Autoclave Foaming of Poly(ε-Caprolactone) Using Carbon Dioxide: Impact of Crystallization on Cell Structure

Reignier, Joël; Gendron, Richard; Champagne, Michel

doi:10.1177/0021955x07079591

Cited by 38 publications

(45 citation statements)

References 26 publications

(35 reference statements)

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“…[11,17,18] Making this process suitable for the incorporation of heat labile molecules within the scaffold before the foaming process may represent a great challenge in TE; [7,9] in this work we focused on the solid-state foaming of PCL and PCL-HA nanocomposite and performed the entire process at 37 8C.…”

Section: Resultsmentioning

confidence: 99%

Design of Bimodal PCL and PCL‐HA Nanocomposite Scaffolds by Two Step Depressurization During Solid‐state Supercritical CO₂ Foaming

Salerno

Zeppetelli

Maio

et al. 2011

Macromol. Rapid Commun.

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This communication reports the design and fabrication of porous scaffolds of poly(ε-caprolactone) (PCL) and PCL loaded with hydroxyapatite (HA) nanoparticles with bimodal pore size distributions by a two step depressurization solid-state supercritical CO(2) (scCO(2) ) foaming process. Results show that the pore structure features of the scaffolds are strongly affected by the thermal history of the starting polymeric materials and by the depressurization profile. In particular, PCL and PCL-HA nanocomposite scaffolds with bimodal and uniform pore size distributions are fabricated by quenching molten samples in liquid N(2) , solubilizing the scCO(2) at 37 °C and 20 MPa, and further releasing the blowing agent in two steps: (1) from 20 to 10 MPa at a slow depressurization rate, and (2) from 10 MPa to the ambient pressure at a fast depressurization rate. The biocompatibility of the bimodal scaffolds is finally evaluated by the in vitro culture of human mesenchymal stem cells (MSCs), in order to assess their potential for tissue engineering applications.

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Section: Resultsmentioning

confidence: 99%

Design of Bimodal PCL and PCL‐HA Nanocomposite Scaffolds by Two Step Depressurization During Solid‐state Supercritical CO₂ Foaming

Salerno

Zeppetelli

Maio

et al. 2011

Macromol. Rapid Commun.

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show abstract

“…Additionally, the presence of the crystal structure means the amount of CO 2 available for bubble growth decreased and the CO 2 concentration in the polymer blend remained higher. As a consequence, the dissolved CO 2 was used for cell nucleation and cell density increased . In blends with higher PLA contents, crystallinity is lower and the polymer receives more blowing agent during saturation because of a greater proportion of amorphous regions .…”

Section: Resultsmentioning

confidence: 99%

Biopolymer foams from Novatein thermoplastic protein and poly(lactic acid)

Walallavita

Verbeek

Lay

2017

J of Applied Polymer Sci

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A batch processing method is used to fabricate foams comprising of a blend of poly(lactic acid) (PLA) and Novatein, a protein-based thermoplastic. Various compositions of Novatein/PLA are prepared with and without a compatibilizer, PLA grafted with itaconic anhydride (PLA-g-IA). Pure Novatein cannot form a cellular structure at a foaming temperature of 80 8C, however, in a blend with 50 wt % of PLA, microcells form with smaller cell sizes (3.36 mm) and higher cell density (8.44 3 10 21 cells cm 23 ) compared to pure PLA and blends with higher amounts of PLA. The incorporation of 50 wt % of semicrystalline Novatein stiffens the amorphous PLA phase, which restrains cell coalescence and cell collapse in the blends. At a foaming temperature of 140 8C, NTP 30 -PLA 70 shows a unique interconnected porous morphology which can be attributed to the CO 2 -induced plasticization effect. V C 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45561.

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“…Based on the above analyses, the selected four PCL samples show varied thermal and rheological properties, which may be a favorable aspect for the morphological optimization of PCL scaffolds by providing rich choices. Previous studies have shown that for PCL, foaming at melt state, mild pressure and rapid depressurization are beneficial to acquire a favorable interconnected and macroporous structure [22][23][24][25]27]. Lian, Z. et al has reported that the −dTm/dP of PCL-CO 2 system within 10 MPa is 2.02 • C/MPa, according to the Clapeyron equation [40].…”

Section: Porous Morphology Of Pcl Scaffoldsmentioning

confidence: 99%

“…With the increase of foaming temperature, the foaming process shifts from a solid-state to a melt-state, which generally results in a relatively larger pore size and higher porosity of PCL foams [22]. However, excessive high foaming temperature can also lead to a visible collapse and dense phase of scaffolds [22][23][24][25]. Meanwhile, it has been reported that PCL foams tend to generate favorable macropores when processed under low foaming pressure [23,24,26].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of PCL Scaffolds by Supercritical CO2 Foaming Based on the Combined Effects of Rheological and Crystallization Properties

et al. 2020

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Polycaprolactone (PCL) scaffolds have recently been developed via efficient and green supercritical carbon dioxide (scCO2) melt-state foaming. However, previously reported gas-foamed scaffolds sometimes showed insufficient interconnectivity or pore size for tissue engineering. In this study, we have correlated the thermal and rheological properties of PCL scaffolds with their porous morphology by studying four foamed samples with varied molecular weight (MW), and particularly aimed to clarify the required properties for the fabrication of scaffolds with favorable interconnected macropores. DSC and rheological tests indicate that samples show a delayed crystallization and enhanced complex viscosity with the increasing of MW. After foaming, scaffolds (27 kDa in weight-average molecular weight) show a favorable morphology (pore size = 70–180 μm, porosity = 90% and interconnectivity = 96%), where the lowest melt strength favors the generation of interconnected macropore, and the most rapid crystallization provides proper foamability. The scaffolds (27 kDa) also possess the highest Young’s modulus. More importantly, owing to the sufficient room and favorable material transportation provided by highly interconnected macropores, cells onto the optimized scaffolds (27 kDa) perform vigorous proliferation and superior adhesion and ingrowth, indicating its potential for regeneration applications. Furthermore, our findings provide new insights into the morphological control of porous scaffolds fabricated by scCO2 foaming, and are highly relevant to a broader community that is focusing on polymer foaming.

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Autoclave Foaming of Poly(ε-Caprolactone) Using Carbon Dioxide: Impact of Crystallization on Cell Structure

Cited by 38 publications

References 26 publications

Design of Bimodal PCL and PCL‐HA Nanocomposite Scaffolds by Two Step Depressurization During Solid‐state Supercritical CO₂ Foaming

Design of Bimodal PCL and PCL‐HA Nanocomposite Scaffolds by Two Step Depressurization During Solid‐state Supercritical CO₂ Foaming

Biopolymer foams from Novatein thermoplastic protein and poly(lactic acid)

Fabrication of PCL Scaffolds by Supercritical CO2 Foaming Based on the Combined Effects of Rheological and Crystallization Properties

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Autoclave Foaming of Poly(ε-Caprolactone) Using Carbon Dioxide: Impact of Crystallization on Cell Structure

Cited by 38 publications

References 26 publications

Design of Bimodal PCL and PCL‐HA Nanocomposite Scaffolds by Two Step Depressurization During Solid‐state Supercritical CO2 Foaming

Design of Bimodal PCL and PCL‐HA Nanocomposite Scaffolds by Two Step Depressurization During Solid‐state Supercritical CO2 Foaming

Biopolymer foams from Novatein thermoplastic protein and poly(lactic acid)

Fabrication of PCL Scaffolds by Supercritical CO2 Foaming Based on the Combined Effects of Rheological and Crystallization Properties

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Product

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About

Design of Bimodal PCL and PCL‐HA Nanocomposite Scaffolds by Two Step Depressurization During Solid‐state Supercritical CO₂ Foaming

Design of Bimodal PCL and PCL‐HA Nanocomposite Scaffolds by Two Step Depressurization During Solid‐state Supercritical CO₂ Foaming