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An Approach to the Impact Simulation on Foamed Injection Molded Polypropylene Parts: An Example of Application in the Automotive Industry. Polymers (Basel) 2023; 15:polym15040936. [PMID: 36850220 PMCID: PMC9961383 DOI: 10.3390/polym15040936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/07/2023] [Accepted: 02/08/2023] [Indexed: 02/16/2023] Open
Abstract
An approach to the simulation of foamed injection molded Polypropylene parts subjected to impact loading is presented in this paper. The proposed method, which considers strain-rate-dependent material properties and the possible occurrence of fracture, is, in particular, suitable for parts manufactured with core-back technology. The method was developed to be used within the functionality of a commercial Finite Element solver using a shell-type element mesh. The material model is based on a three-layer structure, with two compact skin layers and a foamed core layer made of expanded material. The properties of the foamed material are assumed as those of the compact grade scaled by a suitable factor, which is identified via inverse engineering on a set of bending tests executed on specimens having different foam densities. The fracture of the material is then predicted using a damage model which considers the effects of triaxiality. The approach is then validated on industrial parts from the automotive sector, subjected to impact in a component test. Despite the simplicity of the presented approach, which makes this method suitable for industrial applications and especially for early-stage design, the validation shows a sufficiently accurate simulation of part behavior under the impact, with a reasonable prediction of damage and fracture.
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2
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Tian Y, Gong C, Zhou H, Jiang Z, Wang X, Tang L, Cao K. Halogen‐free intumescent flame retardancy and mechanical properties of the microcellular polypropylene with low expansion ratio via continuous extrusion assisted by subcritical
CO
2
. J Appl Polym Sci 2022. [DOI: 10.1002/app.51971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Yichen Tian
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering Zhejiang University Hangzhou China
| | - Changjing Gong
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering Zhejiang University Hangzhou China
| | - Hongfu Zhou
- School of Materials and Mechanical Engineering Beijing Technology and Business University Beijing China
| | - Ziyin Jiang
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering Zhejiang University Hangzhou China
| | - Xiangdong Wang
- School of Materials and Mechanical Engineering Beijing Technology and Business University Beijing China
| | - Longcheng Tang
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education Hangzhou Normal University Hangzhou China
| | - Kun Cao
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering Zhejiang University Hangzhou China
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3
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Ren J, Lin L, Jiang J, Li Q, Hwang SS. Effect of Gas Counter Pressure on the Surface Roughness, Morphology, and Tensile Strength between Microcellular and Conventional Injection-Molded PP Parts. Polymers (Basel) 2022; 14:polym14061078. [PMID: 35335409 PMCID: PMC8955146 DOI: 10.3390/polym14061078] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 02/25/2022] [Accepted: 03/04/2022] [Indexed: 02/01/2023] Open
Abstract
Microcellular injection-molded parts have surface defect problems. Gas counter pressure (GCP) is one of the methods to reduce surface defects. This study investigated the effect of GCP on the surface roughness, morphology, and tensile strength of foamed and conventional injection-molded polypropylene (PP) products. GCP is generated by filling up the mold cavity with nitrogen during the injection-molding (IM) process. It can delay foaming and affect flow characteristics of microcellular and conventional injection-molding, which cause changes in the tensile strength, flow length, cell morphology, and surface quality of molded parts. The mechanism was investigated through a series of experiments including tuning of GCP and pressure holding duration. Surface roughness of the molded parts decreased with the increase in GCP and pressure holding duration. Compared to microcellular IM, GCP-assisted foaming exhibited much better surface quality and controllable skin layer thickness.
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Affiliation(s)
- Jianping Ren
- Mould Research Institute, Taizhou Vocational College of Science and Technology, Taizhou 318020, China; (J.R.); (L.L.)
- National International Joint Research Center Micro-Nano Molding Technology, Zhengzhou University, Zhengzhou 450001, China; (J.J.); (Q.L.)
| | - Long Lin
- Mould Research Institute, Taizhou Vocational College of Science and Technology, Taizhou 318020, China; (J.R.); (L.L.)
| | - Jing Jiang
- National International Joint Research Center Micro-Nano Molding Technology, Zhengzhou University, Zhengzhou 450001, China; (J.J.); (Q.L.)
| | - Qian Li
- National International Joint Research Center Micro-Nano Molding Technology, Zhengzhou University, Zhengzhou 450001, China; (J.J.); (Q.L.)
| | - Shyh-Shin Hwang
- Department of Mechanical Engineering, Chien-Hsin University of Science and Technology, Chung-Li 32097, Taiwan
- Correspondence: ; Tel.: +886-935187801
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4
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Mendoza-Cedeno S, Kweon MS, Newby S, Shivokhin M, Pehlert G, Lee PC. Improved Cell Morphology and Surface Roughness in High-Temperature Foam Injection Molding Using a Long-Chain Branched Polypropylene. Polymers (Basel) 2021; 13:polym13152404. [PMID: 34372006 PMCID: PMC8348131 DOI: 10.3390/polym13152404] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/16/2021] [Accepted: 07/17/2021] [Indexed: 11/21/2022] Open
Abstract
Long-chain branched polypropylene (LCB PP) has been used extensively to improve cell morphologies in foaming applications. However, most research focuses on low melt flow rate (MFR) resins, whereas foam production methods such as mold-opening foam injection molding (MO-FIM) require high-MFR resins to improve processability. A systematic study was conducted comparing a conventional linear PP, a broad molecular weight distribution (BMWD) linear PP, and a newly developed BMWD LCB PP for use in MO-FIM. The effects of foaming temperature and molecular architecture on cell morphology, surface roughness, and mechanical properties were studied by utilizing two chemical blowing agents (CBAs) with different activation temperatures and varying packing times. At the highest foaming temperatures, BMWD LCB PP foams exhibited 887% higher cell density, 46% smaller cell sizes, and more uniform cell structures than BWMD linear PP. Linear PP was found to have a surface roughness 23% higher on average than other resins. The BMWD LCB PP was found to have increased flexural modulus (44%) at the cost of decreased toughness (−88%) compared to linear PP. The branched architecture and high molecular weight of the BMWD LCB PP contributed to improved foam morphologies and surface quality in high-temperature MO-FIM conditions.
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Affiliation(s)
- Steven Mendoza-Cedeno
- Department of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, ON M5S 3G8, Canada; (S.M.-C.); (M.S.K.)
| | - Mu Sung Kweon
- Department of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, ON M5S 3G8, Canada; (S.M.-C.); (M.S.K.)
| | - Sarah Newby
- ExxonMobil Chemical Company, 5200 Bayway Drive, Baytown, TX 77520, USA; (S.N.); (M.S.); (G.P.)
| | - Maksim Shivokhin
- ExxonMobil Chemical Company, 5200 Bayway Drive, Baytown, TX 77520, USA; (S.N.); (M.S.); (G.P.)
| | - George Pehlert
- ExxonMobil Chemical Company, 5200 Bayway Drive, Baytown, TX 77520, USA; (S.N.); (M.S.); (G.P.)
| | - Patrick C. Lee
- Department of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, ON M5S 3G8, Canada; (S.M.-C.); (M.S.K.)
- Correspondence: ; Tel.: +1-(416)-946-5407
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5
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Prompt Determination of the Mechanical Properties of Industrial Polypropylene Sandwich Pipes. MATERIALS 2021; 14:ma14092128. [PMID: 33922316 PMCID: PMC8122841 DOI: 10.3390/ma14092128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 04/19/2021] [Accepted: 04/19/2021] [Indexed: 11/17/2022]
Abstract
A simple and prompt method to determine the mechanical properties of industrial multilayer extrusion polypropylene pipes for a gravity sewer network is suggested. The engineering formulas included for calculating the permissible thickness and relative position of a foam core in the pipes are based on a linear-elastic approximation and the rule of mixtures. The applicability of the approximation was justified experimentally during investigation of the effective tensile characteristics of single- and multilayer pipes and each layer specimen by using traditional tests and finite-element calculations. The results obtained were used to formulate engineering recommendations for calculations of this type.
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Tsagdi A, Drossos I, Georgiou D, Exarhopoulos S, Karasiotas G, Kallitsis JK, Kalogianni EP. Injection Molded PP Foams Using Food Ingredients for Food Packaging Applications. Polymers (Basel) 2021; 13:polym13020288. [PMID: 33477424 PMCID: PMC7830478 DOI: 10.3390/polym13020288] [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: 12/11/2020] [Revised: 01/12/2021] [Accepted: 01/14/2021] [Indexed: 11/29/2022] Open
Abstract
A new approach to the creation of polypropylene (PP) based foaming materials was developed using food grade foaming agents that were coated on the PP pellets. More specifically, sodium bicarbonate and organic acids were used to coat PP pellets using either polyethyleneoxide (PEO) or lipid esters as coating stabilizers. In order to overcome the problem of the thermal decomposition of sodium bicarbonate at temperatures lower than the PP melting temperature, which makes the direct foaming during melt mixing impossible, the proposed methodology was proved quite efficient. Thus, new PP masterbatches were prepared, where the foaming agents were incorporated as coating at PP pellets at contents up to 10%, and initially used in Lab scale injection machines in order to find the best combination of materials that resulted in the production of foamed articles. Subsequently selected material combinations were tested in an industrial scale injection molding machine, where an optimization of the injection parameters was attempted. The outcome of this was the production of PP articles with significantly increased void fraction, up to 14%, decreased thermal conductivity, up to 20%, and various pore sizes as was observed via microscopic examination using SEM and CLSM.
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Affiliation(s)
- Artemis Tsagdi
- Department of Chemistry, University of Patras, GR-26504 Patras, Greece; (A.T.); (J.K.K.)
| | - Ioannis Drossos
- Thrace Plastics Pack S.A., Member of Thrace Group Companies, GR-67100 Magiko Xanthi, Greece; (I.D.); (G.K.)
| | - Despoina Georgiou
- Department of Food Science and Technology, International Hellenic University, GR-57001 Thermi, Greece; (D.G.); (S.E.)
| | - Stylianos Exarhopoulos
- Department of Food Science and Technology, International Hellenic University, GR-57001 Thermi, Greece; (D.G.); (S.E.)
| | - Georgios Karasiotas
- Thrace Plastics Pack S.A., Member of Thrace Group Companies, GR-67100 Magiko Xanthi, Greece; (I.D.); (G.K.)
| | - Joannis K. Kallitsis
- Department of Chemistry, University of Patras, GR-26504 Patras, Greece; (A.T.); (J.K.K.)
| | - Eleni P. Kalogianni
- Department of Food Science and Technology, International Hellenic University, GR-57001 Thermi, Greece; (D.G.); (S.E.)
- Correspondence: ; Tel.: +30-2310-013907
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7
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Suethao S, Shah DU, Smitthipong W. Recent Progress in Processing Functionally Graded Polymer Foams. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E4060. [PMID: 32933128 PMCID: PMC7560401 DOI: 10.3390/ma13184060] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/05/2020] [Accepted: 09/08/2020] [Indexed: 01/08/2023]
Abstract
Polymer foams are an important class of engineering material that are finding diverse applications, including as structural parts in automotive industry, insulation in construction, core materials for sandwich composites, and cushioning in mattresses. The vast majority of these manufactured foams are homogeneous with respect to porosity and structural properties. In contrast, while cellular materials are also ubiquitous in nature, nature mostly fabricates heterogeneous foams, e.g., cellulosic plant stems like bamboo, or a human femur bone. Foams with such engineered porosity distribution (graded density structure) have useful property gradients and are referred to as functionally graded foams. Functionally graded polymer foams are one of the key emerging innovations in polymer foam technology. They allow enhancement in properties such as energy absorption, more efficient use of material, and better design for specific applications, such as helmets and tissue restorative scaffolds. Here, following an overview of key processing parameters for polymer foams, we explore recent developments in processing functionally graded polymer foams and their emerging structures and properties. Processes can be as simple as utilizing different surface materials from which the foam forms, to as complex as using microfluidics. We also highlight principal challenges that need addressing in future research, the key one being development of viable generic processes that allow (complete) control and tailoring of porosity distribution on an application-by-application basis.
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Affiliation(s)
- Supitta Suethao
- Specialized Center of Rubber and Polymer Materials in Agriculture and Industry (RPM), Department of Materials Science, Faculty of Science, Kasetsart University, Chatuchak, Bangkok 10900, Thailand;
| | - Darshil U. Shah
- Centre for Natural Material Innovation, Department of Architecture, University of Cambridge, Cambridge CB2 1PX, UK;
| | - Wirasak Smitthipong
- Specialized Center of Rubber and Polymer Materials in Agriculture and Industry (RPM), Department of Materials Science, Faculty of Science, Kasetsart University, Chatuchak, Bangkok 10900, Thailand;
- Office of Natural Rubber Research Program, Thailand Science Research and Innovation (TSRI), Chatuchak, Bangkok 10900, Thailand
- Office of Research Integration on Target–Based Natural Rubber, National Research Council of Thailand (NRCT), Chatuchak, Bangkok 10900, Thailand
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8
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Contreras V, Maturana FJ, Poveda J, Núñez KC, Merino JC, Pastor JM. Optimization of injection parameters to obtain selected properties on foamed PP with hollow glass microspheres and thermally expandable microspheres using Taguchi method. J CELL PLAST 2020. [DOI: 10.1177/0021955x20943097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A foaming system composed by hollow glass microspheres (HGM) and thermally expandable microspheres (EM) was used to achieve a balance between selected properties of foamed polypropylene (PP) by injection molding, combining the higher flexural properties and lower density required on automotive interior parts. Taguchi’s L16 (44.23) was employed for the experimental plan and signal to noise ratio (S/N) for the optimization of the system raised. The two important injection molding parameters affecting selected properties were melt and mold temperature. The most important effect on flexural modulus was the amount of HGM, and for density the amount of EM.
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Affiliation(s)
- Vicente Contreras
- Department of Condensed Matter Physics, University of Valladolid, Valladolid, Spain
| | - Francisco J Maturana
- Foundation for Research and Development in Transport and Energy (CIDAUT), Materials-Process-Product Area, Valladolid, Spain
| | - Jesús Poveda
- Foundation for Research and Development in Transport and Energy (CIDAUT), Materials-Process-Product Area, Valladolid, Spain
| | - Karina C Núñez
- Foundation for Research and Development in Transport and Energy (CIDAUT), Materials-Process-Product Area, Valladolid, Spain
| | - Juan C Merino
- Department of Condensed Matter Physics, University of Valladolid, Valladolid, Spain
- Foundation for Research and Development in Transport and Energy (CIDAUT), Materials-Process-Product Area, Valladolid, Spain
| | - José M Pastor
- Department of Condensed Matter Physics, University of Valladolid, Valladolid, Spain
- Foundation for Research and Development in Transport and Energy (CIDAUT), Materials-Process-Product Area, Valladolid, Spain
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9
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Díaz‐Ovalle CO, Castrejón‐González EO, González‐Núñez R, Ramos‐Ojeda E, Herrera‐Pérez G. Analysis of bubble formation during injection molding of polymeric foams by computational fluid dynamics simulations. ASIA-PAC J CHEM ENG 2020. [DOI: 10.1002/apj.2474] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | | | | | - Erika Ramos‐Ojeda
- Departamento de IngenieríasTecnológico Nacional de México/I.T. Roque Celaya Mexico
| | - Gabriel Herrera‐Pérez
- Departamento de Ingeniería en MaterialesTecnológico Nacional de México/ITESI Irapuato Mexico
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10
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Yeh SK, Yang SH, Han L, Liu HY, Liao YS, Chang YC. Foam extrusion of polypropylene–rice husk composites using CO2 as the blowing agent. J CELL PLAST 2019. [DOI: 10.1177/0021955x19839744] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Shu-Kai Yeh
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, ROC
| | - Ssu-Hsuan Yang
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, ROC
| | - Long Han
- Huntsman LLC, The Woodlands, TX, USA
| | - Hung-Yun Liu
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, ROC
| | - Yi-Syun Liao
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, ROC
| | - Yi-Chun Chang
- Miniwiz Sustainable Energy Development Co., Ltd, Taipei, Taiwan, ROC
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11
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Xie P, Wu G, Cao Z, Han Z, Zhang Y, An Y, Yang W. Effect of Mold Opening Process on Microporous Structure and Properties of Microcellular Polylactide⁻Polylactide Nanocomposites. Polymers (Basel) 2018; 10:polym10050554. [PMID: 30966588 PMCID: PMC6415379 DOI: 10.3390/polym10050554] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 05/06/2018] [Accepted: 05/09/2018] [Indexed: 11/16/2022] Open
Abstract
Cell structure is a key factor that determines the final properties of microcellular polylactide (PLA) product. In the mold opening process, adjusting the rate of mold opening can effectively control cell structure. PLA and PLA composites with a void fraction as high as 50% were fabricated using the mold opening technique. The effects of mold opening rate and the addition of nanoclay on the cell structure, mechanical properties, and surface quality of microcellular PLA and PLA composites samples were investigated. The results showed that finer cell structure was received in the microcellular PLA samples and the surface quality was improved effectively when decreasing the rate of mold opening. The effect of mold opening rate on the foaming behavior of microcellular PLA⁻nanoclay was the same as that of microcellular PLA. The addition of 5 wt % nanoclay significantly improved the foaming properties, such as cell density, cell size, and structural uniformity, which consequently enhanced the mechanical properties of foams and the surface quality.
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Affiliation(s)
- Pengcheng Xie
- College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Gaojian Wu
- College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Zhida Cao
- College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Zhizhong Han
- College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Youchen Zhang
- College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Ying An
- College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Weimin Yang
- College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China.
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12
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Dutta A, Sankarpandi S, Ghosh AK. Evaluation of polypropylene/clay nanocomposite foamability based on their morphological and rheological aspects. J CELL PLAST 2018. [DOI: 10.1177/0021955x18770439] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
To identify the effect of rheological influence on the development of microstructure in polypropylene/clay nanocomposites and thereby the influence of the developed microstructure on the foamability of the nanocomposites, a set of nanocomposites was prepared and batch foamed using supercritical CO2. Polypropylene and nanoclay were selected for preparing nanocomposites. During foaming, the nanocomposites were saturated with CO2 gas for three different time periods and subsequently in-situ heating was done to achieve cell growth. The gas saturation was done at subcritical condition followed by the foaming at critical condition of CO2. Thermal studies of the composites were investigated through differential scanning calorimetry, and clay dispersion morphology was investigated and validated using wide-angle X-ray diffraction, transmission electron microscopy, and parallel plate rheology. The improvement in foam morphology (cell size and cell density) and subsequent reduction in foam density was analyzed. The fingerprint characteristics of nanocomposites have an enormous role on foam structure development. With the increase in clay loading, cell density increased; furthermore, with an increase in saturation time, there was a phenomenal decrease in expansion ratio of neat polypropylene due to CO2-induced crystallization which could be mitigated by the incorporation of nanoclay into the polypropylene matrix. Therefore, nanoclay could be exploited as the inhibitor of CO2-induced crystallization.
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Affiliation(s)
- Anindya Dutta
- Centre for Polymer Science and Engineering, Indian Institute of Technology Delhi, New Delhi, India
| | - Sabapathy Sankarpandi
- Centre for Polymer Science and Engineering, Indian Institute of Technology Delhi, New Delhi, India
| | - Anup K Ghosh
- Centre for Polymer Science and Engineering, Indian Institute of Technology Delhi, New Delhi, India
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