1
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Xu Y, Guo P, Zhang H, Ren M, Lyu M. Effect of Janus Nanosheets in Polypropylene on Rheological Properties and Autoclave Foam Performance. Polymers (Basel) 2023; 15:3433. [PMID: 37631491 PMCID: PMC10458347 DOI: 10.3390/polym15163433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/03/2023] [Accepted: 08/10/2023] [Indexed: 08/27/2023] Open
Abstract
Our experiment revealed that the addition of Janus nanosheets to polypropylene (PP) has a significant impact on the viscoelasticity of the composite system. Specifically, when 0.10 wt% of Janus nanosheets were added, the complex viscosity of the composite system increased. However, when we added less than 0.05 wt% of Janus nanosheets, there was a reduction in complex viscosity, which is known as the non-Einstein phenomenon. The Cole-Cole plot showed that the nanosheet network structure did not have a significant effect on the viscosity of the composite system. Additionally, we used carbon dioxide as a foaming agent to autoclave foaming using modified PP from Janus nanosheets, and the results demonstrated that increasing the number of Janus nanosheets decreased the apparent density and strengthened the cell structure of foaming beads, resulting in improved closed porosity.
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Affiliation(s)
| | | | | | | | - Mingfu Lyu
- SINOPEC Beijing Research Institute of Chemical Industry, Beijing 100013, China; (Y.X.); (P.G.); (H.Z.); (M.R.)
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2
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Liu F, Shen C, Jiang X, You F, Yao C, Shangguan Y. Enhancing the mechanical properties and foaming performance of polypropylene through melt grafting reaction by using trimethylolpropane triacrylate. Polym Bull (Berl) 2022. [DOI: 10.1007/s00289-022-04644-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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3
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Kuhnigk J, Krebs N, Mielke C, Standau T, Pospiech D, Ruckdäschel H. Influence of Molecular Weight on the Bead Foaming and Bead Fusion Behavior of Poly(butylene terephthalate) (PBT). Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.2c03233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Justus Kuhnigk
- Department of Polymer Engineering, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Niko Krebs
- Department of Polymer Engineering, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Christian Mielke
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Street 6, 01069 Dresden, Germany
| | - Tobias Standau
- Department of Polymer Engineering, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Doris Pospiech
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Street 6, 01069 Dresden, Germany
| | - Holger Ruckdäschel
- Department of Polymer Engineering, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
- Bavarian Polymer Institute and Bayreuth Institute of Macromolecular Research, University of Bayreuth, 95447 Bayreuth, Germany
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4
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Influence of Carbon Dioxide on the Glass Transition of Styrenic and Vinyl Pyridine Polymers: Comparison of Calorimetric, Creep, and Rheological Experiments. ADVANCES IN POLYMER TECHNOLOGY 2022. [DOI: 10.1155/2022/5602902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The glass transition of amorphous polymers determines the mobility of polymer chains and the time scale of relaxation processes. The glass transition temperature is reduced by the presence of low molecular weight molecules, e.g., dissolved gases or organic solvents. The quantitative knowledge of reduction of the glass transition temperature caused by the addition of carbon dioxide in a polymer melt is highly relevant for foam extrusion. However, measurement of the reduction of glass transition temperature caused by gas loading has to be performed under elevated pressure which implies high experimental efforts. In this work, we discuss and compare three methods for determination of the influence of carbon dioxide on thermal properties of amorphous polymers, i.e., calorimetric measurements, creep tests, and rheological experiments. The advantages and disadvantages of these methods are elucidated. Furthermore, the influence of molecular structure of the styrenic and vinylpyridine polymers on the glass transition temperature is discussed. Polystyrene generally shows the highest reduction of glass transition temperature. Poly(2-vinylpyridine) and poly(4-vinylpyridine) show a slightly less pronounced behaviour in comparison to polystyrene because of the lower polarity of polystyrene. Poly(α-methyl styrene) is associated with a different dependence of glass transition temperature on gas loading in calorimetric and rheological experiments.
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5
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Yu X, Ren J, He J, Su L, Liu F. Effect of compatibilizer on the structure and property of polycarbonate/polypropylene alloys. J Appl Polym Sci 2022. [DOI: 10.1002/app.52957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Xingxing Yu
- National‐certified Enterprise Technology Center Kingfa Sci. & Tech. Co., Ltd Guangzhou China
- School of Materials Science and Engineering South China University of Technology Guangzhou China
| | - Jifu Ren
- National‐certified Enterprise Technology Center Kingfa Sci. & Tech. Co., Ltd Guangzhou China
| | - Jingwei He
- School of Materials Science and Engineering South China University of Technology Guangzhou China
| | - Long Su
- National‐certified Enterprise Technology Center Kingfa Sci. & Tech. Co., Ltd Guangzhou China
| | - Fang Liu
- School of Materials Science and Engineering South China University of Technology Guangzhou China
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6
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Sandino C, Peuvrel-Disdier E, Agassant JF, Laure P, Boyer SAE, Hibert G, Trolez Y. Extrusion foaming of linear and branched polypropylenes – input of the thermomechanical analysis of pressure drop in the die. INT POLYM PROC 2022. [DOI: 10.1515/ipp-2022-0025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
This paper aims at a better understanding of the polypropylene (PP) physical extrusion foaming process with the objective of obtaining the lowest possible foam density. Two branched PPs were compared to the corresponding linear ones. Their shear and elongation viscosities were measured as well as their crystalline properties. Trials were conducted in a single screw extruder equipped with a gear pump and a static mixer cooler to adjust the melt temperature at the final die. The effect of decreasing this temperature on the PP foamability and on the pressure drop in the die was analyzed. The foam density of branched PPs varies from high to low values while decreasing the foaming temperature. In the same processing conditions, the foam density of linear PPs does not decrease so much, as already evidenced in the literature. The foamability transition coincides with an increase of the pressure drop in the die. The originality of the work lies in the thermomechanical analysis of the polymer flow in the die which allows the identification of the relevant physical phenomena for a good foamability. The comparison of the experimental pressure drops in the die and the computed ones with the identified purely viscous behavior points out the influence of the foaming temperature and of the PP structure. At high foaming temperature the discrepancy between experimental measurements and the computed pressure drops remains limited. It increases when decreasing the foaming temperature, but the mismatch is much more important for branched PPs than for linear ones. This difference is analyzed as a combination of the activation energy of the viscosity, the elongational viscosity in the convergent geometry of the die which is much more important for branched PPs than for linear ones, and the onset of crystallization which occurs at higher temperature for branched PPs than for linear PPs.
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Affiliation(s)
- Carlos Sandino
- Mines Paris, PSL University , Centre de mise en forme des matériaux (CEMEF), CNRS UMR 7635, CS 10207, 06904 Sophia Antipolis cedex , France
| | - Edith Peuvrel-Disdier
- Mines Paris, PSL University , Centre de mise en forme des matériaux (CEMEF), CNRS UMR 7635, CS 10207, 06904 Sophia Antipolis cedex , France
| | - Jean-François Agassant
- Mines Paris, PSL University , Centre de mise en forme des matériaux (CEMEF), CNRS UMR 7635, CS 10207, 06904 Sophia Antipolis cedex , France
| | - Patrice Laure
- Mines Paris, PSL University , Centre de mise en forme des matériaux (CEMEF), CNRS UMR 7635, CS 10207, 06904 Sophia Antipolis cedex , France
- Laboratoire J.-A. Dieudonné, CNRS UMR 6621 , Université Côte d’Azur , Parc Valrose, 06108 Nice Cedex 02 , France
| | - Séverine A. E. Boyer
- Mines Paris, PSL University , Centre de mise en forme des matériaux (CEMEF), CNRS UMR 7635, CS 10207, 06904 Sophia Antipolis cedex , France
| | - Geoffrey Hibert
- TotalEnergies One Tech Belgium , Zone Industrielle Feluy C, B 7181 Feluy , Belgium
| | - Yves Trolez
- TotalEnergies One Tech Belgium , Zone Industrielle Feluy C, B 7181 Feluy , Belgium
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7
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Development of a Rheology Die and Flow Characterization of Gas-Containing Polymer Melts. Polymers (Basel) 2021; 13:polym13193305. [PMID: 34641121 PMCID: PMC8512105 DOI: 10.3390/polym13193305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 09/20/2021] [Accepted: 09/23/2021] [Indexed: 11/16/2022] Open
Abstract
We present a novel measurement die for characterizing the flow behavior of gas-containing polymer melts. The die is mounted directly on the injection-molding cylinder in place of the mold cavity and thus enables near-process measurement of viscosity (i.e., under the conditions that would be present were a mold attached). This integration also resolves the issue of keeping gas-containing polymer melts under pressure during measurement to prevent desorption. After thermal characterization of the die, various correction approaches were compared against each other to identify the most suitable one for our case. We conducted measurements using polypropylene in combination with two different chemical blowing agents. Increasing the blowing-agent content to up to 6% revealed an interestingly low influence of gases on melt viscosity, which was confirmed by elongational viscosity measurements. For verification, we compared our results to corresponding measurements taken on a high-pressure capillary rheometer and found that they were in excellent agreement. Our die cannot only be used for rheological characterization. Combined with ultrasound sensors, it provides an innovative way of measuring the volumetric flow rate. This development represents an important step in improving the sustainability of gas-containing polymer processing.
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New Insights on Expandability of Pre-Cured Epoxy Using a Solid-State CO 2-Foaming Technique. Polymers (Basel) 2021; 13:polym13152441. [PMID: 34372043 PMCID: PMC8348596 DOI: 10.3390/polym13152441] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/20/2021] [Accepted: 07/22/2021] [Indexed: 11/18/2022] Open
Abstract
Foaming an epoxy is challenging because the process involves the curing reaction of epoxy and hardener (from monomer to oligomer, to a gel and a final three-dimensional crosslinked network) and the loading of gas phase into the epoxy phase to develop the cellular structure. The latter process needs to be carried out at the optimum curing stage of epoxy to avoid cell coalescence and to allow expansion. The environmental concern regarding the usage of chemical blowing agent also limits the development of epoxy foams. To surmount these challenges, this study proposes a solid-state CO2 foaming of epoxy. Firstly, the resin mixture of diglycidylether of bisphenol-A (DGEBA) epoxy and polyamide hardener is pre-cured to achieve various solid-state sheets (preEs) of specific storage moduli. Secondly, these preEs undergo CO2 absorption using an autoclave. Thirdly, CO2 absorbed preEs are allowed to free-foam/expand in a conventional oven at various temperatures; lastly, the epoxy foams are post-cured. PreE has a distinctive behavior once being heated; the storage modulus is reduced and then increases due to further curing. Epoxy foams in a broad range of densities could be fabricated. PreE with a storage modulus of 4 × 104–1.5 × 105 Pa at 30 °C could be foamed to densities of 0.32–0.45 g/cm3. The cell morphologies were revealed to be star polygon shaped, spherical and irregularly shaped. The research proved that the solid-state CO2-foaming technique can be used to fabricate epoxy foams with controlled density.
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9
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Rainglet B, Chalamet Y, Bounor-Legaré V, Delage K, Forest C, Cassagnau P. Polypropylene foams under CO2 batch conditions: From formulation and rheological modeling to cell-growth simulation. POLYMER 2021. [DOI: 10.1016/j.polymer.2021.123496] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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Zhang X, Wang X, Dong B, Zheng G, Chen J, Shen C, Park CB. Synergetic effect of crystal nucleating agent and melt self-enhancement of isotactic polypropylene on its rheological and microcellular foaming properties. J CELL PLAST 2020. [DOI: 10.1177/0021955x20969553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Crystal nucleating agent Bis (3, 4- dimethylbenzylidene) sorbitol (DMDBS) was used to tune the melt strength and microcellular foaming properties of isotactic polypropylene (iPP) in this study. Rheological testing results reveal that the introduction of DMDBS could enhance the storage modulus and complex viscosity of iPP, obviously increase its crystallization onset temperature, compared to its counterparts without DMDBS. The addition of DMDBS could also significantly increase the cell nucleating ability of iPP, due to its large surface, cooperating with a thermal history control treatment. Quite fine microcellular iPP/DMDBS foams were fabricated with relatively small average cell sizes of nano to several micrometers, and cell densities up to 1011∼1012 cells/cm3, using the synergy effect of DMDBS and iPP’s melt self-enhancement. Under a comparatively low re-saturation pressure of 8 to 12 MPa, ideal microcellular foams could be generated, at a temperature zone of 158 to 162°C, which is slightly below to iPP’s original pellets nominal melting point.
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Affiliation(s)
- Xiaoli Zhang
- School of Materials Science and Engineering, National Engineering Research Center for Advanced Polymer Processing Technology
| | - Xihuan Wang
- School of Materials Science and Engineering, National Engineering Research Center for Advanced Polymer Processing Technology
| | - Binbin Dong
- Microcellular Plastics Manufacturing Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Guoqiang Zheng
- School of Materials Science and Engineering, National Engineering Research Center for Advanced Polymer Processing Technology
| | - Jingbo Chen
- School of Materials Science and Engineering, National Engineering Research Center for Advanced Polymer Processing Technology
| | - Changyu Shen
- School of Materials Science and Engineering, National Engineering Research Center for Advanced Polymer Processing Technology
| | - Chul B Park
- Microcellular Plastics Manufacturing Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
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11
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Expanded Polycarbonate (EPC)-A New Generation of High-Temperature Engineering Bead Foams. Polymers (Basel) 2020; 12:polym12102314. [PMID: 33050426 PMCID: PMC7601122 DOI: 10.3390/polym12102314] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/05/2020] [Accepted: 10/08/2020] [Indexed: 11/28/2022] Open
Abstract
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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12
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Dörr D, Standau T, Murillo Castellón S, Bonten C, Altstädt V. Rheology in the Presence of Carbon Dioxide (CO 2) to Study the Melt Behavior of Chemically Modified Polylactide (PLA). Polymers (Basel) 2020; 12:polym12051108. [PMID: 32414010 PMCID: PMC7285241 DOI: 10.3390/polym12051108] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/06/2020] [Accepted: 05/12/2020] [Indexed: 11/21/2022] Open
Abstract
For the preparation of polylactide (PLA)-based foams, it is commonly necessary to increase the melt strength of the polymer. Additives such as chain extenders (CE) or peroxides are often used to build up the molecular weight by branching or even crosslinking during reactive extrusion. Furthermore, a blowing agent with a low molecular weight, such as carbon dioxide (CO2), is introduced in the foaming process, which might affect the reactivity during extrusion. Offline rheological tests can help to measure and better understand the kinetics of the reaction, especially the reaction between the polymer and the chemical modifier. However, rheological measurements are mostly done in an inert nitrogen atmosphere without an equivalent gas loading of the polymer melt, like during the corresponding reactive extrusion process. Therefore, the influence of the blowing agent itself is not considered within these standard rheological measurements. Thus, in this study, a rheometer equipped with a pressure cell is used to conduct rheological measurements of neat and chemical-modified polymers in the presence of CO2 at pressures up to 40 bar. The specific effects of CO2 at elevated pressure on the reactivity between the polymer and the chemical modifiers (an organic peroxide and as second choice, an epoxy-based CE) were investigated and compared. It could be shown in the rheological experiments that the reactivity of the chain extender is reduced in the presence of CO2, while the peroxide is less affected. Finally, it was possible to detect the recrystallization temperature Trc of the unmodified and unbranched sample by the torque maximum in the rheometer, representing the tear off of the stamp from the sample. Trc was about 13 K lower in the CO2-loaded sample. Furthermore, it was possible to detect the influences of branching and gas loading simultaneously. Here the influence of the branching on Trc was much higher in comparison to a gas loading.
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Affiliation(s)
- Dominik Dörr
- Department of Polymer Engineering, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany; (D.D.); (T.S.)
| | - Tobias Standau
- Department of Polymer Engineering, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany; (D.D.); (T.S.)
| | - Svenja Murillo Castellón
- Institut für Kunststofftechnik, University of Stuttgart, Pfaffenwaldring 32, 70569 Stuttgart, Germany; (S.M.C.); (C.B.)
| | - Christian Bonten
- Institut für Kunststofftechnik, University of Stuttgart, Pfaffenwaldring 32, 70569 Stuttgart, Germany; (S.M.C.); (C.B.)
| | - Volker Altstädt
- Department of Polymer Engineering, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany; (D.D.); (T.S.)
- Bavarian Polymer Institute, Universitätsstraße 30, 95447 Bayreuth, Germany
- Correspondence: ; Tel.: +49-921-55-7471
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13
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A facile methodology to effectively improve the melt strength and microcellular foamability of isotactic polypropylene. JOURNAL OF POLYMER RESEARCH 2020. [DOI: 10.1007/s10965-020-02101-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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14
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Weingart N, Raps D, Lu M, Endner L, Altstädt V. Comparison of the Foamability of Linear and Long-Chain Branched Polypropylene-The Legend of Strain-Hardening as a Requirement for Good Foamability. Polymers (Basel) 2020; 12:polym12030725. [PMID: 32213998 PMCID: PMC7183088 DOI: 10.3390/polym12030725] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 03/19/2020] [Accepted: 03/21/2020] [Indexed: 11/17/2022] Open
Abstract
Polypropylene (PP) is an outstanding material for polymeric foams due to its favorable mechanical and chemical properties. However, its low melt strength and fast crystallization result in unfavorable foaming properties. Long-chain branching of PP is regarded as a game changer in foaming due to the introduction of strain hardening, which stabilizes the foam morphology. In this work, a thorough characterization with respect to rheology and crystallization characteristics of a linear PP, a PP/PE-block co-polymer, and a long-chain branched PP are conducted. Using these results, the processing window in foam-extrusion trials with CO2 and finally the foam properties are explained. Although only LCB-PP exhibits strain hardening, it neither provide the broadest foaming window nor the best foam quality. Therefore, multiwave experiments were conducted to study the gelation due to crystallization and its influence on foaming. Here, linear PP exhibited a gel-like behavior over a broad time frame, whereas the other two froze quickly. Thus, apart from strain hardening, the crystallization behavior/crystallization kinetics is of utmost importance for foaming in terms of a broad processing window, low-density, and good morphology. Therefore, the question arises, whether strain hardening is really essential for low density foams with a good cellular morphology.
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Affiliation(s)
- Nick Weingart
- Department of Polymer Engineering, University of Bayreuth, 95447 Bayreuth, Germany; (N.W.); (D.R.); (L.E.)
| | - Daniel Raps
- Department of Polymer Engineering, University of Bayreuth, 95447 Bayreuth, Germany; (N.W.); (D.R.); (L.E.)
| | - Mingfu Lu
- SINOPEC Beijing Research Institute of Chemical Industry, Beijing, 100013, China;
| | - Lukas Endner
- Department of Polymer Engineering, University of Bayreuth, 95447 Bayreuth, Germany; (N.W.); (D.R.); (L.E.)
| | - Volker Altstädt
- Department of Polymer Engineering, University of Bayreuth, 95447 Bayreuth, Germany; (N.W.); (D.R.); (L.E.)
- Correspondence: ; Tel.: +49-921-557471
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15
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Bethke C, Goedderz D, Weber L, Standau T, Döring M, Altstädt V. Improving the flame‐retardant property of bottle‐grade PET foam made by reactive foam extrusion. J Appl Polym Sci 2020. [DOI: 10.1002/app.49042] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Christian Bethke
- Department of Polymer EngineeringUniversity of Bayreuth Bayreuth Germany
| | - Daniela Goedderz
- Fraunhofer Institute for Structural Durability and System Reliability LBF Darmstadt Germany
- Ernst‐Berl Institute for Chemical Engineering and Macromolecular Science, Technische Universität Darmstadt Darmstadt Germany
| | - Lais Weber
- Fraunhofer Institute for Structural Durability and System Reliability LBF Darmstadt Germany
- Ernst‐Berl Institute for Chemical Engineering and Macromolecular Science, Technische Universität Darmstadt Darmstadt Germany
| | - Tobias Standau
- Department of Polymer EngineeringUniversity of Bayreuth Bayreuth Germany
| | - Manfred Döring
- Fraunhofer Institute for Structural Durability and System Reliability LBF Darmstadt Germany
| | - Volker Altstädt
- Department of Polymer EngineeringUniversity of Bayreuth Bayreuth Germany
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16
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Keilholz C, Raps D, Köppl T, Altstädt V. Influence of nucleating agent type on the morphology of extruded polyetherimide foam for printed circuit boards*. J CELL PLAST 2019. [DOI: 10.1177/0021955x19864107] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This work focuses on the development of foamed high temperature thermoplastic substrates for printed circuit boards. For this application it is necessary to achieve mean cell diameters smaller than 30 µm in order to be able to realize vias and high packaging densities (miniaturization). Different additives as nucleating agents, namely macro- and micro-crystalline talc, silica, calcium carbonate, and wollastonite, were melt-compounded with polyetherimide using a twin-screw extruder. Foamed samples are prepared by foam extrusion using a slit die and CO2 as physical blowing agent. The aim of this study is to analyze the influence of the mean particle size and the particle surface tension on the mean cell diameters. Therefore, the shape of the additives, the foam morphology, and the elongational viscosity were considered. The additives with a suitable particle size and surface tension exhibit a positive influence on the foam morphology, resulting in smaller cell diameters (<30 µm), a narrower cell size distribution and a foam density lower than 900 kg/m3. If the mean particle diameter of the nucleating agents is lower than 0.6 µm in this study, no nucleation effect could be observed. This is related to the fact that no heterogeneous nucleation occurs, if the particle diameter is too small. If the mean particle diameter of the used additives is larger than 1.5 µm, which could be demonstrated in this study in case of polyetherimide, then the additive acts as nucleating agent and heterogeneous nucleation occurs. Furthermore, it was observed that the mean cell diameter was affected by the different surface tensions of the studied nucleating agents.
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Affiliation(s)
- Clemens Keilholz
- Department of Polymer Engineering, University of Bayreuth, Bayreuth, Germany
| | - Daniel Raps
- Department of Polymer Engineering, University of Bayreuth, Bayreuth, Germany
| | - Thomas Köppl
- Department of Polymer Engineering, University of Bayreuth, Bayreuth, Germany
| | - Volker Altstädt
- Department of Polymer Engineering, University of Bayreuth, Bayreuth, Germany
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17
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Standau T, Castellón SM, Delavoie A, Bonten C, Altstädt V. Effects of chemical modifications on the rheological and the expansion behavior of polylactide (PLA) in foam extrusion. E-POLYMERS 2019. [DOI: 10.1515/epoly-2019-0030] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractIt is well known that polylactide (PLA) is difficult to foam due to its low melt strength. Thus, many ways were described in the literature to enhance the foamability. However, the melt strength was actually determined only in a limited number of publications. In this study, the addition of chemical modifiers was used to change the rheological behavior of PLA and thereby improve its foamability in foam extrusion process. For the first time the use of dicumyl peroxide modified PLA in foam extrusion is described. Both modifications lead to a distinct increase in melt strength. Here, the highest increase was shown for the PLA modified with dicumyl peroxide. Furthermore, strain hardening was observed for PLA modified with the peroxide. Low density foams were achieved for neat and modified PLA in foam extrusion. Neat PLA showed a density of 45 kg/m3, while the peroxide modified PLA showed the highest expansion with a density reduction down to 32 kg/m3. Both modifications result in a more uniform cell structure and an improved compression strength. Here, the foamed, peroxide modified PLA showed outstanding performance compared to neat PLA foam with twice the compression strength (151 Pa) even at a 30% lower density.
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Affiliation(s)
- Tobias Standau
- Department of Polymer Engineering, University of Bayreuth Universitätsstraße30, 95447Bayreuth – Germany
| | - Svenja Murillo Castellón
- Institut für Kunststofftechnik, University of Stuttgart Pfaffenwaldring32, 70569Stuttgart – Germany
| | - Agathe Delavoie
- Department of Polymer Engineering, University of Bayreuth Universitätsstraße30, 95447Bayreuth – Germany
| | - Christian Bonten
- Institut für Kunststofftechnik, University of Stuttgart Pfaffenwaldring32, 70569Stuttgart – Germany
| | - Volker Altstädt
- Department of Polymer Engineering, University of Bayreuth Universitätsstraße30, 95447Bayreuth – Germany
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18
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Modification of iPP microcellular foaming behavior by thermal history control and nucleating agent at compressed CO2. J Supercrit Fluids 2018. [DOI: 10.1016/j.supflu.2017.11.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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19
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Pepper KJ, Masson T, De Focatiis D, Howdle SM. Can a combination of poly(ethylene glycol) and dense phase carbon dioxide improve processing of polylactide? A high pressure rheology investigation. J Supercrit Fluids 2018. [DOI: 10.1016/j.supflu.2017.10.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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20
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Wan C, Lu Y, Liu T, Zhao L, Yuan W. Foaming of Low Density Polyethylene with Carbon Dioxide Based on Its in Situ Crystallization Behavior Characterized by High-Pressure Rheometer. Ind Eng Chem Res 2017. [DOI: 10.1021/acs.iecr.7b02842] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chen Wan
- Shanghai Key Laboratory
of
Multiphase Materials Chemical Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Yiquan Lu
- Shanghai Key Laboratory
of
Multiphase Materials Chemical Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Tao Liu
- Shanghai Key Laboratory
of
Multiphase Materials Chemical Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Ling Zhao
- Shanghai Key Laboratory
of
Multiphase Materials Chemical Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Weikang Yuan
- Shanghai Key Laboratory
of
Multiphase Materials Chemical Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China
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21
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Wan C, Sun G, Liu T, Esseghir M, Zhao L, Yuan W. Rheological properties of HDPE and LDPE at the low-frequency range under supercritical CO2. J Supercrit Fluids 2017. [DOI: 10.1016/j.supflu.2016.12.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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22
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Zhang R, Xiong Y, Liu Q, Hu S. Improved cell morphology and thermal properties of expanded polypropylene beads by the addition of PP with a high melting point. J Appl Polym Sci 2017. [DOI: 10.1002/app.45121] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Rong Zhang
- Hubei Provincial Key Laboratory of Green Materials for Light Industry; Hubei University of Technology; Wuhan Hubei 430068 People's Republic of China
| | - Yezhi Xiong
- Hubei Provincial Key Laboratory of Green Materials for Light Industry; Hubei University of Technology; Wuhan Hubei 430068 People's Republic of China
| | - Qingting Liu
- Hubei Provincial Key Laboratory of Green Materials for Light Industry; Hubei University of Technology; Wuhan Hubei 430068 People's Republic of China
| | - Shengfei Hu
- Hubei Provincial Key Laboratory of Green Materials for Light Industry; Hubei University of Technology; Wuhan Hubei 430068 People's Republic of China
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23
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24
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Zhang L, Zhao G, Dong G, Li S, Wang G. Bubble morphological evolution and surface defect formation mechanism in the microcellular foam injection molding process. RSC Adv 2015. [DOI: 10.1039/c5ra07512b] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A multiphase model was established to simulate the bubble morphological evolution in MFIM, and a new phenomenon of surface collapse and pits with the gradient depth was discovered.
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Affiliation(s)
- Lei Zhang
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education)
- Shandong University
- Jinan
- PR China
| | - Guoqun Zhao
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education)
- Shandong University
- Jinan
- PR China
| | - Guiwei Dong
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education)
- Shandong University
- Jinan
- PR China
| | - Shuai Li
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education)
- Shandong University
- Jinan
- PR China
| | - Guilong Wang
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education)
- Shandong University
- Jinan
- PR China
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