Fabrication of Polyether–Ether–Ketone Foams with Superior Properties and Mitigated Weld Lines by Microcellular Injection Molding

Feng, Yu-Teng; Wang, Lin; Mi, Hao‐Yang; Gu, Laifa; Dong, Binbin; Liu, Chuntai; Shen, Changyu

doi:10.1002/adem.202100766

Cited by 9 publications

(10 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Further increase in void‐to‐solid ratio caused the over‐expansion of internal bubbles in the plastic part, 39,40 which resulted in the coalescence and collapse of bubbles due to the diffusion and escaping of gas from the cells. When the injection volume was further declined to 65 mm, a short‐shot phenomenon occurred which resulted in severe gas escaping during the cooling period, 41,42 thus, significantly affecting the dimension accuracy of the foamed PA66 gears. These results proved that there was an optimum point for the foamed PA66 gear parts to obtain the lowest shrinkage ratio when the maximum foaming ratio was realized by controlling the injection volume.…”

Section: Resultsmentioning

confidence: 99%

Microcellular injection molding of foamed engineering plastic parts with high dimensional accuracy

Feng

Zhan

et al. 2023

J of Applied Polymer Sci

View full text Add to dashboard Cite

Polyformaldehyde (POM) and Polyamide 66 (PA66) are engineering plastics with excellent mechanical properties and thermal stability. Producing microcellular injection molded POM and PA66 parts with high dimensional accuracy would be beneficial to reduce material cost and product quality. In this research, foamed POM and PA66 gear parts were fabricated by using microcellular injection molding with supercritical nitrogen as the blowing agent. Compared to conventional injection molded parts (parts that foaming is not involved), the foamed POM and PA66 gear parts achieved 5% and 10% average weight reduction, respectively. The foamed parts displayed a lower shrinkage ratio when compared to the solid counterparts, which was attributed to the cell expansion that offset part of the inward shrinkage stress. Moreover, POM gear parts with a higher crystallinity degree presented more serious shrinkage ratio compared to the PA66 gear parts, which contributed to the denser polymer molecular chains arrangement. The shrinkage ratio in both directions of PA66 foamed gear parts depended on the injection volume, and the lowest shrinkage ratio of 0.043‰ was obtained at the injection volume of 74 mm, when the polymer reached the maximum foaming ratio. The findings from this study could provide practical guidance for preparing microcellular injection molded products with high dimensional accuracy.

show abstract

Section: Resultsmentioning

confidence: 99%

Microcellular injection molding of foamed engineering plastic parts with high dimensional accuracy

Feng

Zhan

et al. 2023

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

“…Most of the researchers used dumbbell-shaped tensile test specimens with and without weld-line. [1][2][3]52,53 In two cavity mold one cavity filled with two opposite side gates which reproduce stagnation weld-line at the center of specimen 52 and the second cavity is filled with single gate where no weld-line is formed. The typical picture of the specimens is shown in Figure 11.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…Subsequent paragraphs explain experimental procedures to study the weld‐lines. Most of the researchers used dumbbell‐shaped tensile test specimens with and without weld‐line 1–3,52,53 . In two cavity mold one cavity filled with two opposite side gates which reproduce stagnation weld‐line at the center of specimen 52 and the second cavity is filled with single gate where no weld‐line is formed.…”

Section: Methods Of Evaluating Weld‐line and Weld‐line Strengthmentioning

confidence: 99%

Weld‐lines and its strength evaluation in injection molded parts: A review

Jadhav,

Gaval,

Solanke

et al. 2023

Polymer Engineering & Sci

View full text Add to dashboard Cite

Injection molding manufacturing is immensely popular nowadays because of its excellent manufacturability for complex designs produced from a wide range of different engineering plastic materials. Weld‐line is a defect that arises in injection molding when two or more flow fronts collide. The weld‐lines are undesirable from both aesthetic and functional points of view and their effect is different for varied materials, process conditions, loadings, forms of weld‐line, etc. The presence of a weld‐line weakens components locally due to insufficient intermolecular diffusion, v‐notch formation, fiber anisotropy, insufficient process conditions, and so on. When a component is under load, crack propagation usually begins with a weak weld‐line area. Therefore, the designer should anticipate the presence of weld‐lines and their strength to avoid failure of components during operation. In this article, the review of published research work on weld‐line formation during injection molding has been summarized. The review focuses on the phenomenon of weld‐line formation, the type of weld‐lines, and the importance of weld‐line evaluations. The theoretical, experimental, and computational approaches to analyzing weld‐line and its strength are covered in detail. At last, methods for reducing weld‐lines and increasing the strength of weld‐line area have been discussed. This review also gathers data on weld‐line strength with respect to different materials.Highlights Details of weld‐line formation and its types. Importance of weld‐line evaluation. Methods of weld‐line strength evaluation. Methods of reduction of the number of weld‐line and its effect. Summary of weld‐line strength for different material.

show abstract

“…Compared with normal CNF/PEEK composites, CNF/PEEK foams can achieve 20% weight loss and maintain initial flexural strength, which indicates the availability of PEEK foams in radomes. Feng et al 21 employed SCF foam injection molding to gain microporous PEEK with 10% weight loss. It reveals that the availability of PEEK foams fabricated by microcellular injection molding with supercritical fluid.…”

Section: Introductionmentioning

confidence: 99%

Lightweight, low temperature fatigue resistant, and low dielectric microcellular polyetheretherketone foams fabricated by microcellular injection molding

Xie

et al. 2022

J of Applied Polymer Sci

View full text Add to dashboard Cite

In this study, microcellular injection molding with supercritical nitrogen was employed to fabricate polyetheretherketone (PEEK) foams. The results showed that microporous PEEK specimens with weight loss up to 22% (specific strength of 58.16) and a low dielectric constant of 2.29 were achieved successfully. It is demonstrated that the microcellular structures and distribution varied with filling distance, due to the variation of pressure and temperature of melt in the mold cavity. Moreover, the low‐temperature resistance of foamed PEEK specimen was evaluated with ultra‐low temperature cycling test. It is found that foamed PEEK specimens demonstrate the same level of performance under low temperature conditions, which provides potential application in extreme environments. PEEK specimens have dielectric constant fluctuations in the X‐band due to the polarization of the molecular chains. In the PEEK foams, microcellular structure significantly influenced their dielectric properties. The wider cell layer enables higher gas content in PEEK foams, resulting in lower dielectric constant. Furthermore, crystallization can suppress the orientational polarization of molecular chains, and thus higher crystallinity results in a smaller dielectric constant. The lightweight, low‐temperature fatigue‐resistant, low‐dielectric microporous PEEK products have tremendous promise as insulation materials in many applications such as communications and microelectronics.

show abstract

Fabrication of Polyether–Ether–Ketone Foams with Superior Properties and Mitigated Weld Lines by Microcellular Injection Molding

Cited by 9 publications

References 42 publications

Microcellular injection molding of foamed engineering plastic parts with high dimensional accuracy

Microcellular injection molding of foamed engineering plastic parts with high dimensional accuracy

Weld‐lines and its strength evaluation in injection molded parts: A review

Lightweight, low temperature fatigue resistant, and low dielectric microcellular polyetheretherketone foams fabricated by microcellular injection molding

Contact Info

Product

Resources

About