Effect of CO<sub>2</sub> on the crystallization of poly(lactic acid) homo-crystallites <i>via</i> influencing the crystal structure of stereocomplex crystallites

Peng, Qianyun; Li, Shaojie; Liu, Feng; Liao, Xia; Li, Guangxian

doi:10.1039/d2ce01254e

Cited by 7 publications

(3 citation statements)

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“…It has been demonstrated that the foaming conditions, such as foaming temperature and time, blowing agent concentration, and saturation time, greatly affect the crystallinity, density, and dimensional stability of PLA foams [238]. Particularly, the dissolved gas used in foaming has great influence on the crystallization and melting behaviours of PLA [239,240]. Among the gases commonly used in PLA foaming, CO 2 is much more soluble in PLA compared to N 2 [39,76].…”

Section: Poly (Lactic Acid) (Pla)mentioning

confidence: 99%

Forefront Research of Foaming Strategies on Biodegradable Polymers and Their Composites by Thermal or Melt-Based Processing Technologies: Advances and Perspectives

Gonçalves,

Reis,

Fernandes

2024

Polymers

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The last few decades have witnessed significant advances in the development of polymeric-based foam materials. These materials find several practical applications in our daily lives due to their characteristic properties such as low density, thermal insulation, and porosity, which are important in packaging, in building construction, and in biomedical applications, respectively. The first foams with practical applications used polymeric materials of petrochemical origin. However, due to growing environmental concerns, considerable efforts have been made to replace some of these materials with biodegradable polymers. Foam processing has evolved greatly in recent years due to improvements in existing techniques, such as the use of supercritical fluids in extrusion foaming and foam injection moulding, as well as the advent or adaptation of existing techniques to produce foams, as in the case of the combination between additive manufacturing and foam technology. The use of supercritical CO2 is especially advantageous in the production of porous structures for biomedical applications, as CO2 is chemically inert and non-toxic; in addition, it allows for an easy tailoring of the pore structure through processing conditions. Biodegradable polymeric materials, despite their enormous advantages over petroleum-based materials, present some difficulties regarding their potential use in foaming, such as poor melt strength, slow crystallization rate, poor processability, low service temperature, low toughness, and high brittleness, which limits their field of application. Several strategies were developed to improve the melt strength, including the change in monomer composition and the use of chemical modifiers and chain extenders to extend the chain length or create a branched molecular structure, to increase the molecular weight and the viscosity of the polymer. The use of additives or fillers is also commonly used, as fillers can improve crystallization kinetics by acting as crystal-nucleating agents. Alternatively, biodegradable polymers can be blended with other biodegradable polymers to combine certain properties and to counteract certain limitations. This work therefore aims to provide the latest advances regarding the foaming of biodegradable polymers. It covers the main foaming techniques and their advances and reviews the uses of biodegradable polymers in foaming, focusing on the chemical changes of polymers that improve their foaming ability. Finally, the challenges as well as the main opportunities presented reinforce the market potential of the biodegradable polymer foam materials.

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Section: Poly (Lactic Acid) (Pla)mentioning

confidence: 99%

Forefront Research of Foaming Strategies on Biodegradable Polymers and Their Composites by Thermal or Melt-Based Processing Technologies: Advances and Perspectives

Gonçalves,

Reis,

Fernandes

2024

Polymers

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“…24,25 As a non-toxic, green and environmentally friendly solvent, carbon dioxide (CO 2 ) could penetrate into the molecular chain of polymer, act as a compatible diluent, reduce the concentration of the molecular chain, weaken the interactions between molecular chains and promote the movement of the molecular chain, thus affecting the crystallization of the polymer, which could alter the crystallization kinetics, crystal form and spherulite morphology of polymer. [26][27][28][29][30][31][32][33][34][35] Li et al 36 found that PEO-b-PCL formed common spherulites under air, and generated ring band spherulites under CO 2 . As CO 2 pressure increased, the formation mechanism of ring band spherulite changed from periodic twisting of lamellae to two-step growth.…”

Section: Introductionmentioning

confidence: 99%

“…In addition to introducing polymers as compatible diluents, organic solvents could also serve as compatible diluents to enhance the unbalanced stress of polymer, leading to form ring band spherulite 24,25 . As a non‐toxic, green and environmentally friendly solvent, carbon dioxide (CO 2 ) could penetrate into the molecular chain of polymer, act as a compatible diluent, reduce the concentration of the molecular chain, weaken the interactions between molecular chains and promote the movement of the molecular chain, thus affecting the crystallization of the polymer, which could alter the crystallization kinetics, crystal form and spherulite morphology of polymer 26–35 . Li et al 36 found that PEO‐b‐PCL formed common spherulites under air, and generated ring band spherulites under CO 2 .…”

Section: Introductionmentioning

confidence: 99%

Effect of carbon dioxide on lamellar arrangement in poly(lactic acid) ring band spherulites

Peng,

Li,

Liu

et al. 2023

Journal of Polymer Science

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In this research, the formation of ring band spherulite of poly(lactic acid) (PLA) under carbon dioxide (CO2) was in‐situ studied and the internal lamellar arrangement of ring band spherulite formed under CO2 was revealed for the first time. The spherulites by PLA crystallized under air and different CO2 pressures have been studied, and the surface and internal lamellar arrangement of the ring band spherulites have also been analyzed in detail. It was found that PLA would form ring band spherulite under air and 6 MPa CO2, while the internal structures of the two types of ring band spherulites were different. The surface height difference of ring band spherulites formed under air was small, at 278.9 nm, and the twisting angle of the lamellae was also small. However, the difference in the surface height of the ring band spherulite formed under 6 MPa CO2 was big, reaching 778.3 nm. Through analysis on the internal lamellar arrangement of the ring band spherulite, it was found that the valley for the ring band spherulites formed under 6 MPa CO2 was composed of flat‐on lamellae, the ridge was composed of edge‐on lamellae and the sudden twist occurred between the flat‐on lamellae and edge‐on lamellae.

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Optimization and regulation of alcohol-based co-foaming agents on foaming behavior of ultra-low dielectric constant polyarylene ether nitrile foam in supercritical CO2

Shi,

Tang,

Zhao

et al. 2024

Applied Materials Today

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Effect of CO₂ on the crystallization of poly(lactic acid) homo-crystallites via influencing the crystal structure of stereocomplex crystallites

Abstract: The crystallization of poly(lactic acid) (PLA) homo-crystallites (HC) and stereocomplex crystallites (SC) is quite complicated for the inducing and competing effects of SC on HC. Furthermore, carbon dioxide (CO2) would...

Cited by 7 publications

References 46 publications

Forefront Research of Foaming Strategies on Biodegradable Polymers and Their Composites by Thermal or Melt-Based Processing Technologies: Advances and Perspectives

Forefront Research of Foaming Strategies on Biodegradable Polymers and Their Composites by Thermal or Melt-Based Processing Technologies: Advances and Perspectives

Effect of carbon dioxide on lamellar arrangement in poly(lactic acid) ring band spherulites

Optimization and regulation of alcohol-based co-foaming agents on foaming behavior of ultra-low dielectric constant polyarylene ether nitrile foam in supercritical CO2

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Effect of CO2 on the crystallization of poly(lactic acid) homo-crystallites via influencing the crystal structure of stereocomplex crystallites

Abstract: The crystallization of poly(lactic acid) (PLA) homo-crystallites (HC) and stereocomplex crystallites (SC) is quite complicated for the inducing and competing effects of SC on HC. Furthermore, carbon dioxide (CO2) would...

Cited by 7 publications

References 46 publications

Forefront Research of Foaming Strategies on Biodegradable Polymers and Their Composites by Thermal or Melt-Based Processing Technologies: Advances and Perspectives

Forefront Research of Foaming Strategies on Biodegradable Polymers and Their Composites by Thermal or Melt-Based Processing Technologies: Advances and Perspectives

Effect of carbon dioxide on lamellar arrangement in poly(lactic acid) ring band spherulites

Optimization and regulation of alcohol-based co-foaming agents on foaming behavior of ultra-low dielectric constant polyarylene ether nitrile foam in supercritical CO2

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Product

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Effect of CO₂ on the crystallization of poly(lactic acid) homo-crystallites via influencing the crystal structure of stereocomplex crystallites