Expanded polyamide 12 bead foams (ePA) thermo-mechanical properties of molded parts

Dörr, Dominik; Raps, Daniel; Kirupanantham, Dharan; Holmes, Christopher; Altstädt, Volker

doi:10.1063/1.5142952

Cited by 19 publications

(18 citation statements)

References 11 publications

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“…Chain extenders are widely used in the polymer industry, especially in the recycling industry, due to the chain degradation during processing at high temperatures and the resulting loss of properties [1]. Furthermore, they are often used in polymer foaming processes to increase the melt-strength of polyesters and polyamides to enhance the foamability and moldability of bead foams [2][3][4]. During chain extension a bi-or multifunctional reactant reacts with the end groups of polycondensates and the molecular weight increases [5].…”

Section: Introductionmentioning

confidence: 99%

Rheological Study of Gelation and Crosslinking in Chemical Modified Polyamide 12 Using a Multiwave Technique

2020

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When processing particular polymers, it may be necessary to increase the molecular weight, for example, during polymer recycling or foaming. Chemical additives such as chain extenders (CE) are often used to build up the molecular weight during reactive extrusion. One issue of chain extenders, however, is that they can cause gelation or crosslinking of the polymer during processes with long residence times. This can lead to strong process fluctuations, undesired process shutdowns due to uncontrollable torque and pressure fluctuations and finally consistent material quality cannot be guaranteed. To measure and understand the reactivity between the polymer and the CE a rheological test can help. However, the standard gel point evaluation used for thermosets by examining the point of intersection of storage- and loss modules is not suitable, as this method is frequency-dependent. This study uses a multiwave rheology test to identify the gel-point more reliably. Both evaluation methods were compared on a polyamide 12 system, which is modified with an industrially relevant chain extender. The results show that the multiwave test can be applied on a chemical modified thermoplastic system and that the material system indicates a general tendency to crosslink. The frequency-independent gel-point evaluation shows that the gel-point itself is dependent on the processing temperature. Finally, it was possible to detect undesired side reactions, which are not recognizable with the standard testing method. Both findings are directly relevant for the reactive extrusion process and help to understand the mechanism of gelation.

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Section: Introductionmentioning

confidence: 99%

Rheological Study of Gelation and Crosslinking in Chemical Modified Polyamide 12 Using a Multiwave Technique

2020

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“…Commodity foams like expanded PS (EPS) or expanded PP (EPP) are usually used for low to mid-temperature applications [ 4 , 5 ], while the variety of polymer foams for higher usage temperatures becomes significantly scarce, especially for engineering materials [ 6 ]. Only a few bead foam options exist for elevated temperature applications, i.e., expanded PET (EPET) distributed by the company Armacell [ 7 ]; expanded PBT (EPBT), a development of the department of Polymer Engineering [ 8 ]; several polyamide bead foams (EPA) (by Asahi Kasei [ 9 ], a PA 6 bead foam Ultramid ® by BASF SE [ 10 ], and a polyamide 12 (PA12) bead foam developed by the department of Polymer Engineering [ 11 ]), a SunForce ® modified polyphenyl ether (mPPE) bead foam by Asahi Kasei [ 12 ]; and a polyether sulfone (PESU) bead foam developed by BASF SE [ 13 ]. The newest high-temperature bead foam, which will be introduced in this work, is expanded polycarbonate (EPC), and was developed in collaboration with Covestro Deutschland AG and the department of Polymer Engineering.…”

Section: Introductionmentioning

confidence: 99%

Expanded Polycarbonate (EPC)—A New Generation of High-Temperature Engineering Bead Foams

et al. 2020

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Bead foams serve in a wide variety of applications, from insulation and packaging to midsoles in shoes. However, the currently used materials are limited to somewhat low temperature or exhibit significant changes in modulus in the temperature range of many applications due to their glass transition. By comparison, polycarbonate (PC) exhibits almost constant mechanics for temperatures up to 130 °C. Therefore, it appears as an advantageous base material for bead foams. The aim of the publication is to provide comprehensive data on the properties of expanded PC (EPC) in comparison to already commercially available expanded polypropylene, EPP, and expanded polyethylene-terephthalate, EPET. A special focus is set on the thermo-mechanical properties as these are the most lacking features in current materials. In this frame, dynamic mechanical analysis, and tensile, bending, compression and impact tests at room temperature (RT), 80 °C, and 110 °C are conducted for the three materials of the same density. Already at RT, EPC exhibits superior mechanics compared to its peers, which becomes more pronounced toward higher temperature. This comes from the low sensitivity of properties to temperature as EPC is used below its glass transition. In summary, EPC proves to be an outstanding foam material over a broad range of temperatures for structural applications.

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“…Dorr et al successfully prepared a new type of bead foam (EPA), made from the engineering polymer PA12, with an average cell size of fewer than 50 μm, through utilizing two FAs: CO 2 and ethanol. 66 Compared with commercially available EPP (BASF, Neopolen P), EPA had better thermal stability, stability of dynamic mechanical properties, stability of storage modulus, and heat deformation resistance, which indicated that using multiple FAs is one of the good ways to enhance the performance of PA foams. Jiang et al compared the impact of short-shot and coreback foaming processes on the performance of PA foams (Figure 6b).…”

Section: Strategies For Improving Performances Of Pa Foamsmentioning

confidence: 99%

Preparation Methods, Performance Improvement Strategies, and Typical Applications of Polyamide Foams

Jiang

Gong

et al. 2021

Ind. Eng. Chem. Res.

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Polyamide (PA) foams have been widely applied in many areas due to their outstanding properties and currently are receiving more extensive attention from the fundamental research and materials communities. However, poor melt strength and low matrix modulus seriously affect the preparation of high-performance PA foams and hinder their commercialization process. To overcome the limitations, a lot of efforts have been devoted to the research subject. In spite of the striking progress made dealing with PA foams, there has been no review to summarize the studies yet. This review begins with the consideration of the foaming process of PA and commonly used methods for PA foaming. Special emphasis is placed on effective means to enhance the performance of PA foams. Then, the typical applications of PA foams are presented, such as flame retardant, oil spill cleaning, electromagnetic shielding, and tissue engineering. Finally, the future perspective of PA foams will be outlined as well as the recommended future research directions about them.

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Expanded polyamide 12 bead foams (ePA) thermo-mechanical properties of molded parts

Cited by 19 publications

References 11 publications

Rheological Study of Gelation and Crosslinking in Chemical Modified Polyamide 12 Using a Multiwave Technique

Rheological Study of Gelation and Crosslinking in Chemical Modified Polyamide 12 Using a Multiwave Technique

Expanded Polycarbonate (EPC)—A New Generation of High-Temperature Engineering Bead Foams

Preparation Methods, Performance Improvement Strategies, and Typical Applications of Polyamide Foams

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