Novel approach based on autoclave bead foaming to produce expanded polycarbonate (EPC) bead foams with microcellular structure and controlled crystallinity

Sánchez-Calderón, Ismael; Bernardo, Victoria; León, Judith Martín‐de; Rodríguez‐Pérez, Miguel Ángel

doi:10.1016/j.matdes.2021.110200

Cited by 14 publications

(8 citation statements)

References 24 publications

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“…58 During the process of cell growth, the merging of cells occurred owing to the intersqueezing effects of expandable PC beads. 32 Consequently, this led to the formation of large bubbles, also resulting in a high expansion ratio. However, with a further increase in temperature, the viscosity and melt strength of the polymer decreased drastically, making it easier for the bubbles to collapse and yielding reductions in cell diameters.…”

Section: Sem Morphology Observationsmentioning

confidence: 99%

Microwave-Induced Facile Molding of Lightweight and High-Strength Segregated-CNTs/Polycarbonate Foams

Yang,

Feng,

et al. 2024

Ind. Eng. Chem. Res.

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Polymer foams have attracted great attention in various fields due to the excellent properties brought by their unique microporous structures. However, the severe thermal stability of commodity thermoplastic polymer and foams hindered them from high-end applications. Polycarbonate (PC) is a widely recognized engineering plastic with an amorphous structure. Herein, a facile technique was proposed for preparing lightweight and high-strength segregated-CNTs/PC foams by microwaveinduced selective heating and molding. The microstructures, mechanical properties, thermal properties, and sinter molding behaviors of the CNTs/PC foams were studied by investigating the effects of microwave power, irradiation time, and microwave absorbent contents. Upon in situ molding of the CNTs-coated expandable PC granules inside microwave transparent molds of various geometric shapes, CNTs served as solders to form CNTs/ PC foam. By modifying the foaming parameters, CNTs/PC foams with densities ranging from 0.19 to 0.27 g/cm 3 and cell sizes of 5−25 μm were successfully obtained. Mechanical testing revealing that the CNTs/PC foam prepared under 2880 W microwave power and a welding time of 25 s exhibited the optimal expansion ratio. Under the ablation test, the CNTs/PC foams showed good heat insulation. This study opens a new direction for the molding of high-performance and engineering thermoplastic foams.

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Section: Sem Morphology Observationsmentioning

confidence: 99%

Microwave-Induced Facile Molding of Lightweight and High-Strength Segregated-CNTs/Polycarbonate Foams

Yang,

Feng,

et al. 2024

Ind. Eng. Chem. Res.

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“…Therefore, it is necessary to study a simple and rapid method to improve the melt strength and CO 2 concentration of PET, and finally obtain high‐strength PET foam with a high expansion ratio and to study the foaming behavior of the PET blend systematically. Polycarbonate (PC) is a well‐known engineering thermoplastic that is widely used in industry due to its versatility (excellent mechanical properties, insulation resistance and heat resistance), environment‐friendly process ability and recyclability 35,36 . In addition, due to its high molecular chain rigidity, PC possess high melt strength.…”

Section: Introductionmentioning

confidence: 99%

“…Polycarbonate (PC) is a well-known engineering thermoplastic that is widely used in industry due to its versatility (excellent mechanical properties, insulation resistance and heat resistance), environment-friendly process ability and recyclability. 35,36 In addition, due to its high molecular chain rigidity, PC possess high melt strength. Supercritical CO 2 foaming technology is now commonly used in foam production, which is cheap, non-toxic, and environmentally friendly.…”

mentioning

confidence: 99%

Foaming behaviors and mechanical properties investigation of high‐strength polyethylene terephthalate/polycarbonate bead foam

Wang,

Xu,

Bai

et al. 2023

J of Applied Polymer Sci

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Due to the low melt strength, PET foam cells easily grow, and due to the low CO2 concentration in PET, generating more nucleation sites during the foaming process is difficult. As a result, PET foam produced using the supercritical CO2 foaming method possesses a large cell size and a low expansion ratio, which leads to poor mechanical performance. In addition, there has not been much research on how to improve CO2 concentration in PET. In this work, the PC with higher melt strength and CO2 absorption capacity was incorporated into the PET matrix to improve the foaming behaviors of the blend. The results showed that the melt strength and CO2 concentration of PET/PC blends are much higher than that of pure PET. For instance, the melt strength and CO2 concentration of the PET/PC10 blend would be more than twice that of pure PET when the PC content is only 10%wt. By studying the foaming behavior, it was found that high melt strength inhibited the cell overgrowth and collapse of PET/PC foam, resulting in the foam with good cell structure was obtained. In addition, the high CO2 concentration in PET/PC blend is conducive to cell nucleation, thereby increasing the foam expansion ratio during the CO2 foaming process. Finally, the PET/PC blend foam with excellent mechanical properties was obtained. To be specific, the expansion ratio of the PET/PC blend foam was about 9.61, and the average cell size was only 40.38 μm. And the PET/PC blend foam possessed an excellent compressive strength of 7.41 MPa due to the strong interfacial bead cohesion, which showed the application prospect in the field of construction engineering.

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“…Polymer foams with excellent micro/nanocellular structure are widely used in electronics, the automotive industry, the aerospace industry, packaging, building construction, and medical applications because of their lightweight, good mechanical strength, and high thermal insulation properties. − Recently, foaming of polymer blends has received extensive attention within both scientific and industrial communities because it can well integrate the diverse properties of different polymers into a hybrid foam, which cannot be obtained with conventional homopolymer foam materials. − However, most polymer blends are thermodynamically immiscible because of the low mixing entropy of polymer chains and unfavorable enthalpic interaction between the components. , As a result, poor interfacial interaction and unstable morphologies are often presented in polymer blends, leading to the formation of large domains that seriously restrict their foaming behavior and mechanical performance. Therefore, enhancing interfacial adhesion and strength is very essential for the improvement of foamability and end-use properties of polymer blends.…”

Section: Introductionmentioning

confidence: 99%

Strengthening Interfacial Adhesion and Foamability of Immiscible Polymer Blends via Rationally Designed Reactive Macromolecular Compatibilizers

Wang

Zhang

Wang

et al. 2022

ACS Appl. Mater. Interfaces

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Foams made of immiscible polymer blends have attracted great interest in both academia and industry, because of the integration of desirable properties of different polymers in a hybrid foam. However, the foamability and end-use properties are hampered because of the poor interfacial strength within the immiscible blends. Furthermore, few investigations have been carried out on the mechanisms by which interfacial strength and structure affect the foamability of polymer blends. In this work, two different reactive interfacial compatibilizers, i.e., poly(styrene-coglycidyl methacrylate)-graf t-poly(L-lactide) and poly(styrene-coglycidyl methacry-late)-graf t-poly(D-lactide), abbreviated as SG-g-PLLA and SG-g-PDLA, respectively, were designed and synthesized through reactive melt blending and subsequently applied to strengthen the interfacial strength and foamability of immiscible poly(butylene adipate-co-terephthalate) (PBAT)/poly(L-lactide) (PLLA) blends. Both compatibilizers could remarkably enhance the interfacial strength and foamability of the PBAT/PLLA blends, as evidenced by the significantly elongated dispersed phase in the resulting cocontinuous phase and more than 7000-fold increase in the cell density. Furthermore, the improved foamability was quantitively explained by the reduced gas diffusion and increased melt strength. Strikingly, the SG-g-PDLA introduced a stereocomplex crystal at the interface (i-SC), providing highly strengthened interfaces and nanoscale heterogeneous nucleation sites, which led to an energetically favorable cell nucleation. Moreover, foams with specifically laminated cell structures were fabricated by combining pressure-induced flow processing and i-SC strengthened interfaces. This work provides insight into the relationship between interfacial strength and formability of immiscible polymer blends and offers new possibilities for controlling cell morphologies and designing unique cell structures for polymer foams.

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Novel approach based on autoclave bead foaming to produce expanded polycarbonate (EPC) bead foams with microcellular structure and controlled crystallinity

Cited by 14 publications

References 24 publications

Microwave-Induced Facile Molding of Lightweight and High-Strength Segregated-CNTs/Polycarbonate Foams

Microwave-Induced Facile Molding of Lightweight and High-Strength Segregated-CNTs/Polycarbonate Foams

Foaming behaviors and mechanical properties investigation of high‐strength polyethylene terephthalate/polycarbonate bead foam

Strengthening Interfacial Adhesion and Foamability of Immiscible Polymer Blends via Rationally Designed Reactive Macromolecular Compatibilizers

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