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Liu H, Zhao F, Li H, Xie H, Jiang C, Xie L. Modified hollow glass microspheres composite isocyanate-based polyimide foam with improving mechanical and thermal insulation properties. HIGH PERFORM POLYM 2022. [DOI: 10.1177/09540083221074606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In this work, hollow glass microspheres (HGM) were introduced into the polyimide matrix as an effective reinforcement filler to improve the mechanical and thermal insulation properties of the polyimide foams (PIF). The HGM was surface-modified with the silane coupling agent to enhance the interfacial compatibility with PIF. Experimental results revealed that the average cellular diameter of PIF decreased obviously with the addition of the modified HGM (M-HGM). The apparent density of foams also increased from 15.85 to 18.34 kg/m3 when the M-HGM combination was changed from 0 to 12 percent (wt.%). Compared with the pure PIF, the composite foams added 8 wt.% M-HGM showed high compression strength (65 kPa) and compression modulus (1147 kPa), resulting in a distinct enhancement in mechanical properties. Furthermore, the addition of M-HGM filler also improved the thermal insulation performance of PIF, which exhibited the minimum thermal conductivity of 29.48 mW·m−1·K−1 with 8 wt.% M-HGM. Thus, considering the improved mechanical and insulation properties of the prepared PIF, it could be a promising candidate for the high temperature-resistant thermal insulating applications.
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Affiliation(s)
- Hao Liu
- College of Chemistry and Chemical Engineering, Central South University, Hunan, China
| | - Fuxing Zhao
- College of Chemistry and Chemical Engineering, Central South University, Hunan, China
| | - Hanxin Li
- College of Chemistry and Chemical Engineering, Central South University, Hunan, China
| | | | - Chongwen Jiang
- College of Chemistry and Chemical Engineering, Central South University, Hunan, China
- Hunan Provincial Key Laboratory of Efficient and Clean Utilization of Manganese Resources, Central South University, Hunan, China
| | - Le Xie
- College of Chemistry and Chemical Engineering, Central South University, Hunan, China
- Hunan Provincial Key Laboratory of Efficient and Clean Utilization of Manganese Resources, Central South University, Hunan, China
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Li S, Jiang S, Gong S, Ma S, Yang H, Pan K, Deng J. Preparation Methods, Performance Improvement Strategies, and Typical Applications of Polyamide Foams. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.1c03715] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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High-Performance of a Thick-Walled Polyamide Composite Produced by Microcellular Injection Molding. MATERIALS 2021; 14:ma14154199. [PMID: 34361391 PMCID: PMC8348799 DOI: 10.3390/ma14154199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/20/2021] [Accepted: 07/24/2021] [Indexed: 11/17/2022]
Abstract
Lightweight moldings obtained by microcellular injection molding (MIM) are of great significance for saving materials and reducing energy consumption. For thick-walled parts, the standard injection molding process brings some defects, including a sink mark, warpage, and high shrinkage. Polyamide 66 (PA66)/glass fiber (GF) thick-walled moldings were prepared by MuCell® technology. The influences of moldings thickness (6 and 8.4 mm) and applied nitrogen pressure (16 and 20 MPa) on the morphology and mechanical properties were studied. Finally, the microcellular structure with a small cell diameter of about 30 μm was confirmed. Despite a significant time reduction of the holding phase (to 0.3 s), high-performance PA66 GF30 foamed moldings without sink marks and warpage were obtained. The excellent strength properties and favorable impact resistance while reducing the weight of thick-walled moldings were achieved. The main reason for the good results of polyamide composite was the orientation of the fibers in the flow direction and the large number of small nitrogen cells in the core and transition zone. The structure gradient was analysed and confirmed with scanning electron microscopy (SEM) images, X-ray micro computed tomography (micro CT) and finite element method (FEM) simulation.
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Rivera-Salinas JE, Gregorio-Jáuregui KM, Fonseca-Florido HA, Ávila-Orta CA, Ramírez-Vargas E, Romero-Serrano JA, Cruz-Ramírez A, Gutierréz-Pérez VH, Olvera-Vazquez SL, Rosales-Marines L. Numerical Study Using Microstructure Based Finite Element Modeling of the Onset of Convective Heat Transfer in Closed-Cell Polymeric Foam. Polymers (Basel) 2021; 13:polym13111769. [PMID: 34071343 PMCID: PMC8199126 DOI: 10.3390/polym13111769] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 11/22/2022] Open
Abstract
The thermal performance of closed-cell foams as an insulation device depends on the thermal conductivity. In these systems, the heat transfer mode associated with the convective contribution is generally ignored, and studies are based on the thermo-physical properties that emerge from the conductive contribution, while others include a term for radiative transport. The criterion found in the literature for disregarding convective heat flux is the cell diameter; however, the cell size for which convection is effectively suppressed has not been clearly disclosed, and it is variously quoted in the range 3–10 mm. In practice, changes in thermal conductivity are also attributed to the convection heat transfer mode; hence, natural convection in porous materials is worthy of research. This work extends the field of study of conjugate heat transfer (convection and conduction) in cellular materials using microstructure-based finite element analysis. For air-based insulating materials, the criteria to consider natural convection (Ra=103) is met by cavities with sizes of 9.06 mm; however, convection is developed into several cavities despite their sizes being lower than 9.06 mm, hence, the average pore size that can effectively suppress the convective heat transfer is 6.0 mm. The amount of heat transported by convection is about 20% of the heat transported by conduction within the foam in a Ra=103, which, in turn, produces an increasing average of the conductivity of about 4.5%, with respect to a constant value.
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Affiliation(s)
- Jorge-Enrique Rivera-Salinas
- Catedrático CONACyT—Departamento de Procesos de transformación, Centro de Investigación en Química Aplicada—CIQA, Saltillo 25294, Coahuila, Mexico
- Correspondence:
| | - Karla-Monzerratt Gregorio-Jáuregui
- Departamento de Ingeniería en Metalurgia y Materiales, Instituto Politécnico Nacional, Escuela Superior de Ingeniería Química e Industrias Extractivas—ESIQIE, UPALM, Ciudad de México 07738, CDMX, Mexico; (K.-M.G.-J.); (J.-A.R.-S.); (A.C.-R.)
| | - Heidi-Andrea Fonseca-Florido
- Catedrático CONACyT—Departamento de Materiales Avanzados, Centro de Investigación en Química Aplicada—CIQA, Saltillo 25294, Coahuila, Mexico;
| | - Carlos-Alberto Ávila-Orta
- Departamento de Materiales Avanzados, Centro de Investigación en Química Aplicada—CIQA, Saltillo 25294, Coahuila, Mexico;
| | - Eduardo Ramírez-Vargas
- Departamento de Procesos de transformación, Centro de Investigación en Química Aplicada—CIQA, Saltillo 25294, Coahuila, Mexico;
| | - José-Antonio Romero-Serrano
- Departamento de Ingeniería en Metalurgia y Materiales, Instituto Politécnico Nacional, Escuela Superior de Ingeniería Química e Industrias Extractivas—ESIQIE, UPALM, Ciudad de México 07738, CDMX, Mexico; (K.-M.G.-J.); (J.-A.R.-S.); (A.C.-R.)
| | - Alejandro Cruz-Ramírez
- Departamento de Ingeniería en Metalurgia y Materiales, Instituto Politécnico Nacional, Escuela Superior de Ingeniería Química e Industrias Extractivas—ESIQIE, UPALM, Ciudad de México 07738, CDMX, Mexico; (K.-M.G.-J.); (J.-A.R.-S.); (A.C.-R.)
| | - Víctor-Hugo Gutierréz-Pérez
- Departamento de Formación Profesional Específica, Instituto Politécnico Nacional—Unidad Profesional Interdisciplinaria de Ingeniería Campus Zacatecas—UPIIZ, Zacatecas 98160, Zacatecas, Mexico; (V.-H.G.-P.); (S.-L.O.-V.)
| | - Seydy-Lizbeth Olvera-Vazquez
- Departamento de Formación Profesional Específica, Instituto Politécnico Nacional—Unidad Profesional Interdisciplinaria de Ingeniería Campus Zacatecas—UPIIZ, Zacatecas 98160, Zacatecas, Mexico; (V.-H.G.-P.); (S.-L.O.-V.)
| | - Lucero Rosales-Marines
- Facultad de Ciencias Químicas, Universidad Autónoma de Coahuila, Blvd. Venustiano Carranza e Ing. José Cárdenas Valdés, Saltillo 2528, Coahuila, Mexico;
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García Hernández Z, Miranda Teran ZN, González Morones P, Yañez Macías R, Solís Rosales SG, Romero GY, Sifuentes‐Nieves I, Hernández‐Hernández E. Performance of nylon 6 composites reinforced with modified agave fiber: Structural, morphological, and mechanical features. J Appl Polym Sci 2021. [DOI: 10.1002/app.50857] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Zureima García Hernández
- Departamento de Materiales Avanzados Centro de Investigación en Química Aplicada Saltillo Mexico
| | | | - Pablo González Morones
- Departamento de Materiales Avanzados Centro de Investigación en Química Aplicada Saltillo Mexico
| | - Roberto Yañez Macías
- Departamento de Materiales Avanzados Centro de Investigación en Química Aplicada Saltillo Mexico
| | - Silvia G. Solís Rosales
- Departamento de Materiales Avanzados Centro de Investigación en Química Aplicada Saltillo Mexico
| | - Gabriela Yolotzin Romero
- Departamento de Materiales Avanzados Centro de Investigación en Química Aplicada Saltillo Mexico
| | - Israel Sifuentes‐Nieves
- Departamento de Materiales Avanzados Centro de Investigación en Química Aplicada Saltillo Mexico
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