Comparison of melting and crystallization behaviors of polylactide under high-pressure CO2, N2, and He

Nofar, Mohammadreza; Tabatabaei, Alireza; Ameli, Amir; Park, Chul

doi:10.1063/1.4873791

Cited by 21 publications

(32 citation statements)

References 14 publications

(30 reference statements)

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“…However, excessive high pressure would induce a depression in the crystallinity, decreased density of amorphous phase, and conformational changes in the polymer matrix (Molinaro et al., 2015; Zhu et al., 2014). Higher pressure decreased the number of crystallites according to the Scherrier equation (Nofar et al., 2013). The X c value slightly increased while contacting with acetic acid solution during day 60 of storage irrespective of the high‐pressure treatment.…”

Section: Resultsmentioning

confidence: 99%

Migration kinetic of silver from polylactic acid nanocomposite film into acidic food simulant after different high‐pressure food processing

Zhu,

Fan,

Cheng

et al. 2021

Journal of Food Science

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The migration study of nano‐Ag migration from polylactic acid (PLA) films was studied. Samples treated by high‐pressure food processing (0, 100, 200, 300, and 400 MPa pressure) were soaked in acetic acid solution and incubated at 20 °C for 90 days. At the end of storage, nano‐Ag particles (AgNPs) migration from the PLA/AgNPs composite film treated under 200 MPa high pressure was the lowest. However, AgNPs migration was accelerated under 400 MPa high pressure. High‐pressure processing (200 MPa) could cause denser structure and higher crystallinity degree in films than other treatments. Lower amount of AgNPs induced a decline in the intensity of specific characteristic peaks. The diffraction peak intensity of α‐crystal for the film sample treated with 400 MPa was the lowest on day 60. The crystallization index of the PLA matrix changed with different high‐pressure processing. The result indicated that appropriate high‐pressure food processing could effectively suppress AgNPs migration from PLA‐based film while contacting with acidic acid food simulant. Practical Application The release of nanoparticles from food packaging material is a very important matter when the migration is concerned with regulatory and toxicity issues. The study described the migration kinetic of AgNPs from PLA nanocomposite film into acidic food simulant after different high‐pressure food processing. The results indicated that the PLA/AgNPs nanocomposite film was safe for acidic food after high‐pressure treatment.

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Section: Resultsmentioning

confidence: 99%

Migration kinetic of silver from polylactic acid nanocomposite film into acidic food simulant after different high‐pressure food processing

Zhu,

Fan,

Cheng

et al. 2021

Journal of Food Science

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“…The plasticizing effect of CO 2 facilitates the mobility of PLA molecules and then promote the growth rate of nucleated spherulites, thus forming large-sized spherulites. 2,[30][31][32] With raising the foaming pressure to 14 MPa, small-sized spherulites are formed. Similar phenomenon was observed by Park et al 30 and Yang et al 33 Park et al 30 reported that the PLA sample exposed to 6 MPa CO 2 pressure exhibits more crystallite content with a much smaller size compared with the sample exposed to 1.5 MPa.…”

Section: Effect Of Foaming Pressure On Cellular Structure In Constantmentioning

confidence: 99%

“…This may be attributed to higher concentration of CO 2 and its enhanced plasticizing effect to the PLA. 2,22,[30][31][32][33][34][35] Further raising the foaming pressure to 18 and 22 MPa, the spherulite size is further decreased and the entity (spherulite) is too small to be observed by SEM observation. Moreover, low PLA melt strength induces the rupture of more cells in the samples.…”

Section: Effect Of Foaming Pressure On Cellular Structure In Constantmentioning

confidence: 99%

Tuning cell structure and expansion ratio of thick-walled biodegradable poly(lactic acid) foams prepared using supercritical CO₂

Huang

2019

Journal of Cellular Plastics

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Thick-walled poly(lactic acid) samples are foamed using supercritical carbon dioxide as physical foaming agent over a wide saturation time range using a constant-temperature mode and a wide foaming pressure range using the constant-temperature mode and a varying-temperature mode. Using the constant-temperature mode, three regions with no-celled core and two regions with cells of different diameters appear on the fractured surfaces of the foamed samples prepared at 5 and 10 min saturation times, respectively, whereas a relatively uniform cellular structure is obtained at 20–180 min saturation times. Raising the foaming pressure can improve the cellular structure uniformity. Moreover, prolonging saturation time or raising foaming pressure results in rupture of more cell walls and so formation of open-celled structure to a certain extent. Using the varying-temperature mode, a bimodal cellular structure with stamen-like cells and a trimodal cellular structure with an extraordinarily high expansion ratio (76.2) are successively achieved during raising the foaming pressure (18–22 MPa). The formation mechanisms for the bimodal and trimodal cellular structures are analyzed based on the result of the foaming pressure effect on the cellular structure in the foamed poly(lactic acid) samples prepared using the constant-temperature mode.

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“…However, several drawbacks also limit the production and application of PLA products. These drawbacks include a low service temperature [ 22 ], low melt strength [ 20 , 23 , 24 , 25 , 26 , 27 ], and slow crystallization rate [ 28 , 29 , 30 , 31 ]. A relatively higher melt strength is normally required to sustain cell growth in the foaming processing, and the enhanced crystallization kinetics is needed during the final cell stabilization to avoid cell collapse and coalescence [ 28 , 30 ].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Desirable Porous Cell Structure Polylactide/Wood Flour Composite Foams Assisted by Chain Extender

Wang

Song

et al. 2017

Materials

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Polylactide (PLA)/wood flour composite foam were prepared through a batch foaming process. The effect of the chain extender on the crystallization behavior and dynamic rheological properties of the PLA/wood flour composites were investigated as well as the crystal structure and cell morphology of the composite foams. The incorporation of the chain extender enhanced the complex viscosity and storage modulus of PLA/wood flour composites, indicating the improved melt elasticity. The chain extender also led to a decreased crystallization rate and final crystallinity of PLA/wood flour composites. With an increasing chain extender content, a finer and more uniform cell structure was formed, and the expansion ratio of PLA/wood flour composite foams was much higher than without the chain extender. Compared to the unfoamed composites, the crystallinity of the foamed PLA/wood flour composites was improved and the crystal was loosely packed. However, the new crystalline form was not evident.

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Comparison of melting and crystallization behaviors of polylactide under high-pressure CO2, N2, and He

Cited by 21 publications

References 14 publications

Migration kinetic of silver from polylactic acid nanocomposite film into acidic food simulant after different high‐pressure food processing

Migration kinetic of silver from polylactic acid nanocomposite film into acidic food simulant after different high‐pressure food processing

Tuning cell structure and expansion ratio of thick-walled biodegradable poly(lactic acid) foams prepared using supercritical CO₂

Preparation of Desirable Porous Cell Structure Polylactide/Wood Flour Composite Foams Assisted by Chain Extender

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Comparison of melting and crystallization behaviors of polylactide under high-pressure CO2, N2, and He

Cited by 21 publications

References 14 publications

Migration kinetic of silver from polylactic acid nanocomposite film into acidic food simulant after different high‐pressure food processing

Migration kinetic of silver from polylactic acid nanocomposite film into acidic food simulant after different high‐pressure food processing

Tuning cell structure and expansion ratio of thick-walled biodegradable poly(lactic acid) foams prepared using supercritical CO2

Preparation of Desirable Porous Cell Structure Polylactide/Wood Flour Composite Foams Assisted by Chain Extender

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Product

Resources

About

Tuning cell structure and expansion ratio of thick-walled biodegradable poly(lactic acid) foams prepared using supercritical CO₂