Preparation of lightweight PBS foams with high ductility and impact toughness by foam injection molding

Jiangbin Xu; Jinfu Xing; Mei Luo; Tingyu Li; Bujin Liu; Xiangbu Zeng; Tuanhui Jiang; Xian Wu; Li He

doi:10.1515/epoly-2024-0034

Artikel Open Access

Preparation of lightweight PBS foams with high ductility and impact toughness by foam injection molding

Jiangbin Xu , Jinfu Xing , Mei Luo , Tingyu Li , Bujin Liu , Xiangbu Zeng , Tuanhui Jiang , Xian Wu und Li He

Veröffentlicht/Copyright: 29. Juni 2024

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Abstract

Lightweight and highly tough polymer foams play a crucial role in resource conservation and environmental protection. One such biodegradable material that has garnered attention for its excellent processability and mechanical properties is polybutylene succinate (PBS). However, achieving PBS foams with superior mechanical properties remains a significant challenge. In this study, we prepared PBS foams with higher ductility and impact toughness using foam injection molding. The improved ductility of these foams can be attributed to the highly oriented cellular structure along the direction of the tensile load, transforming from regular circular shapes to tubular ones. This cellular structure effectively blunts crack tips, thereby enhancing impact performance. When the mold-opening distance is 0.4 mm, the fracture elongation of PBS foams is 486%, the tensile toughness is 4,586 MJ·cm⁻³, and the impact strength is 12.73 kJ·m⁻². These values are 98%, 53%, and 29% higher than those of unfoamed PBS, respectively. As the mold-opening distance increases, the relative density of PBS foams decreases, leading to a reduction in fracture elongation, tensile toughness, and impact strength. Interestingly, the specific impact strength of PBS foams consistently surpasses that of unfoamed PBS, and increases proportionally to the mold-opening distance.

Graphical abstract

Keywords: polybutylene succinate; foam injection molding; cell morphology; ductility; impact toughness

1 Introduction

Polymer foams not only save materials and reduce product weight, but also provide products with excellent properties such as sound insulation, thermal insulation, high specific strength, and insulation (1). However, plastic pollution is a growing concern due to the large accumulation of plastic waste in the natural environment over a long period of time (2). Therefore, biodegradable polymer foams are considered an effective solution to mitigate plastic pollution (3). Polybutylene succinate (PBS), one of the most important biodegradable polymers in the market, has attracted much attention due to its excellent processability, good heat resistance and high mechanical properties (4,5). PBS has a tensile strength of 30–35 MPa, comparable to polypropylene (19–45 MPa, with an average tensile strength of 32.7 MPa). Compared to polylactic acid (PLA), PBS has higher flexibility. Additionally, the melting point of PBS is 110–115°C, very close to that of low-density polyethylene (6). As a result, PBS foam is expected to be a partial replacement for petrochemical polymer foams in industries such as automotive parts, building materials, furniture and electronics (7).

Research on PBS foams has made some progress (8,9,10). And these studies have been devoted to the development of PBS composite foams by blending PBS with other materials (11,12,13,14), with the expectation of improving the foaming performance as well as the mechanical properties. The incorporation of nanofillers has proven beneficial, as it improves the melt strength of the polymer, promotes cell nucleation, and consequently enhances the foaming properties of PBS (15,16,17). Lim et al. (18) showed that adding an appropriate amount of carbon nanofiber (CNF) could improve the tensile strength of PBS/CNF composite foam, while the elongation at break decreased with the increase in CNF content. Zhou et al. (19) prepared PLA/PBS/organic montmorillonite (OMMT) composite foams. Their findings revealed that the addition of 3% OMMT significantly enhanced the impact and tensile strength of the composite foams. However, as the OMMT content increased further, the mechanical properties instead decreased. This can be attributed to the higher surface energy of nanofillers, which tend to agglomerate when blended with polymers, resulting in lower foaming and mechanical properties. Chen et al. (20) conducted a comparison between PBS/polytetrafluoroethylene (PTFE) foams and PBS/PTFE unfoamed to evaluate their tensile properties. The study observed a significant decrease in tensile strength and tensile modulus with foaming. However, the elongation at break increased from 7% to 14%. The in situ fiber network structure formed by PTFE effectively restricted the relaxation of PBS molecular chains, thereby increasing melt strength and significantly improving foaming performance. Despite the potential of nanofillers to enhance the foaming and mechanical properties of PBS foams, the current technology faces challenges in achieving uniform dispersion in the polymer matrix. Consequently, it may not be a cost-effective approach for actual production (21).

A substantial amount of research indicates that cell morphology is closely associated with mechanical properties (22,23,24). For instance, Sun and Liang (25) developed a micro-layered foam with alternating skin/foam layers and observed a significant increase in tensile strength and elongation at break compared to single-layer foam sheets. Bao et al. (26) successfully prepared polystyrene (PS) foams with an oriented cell morphology using batch foaming process. The study revealed that the oriented cell morphology perpendicular to the impact direction can greatly absorb energy, resulting in a significant increase in the impact strength of PS foams. According to Wang et al. (21), the thickness of the solid skin layer has a positive effect on the elongation at break and tensile toughness. However, the cell density does not have a significant impact on the elongation at break. Additionally, higher relative density in polymer foams has been shown to greatly enhance impact performance and tensile properties (27,28,29,30). Miller and Kumar (31) conducted a study on microcellular and nanocellular foams, revealing that nanocellular foams significantly improve tensile and impact properties, with consistently higher impact strength than solid components and microcellular foams. However, microcellular foams consistently exhibit lower mechanical properties compared to solid components. Although supercritical batch foaming can produce foams with extremely small cell sizes, even nanocellular structures, leading to improved mechanical properties that surpass those of solid components, it requires specialized equipment. Therefore, foam injection molding remains the preferred industrial method for polymer foam production.

Foam injection molding has found widespread application in the foam product manufacturing industry due to its exceptional processing flexibility, low energy consumption, high efficiency, and the capacity to produce intricately structured products (32,33). In the past, foam injection molding used closed mold cavities, which not only resulted in very limited weight reduction but also led to unsatisfactory surface quality of foamed products (34). In response to this challenge, a groundbreaking core-back foam injection molding technology has emerged.

During the foaming process, polymer melt/gas forms a homogeneous system under high pressure in the mold cavity after filling. Subsequently, precise core retreat programming causes the mold to open to a specific distance, resulting in a rapid pressure drop. This pressure fluctuation induces thermodynamic instability, leading to the generation of numerous stable foam cell nuclei (35,36). Following this, a substantial amount of gas infiltrates these foam cell nuclei, propelling the expansion of the foam cells. Ultimately, as the gas is consumed and the melt temperature decreases, the viscosity gradually rises, significantly boosting the growth resistance of the foam cells and solidifying their shape. Consequently, the introduction of core-back foam molding technology effectively segregates the polymer melt filling from the foaming process, facilitating the production of foamed products with a more refined foam cell structure. Moreover, through core retreat programming, a wider space is allocated for the development and expansion of foam cells, thereby greatly enhancing the weight reduction effect of foamed plastics.

However, there is limited research on preparing PBS foams using foam injection molding due to the linear structure of PBS molecular chains, which makes them prone to untangling. Additionally, foam injection molding requires higher processing temperatures (37), leading to a decrease in the melt strength and viscosity of PBS. This makes it easier for the cells to merge and collapse during the foaming process. Therefore, achieving PBS foam with excellent foaming and mechanical properties through foam injection molding poses a significant challenge. To address this, Ykhlef and Lafranche (38) investigated the effect of different molecular structures on the foaming properties of PBS by preparing linear PBS (L-PBS), ramified/branched PBS (B-PBS), and semi-networked PBS (C-PBS) foams using foam injection molding. Their findings suggested that higher strain hardening and viscosity could enhance cell growth resistance and optimize foaming performance. Kittipong et al. (39) used azodicarbonamide (ADC) as a foaming agent to prepare PLA/PBS/activated carbon composite foam through injection molding process. The results showed that as the PBS content increased from 0% to 100%, the tensile strength decreased from 33 MPa to 24 MPa, and the elongation at break increased from 3% to 10%. Furthermore, when the PBS content exceeded 40%, the foaming performance gradually improved with further increase in PBS content. Subsequently, Campuzano and Lopex (40) similarly used chemical injection foaming to prepare PLA/PBS (40/60) composite foam. However, due to poor compatibility between the two phases, this led to a decrease in tensile and impact performance. Although PBS foams with excellent impact strength and toughness have promising applications, previous research has shown that it is challenging to prepare polymer foams with higher impact performance and elongation than solid products (41,42). Consequently, further research on PBS foam based on foam injection molding process and the preparation of PBS foam with excellent foaming and mechanical properties is of great significance for expanding its application areas.

This study successfully prepared PBS foams with varying weight reductions using ADC as the blowing agent through foam injection molding. The results showed that these PBS foams not only had reduced weight but also demonstrated improved impact properties and ductility compared to unfoamed PBS. In order to understand these findings, the micromorphology of tensile and impact specimens was analyzed using scanning electron microscope (SEM), and the mechanism behind the enhancement of ductility and impact properties was discussed.

2 Materials and methods

2.1 Materials

PBS (TH803S, melting temperature 114℃, Melt index is 5–8 g per 10 min [190℃, 2.16 kg]) purchased from Lanshan Tunhe Co., Ltd in Xinjiang, China. The foaming agent azodicarbonamide, with a gas yield of approximately 230 mL·g⁻¹, was provided by Wuhan Hanhong Chemical Plant, China.

2.2 Preparation of PBS foams

The dried PBS was evenly mixed with 0.8 wt% ADC foaming agent and added to the injection molding machine (EM120-V, Guangdong Zhende Plastic Machinery Co., Ltd, China). Subsequently, the foamed samples were obtained through core-back technology (Figure 1). Generally, core-back injection foaming process includes key steps such as injection, core-back, and cooling molding (43). During the foaming process, the gas generated from the decomposition of ADC blowing agent and PBS form a uniform mixture under the shearing action of the screw. Then, this mixture was injected into the mold cavity at a higher injection pressure to ensure that the mold cavity is completely filled. Subsequently, the mold cavity expands a certain distance along the thickness direction of the foaming sample through core-back, leading to a rapid decrease in melt pressure. This instantaneous significant pressure drop is the key triggering factor for nucleation and growth of cells, and helps to achieve a fine cell structure. Finally, the melt inside the mold rapidly cools, the cell growth stops, and a typical sandwich structure is formed (42). The specific injection parameters are listed in Table 1. A sample without the addition of an ADC foaming agent and with a thickness of 4 mm was considered as unfoamed PBS.

Figure 1

(a) Schematic diagram of mold-opening foam injection molding. (b) PBS foam samples.

Table 1

Process conditions used in microcellular injection molding

Parameters	Values
Mold temperature (℃)	50
Melt temperature (℃)	160
Mold-opening distance (mm)	0.4, 0.6, 0.8, 1
Cooling time (s)	35
Injection time (s)	0.6
Injection speed (mL·s⁻¹)	77
Injection pressure (MPa)	137

2.3 Testing and characterization

2.3.1 Mechanical properties testing

The tensile properties were evaluated using an electronic universal testing machine (CMT 6104, MTS Industrial Systems (China) Co., Ltd) in accordance with GB/T 1040.2-2006. The standard dimensions of the dumbbell-shaped sample are as shown in Figure 1b. The tests were conducted at a consistent tensile speed of 50 mm·min⁻¹. The reported values represent the average of five measurements.

According to the national standard GB/T1843, a cantilever beam notched impact test was conducted using a pendulum-type impact testing machine (ZBC-4B, Shenzhen Xin Sansi Measurement Technology Co., Ltd, China). The impact energy of the pendulum is 2.75 J. Prior to the impact test, all samples of size 80 × 10 × 4 mm³ were notched using a notching machine (Matest Industrial Systems (China) Co., Ltd) to create a “V”-shaped notch with a depth of 2 mm. The reported values are the averages of ten measurements. In order to further investigate the effect of mold opening distance on the mechanical properties of foamed samples, this study specifically introduces tensile toughness, specific tensile strength, and specific impact strength. The specific calculation formulas are as follows:

Toughness is the integral area enclosed by the stress–strain curve and the abscissa

(1) ∫ 0 ε b σ ( ε ) d ε

Specific tensile strength is the ratio of tensile strength to density

(2) σ s = σ ρ

Specific impact strength is the ratio of impact strength to density

(3) I s = I ρ

where σ(ε) is the function relationship between stress and strain; ε _b is the fracture tensile strain; σ _s is the Specific tensile strength, MPa·g⁻¹·cm⁻³; σ is the tensile strength, MPa; ρ is the density of sample, g·cm⁻³; I _s is the specific impact strength, Jm·kg⁻¹; and I is the impact strength, kJ·m⁻².

2.3.2 Cell morphology characterization

The foam samples were submerged and frozen in liquid nitrogen for 4 h, followed by low-temperature fracturing and gold sputtering of the fracture surfaces. The morphology of cellular structures in PBS foam materials was observed using a SEM (EM 6200, Beijing Zhongke Instrument Co., Ltd, China). The cell size and cell density of the foams were calculated using Image Plus software. The cell size and cell density was calculated using the following formula:

(4) D = ∑ i = 1 n d i n

(5) N 0 = n A 3 2 V f

(6) V f = ρ 0 ρ f

where D is the average cell size, µm; d _i is the size of a single cell, µm; n is the number of cells in the SEM image; N ₀ is the cell density, cells·cm⁻³; V _f is the volume expansion ratio of the foam; ρ 0 and ρ f are the apparent densities of samples before and after foaming process; and A is the micrograph area, cm².

2.3.3 Density testing

The density of the samples is measured using the Archimedes method and the drainage density measurement mode of the XS205 precision analytical balance (Mettler Toledo, Switzerland), according to the measurement standard GB1033-86. The density of five samples in each group is measured to calculate the average value, which is recorded as the density of that group.

3 Results and discussion

3.1 Foaming performance of PBS foams

The mold-opening distance plays a crucial role in the production and application of injection molded foams, especially when aiming for high weight reduction ratio. Figure 2 illustrates the cellular structure and cell size distribution of PBS foams at different mold-opening distances. As the distance of the mold opening increases, the size of the cells first decreases and then increases. Meanwhile, the cell density first increases and then decreases (Figure 4a). Specifically, when the mold opening distance is 0.8 mm, the cell size is 31.74 µm, and the cell density is 1.24 × 10⁷ cells·cm⁻³. At this point, the foaming performance is optimal. This can be attributed to the significant influence of the mold opening distance on the cell nucleation process. As shown in Figure 3a, when the mold-opening distance is small, the pressure in the mold cavity may not be fully released, resulting in limited pressure drop and insufficient driving force for nucleation (44). As a result, only a limited number of cell nuclei are formed, and a large amount of gas enters these nuclei from the melt. Therefore, the number of cells decreases, and cell size increases. As shown in Figure 3b and c, when the mold-opening distance increases, the pressure in the cavity is more fully released, resulting in sufficient pressure drop and a significant increase in driving force for nucleation, this leads to a significant increase in the number of cells and a corresponding decrease in cell size. However, when the mold-opening distance increases to 1 mm, the cells continue to enlarge, leading to an increased foaming ratio. Additionally, the probability of compression and merging between cells also increases (45). Consequently, the cell size becomes larger and the cell density decreases.

Figure 2

Histograms of the cellular structure and cell size distribution of PBS foams at different mold-opening distances: (a) and (a1) 0.4 mm, (b) and (b1) 0.6 mm, (c) and (c1) 0.8 mm, and (d) and (d1) 1 mm.

Figure 3

PBS foams at different mold-opening distances: (a) cell size and cell density; (b) density and relative density; and (c) weight reduction ratio.

Figure 4

Schematic diagram of the cell morphology evolution of the PBS foams at different mold-opening distances: (a) 0.4 mm, (b) 0.6 mm, (c) 0.8 mm, and (d) 1 mm.

In combination with Figure 4b and c, it can be observed that the density of PBS foam decreases as the mold-opening distance increases. The relative density is determined by comparing the density of the PBS sample to that of unfoamed PBS, where the relative density of unfoamed PBS is 1 mm. As the mold-opening distance increases, the weight loss rate of PBS also increases, resulting in a gradual decrease in the relative density of PBS foams. These findings indicate that increasing the mold-opening distance effectively reduces the resistance to cell growth and enhances the foam ratio (46).

3.2 Tensile properties of PBS foams

Tensile tests were conducted to assess the tensile properties of both unfoamed and foamed PBS. Figure 5a presents the stress–strain curves, indicating that both unfoamed PBS and PBS foams exhibited plastic deformation and typical ductile fracture during the tensile process. The fracture behavior was characterized by evident yielding and necking. As the mold-opening distance gradually increased, several changes were observed: the relative density of PBS foams decreased, the weight loss increased, and the unfoamed region responsible for load support decreased. Consequently, the tensile strength decreased with the increase in the mold-opening distance and remained lower than that of unfoamed PBS (Figure 5b). However, the elongation at break of PBS foams increased from 245% to 486%, indicating a significant improvement in their ductility, which corresponds to a 98% increase compared to unfoamed PBS. The decrease in relative density and increase in weight loss with the increase in the mold-opening distance led to a decrease in the elongation at break (31,47). Nevertheless, the elongation at break still remained relatively high, suggesting that foaming effectively enhances the ductility of PBS. This can be attributed to the plastic deformation of a large number of cells in the PBS foams when subjected to tensile stress, which effectively disperses the stress, reduces stress concentration, and hinders crack propagation. The tensile toughness is presented in Figure 5c. The tensile toughness increased from 2,995 to 4,586 MJ·cm⁻³, a 53% increase, when the mold-opening distance was 0.4 mm compared to unfoamed PBS. Although the tensile strength of PBS foams significantly decreased compared to unfoamed PBS, the tensile toughness was notably enhanced. The increase in tensile toughness of PBS foams is primarily influenced by the significant improvement in the elongation at break. To comprehensively evaluate the tensile properties and weight reduction effect of PBS foams, Figure 5d demonstrates the specific tensile strength. Compared to unfoamed PBS, the specific tensile strength of PBS foam is significantly reduced due to the significant decrease in tensile strength after foaming.

Figure 5

PBS unfoamed and PBS foams at different mold-opening distances: (a) tensile stress–strain; (b) tensile performance; (c) tensile toughness; and (d) specific tensile strength.

Research on cell morphology contributes to the explanation of the toughening mechanism of PBS foams. Figure 6 shows SEM images of the sample interior along the tensile load direction for unfoamed PBS and PBS foams at different mold-opening distances. Unfoamed PBS developed numerous cracks along the stretching direction, while the cells in the PBS foams underwent severe deformation and became highly oriented in the tensile load direction. Analyzing the reasons, as shown in Figure 7, the cells display a regular circular shape when no tensile stress is applied. During the initial stage of the tensile test, the cells gradually change into an elliptical shape. After reaching the yield point, the neck region of all the specimens begins to deform in a concentrated manner, exhibiting necking. The cells then undergo more intense plastic deformation, being stretched from their initial circular shape into a tubular form. The cells become highly oriented along the tensile load direction, accompanied by a gradual reduction in the thickness of the cell walls as well as the merging of cells. The orientation of the cells along the stretching direction and the plastic deformation can not only blunt the propagation of cracks but also effectively reduce stress concentration, leading to an improvement in the ductility of the PBS foams (48). In the later stages of the necking phase, localized cracks occur in the PBS foams due to intensified stress concentration. Under tensile stress, the cell walls undergo ductile tearing, resulting in the deformation of cells on the tensile fracture surface and the stretching and yielding of the cell walls. This is depicted in Figure 8.

Figure 6

SEM images of sample interior along the tensile load direction for PBS unfoamed and PBS foams at different mold-opening distances: (a, a1) PBS unfoamed; (b) 0.4 mm; (c) 0.6 mm; (d) 0.8 mm; and (e) 1 mm.

Figure 7

Schematic diagram of changes in cell morphology during tensile testing.

$Figure 8 The tensile fracture surfaces of unfoamed PBS and PBS foams at different mold-opening distances; (a) PBS unfoamed; (b) 0.4 mm; (c) 0.6 mm; (d) 0.8 mm; and (e) 1 mm.$

Figure 8

The tensile fracture surfaces of unfoamed PBS and PBS foams at different mold-opening distances; (a) PBS unfoamed; (b) 0.4 mm; (c) 0.6 mm; (d) 0.8 mm; and (e) 1 mm.

3.3 Impact properties of PBS foams

According to Figure 9a, the impact strength of all PBS foam samples is higher than that of unfoamed PBS. When the mold-opening distance is set to 0.4 mm, the impact strength of the PBS foams increases from 9.84 to 12.73 kJ·m⁻², a 29% increase compared to unfoamed PBS. This can be attributed to the fact that a large number of cells not only absorb part of the impact energy but also effectively reduce the stress concentration at the crack tip, thereby improving impact toughness (49). However, as the mold-opening distance increases, the relative density of PBS foams decreases, resulting in a greater reduction in weight and a smaller area of unfoamed material. Consequently, the ability of PBS foams to withstand impact stress diminishes, leading to a decline in impact strength. This has been observed in previous studies (26,50,51,52). To comprehensively evaluate the impact performance and the effect of weight loss, Figure 9b presents the specific impact strength of both unfoamed PBS and PBS foams. Since the specific impact strength considers the material’s density, it can more accurately reflect the material’s impact properties under varying density conditions. The results demonstrate that all microporous parts exhibit a higher specific impact strength than solid parts. Interestingly, the specific impact strength of PBS foam shows a consistent upward trend with an increase in mold opening distance. In comparison to unfoamed PBS, the specific impact strength of PBS foams has increased from 7.81 to 12.31 Jm·kg⁻¹, representing a 58% increase. This indicates that even with a certain loss of material density, the cells in PBS foams can still effectively absorb impact energy. This finding demonstrates significant potential for applications requiring lightweight materials with high impact strength.

Figure 9

PBS unfoamed and PBS foams at different mold-opening distances: (a) impact strength and (b) specific impact strength.

The improvement in impact strength of PBS foams can be attributed to its fracture behavior. Figure 10 shows the impact fracture pattern of unfoamed PBS and PBS foams at different die opening distances. The impact fracture surface of unfoamed PBS is flat and smooth, indicating typical brittle fracture. On the other hand, the impact fracture surface of PBS foams is rough and uneven, demonstrating typical ductile fracture characteristics. The increase in impact strength is primarily achieved by increasing the plastic deformation of the cells and the crack propagation path. When PBS foams experience an impact, the cells in the crack initiation zone near the impact notch undergo stretching, yielding, and deformation. These cells experience a triaxial stress state, which helps disperse stress ahead of the crack tip. The deformation of these cells, along with the stretching of the cell walls, plays a crucial role in absorbing the impact energy. Moreover, the presence of cells in the foamed sample blunts the tips of the cracks, leading to the creation of many secondary cracks. These secondary cracks propagate, forming smaller cracks that eventually merge and peel away portions of the structure, resulting in a rough and uneven fracture surface morphology. Consequently, the presence of cells significantly increases the crack propagation path, enabling the absorption of more impact energy and ultimately improving the toughness of the material (53). Overall, foamed PBS exhibits higher impact performance compared to unfoamed PBS.

$Figure 10 The impact fracture morphology of unfoamed PBS and PBS foams at different mold-opening distances; (a) and (a1) PBS unfoamed; (b) and (b1) 0.4 mm; (c) and (c1) 0.6 mm; (d) and (d1) 0.8 mm; and (e) and (e1) 1 mm.$

Figure 10

The impact fracture morphology of unfoamed PBS and PBS foams at different mold-opening distances; (a) and (a1) PBS unfoamed; (b) and (b1) 0.4 mm; (c) and (c1) 0.6 mm; (d) and (d1) 0.8 mm; and (e) and (e1) 1 mm.

4 Conclusion

In this study, PBS foams with higher ductility and impact toughness were prepared through injection molding. The cell size and cell density of the foams were influenced by the mold-opening distance. Initially, increasing the mold-opening distance resulted in a decrease and then an increase in cell size, while the cell density showed an opposite trend. Compared to unfoamed PBS, PBS foams exhibited significantly improved ductility, tensile toughness, and impact performance. The enhanced ductility in PBS foams can be attributed to the high degree of cell orientation along the direction of the tensile load and the transformation of cell shapes from regular circular forms to tubular forms. When the mold-opening distance was 0.4 mm, PBS foams demonstrated an elongation at break of 486%, a tensile toughness of 4,586 MJ·cm⁻³, and an impact strength of 12.73 kJ·m⁻². These values were 98%, 53%, and 29% higher, respectively, than unfoamed PBS. Furthermore, as the mold opening distance increased, the relative density of the PBS foams decreased, resulting in a decline in mechanical properties. Interestingly, the specific impact strength of the PBS foam increased with greater distance from the mold opening. Compared to unfoamed PBS, the specific impact strength increased from 7.81 to 12.32 Jm·kg⁻¹, representing a 58% increase. Considering the excellent performance of PBS foams, as well as the cost-effectiveness and efficiency of injection molding, this study offers valuable insights for the industrial production of high-toughness PBS foams.

Funding information: The authors express their sincere thanks to National Natural Science Foundation of China (No. 51863003 and No. 52063008), Research start-up Foundation for Advanced Talents of Guizhou Institute of Technology (XJGC20190668), the Thousand Level Innovative Talents Project of Guizhou Province (No. GCC[2022]045), the Foundation of Guizhou Scientific Research Institute (QianKeFuQi 2023(001), 2023(035)) for their financial support.
Author contributions: Jiangbin Xu: conceptualization, investigation, formal analysis, and writing – original draft. Jinfu Xing: conceptualization, investigation, validation, and formal analysis. Mei Luo: literature collection and review and data curation; Tingyu Li: literature collection and review, and ormal analysis. Bujin Liu: resources and supervision; Xiangbu Zeng: project administration and resources. Tuanhui Jiang: funding acquisition, project administration, investigation, and validation. Xian Wu: funding acquisition, conceptualization, investigation, formal analysis, and writing – review and editing. He Li: conceptualization, funding acquisition, resources, supervision, methodology, and formal analysis.
Conflict of interest: The authors state no conflict of interest.
Data availability statement: The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

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Received: 2024-03-15

Revised: 2024-04-26

Accepted: 2024-04-27

Published Online: 2024-06-29

This work is licensed under the Creative Commons Attribution 4.0 International License.

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https://doi.org/10.1515/epoly-2024-0034

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polybutylene succinate; foam injection molding; cell morphology; ductility; impact toughness

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