Evaluation of Out-of-Autoclave (OOA) epoxy system

Guilherme, Fernanda; Cassu, Silvana Navarro; Diniz, Milton Faria; Leal, Tanila Penteado de Faria Gonzales; Sanches, Natália Beck; Dutra, Rita de Cássia Lazzarini

doi:10.1590/0104-1428.16016

Cited by 5 publications

(4 citation statements)

References 13 publications

(16 reference statements)

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“…Advanced composites in the form of fiber‐reinforced composites (FRC) are widely used in applications for lightweight structures, replacing metallic materials, due to their commendable mechanical properties, design flexibility, and corrosion‐free structures. [ 1–5 ] Autoclave processing which utilizes above‐ambient pressures (typically ranges from 5 to 10 atm) during a high‐temperature curing process, is a robust technique to produce FRC. However, the high‐acquisition, operation, and maintenance costs associated with autoclave shells, time‐consuming curing processes, and limited composite size motivate the need for more economical and flexible alternative manufacturing techniques.…”

Section: Introductionmentioning

confidence: 99%

Effects of processing parameters for vacuum‐bag‐only method on void content and mechanical properties of laminated composites

et al. 2020

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Process parameters for vacuum‐bag‐only (VBO) method are of critical importance to control manufacturing‐induced void content and mechanical properties of laminated composites. Currently, no comparative studies are readily available on various VBO processing parameters namely bagging techniques, cure cycles, and laminate thicknesses on induced defects and mechanical properties. Hence, this study investigates the effects of these parameters on manufacturing‐induced void content and mechanical properties of composite laminates. Laminate samples were manufactured using L27 Taguchi orthogonal array experimental plan. Void contents, tensile and flexural properties of these samples were evaluated. Double VBO technique and direct (modified) cure cycle were found to be the most promising parameters in achieving the lowest void content among choices of bagging techniques and cure cycles, respectively. However, improved mechanical properties were achieved using a single VBO technique due to the higher fiber reinforcement volume fraction. In comparison to a typical cure cycle, the modified cure cycles were able to reduce surface porosity and through‐thickness void by 48.33% and 23.7%, respectively, whereas the tensile and flexural properties were increased by 2% to 3% and 17% to 20%, respectively. In addition, no significant interaction between parameters was observed.

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Section: Introductionmentioning

confidence: 99%

Effects of processing parameters for vacuum‐bag‐only method on void content and mechanical properties of laminated composites

et al. 2020

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“…Several studies have investigated the curing of epoxy resins using different curing agents [1,3,[20][21][22][23][24][25][26][27]. Most of these studies included epoxy resins cured with amines.…”

Section: Introductionmentioning

confidence: 99%

Investigation and assessment of epoxy resin adhesives using Fourier‐transform infrared spectrometry

Şengül

Tüzün

2023

Materialwissenschaft Werkst

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Epoxy resin adhesives are very attractive for many industries, especially in the aerospace and automotive industries because they eliminate heavy connection elements, such as bolts and screws, and reduce the total weight. This study assesses developed epoxy resin adhesives using Fourier‐transform infrared spectrometry. The curing reaction between Epikote 828 epoxy resin and Epikure polyamidoamine curing agent 3090, and the chemical structure of the additives (CAB‐O‐SIL TS‐720) used for rheology control and six different types of fillers (calcite with particle diameters of 700 nm, 5 μm, and 10 μm, coated calcite with a particle diameter of 900 nm, and barite and calcite with a particle diameter of 5 μm) employed in the adhesives are investigated. The Fourier‐transform infrared spectrometry results of the epoxy resin and curing agent demonstrate that 83.5 % epoxy conversion is achieved at a temperature of 25 °C. The chemical composition of the additives with six different types of fillers and 1 %, 3 %, and 5 % additions of CAB‐O‐SIL TS‐720 prepared in both nujol mull and potassium bromide discs is characterized using Fourier‐transform infrared spectrometry. The potassium bromide discs yield higher intensities owing to good packing of cubic particles of potassium bromide with nano particle size CAB‐O‐SIL TS‐720 and all filler types.

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“…There are several studies approaching the cure of epoxy resin using different curing agents (CA) (Andrade et al 2008, Wang et al 2018, Krauklis & Echtermeyer 2018, Iheaturu & Ofoegbu 2018, Konuray et al 2017, Kiran & Gaur 2016, Yamasaki & Morita 2012, Hardis 2012, González et al 2012, Lakshmi et al 2010, Raditoiu et al 2009, Fang et al 2008, Costa et al 2005, 1999, Romão et al 2004, 2006, 2003, Zeiss 2018, Guilherme et al 2017, Strzelec et al 2012). The majority of the studies approaches compositions with amines.…”

Section: Introductionmentioning

confidence: 99%

“…Differential exploratory calorimetry (DSC) and FT-IR transmission, in the middle infrared region (MIR), are the most applied. Thermogravimetric analysis (TGA) can be used offline (without coupling techniques) or online (coupled with FT-IR, for example) to determine the degradation temperature of the system and for the characterization and identification of different CAs (Guilherme et al 2017, Romão et al 2006, 2003.…”

Section: Introductionmentioning

confidence: 99%

Qualitative and quantitative evaluation of epoxy systems by Fourier transform infrared spectroscopy and the flexibilizing effect of mercaptans

Janzen

Diniz

Azevedo³

et al. 2021

An. Acad. Bras. Ciênc.

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Epoxy systems are widely applied as adhesives in the aerospace industry. They have excellent adhesion properties, however, being thermosetting, epoxy systems show fracture brittleness characteristics. Polysulfi de and polymercaptans are good options to increase the fl exibility of the epoxy adhesive. Thermal analysis techniques are generally used to evaluate the curing degree of epoxy systems. In most cases, when infrared (IR) analysis is used, it is employed qualitatively. This paper presents the reaction study of a DGEBA epoxy prepolymer with diethylenetriamine (DETA) and linear and branched dodecyl mercaptans as fl exibilizers. Conversion data and curing time were assessed qualitatively and quantitatively by Fourier Transform Infrared Spectroscopy (FT-IR) in the medium infrared region (MIR) and in the near infrared region, using near infrared refl ectance accessory (NIRA). NIRA methodology showed satisfactory results, with errors between 3 and 7%, especially in samples with lower amine contents. Mechanical tests confi rmed the fl exibilization of the cured epoxy system by the addition of mercaptans, indicating a lower crosslinking degree in the matrix. Young's modulus (E) signifi cantly decreased from 2017 MPa to 578 MPa with the addition of approximately 20 wt% of normal dodecyl mercaptan to the epoxy system.

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Evaluation of Out-of-Autoclave (OOA) epoxy system

Cited by 5 publications

References 13 publications

Effects of processing parameters for vacuum‐bag‐only method on void content and mechanical properties of laminated composites

Effects of processing parameters for vacuum‐bag‐only method on void content and mechanical properties of laminated composites

Investigation and assessment of epoxy resin adhesives using Fourier‐transform infrared spectrometry

Qualitative and quantitative evaluation of epoxy systems by Fourier transform infrared spectroscopy and the flexibilizing effect of mercaptans

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