Environmentally Friendly Polylactic Acid-Based Thermal Insulation Foams Blown with Supercritical CO<sub>2</sub>

Gong, Pengjian; Zhai, Shuo; Lee, Richard; Zhao, Changzhi; Buahom, Piyapong; Li, Guangxian; Park, Chul

doi:10.1021/acs.iecr.7b05023

Cited by 52 publications

(38 citation statements)

References 48 publications

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“…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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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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“…To overcome these problems, attempts are being made to develop harmless and eco‐friendly thermal insulation materials. Specifically, polylactic acid (PLA), the biodegradable polymer with low thermal conductivity, when foamed for thermal insulation using supercritical CO 2 has a recorded thermal conductivity of about 30 mW/mK [ 1 ] ; however, this is still higher than that of EPS and PU foam. There are several methods to decrease the thermal conductivity of thermal insulation material, and one of them involves using micro or nanofibers.…”

Section: Introductionmentioning

confidence: 99%

Effect of ammonium polyphosphate and acrylic acid onNaCltreated electrospunPLAmicrofiber mat

Yoon

Jeon

et al. 2020

Polymer Engineering & Sci

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In this study, insulation material was developed using polylactic acid (PLA), which is one of the most widely-used biodegradable polymers. The PLA was fabricated into a fiber mat shape using the electrospinning method, and NaCl salt was added to achieve thinner fiber diameter. This fiber-based mat showed lower thermal conductivity than PLA blocks but had poor tensile strength and heat stability. To improve these mechanical and thermal properties, ammonium polyphosphate (APP) and acrylic acid (AA) were added; AA was used to better bond the APP with the polymer matrix. The APP/AA mixed PLA fiber mat showed improved performance overall; with the addition of these materials, the thermal conductivity was about 35 mW/mK, which was slightly lower than before, the tensile stress improved about two times. Thermal stability was also augmented as the increase in the weight percentage of the sample residue after the thermogravimetric analysis indicated.

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“…Polymer foams have become one of such material types due to their advantages including low thermal conductivity, light weight, high strength, good weatherability, and low cost . As thermal insulation materials, polymer foams are playing an increasingly significant role in many fields such as construction, transportation, packaging, automobile, and aerospace industries …”

Section: Introductionmentioning

confidence: 99%

Thermal‐Insulation, Electrical, and Mechanical Properties of Highly‐Expanded PMMA/MWCNT Nanocomposite Foams Fabricated by Supercritical CO₂ Foaming

Zhao

Wang

et al. 2019

Macro Materials & Eng

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Poly(methyl methacrylate) (PMMA) foams exhibit many advantages over the most popular polystyrene (PS) foams, which make them an ideal candidate for thermal insulation application. First, PMMA has lower carbon content, lower burning rate, smaller heat release rate, and lower smoke emission than PS. [7] So, PMMA foams need less flame retardants than PS foams when used as construction thermal insulation materials, which helps reduce the overall production costs and mitigate the greenhouse effect. Second, PMMA can strongly absorb infrared light in the wavelength range of 2.8-25 µm, [8] while PS can hardly absorb infrared light. Thus, the low-density PMMA foams are expected to block more thermal radiations than the PS foams with the same density. Third, PMMA has higher CO 2 solubility than PS because the carbonyl group in PMMA has stronger adsorption capacity for CO 2 than the benzene ring in PS. [9] The higher CO 2 solubility makes it much easier to prepare low-density PMMA foam, enhancing foam's thermal insulation. Carbon nanotubes (CNTs) with unique electrical, mechanical, and thermal properties have exhibited great value in designing electrical conductive composites, [10,11] electromagnetic interference shielding, [12,13] and energy harvesting materials. [14] These excellent properties of CNTs also make them ideal fillers to design polymer foams for some important reasons. First, CNTs are excellent heterogeneous nucleating agent to increase the cell density. Cell nucleation is more likely to occur at the interfaces between fillers and polymer matrix because of the relatively low free energy barrier for heterogeneous nucleation. [15][16][17] Due to their high aspect ratio and specific area, uniformly dispersed CNTs can offer much more interfaces as the heterogeneous nucleation sites than many other spherical (i.e., nano SiO 2 [18] ) or lamellar fillers (i.e., nano clay [19] ). Moreover, CNTs can endow the polymer foams with multifunctionality by offering the same advantages that they offer in the bulk while not decreasing foam's other properties. For example, CNTs are one kind of good wave-absorbing material that can be recognized as black bodies. In electromagnetic fields, CNTs can attenuate electromagnetic radiation by forming a conductive network (conductivity loss), [12,20] or by the polarization of CNT/polymer interfaces (dielectric loss), [21,22] or by scattering and multiple Polymer Nanocomposite Foaming behavior of poly(methyl methacrylate) (PMMA)/multi-walled carbon nanotubes (MWCNTs) nanocomposites and thermally-insulating, electrical, and mechanical properties of the nanocomposite foams are investigated. PMMA/MWCNT nanocomposites containing various amounts of MWCNTs are first prepared by combining solution and melt blending methods, and then foamed using CO 2 . The foaming temperature and MWCNT content are varied for regulating the structure of PMMA/MWCNT nanocomposite foams. The electrical conductivity measurement results show that MWCNTs have little effect on the electrical conductivity of foams with l...

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Environmentally Friendly Polylactic Acid-Based Thermal Insulation Foams Blown with Supercritical CO₂

Cited by 52 publications

References 48 publications

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

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

Effect of ammonium polyphosphate and acrylic acid onNaCltreated electrospunPLAmicrofiber mat

Thermal‐Insulation, Electrical, and Mechanical Properties of Highly‐Expanded PMMA/MWCNT Nanocomposite Foams Fabricated by Supercritical CO₂ Foaming

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Environmentally Friendly Polylactic Acid-Based Thermal Insulation Foams Blown with Supercritical CO2

Cited by 52 publications

References 48 publications

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

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

Effect of ammonium polyphosphate and acrylic acid onNaCltreated electrospunPLAmicrofiber mat

Thermal‐Insulation, Electrical, and Mechanical Properties of Highly‐Expanded PMMA/MWCNT Nanocomposite Foams Fabricated by Supercritical CO2 Foaming

Contact Info

Product

Resources

About

Environmentally Friendly Polylactic Acid-Based Thermal Insulation Foams Blown with Supercritical CO₂

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

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

Thermal‐Insulation, Electrical, and Mechanical Properties of Highly‐Expanded PMMA/MWCNT Nanocomposite Foams Fabricated by Supercritical CO₂ Foaming