Mechanism of bubble nucleation in poly(ε-caprolactone) foaming at low temperature

Wang, Linyan; Zhou, Hongfu; Wang, Xiangdong; Mi, Jianguo

doi:10.1016/j.polymer.2015.10.012

Cited by 8 publications

(5 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Studies have shown that large pores with a diameter greater than 100 µm are useful for stem cell adhesion, proliferation, and migration, whereas small pores with a diameter ranging from 1 to 50 µm are useful for transporting nutrients and waste within the scaffold [219]. In addition, an interconnected porosity to allow for the vascularization and diffusion of nutrients, besides an adequate pore size to promote cell adhesion, is an essential characteristic when considering tissue engineering applications [18,305]. The pore size range most suitable for cell culture depends on the material and the type of cell, but for the case of bone generation, the suitable pore size is between 100 and 400 µm [306].…”

Section: Poly(ε-caprolactone) (Pcl)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

View full text Add to dashboard Cite

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.

show abstract

Section: Poly(ε-caprolactone) (Pcl)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

View full text Add to dashboard Cite

show abstract

“…In the present investigation, CO 2 is modeled as a spherical molecule, and the LJ parameters (σ CO 2 = 3.94 Å and ε CO 2 = 1.62 kJ/mol) are taken from ref without any adjustment. Such parameters have been tested to be suitable for polymer–CO 2 systems . Meanwhile, polymers are modeled as semiflexible chains with 100 repeat monomers.…”

Section: Theoretical Sectionmentioning

confidence: 99%

“…Such parameters have been tested to be suitable for polymer−CO 2 systems. 42 Meanwhile, polymers are modeled as semiflexible chains with 100 repeat monomers. Our calculations reveal that, once the number of repeat units reaches 100, the effect of chain length on the CO 2 solubility is trivial.…”

Section: Theoretical Sectionmentioning

confidence: 99%

Modeling Solubility and Interfacial Properties of Carbon Dioxide Dissolved in Polymers

Wang

Zhou

Wang

et al. 2016

Ind. Eng. Chem. Res.

Self Cite

View full text Add to dashboard Cite

A classical density functional theory approach has been applied to evaluate the solubility and interfacial properties of CO 2 dissolved in poly(methyl methacrylate) (PMMA) and polystyrene (PS) matrices quantitatively. Apart from the freeenergy functional for hard-sphere reference given by the fundamental measure theory, a weighted free-energy functional for attractive dispersion and the contributions of chain connectivity and conformation have been integrated into the theoretical model to improve its predictive capability. The force-field parameters are cited from the literature, except that the Lennard-Jones potentials of sites are regressed to reproduce the experimental gas−liquid phase equilibria of pure PMMA and PS. It is shown that, in the two systems, the current model provides reliable predictive results of solubilities, swelling ratios, and interfacial tensions, which are particularly important in the bubble nucleation during polymer foaming.

show abstract

“…Although these hypotheses are invaluable in providing accumulated experiences, they need further studies to verify the reliability. On the other hand, density functional theory (DFT) has achieved good performance in polymer foaming systems. − Within the theoretical framework, a bubble nucleation occurs in the actual environment, involving the local supersaturation of dissolved CO 2 and subsaturation of the polymer matrix as well as the interfacial tensions of bubble–melt–interface three-phase contact. The influence of experiment conditions, component characteristics, and interfacial structures on bubble nucleation can be calculated by minimizing the grand potential of the system.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of Heterogeneous Bubble Nucleation in Polymer Blend Foaming

Zhou

et al. 2021

J. Phys. Chem. B

Self Cite

View full text Add to dashboard Cite

A three-dimensional heterogeneous bubble nucleation model is constructed to provide a reasonable explanation at the molecular level for the foaming mechanism of polypropylene (PP) and polystyrene (PS) blends. CO2 solubilities and supersaturation rations are quantitatively calculated to help interpret the contribution of each phase of the blend in the CO2 dissolution stage. The spatial density profiles of polymer/CO2 binary melt around different polymer chains are presented to give an intuitive perspective to the thermodynamic driving force. The predicted interfacial tension and contact angles of critical bubbles provide valid evidence to distinguish the wettability of CO2 in different regions. The values of predicted free-energy barriers, critical radii, and nucleation number densities imply that bubbles that nucleate in the PP and PS blend interfacial region attached to the PS-rich phase achieve the smallest size and largest number density. The reliability of the theoretical model has been tested by partial available experimental data.

show abstract

Mechanism of bubble nucleation in poly(ε-caprolactone) foaming at low temperature

Cited by 8 publications

References 50 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

Modeling Solubility and Interfacial Properties of Carbon Dioxide Dissolved in Polymers

Mechanism of Heterogeneous Bubble Nucleation in Polymer Blend Foaming

Contact Info

Product

Resources

About