Investigation on energy director-less ultrasonic welding of polyetherimide (PEI)- to epoxy-based composites

Tsiangou, Eirini; Freitas, Sofia Teixeira de; Villegas, Irene Fernández; Benedictus, Rinze

doi:10.1016/j.compositesb.2019.107014

Cited by 64 publications

(31 citation statements)

References 13 publications

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“…The very short heating time in ultrasonic welding (which can be as short as a couple of hundred milliseconds) makes it however possible to avoid thermal degradation of the thermoset polymer even when the welding temperature is higher than its degradation temperature (Villegas and Vizcaino Rubio, 2015), resulting in welded joints with excellent quality (Figure 7). To illustrate this point the results of a recent study by Tsiangou et al (2019) show that CF/PEI to CF/epoxy ultrasonically welded joints achieved the same (single-lap shear) strength as reference CF/PEI to CF/epoxy joints obtained through an autoclave co-curing process. In that study, a thin PEI film (60 µm-thick) was used on the CF/epoxy adherends as the thermoplastic coupling layer.…”

Section: Ultrasonic Welding Of Dissimilar Composite Materialsmentioning

confidence: 90%

Ultrasonic Welding of Thermoplastic Composites

Villegas

2019

Front. Mater.

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Ultrasonic welding is a very fast and energy-efficient technique for the joining of thermoplastic composites. This article looks into main aspects of ultrasonic welding of continuous fiber-reinforced thermoplastic composites, namely energy directors, process parameters, in situ process monitoring, welding of dissimilar composite materials and upscaling routes. From the author's viewpoint these are key topics for deepening our insight into the ultrasonic welding process and, eventually, for enabling its future industrialization.

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Section: Ultrasonic Welding Of Dissimilar Composite Materialsmentioning

confidence: 90%

Ultrasonic Welding of Thermoplastic Composites

Villegas

2019

Front. Mater.

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“…Two PEI coupling layers with two different thicknesses were used, a 60-µm-thick PEI film provided by SABIC (The Netherlands), and a 250-µm-thick PEI film provided by LITE (Germany). The 60-µm-thick PEI film was chosen due to its usage in prior studies considering ultrasonic welding of thermoset- and thermoplastic-based composites, 1,11 and the 250-µm-thick PEI film was chosen due to its availability as an ED in the same studies. Analysis to determine the chemistry of the two different PEI films was not performed.…”

Section: Methodsmentioning

confidence: 99%

“…Due to the limited miscibility between the two materials after the gelation point of the epoxy resin, phase separation occurs, which results in the formation of a gradient interphase. 11 Figure 2 shows the morphology of this interphase, which consists of epoxy spheres dispersed in a PEI-rich matrix, with diameters decreasing towards the PEI coupling layer. The interphase has a varying thickness, with a maximum of 25 µm.…”

Section: Methodsmentioning

confidence: 99%

Ultrasonic welding of epoxy- to polyetheretherketone- based composites: Investigation on the material of the energy director and the thickness of the coupling layer

Tsiangou

Freitas

Villegas

et al. 2020

Journal of Composite Materials

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Ultrasonic welding is a highly promising technique for joining thermoplastic to thermoset composites. A neat thermoplastic coupling layer is co-cured on the surface to be welded to make the thermoset composite ‘weldable’. A reliable bond is attained when miscible thermoplastic and thermoset materials are chosen. For welding carbon fibre/polyetheretherketone (PEEK) to thermoset composite samples, a PEEK film is not preferable due to its immiscibility with epoxy resins. On the other hand, polyetherimide is an excellent candidate, since it is known to be miscible to most epoxy systems at high temperatures and PEEK polymers. This study focusses on two main subjects; firstly, the nature of the material of the energy director, i.e. a flat thermoplastic film used to promote heat generation at the interface. In this case, the energy director can be either polyetherimide, as in the coupling layer or PEEK material, as in the matrix of the thermoplastic composite adherend. It was found that both materials can produce welds with similar mechanical performance. This study focusses secondly on the thickness of the coupling layer. Due to the high melting temperature of the PEEK matrix, a 60-µm-thick coupling layer was seemingly too thin to act as a thermal barrier for the epoxy resin for heating times long enough to produce fully welded joints. Such an issue was found to be overcome by increasing the thickness of the coupling layer to 250 µm, which resulted in high-strength welds.

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“…Thermoplastic composite joining to thermoset composite is studied with different thermoplastic films as an interlayer. Some of the investigated polymers are Polyether ether ketone (PEEK) [116], Polysulfone (PSU) [119], Polyphenylene sulfide (PPS), Polystyrene (PS) [120], Polyetherimide (PEI) [118] and Polyvinyl butyral (PVB) [117]. The selection of the coupling film is highly constrained by a multitude of factors, such as the processing temperature, adhesion between the coupling film and the adherend, i.e., compatibility, and other factors [117].…”

Section: Thermoplastic Composites To Other Materialsmentioning

confidence: 99%

“…Tsiangou et al [118] investigated the ultrasonic welding of CF/PEI and CF/Epoxy composite by co-curing the coupling layer of thermoplastic PEI with different thicknesses (0.06 and 0.25 mm), and compares it with the loose ED of the same thickness. The results showed that the welding without the loose ED resulted in the overheating of the adherend, showing voids and porosity at the interface.…”

Section: Thermoplastic Composites To Other Materialsmentioning

confidence: 99%

Advances in Ultrasonic Welding of Thermoplastic Composites: A Review

et al. 2020

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The ultrasonic welding (UW) technique is an ultra-fast joining process, and it is used to join thermoplastic composite structures, and provides an excellent bonding strength. It is more cost-efficient as opposed to the conventional adhesive, mechanical and other joining methods. This review paper presents the detailed progress made by the scientific and research community to date in the direction of the UW of thermoplastic composites. The focus of this paper is to review the recent development of the ultrasonic welding technique for thermoplastic composites to thermoplastic composites, and to dissimilar materials. Different ultrasonic welding modes and their processing parameters, namely, weld time, weld pressure, amplitude, type of energy directors (EDs) affecting the welding quality and the advantages and disadvantages of UW over other bonding techniques, are summarized. The current state of the ultrasonic welding of thermoplastic composites and their future perspectives are also deliberated.

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Investigation on energy director-less ultrasonic welding of polyetherimide (PEI)- to epoxy-based composites

Cited by 64 publications

References 13 publications

Ultrasonic Welding of Thermoplastic Composites

Ultrasonic Welding of Thermoplastic Composites

Ultrasonic welding of epoxy- to polyetheretherketone- based composites: Investigation on the material of the energy director and the thickness of the coupling layer

Advances in Ultrasonic Welding of Thermoplastic Composites: A Review

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