Measuring and understanding cure-dependent viscoelastic properties of epoxy resin: A review

Müller-Pabel, Michael; Agudo, José Alberto Rodriguez; Gude, Μaik

doi:10.1016/j.polymertesting.2022.107701

Cited by 37 publications

(16 citation statements)

References 184 publications

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“…Many efforts were made to model the polymer's viscoelasticity mathematically [13][14][15]: the viscoelastic functions generally depend on temperature and applied stress for polymers and other isotropic and homogeneous materials; they are interconnected, and their relative placement in the time domain was described by Grassia et al [16] A linear behavior is assumed for the material under study: the relaxation functions do not depend on the mechanical input applied to the system. Moreover, the effect of temperature on relaxation phenomena is only used to translate the viscoelastic functions on their timescale, the hypothesis of thermo-rheological simplicity [17].…”

Section: Introductionmentioning

confidence: 99%

A Numerical Model to Predict the Relaxation Phenomena in Thermoset Polymers and Their Effects on Residual Stress during Curing—Part I: A Theoretical Formulation and Numerical Evaluation of Relaxation Phenomena

Verde,

D’Amore,

Grassia

2024

Polymers

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This paper analyzes the effect of crosslinking reactions on a thermoset polymer’s viscoelastic properties. In particular, a numerical model to predict the evolution of epoxy’s mechanical properties during the curing process is proposed and implemented in an Ansys APDL environment. A linear viscoelastic behavior is assumed, and the scaling of viscoelastic properties in terms of the temperature and degree of conversion is modeled using a modified version of the TNM (Tool–Narayanaswamy–Mohynian) model. The effects of the degree of conversion and structural relaxation on epoxy’s relaxation times are simultaneously examined for the first time. This formulation is based on the thermo-rheological and chemo-rheological simplicities hypothesis and can predict the evolution of epoxy’s relaxation phenomena. The thermal–kinetic reactions of curing are implemented in a homemade routine written in APDL language, and the structural module of Ansys is used to predict the polymer’s creep and stress relaxation curves at different temperatures and degrees of conversion.

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Section: Introductionmentioning

confidence: 99%

A Numerical Model to Predict the Relaxation Phenomena in Thermoset Polymers and Their Effects on Residual Stress during Curing—Part I: A Theoretical Formulation and Numerical Evaluation of Relaxation Phenomena

Verde,

D’Amore,

Grassia

2024

Polymers

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“…40 However, a comprehensive and complex experimental characterization of the resin material represents a prerequisite for the use of cure-dependent viscoelastic models. 41…”

Section: Introductionmentioning

confidence: 99%

“…40 However, a comprehensive and complex experimental characterization of the resin material represents a prerequisite for the use of curedependent viscoelastic models. 41 To close this gap and to numerically predict the surface properties of FRP, the cure-dependent visco-thermo-elastic model introduced in 42,43 is used to predict the surface waviness of an epoxy resin composite. The underlying material data are taken from 12,44 and have previously been determined under process-specific conditions.…”

Section: Introductionmentioning

confidence: 99%

Development and verification of a cure-dependent visco-thermo-elastic simulation model for predicting the process-induced surface waviness of continuous fiber reinforced thermosets

Lorenz

Gröger

Müller-Pabel

et al. 2023

Journal of Composite Materials

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Process-induced surface waviness effects represent a major concern for series production of high-quality lightweight structures based on fiber reinforced plastics (FRP). This paper suggests a method for the numerical prediction of these effects by using the example of processing glass fiber reinforced plastics (GFRP) in a resin transfer molding (RTM) process. The influence of reaction kinetics, chemical shrinkage and cure-dependent viscoelastic properties of the resin are taken into account. Furthermore, the dependence of surface quality on curing cycle, consolidation pressure, textile architecture and thickness of neat resin layer (NRL) at the part surface are investigated. The work is based on published material data and a visco-thermo-elastic simulation approach which has been previously presented and validated. All numerical results are compared to the surfaces of FRP plates that were manufactured with the corresponding parameter variations. Based on a literature survey, different surface waviness values have been identified for comparison of experimental and numerical results. Satisfactory agreement between experiments and simulations is found. Furthermore, it is shown that the analyzed NRL thickness has no relevant influence on the surface waviness while the curing temperature significantly affects the surface waviness. The role of relaxation-induced change of the surface waviness is highlighted by performing long-term measurements and corresponding time-dependent simulations. It is concluded that relaxation plays a decisive role in the appropriate selection of the subsequent surface finishing process. The suggested simulation approach provides a basis for optimization strategies to improve surface quality and reduce post-processing effort.

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“…When the temperature rises, the E of polymers tends to decrease, while the E and Tanδ increase until they reach the Tg. The rigidity of the specific polymer composite is recognized as the cause of the decrease in E , whereas E corresponds to the energy dissipation caused by the viscous phase of the polymer [16].…”

Section: Introductionmentioning

confidence: 99%

Effect of Fiber Loading on Thermal Properties of Cellulosic Washingtonia Reinforced HDPE Biocomposites

et al. 2023

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In this research work, we aim to study the effect of the incorporation of vegetable fiber reinforcement on the thermo-mechanical and dynamic properties of a composite formed by a polymeric matrix reinforced with cellulosic fibers with the various Washingtonia fiber (WF) loadings (0%, 10%, 20%, and 30% by wt%) as reinforced material in high-density polyethylene (HDPE) Biocomposites to evaluate the optimum fiber loading of biocomposites. In addition, several characterization techniques (i.e., thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermal mechanical analysis (TMA)) were used to better understand the characteristics of the new composites prepared. With these techniques, we managed to verify the rigidity and thermal stability of the composites so elaborated, as well as the success of the polymer and the structural homogeneity of the obtained biocomposites. Hence, the biocomposite with the best ratio (HDPE/20WF) showed a loss modulus (E″) of 224 MPa, a storage modulus (E′) of 2079 MPa, and a damping factor (Tanδ) of 0.270 to the glass transition (Tg) of 145 °C. In addition, thermomechanical analysis (TMA) of the biocomposite samples exhibited marginally higher Ts compared to the HDPE matrix. The best results were recorded with biocomposites with 20% WF, which showed better thermal properties. This composite material can be used as insulation in construction materials (buildings, false ceilings, walls, etc.).

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Measuring and understanding cure-dependent viscoelastic properties of epoxy resin: A review

Cited by 37 publications

References 184 publications

A Numerical Model to Predict the Relaxation Phenomena in Thermoset Polymers and Their Effects on Residual Stress during Curing—Part I: A Theoretical Formulation and Numerical Evaluation of Relaxation Phenomena

A Numerical Model to Predict the Relaxation Phenomena in Thermoset Polymers and Their Effects on Residual Stress during Curing—Part I: A Theoretical Formulation and Numerical Evaluation of Relaxation Phenomena

Development and verification of a cure-dependent visco-thermo-elastic simulation model for predicting the process-induced surface waviness of continuous fiber reinforced thermosets

Effect of Fiber Loading on Thermal Properties of Cellulosic Washingtonia Reinforced HDPE Biocomposites

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