Curing multidirectional carbon fiber reinforced polymer composites with indirect microwave heating
01 Jul 2018-The International Journal of Advanced Manufacturing Technology (Springer London)-Vol. 97, Iss: 1, pp 1137-1147
TL;DR: In this article, an indirect microwave curing method was proposed to solve the problem of carbon fiber reinforced polymer composite materials used in aerospace products, compared with traditional autoclave curing technologies, and the microwave absorption performance of the indirect microwave heating medium was systematically optimized by evaluating its dielectric properties and reflection loss according to the transmission line theory.
Abstract: Microwave curing technologies have many advantages in manufacturing fiber reinforced polymer composite materials used in aerospace products, compared with traditional autoclave curing technologies. However, multidirectional carbon fiber reinforced polymer composites can hardly be penetrated and heated by microwave directly, which has become a major obstacle in industrial application worldwide. In this paper, an indirect microwave curing method was proposed to solve this problem. The microwave absorption performance of the indirect microwave heating medium was systematically optimized by evaluating its dielectric properties and reflection loss according to the transmission line theory. On this basis, the microwave susceptive mold was carefully designed and manufactured. Subsequently, the multidirectional carbon fiber/epoxy composite was successfully cured with indirect microwave heating, which was demonstrated by the observation of the curing process with infrared thermal imager and differential scanning calorimetry analysis of the final products. Compared with the traditional thermal curing method, the curing cycle and energy consumption were reduced by 42.1% and 75.9% respectively. Results of further characterization experiments indicated that the mechanical properties of indirect microwave cured specimens were slightly higher than those of the thermally cured counterparts.
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TL;DR: In this paper, the influence of microwave power on the mechanical properties of 20-wt.% coir reinforced high-density polyethylene (HDPE) composites was investigated.
Abstract: The present work deals with investigating the influence of microwave power on mechanical properties of 20 wt.% coir reinforced high-density polyethylene (HDPE) composites. Chopped coir/HDPE composi...
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Cites background from "Curing multidirectional carbon fibe..."
...Li, Cheng, and Zhou (2018) used indirect microwave heating to cure multidirectional carbon fiber reinforced polymer composites....
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11 Apr 2019
TL;DR: In this paper, the carbon fibers were successfully recovered by thermolysis under an oxygen atmosphere, and the properties of the recovered carbon fiber were characterized by field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and Raman spectroscope.
Abstract: With the growth of the use of carbon fiber-reinforced polymer (CFRP) in various fields, the recovery of carbon fibers from CFRP waste is becoming a significant research direction. In the present work, degrading epoxy resin and recycling carbon fibers from CFRP waste by microwave thermolysis and traditional thermolysis were studied. The carbon fibers were successfully recovered by thermolysis under an oxygen atmosphere in this study. The properties of the recovered carbon fibers were characterized by field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and Raman spectroscopy. The result shows that using microwave thermolysis to recover carbon fibers from CFRP waste is an attractive prospect. Compared to the traditional method, the reaction time was reduced by 56.67%, and the recovery ratio was increased by 15%. Microwave thermolysis is faster, more efficient, requires less energy, and obtains cleaner recovered carbon fibers than those recovered using traditional thermolysis.
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TL;DR: In this paper, a series of self-resistance electric (SRE) experiments were conducted, in which the temperature distribution field, energy consumption, and curing time of SRE curing process were characterized.
Abstract: Carbon fiber reinforced plastic self-resistance electric (SRE) heating has been conceived as an alternative to out-of-autoclave technology due to its characteristics of uniform heating, fast heating/cooling, low energy consumption, and low equipment investment. In this work, a series of SRE heating experiments were conducted, in which the temperature distribution field, energy consumption, and curing time of SRE curing process were characterized. Comprehensive mechanical tests and microscopic characterization were carried out. The experimental results exhibit that the rapid heating rate of SRE curing process resulted in a weaker matrix performance because of the insufficient time of void elimination, which finally leads to an inferior compression and flexural strength for the composite part, while the fiber preferential heating effect can significantly improve the fiber-resin interfacial strength, because the naturally formed temperature difference along the interfacial area enhanced the adhesive strength of the resin around the interface, which improved the macroscopic tension and interlaminar shear strength.
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TL;DR: In this article , an overview of the basics of microwave heating and the physics behind the microwave processing of polymer composites is presented, and the major constraints in adopting microwave technology for curing composites at the industry scale are highlighted.
Abstract: Search for novel energy-efficient, eco-friendly, and time-saving manufacturing techniques has gained momentum in the recent times. Polymer composites have been increasingly adapted for variety of industrial applications, however, their efficient processing remains challenging. Microwave curing technique has been employed to process thermoset-based composites since 1980, however, processing of thermoplastic-based composites with natural-fibers as reinforcement, calls for additional data and hence investigations. The current work presents an overview of the basics of microwave heating and the physics behind the microwave processing of polymer composites. A state-of-the-art on microwave processing of thermoset and thermoplastic-based composites and developments in microwave joining has been reviewed. The major constraints in adopting microwave technology for curing composites at the industry scale are highlighted. The article also highlights the challenges during microwave processing of sustainable thermoplastic-based polymer composites. Future scope of work to 3D print the polymer matrix composite parts, through microwave scanning route has been indicated.
25 citations
TL;DR: In this paper, a multiphysics model was constructed to reflect the composite curing behavior in a cost-effective manner, which agreed well with the experimental results, and a new indirect microwave curing cycle was designed, and relevant process parameters were determined.
Abstract: Recently, indirect microwave curing technology was developed to process multidirectional carbon fiber reinforced composite materials with high efficient and energy saving purpose. The aim of this paper is to solve the problem of large mid-plane heat generation in manufacturing this kind of materials with large thickness. The difference between the traditional thermal curing and indirect microwave curing processes was analyzed. A Multiphysics model was constructed to reflect the composite curing behavior in a cost-effective manner, which agreed well with the experimental results. On this basis, a new indirect microwave curing cycle was designed, and relevant process parameters were determined. Compared with the manufacturer’s recommended cycle, the degree of mid-plane heat generation was greatly relieved, and a reduction of 34.6% in composite residual strains was achieved. Moreover, the curing cycle was reduced by 38%, while the interlaminar shear strength of the composite was improved by 1.38 times. Corresponding reinforcement mechanisms were explored through the observation of composite cross-sections with optical microscopes.
16 citations
References
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TL;DR: In this paper, the fundamentals of electromagnetic theory, dielectric response, and applications of microwave heating to materials processing, especially fiber composites, are reviewed in this article, and a knowledge of electromagnetic theories and dielectrics is essential to optimize the processing of materials through microwave heating.
Abstract: In microwave processing, energy is supplied by an electromagnetic field directly to the material. This results in rapid heating throughout the material thickness with reduced thermal gradients. Volumetric heating can also reduce processing times and save energy. The microwave field and the dielectric response of a material govern its ability to heat with microwave energy. A knowledge of electromagnetic theory and dielectric response is essential to optimize the processing of materials through microwave heating. The fundamentals of electromagnetic theory, dielectric response, and applications of microwave heating to materials processing, especially fiber composites, are reviewed in this article.
1,296 citations
TL;DR: In this paper, most of the significant phenomena that cause heating during microwave-material interaction and heat transfer during microwave energy absorption in materials are discussed. But, the mechanisms associated with the processing are less understood; popular mechanisms such as dipolar heating and conduction heating have been mostly explored.
Abstract: Efforts to use microwaves in material processing are gradually increasing. However, the phenomena associated with the processing are less understood; popular mechanisms such as dipolar heating and conduction heating have been mostly explored. The current paper reviews most of the significant phenomena that cause heating during microwave–material interaction and heat transfer during microwave energy absorption in materials. Mechanisms involved during interaction of microwave with characteristically different materials – metals, non-metals and composites (metal matrix composites, ceramic matrix composites and polymer matrix composites) have been discussed using suitable illustrations. It was observed that while microwave heating of metal based materials is due to the magnetic field based loss effects, dipolar loss and conduction loss are the phenomena associated with the electric field effects in microwave heating of non-metals. Challenges in processing of advanced materials, particularly composites have been identified from the available literature; further research directions with possible benefits have been highlighted.
502 citations
TL;DR: In this paper, microwave heating was incorporated into the resin transfer molding technique, and a 50% cure cycle time reduction was achieved by using carbon fiber/epoxy composites.
131 citations
TL;DR: In this paper, the authors investigated the use of two epoxy systems where the choice of resin and hardener was based on their measured dielectric loss factors and found that System 1 composites had greater flexural properties and interlaminar shear strengths than System 2 composites when autoclave cured.
Abstract: The ease of heating an epoxy resin with microwaves depends, among other factors, on the dielectric properties of its components at the frequency of the radiation used The majority of the papers published on the microwave curing of reinforced epoxy resin composites have used widely available DGEBA type resins and amine hardeners such as 4,4’-diaminodiphenylsulphone (DDS) This paper investigates the use of two epoxy systems where the choice of resin and hardener was based on their measured dielectric loss factors System 1 contained a resin and hardener with higher loss factors than those used in System 2 The two systems were formulated with polyetherimide (PEI) as a toughening agent Unidirectional carbon fibre prepregs were prepared from both systems Composites were laid up from these prepregs which were then cured in three different ways: autoclave curing, partial autoclave curing followed by microwave post-curing, and microwave curing System 1 composites had greater flexural properties and interlaminar shear strengths than System 2 composites when autoclave cured Flexural properties and interlaminar shear strengths were greater for System 2 in the microwave post-cured composites When fully microwave cured the properties were similar In the microwave cured composites the flexural and interlaminar shear properties were influenced by the structure of the phase separated PEI and the void content
115 citations
TL;DR: In this paper, the authors present the presentation of various multifunctional materials reported in the literature and the processing means developed, focusing on the presentation and processing of different types of materials.
Abstract: Multifunctional materials are designed so as to meet specific requirements through tailored properties. Smart materials can be considered as multifunctional ones that have the ability to react upon an external stimulus, simulating, in this way, the behavior of nature’s materials. Furthermore, the introduction of biomemetics in the material science, allows the designing of materials with similar processes as nature does: building from molecules to complete structures. This paper focuses on the presentation of the various multifunctional materials reported in the literature and the processing means developed.
107 citations