 99%

Thermal properties, rheology and foams of polystyrene-block-poly(4-vinylpyridine) diblock copolymers

Schulze

Handge

Rangou

et al. 2015

Polymer

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of the original manuscript:Schulze, M.; Handge, U.A.; Rangou, S.; Lillepaerg, J.; Abetz, V.: Thermal properties, rheology and foams of polystyrene-blockpoly(4-vinylpyridine) diblock copolymers AbstractIn this study, the thermal and rheological properties of polystyrene-block-poly(4-vinylpyridine)(PS-b-P4VP) diblock copolymers are investigated in order to get information about the optimum foaming temperature. Foams of these diblock copolymers were prepared using the technique of batch foaming with carbon dioxide as environmentally-benign blowing agent. The tailored PS-b-P4VP diblock copolymers with different molecular weights and a cylindrical morphology were prepared and analysed regarding their thermal stability. High-pressure differential scanning calorimetry exposes the plasticising effect of the blowing agent which yields a decrease of the glass transition temperature of the polystyrene and the poly(4-vinylpyridine) blocks. Sorption measurements were performed in order to measure the uptake of carbon dioxide in the diblock copolymer. Additionally, rheological experiments in the oscillatory mode were conducted which confirmed a microphase-separated structure of the PS-b-P4VP diblock copolymers by a plateau of the storage and loss moduli in the temperature range of processing. In shear and melt elongation, the transient shear viscosity and the transient elongational viscosity were much smaller than the linear viscoelastic prediction. The analysis of the foam morphology revealed that the foam density of the diblock copolymers as measured via Archimedes` principle exhibits the lowest foam density at a molecular weight in the order of 160 kg mol -1 .

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Extrusion of linear polypropylene–clay nanocomposite foams

Cited by 53 publications

References 37 publications

Polypropylene–nano‐silica nanocomposite foams: mechanisms underlying foamability, and foam microstructure, crystallinity and mechanical properties

Polypropylene–nano‐silica nanocomposite foams: mechanisms underlying foamability, and foam microstructure, crystallinity and mechanical properties

The simultaneous effect of nucleating and blowing agents on the cellular structure of polypropylene foamed via the extrusion process

Thermal properties, rheology and foams of polystyrene-block-poly(4-vinylpyridine) diblock copolymers

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