Engineering › Mechanical Engineering

Epoxy Resin Curing Processes

Works Count: 30756

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Description

This cluster of papers focuses on the synthesis, modification, and application of epoxy resins and related thermosetting polymers. It covers topics such as toughening mechanisms, cure kinetics, molecular modeling, and the mechanical properties of epoxy-based materials and composite laminates.

Keywords

Epoxy Resins; Polybenzoxazines; Thermosetting Resins; Nanoparticle Modification; Toughening Mechanisms; Cure Kinetics; Molecular Modeling; Composite Laminates; Mechanical Properties; Polymerization

Phenolic Resins: A Century of Progress

2010-01-01

Louis A. Pilato

Toughening mechanisms in elastomer-modified epoxies

1989-07-01

Raymond A. Pearson , A. F. Yee

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Phase separation in epoxy resins containing polyethersulphone

1983-05-01

C. B. Bucknall , Ivana K. Partridge

Hygrothermal effects of epoxy resin. Part II: variations of glass transition temperature

1999-09-01

Jiming Zhou , James P. Lucas

Mechanism and Kinetics of Epoxy−Amine Cure Studied by Differential Scanning Calorimetry

1996-01-01

Sergey Vyazovkin , Nicolas Sbirrazzuoli

The isoconversional kinetic analysis has been applied to nonisothermal DSC data on the cure of an epoxynovolac resin. The process reveals a dependence of the activation energy (Eα) on conversion … The isoconversional kinetic analysis has been applied to nonisothermal DSC data on the cure of an epoxynovolac resin. The process reveals a dependence of the activation energy (Eα) on conversion (α). The shape of the dependence has been interpreted in the terms of the reaction mechanisms. It has been found that the model dα/dt = (k1 + αmk2)(1 − α)n used for the kinetically controlled cure gives rise to the dependence of Eα on α similar to the experimentally found one. To completely describe the diffusion-controlled cure, the effect of both T and α on the change in diffusivity has been taken into account. The equation for the specific rate constant of diffusion, kD(T,α) = Do exp(−ED/RT + Kα), has been induced. Its use allows us to obtain a model dependence of Eα on α closely matching the experimental one. A technique of predicting isothermal cure from the sole dependence of Eα on α has been considered.

Modification of epoxy resin using reactive liquid (ATBN) rubber

2002-02-01

Nourdine Chikhi , S. Fellahi , M. Bakar

A Study on the Volumetric Expansion of Benzoxazine-Based Phenolic Resin

1997-02-01

Hatsuo Ishida , Hong Yee Low

Benzoxazine-based phenolic resin has recently attracted a great deal of attention due to its versatile properties. This paper explores yet another interesting property shown by this class of phenolic resin: … Benzoxazine-based phenolic resin has recently attracted a great deal of attention due to its versatile properties. This paper explores yet another interesting property shown by this class of phenolic resin: volumetric expansion upon polymerization. It is proposed that the volumetric expansion of the benzoxazine resin is mostly due to the consequence of molecular packing influenced by inter- and intramolecular hydrogen bonding. The role of hydrogen bonding on the volumetric expansion has been studied by systematically changing the primary amine used in the benzoxazine monomer synthesis. In comparison to the other known expanding monomer, spiroortho compounds, this resin has been shown to have a high potential for structural/engineering applications. The homopolymers of this resin have a high glass transition temperature (Tg).

A finite element/control volume approach to mold filling in anisotropic porous media

1990-12-01

M. V. Bruschke , Suresh G. Advani

Abstract Mold filling in anisotropic porous media is the governing phenomena in a number of composite manufacturing processes, such as resin transfer molding (RTM) and structural reaction injection molding (SRIM). … Abstract Mold filling in anisotropic porous media is the governing phenomena in a number of composite manufacturing processes, such as resin transfer molding (RTM) and structural reaction injection molding (SRIM). In this paper we present a numerical simulation to predict the flow of a viscous fluid through a fiber network. The simulation is based on the finite element/control volume method. It can predict the movement of a free surface flow front in a thin shell mold geometry of arbitrary shape and with varying thickness. The flow through the fiber network is modeled using Darcy's law. Different permeabilities may be specified in the principal directions of the preform. The simulation permits the permeabilities to vary in magnitude and direction throughout the medium. Experiments were carried out to measure the characteristic permeabilities of fiber preforms. The results of the simulation are compared with experiments performed in a flat rectangular mold using a Newtonian fluid. A variety of preforms and processing conditions were used to verify the numerical model.

Mechanical characterization of copolymers based on benzoxazine and epoxy

1996-09-01

Hatsuo Ishida , Douglas J. Allen

Synthesis and application of epoxy resins: A review

2015-04-06

Fan‐Long Jin , Xiang Li , Soo‐Jin Park

Preparation and characterization of epoxy composites filled with functionalized nanosilica particles obtained via sol–gel process

2001-02-01

Sungtack Kang , Sung Il Hong , Chul Rim Choe +3 more

Hydrogen bonding in polymers. 4. Infrared temperature studies of a simple polyurethane

1986-08-01

Michael M. Coleman , Keun Ho Lee , Daniel J. Skrovanek +1 more

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydrogen bonding in polymers. 4. Infrared temperature studies of a simple polyurethaneMichael M. Coleman, Keun Ho Lee, Daniel J. Skrovanek, and Paul C. PainterCite this: Macromolecules 1986, … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydrogen bonding in polymers. 4. Infrared temperature studies of a simple polyurethaneMichael M. Coleman, Keun Ho Lee, Daniel J. Skrovanek, and Paul C. PainterCite this: Macromolecules 1986, 19, 8, 2149–2157Publication Date (Print):August 1, 1986Publication History Published online1 May 2002Published inissue 1 August 1986https://pubs.acs.org/doi/10.1021/ma00162a008https://doi.org/10.1021/ma00162a008research-articleACS PublicationsRequest reuse permissionsArticle Views3545Altmetric-Citations636LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Influence of particle size and particle size distribution on toughening mechanisms in rubber-modified epoxies

1991-07-01

Raymond A. Pearson , A. F. Yee

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Reaction-induced phase decomposition in polymer blends

1995-01-01

Takanori Inoue

Atomistic molecular modelling of crosslinked epoxy resin

2006-07-01

Chaofu Wu , Weijian Xu

The engineering aspects of automated prepreg layup: History, present and future

2011-12-17

D. Lukaszewicz , Carwyn Ward , Kevin Potter

A Molecular Dynamics Study of Epoxy-Based Networks: Cross-Linking Procedure and Prediction of Molecular and Material Properties

2008-08-21

Vikas Varshney , Soumya S. Patnaik , Ajit K. Roy +1 more

Molecular modeling of thermosetting polymers has been presented with special emphasis on building atomistic models. Different approaches to build highly cross-linked polymer networks are discussed. A multistep relaxation procedure for … Molecular modeling of thermosetting polymers has been presented with special emphasis on building atomistic models. Different approaches to build highly cross-linked polymer networks are discussed. A multistep relaxation procedure for relaxing the molecular topology during cross-linking is proposed. This methodology is then applied to an epoxy-based thermoset (EPON-862/DETDA). Several materials properties such as density, glass transition temperature, thermal expansion coefficient, and volume shrinkage during curing are calculated and found to be in good agreement with experimental results. Along with the material's properties, the simulations also highlight the distribution of molecular weight buildup and inception of gel point during the network formation.

Calorimetric investigation of polymerization reactions. III. Curing reaction of epoxides with amines

1970-06-01

K Horie , Hidefumi Hiura , M. SAWADA +2 more

Abstract The curing reactions of epoxy resin with aliphatic diamines and the reaction of phenyl glycidyl ether with butylamine as a model for the curing reactions were investigated with a … Abstract The curing reactions of epoxy resin with aliphatic diamines and the reaction of phenyl glycidyl ether with butylamine as a model for the curing reactions were investigated with a differential scanning calorimeter (DSC) operated isothermally. The heat of reaction of phenyl glycidyl ether with butylamine is equal to 24.5 ± 0.6 kcal/mole. The rate of reaction was followed over the whole range of conversion for both model and curing reactions. The reactions are accelerated by the hydrogen‐bond donor produced in the system. The rate constants based on the third‐order kinetics were determined and discussed for the model reaction and for the chemically controlled region of curing reactions. The activation energies for these rate constants are 13‐14 kcal/mole. At a later stage of conversion, the curing reactions become controlled by diffusion of functional groups. The final extent of conversion is short of completion for most isothermally cured and even for postcured samples because of crosslinking. It was quantitatively indicated that the final conversion of isothermal cure corresponds to the transition of the system from a viscous liquid to a glass on the basis of the theory of glass transition temperature of crosslinked polymer systems.

Manufacturing Aspects of Advanced Polymer Composites for Automotive Applications

2012-02-09

K. Friedrich , Abdulhakim A. Almajid

Very high thermal conductivity obtained by boron nitride-filled polybenzoxazine

1998-11-01

Hatsuo Ishida , Sarawut Rimdusit

Curing of Epoxy Matrix Composites

1983-03-01

Alfred C. Loos , George Ś. Springer

Models were developed which describe the curing process of composites constructed from continuous fiber-reinforced, thermosetting resin matrix prepreg materials. On the basis of the models, a computer code was developed, … Models were developed which describe the curing process of composites constructed from continuous fiber-reinforced, thermosetting resin matrix prepreg materials. On the basis of the models, a computer code was developed, which for flat-plate composites cured by a specified cure cycle, provides the temperature distribution, the degree of cure of the resin, the resin viscosity inside the composite, the void sizes, the temperatures and pressures inside voids, and the residual stress distribution after the cure. In addition, the computer code can be used to determine the amount of resin flow out of the composite and the resin content of the composite and the bleeder. Tests were performed measuring the temperature distribution in and the resin flow out of composites constructed from Hercules AS/3501-6 graphite epoxy prepreg tape. The data were compared with results calculated with the computer code for the conditions employed in the tests and good agreement was found between the data and the results of the computer code. A parametric study was also performed to illustrate how the model and the associated computer code can be used to determine the appropriate cure cycle for a given application, which results in a composite that is cured uniformly, has a low void content, and is cured in the shortest amount of time.

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A Critical Review: The Modification, Properties, and Applications of Epoxy Resins

2013-01-15

Pragyan Mohan

The article briefly reviews literature on the modification of epoxy resins and their properties, which are used for its industrial applications. Experimental results on modified epoxy resins are collectively summarized, … The article briefly reviews literature on the modification of epoxy resins and their properties, which are used for its industrial applications. Experimental results on modified epoxy resins are collectively summarized, which focus on the structure, curing, and alternate methods for modification of epoxy resins. The several properties such as thermal stability, adhesive, toughness, and electrical conductivity have been studied during the modifications of epoxy resins, which is useful in the field of electronic encapsulation, blending, composites, and nanocomposites, etc. The review concludes with a brief discussion on the most useful valuable modifications for industrial applications.

Recent advancement on polybenzoxazine—A newly developed high performance thermoset

2009-09-23

Yusuf Yağcı , Barış Kışkan , Narendra Nath Ghosh

Abstract Polybenzoxazine is a newly developed addition polymerized phenolic system, having a wide range of interesting features and the capability to overcome several shortcomings of conventional novolac and resole type … Abstract Polybenzoxazine is a newly developed addition polymerized phenolic system, having a wide range of interesting features and the capability to overcome several shortcomings of conventional novolac and resole type phenolic resins. They exhibit (i) near zero volumetric change upon curing, (ii) low water absorption, (iii) for some polybenzoxazines T g much higher than cure temperature, (iv) high char yield, (v) no strong acid catalysts required for curing, (vi) release of no byproduct during curing and also possess thermal and flame retarding properties of phenolics along with the mechanical performance. Though benzoxazine based materials possess several advantages, they have not yet became very attractive to the industries. To improve the mechanical properties and processibility several strategies have been reported including (i) synthesis of benzoxazine monomers with additional functionality, (ii) incorporation of benzoxazine in polymer chain, and (iii) benzoxazine based composites or alloys. In this article, we have discussed about the recent development of benzoxazine chemistry. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5565–5576, 2009

The mechanisms and mechanics of the toughening of epoxy polymers modified with silica nanoparticles

2010-10-31

Tsung‐Han Hsieh , A. J. Kinloch , Kunal Masania +2 more

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Toughening mechanisms of nanoparticle-modified epoxy polymers

2006-12-16

Bernt B. Johnsen , A. J. Kinloch , R. D. Mohammed +2 more

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Physical and mechanical characterization of near-zero shrinkage polybenzoxazines

1996-04-30

Hatsuo Ishida , Douglas J. Allen

A new class of phenolic-like thermosetting resins has been developed that is based on the ring-opening polymerization of a benzoxazine precursor. These new materials were developed to combine the thermal … A new class of phenolic-like thermosetting resins has been developed that is based on the ring-opening polymerization of a benzoxazine precursor. These new materials were developed to combine the thermal properties and flame retardance of phenolics with the mechanical performance and molecular design flexibility of advanced epoxy systems. The polybenzoxazines overcome many of the traditional shortcomings of conventional novolak and resoletype phenolic resins, while retaining their benefits. The physical and mechanical properties of these new polybenzoxazines are investigated and are shown to compare very favorably with those of conventional phenolic and epoxy resins. The ring-opening polymerization of these new materials occurs with either near-zero shrinkage or even a slight expansion upon cure. Dynamic mechanical analysis reveals that these candidates for composite applications possess high moduli and glass transition temperatures, but low crosslink densities. Long-term immersion studies indicate that these materials have a low rate of water absorption and low saturation content. Impact, tensile, and flexural properties are also studied. Results of the dielectric analysis on these polybenzoxazines demonstrate the suitability of these materials for electrical applications. © 1996 John Wiley & Sons, Inc.

Thermal expansion and swelling of cured epoxy resin used in graphite/epoxy composite materials

1980-07-01

Michael J. Adamson

Fracture toughness and failure mechanism of graphene based epoxy composites

2014-04-01

Swetha Chandrasekaran , Narumichi SATO , Folke Johannes Tölle +3 more

Phenolic materials via ring‐opening polymerization: Synthesis and characterization of bisphenol‐A based benzoxazines and their polymers

1994-04-30

Xin Ning , Hatsuo Ishida

Abstract Compounds with bifunctional benzoxazine groups in their molecular structures form crosslinked structures characteristic of phenolic materials through a ring‐opening reaction mechanism. This family of compounds offers greater flexibility than … Abstract Compounds with bifunctional benzoxazine groups in their molecular structures form crosslinked structures characteristic of phenolic materials through a ring‐opening reaction mechanism. This family of compounds offers greater flexibility than conventional novolac or resole resins in terms of molecular design. It is also superior to conventional phenolic resin in process control since it releases no by‐product during curing reactions. The materials thus obtained exhibit excellent mechanical integrity with glass transition temperatures over 200°C. The synthesis, composition, and structural analysis of precursors based on bisphenol‐A are discussed herein. © 1994 John Wiley & Sons, Inc.

Synthesis and Characterization of Novel Benzoxazine Monomers Containing Allyl Groups and Their High Performance Thermosets

2003-07-12

Tarek Agag , Tsutomu Takeichi

Two novel benzoxazine monomers containing allyl groups: 3-allyl-3,4-dihydro-2H-1,3-benzoxazine and bis(3-allyl-3,4-dihydro-2H-1,3-benzoxazinyl)isopropane have been synthesized from phenol and Bisphenol A with allylamine and formaldehyde. Their DSC exhibit two exotherms at ca. 145 … Two novel benzoxazine monomers containing allyl groups: 3-allyl-3,4-dihydro-2H-1,3-benzoxazine and bis(3-allyl-3,4-dihydro-2H-1,3-benzoxazinyl)isopropane have been synthesized from phenol and Bisphenol A with allylamine and formaldehyde. Their DSC exhibit two exotherms at ca. 145 °C and at ca. 220 °C which correspond to allyl and oxazine thermal polymerization, respectively. Both monomers undergo thermal cure with the formation of thermosets having excellent thermomechanical properties. These thermosets exhibit higher Tg (ca. 300 °C), maintain their storage moduli at higher temperature, and have better thermal stability than the corresponding polybenzoxazines without allyl groups.

Cure kinetics characterization and monitoring of an epoxy resin using DSC, Raman spectroscopy, and DEA

2013-02-16

Ricky Hardis , Julie L. P. Jessop , F. E. Peters +1 more

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Process-Induced Stress and Deformation in Thick-Section Thermoset Composite Laminates

1992-03-01

Travis A. Bogetti , John W. Gillespie

A study of process-induced stress and deformation in thick-section thermosetting composite laminates is presented. A methodology is proposed for predict ing the evolution of residual stress development during the curing … A study of process-induced stress and deformation in thick-section thermosetting composite laminates is presented. A methodology is proposed for predict ing the evolution of residual stress development during the curing process. A one- dimensional cure simulation analysis is coupled to an incremental laminated plate theory model to study the relationships between complex gradients in temperature and degree of cure, and process-induced residual stress and deformation. Material models are proposed to describe the mechanical properties, thermal and chemical strains of the thermoset resin during cure. These material models are incorporated into a micromechanics model to pre dict the effective mechanical properties and process-induced strains of the composite dur ing cure. Thermal expansion and cure shrinkage contribute to changes in material specific volume and represent important sources of internal loading included in the analysis. Tem perature and degree of cure gradients that develop during the curing process represent fun damental mechanisms that contribute to stress development not considered in traditional residual stress analyses of laminated composites. Model predictions of cure dependent epoxy modulus and curvature in unsymmetric graphite/epoxy laminates are correlated with experimental data. The effects of processing history (autoclave temperature cure cy cle), laminate thickness, resin cure shrinkage and laminate stacking sequence on the evo lution of process-induced stress and deformation in thick-section glass/polyester and graphite/epoxy laminates during cure are studied. The magnitude of process-induced residual stress is sufficient to mitiate transverse cracks and delammations. The results clearly indicate that the mechanics and performance of thick-section thermoset laminates are strongly dependent on processing history.

Rubber-Toughened Epoxies: A Critical Review

2009-07-22

Reza Bagheri , Bahereh T. Marouf , Raymond A. Pearson

Epoxy resins have been used as structural materials since the late 1940s. Despite their desirable properties such as high strength, excellent creep resistance, and good adhesion, they suffer from low … Epoxy resins have been used as structural materials since the late 1940s. Despite their desirable properties such as high strength, excellent creep resistance, and good adhesion, they suffer from low fracture energy. Rubber modification as a major toughening approach to overcome the inherent brittleness of epoxy polymers was introduced during the early 1970s. Since then, a large number of investigations have been conducted to elucidate different aspects of rubber-toughened epoxies. The present work is a critical review of the field focusing on the important parameters affecting rubber-toughening. The studies reviewed are classified in five categories including roles of matrix ductility, rubber concentration, blend morphology, particle cavitation, and particle/matrix interface. It has been tried to provide an in-depth view of the state-of-the-art knowledge in the field and to direct future studies towards exploring new approaches for toughening of epoxy polymers.

Miscibility, morphology, thermal, and mechanical properties of a DGEBA based epoxy resin toughened with a liquid rubber

2007-11-20

Raju Thomas , Yumei Ding , He Yuelong +5 more

Nanostructured Thermosets from Self-Assembled Amphiphilic Block Copolymer/Epoxy Resin Mixtures

1998-08-18

Paul M. Lipic , Frank S. Bates , Marc A. Hillmyer

Thermoset materials containing ordered structures with ∼10-nm dimensions were prepared from a mixture of a low-molecular-weight poly(ethylene oxide)−poly(ethylene-alt-propylene) (PEO−PEP) diblock copolymer and a poly(Bisphenol-A-co-epichlorohydrin) epoxy resin that selectively mixes with … Thermoset materials containing ordered structures with ∼10-nm dimensions were prepared from a mixture of a low-molecular-weight poly(ethylene oxide)−poly(ethylene-alt-propylene) (PEO−PEP) diblock copolymer and a poly(Bisphenol-A-co-epichlorohydrin) epoxy resin that selectively mixes with the PEO block. The phase behavior of PEO−PEP/epoxy blends, with compositions spanning 10−93 wt % block copolymer, was investigated in the uncured state (without hardener) using small-angle X-ray scattering (SAXS) and dynamic mechanical spectroscopy. Without hardener, the phase behavior of block copolymer/epoxy blends was similar to model block copolymer/homopolymer blends and varied with changes in the blend composition and temperature. The following morphologies were observed with increasing epoxy concentration: lamellar, cubic bicontinuous, hexagonally packed cylinders, body-centered cubic packed spheres, and disordered micelles. Methylene dianiline, an aromatic amine hardener, was added to the blends, and the real-time evolution of the phase behavior with cure was followed using SAXS measurements. As the epoxy molecular weight increased, the PEO block segregated from the epoxy matrix, as indicated by an increase in the principal spacing of the ordered structures and the occurrence of order−order phase transitions at certain compositions. However, macrophase separation between the epoxy and block copolymer did not occur. These results are interpreted as a transition from an equilibrium morphology to a chemically pinned metastable state as the cross-linking reaction progresses through the gel point.

Toughening tetrafunctional epoxy resins using polyetherimide

1989-02-01

C. B. Bucknall , A. H. Gilbert

Effects of cure cycles on void content and mechanical properties of composite laminates

2005-04-11

Ling Liu , Boming Zhang , Dianfu Wang +1 more

Time–temperature–transformation (TTT) cure diagram: Modeling the cure behavior of thermosets

1983-08-01

John B. Enns , J. K. Gillham

Abstract The times to gelation and to vitrification for the isothermal cure of an amine‐cured epoxy (Epon 828/PACM‐20) have been measured on macroscopic and molecular levels by dynamic mechanical spectrometry … Abstract The times to gelation and to vitrification for the isothermal cure of an amine‐cured epoxy (Epon 828/PACM‐20) have been measured on macroscopic and molecular levels by dynamic mechanical spectrometry (torsional braid analysis and Rheometrics dynamic spectrometer), infrared spectroscopy, and gel fraction experiments. The relationships between the extents of conversion at gelation and at vitrification and the isothermal cure temperature form the basis of a theoretical model of the time–temperature–transformation (TTT) cure diagram, in which the times to gelation and to vitrification during isothermal cure versus temperature are predicted. The model demonstrates that the “S” shape of the vitrification curve depends on the reaction kinetics, as well as on the physical parameters of the system, i.e., the glass transition temperatures of the uncured resin ( T g 0 ), the fully cured resin ( T g ∞ ), and the gel ( gel T g ). The bulk viscosity of a reactive system prior to gelation and/or vitrification is also described.

Advances in addition-cure phenolic resins

2004-04-03

C.G.R. Nair

Polybenzoxazines—New high performance thermosetting resins: Synthesis and properties

2007-08-03

Narendra Nath Ghosh , Barış Kışkan , Yusuf Yağcı

Epoxy resins: Chemistry and technology

1974-10-01

Raymond R. Myers

Handbook of Thermoset Plastics

2014-01-01

Sidney H. Goodman

Thermal Analysis of Polymers

2008-07-14

Voids in fiber-reinforced polymer composites: A review on their formation, characteristics, and effects on mechanical performance

2018-11-20

Mahoor Mehdikhani , Larissa Gorbatikh , Ignace Verpoest +1 more

Voids, the most studied type of manufacturing defects, form very often in processing of fiber-reinforced composites. Due to their considerable influence on physical and thermomechanical properties of composites, they have … Voids, the most studied type of manufacturing defects, form very often in processing of fiber-reinforced composites. Due to their considerable influence on physical and thermomechanical properties of composites, they have been extensively studied, with the focus on three research tracks: void formation, characteristics, and mechanical effects. Investigation of voids in composites started around half a century ago and is still an active research field in composites community. This is because of remaining unknowns and uncertainties about voids as well as difficulties in their suppression in modern manufacturing techniques like out-of-autoclave curing and parts with high complexity, further complicated by increased viscosity of modified resins. Finally, this is because of the increasing interest in realization of more accurate void rejection limits that would tolerate some voidage. The current study reviews the research on formation, characterization, and mechanical effects of voids, which has been conducted over the past five decades. Investigation and control of void formation, using experimental and modeling approaches, in liquid composite molding as well as in prepreg composite processing are surveyed. Techniques for void characterization with their advantages and disadvantages are described. Finally, the effect of voids on a broad range of mechanical properties, including inter-laminar shear, tensile, compressive, and flexural strength as well as fracture toughness and fatigue life, is appraised. Both experimental and simulation approaches and results, concerning voids' effects, are reviewed.

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Toughening mechanisms in elastomer-modified epoxies

1986-07-01

Raymond A. Pearson , Albert F. Yee

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Toughening mechanisms in elastomer-modified epoxies

1986-07-01

Albert F. Yee , Raymond A. Pearson

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Thermal Characterization of Polymeric Materials

1981-01-01

Toughness and its mechanisms in epoxy resins

2022-06-11

Xiaoqian Mi , Nuo Liang , Haifeng Xu +4 more

Chemistry and Technology of Epoxy Resins

1993-01-01

Bryan Ellis

Research Progress on Epoxy Resins in Cultural Heritage Conservation

2025-06-24

Zhen‐Xing Tang , Xinyou Liu , Xinhao Feng | Polymers

Epoxy resins have been extensively employed in cultural heritage conservation as both adhesive and reinforcement materials owing to their exceptional bonding strength, relatively low toxicity, and cost-effectiveness. This review initially … Epoxy resins have been extensively employed in cultural heritage conservation as both adhesive and reinforcement materials owing to their exceptional bonding strength, relatively low toxicity, and cost-effectiveness. This review initially outlines the fundamental material characteristics of epoxy resins and subsequently examines their contemporary applications in artifact restoration. Subsequently, it synthesizes the research advancements documented over the past two decades, with a focus on critical challenges associated with their application in cultural heritage preservation, including susceptibility to aging, inherent brittleness, and prolonged curing time. The corresponding modification strategies are systematically examined, including strategies for aging resistance enhancement, toughness improvement, and rapid-curing techniques. Finally, potential future directions for epoxy resin applications in conservation are critically evaluated. This review provides a comprehensive analysis of epoxy resins’ performance and modification methodologies, thereby offering valuable insights to guide future research on its application in cultural heritage conservation.

A gradient boosting decision tree based estimation method for the mixture cure model

2025-06-23

Jianing Zheng , Peizhi Li , Yingwei Peng | Journal of Applied Statistics

Analysis of the Elium®150 thermoplastic resin cure kinetics through a thermosetting approach

2025-06-23

Klara Loos , Luca Lagally , Christian Jochum +1 more | Continuum Mechanics and Thermodynamics

Enhancing toughness of epoxy resin through chain extending and end capping: An exploration of modifier influence

2025-06-23

Wei Yang , Kun Wang , Fan Shi +6 more | European Polymer Journal

Numerical analysis of curing residual stresses in scarf-repaired laminates

2025-06-23

Chao Liang , Shanyong Xuan , Hailong Yang +2 more | Composite Structures

Molecular Level Understanding of Amine Structural Variations on Diaminodiphenyl Sulfone to Thermomechanical Characteristics in Bifunctional Epoxy Resin: Molecular Dynamics Simulation Approach

2025-06-18

Hei Je Jeong , Sung Hyun Kwon , Jihoon Lim +7 more | Polymers

Epoxy-based composite materials, widely used in various industries such as coatings, adhesives, aerospace, electronics, and biomedical engineering, remain a topic of global interest due to their varying characteristics based on … Epoxy-based composite materials, widely used in various industries such as coatings, adhesives, aerospace, electronics, and biomedical engineering, remain a topic of global interest due to their varying characteristics based on the base resin and curing agents used. This paper employs molecular dynamics simulation to examine the thermal and mechanical properties, as well as molecular behaviors, of epoxy systems cured with diglycidyl ether of bisphenol F as the base resin and aromatic amine curing agents, specifically the meta structure of 3,3'-diaminodiphenyl sulfone (3,3'-DDS) and the para structure of 4,4'-diaminodiphenyl sulfone (4,4'-DDS). The 3,3'-DDS system demonstrated a greater density and Young's modulus than the 4,4'-DDS system. This tendency was analyzed based on differences in molecular fractional free volume and cohesive energy density (CED). The 4,4'-DDS system exhibits a higher glass transition temperature (Tg) compared to the 3,3'-DDS system, with values of 406.36 K and 431.22 K, respectively. To understand this behavior, we examined atomic-scale displacements at Tg through mean squared displacement analysis, which revealed that the onset of molecular motion occurs at a lower temperature in the 3,3'-DDS system. Molecular-level study reveals how the structural features of each curing agent appear in thermal and mechanical properties, offering important insights for epoxy system development.

Numerical Modeling of Micro-Mechanical Residual Stresses in Carbon–Epoxy Composites During the Curing Process

2025-06-17

Raffaele Verde , Alberto D’Amore , Luigi Grassia | Polymers

This article analyzes the residual stresses generated during the curing process of thermoset composites. Specifically, a numerical procedure is developed and implemented in Ansys 18.0 to evaluate, at the micromechanical … This article analyzes the residual stresses generated during the curing process of thermoset composites. Specifically, a numerical procedure is developed and implemented in Ansys 18.0 to evaluate, at the micromechanical level, the residual stresses in a carbon epoxy composite that undergoes the process of curing. The viscoelastic behavior of the epoxy material is modeled using a formulation recently published by the same authors. It accounts for the concurrent effect of curing and structural relaxation on epoxy's relaxation times, assuming thermo-rheological and thermo-chemical simplicities. The model validated for the neat epoxy matrix is now tested against the composite application. Various representative volume element (RVE) arrangements and fiber fractions are examined. The proposed procedure can predict the evolution of mechanical properties (apparent stiffness and creep compliance) and the residual stresses that develop in each composite constituent during the cure. It demonstrates that the residual stresses in the matrix are a consistent fraction of an epoxy's nominal strength and significantly influence the transverse mechanical properties of the composite.

Simulation of steel/epoxy laminates for electric engines or generators: Part 1—Characterization and modeling of coating films based on waterborne epoxy varnishes

2025-06-16

Martin Tiefenthaler , Gernot M. Wallner , Cornelia Marchfelder +3 more | Journal of Materials Science

Nanoscale Structure–Property Relationships of Cyanate Ester as a Function of Extent of Cure

2025-06-16

Khatereh Kashmari , Josh Kemppainen , Sagar Patil +3 more | ACS Polymers Au

Epoxy Resin Development for Anticorrosion Coatings

2025-06-16

El‐Sayed Negim , Lyazzat Bekbayeva , Д.С. Пузикова +5 more | Kompleksnoe Ispolzovanie Mineralnogo Syra = Complex Use of Mineral Resources

In this study, a high molecular weight epoxy resin (ELM-NG 900Z) based on diglycidyl ether of bisphenol A was cured with different types of hardeners to examine their impact on … In this study, a high molecular weight epoxy resin (ELM-NG 900Z) based on diglycidyl ether of bisphenol A was cured with different types of hardeners to examine their impact on the physical and mechanical properties of the epoxy resin. The hardeners used were G-5022X70 (140-170 mg KOH/g), G-A0533 (310-350 mg KOH/g), and G-0930 (280-320 mg KOH/g). The results indicated that the hardener G-A0533 provided the best mechanical properties for the epoxy resin compared to other hardeners. Furthermore, various additives including silica fume, talc, barium sulfate, ferric oxide, and pigments were mixed with the epoxy resin in the presence of the hardener G-A0533 to enhance its mechanical properties. It was observed that the addition of 3% silica fume, 10% ferric oxide, and 3% inorganic pigments improved the mechanical properties, while the addition of 5% talc decreased most mechanical properties and only increased hardness. The incorporation of barium sulfate into the epoxy resin enhanced adhesion and flexural strength but decreased tensile strength and hardness. The inclusion of organic pigment had no significant effect on the mechanical properties of the epoxy resin. This enhancement in mechanical properties is attributed to the type of hardener used as well as the types and amounts of additives mixed with the epoxy resin.

Investigation on the Properties of Phenolic-Resin-Based Functional Gradient Thermal Protection Composite Materials

2025-06-13

Jiangman Li , Weixiong Chen , Jianlong Chang | Aerospace

Crosslinked phenolic resin was prepared using hexamethylenetetramine (HMTA) as a crosslinking agent in hydrochloric acid solution. The ablation-heat-resistant material was prepared by a pressure-assisted RTM (resin transfer molding) process with … Crosslinked phenolic resin was prepared using hexamethylenetetramine (HMTA) as a crosslinking agent in hydrochloric acid solution. The ablation-heat-resistant material was prepared by a pressure-assisted RTM (resin transfer molding) process with reinforcing material (quartz fibre 2.5D needle-punched fabric/satin fibre cloth/fibre mesh tire) and matrix (crosslinked phenolic resin). The thermal stability of the cured product was studied by a thermogravimetric analyser (TG and DTG). The mechanical properties, heat resistance, and ablation properties of the composites were tested. The ablation morphology, element analysis, and phase structure of the composites were analysed by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD), respectively. The results show that the phenolic resin has a lower initial viscosity and a longer pot life at 80 °C, and a higher carbon residue rate (70.18%). The tensile strength of the composites is close to 40 MPa, the tensile modulus is higher than 1.35 GPa, the compression modulus is higher than 10 MPa, and the elongation at break is higher than 1.55%. SiO2, SiC, and ZrO2 ceramic phases were formed after ablation, which effectively improved the ablation performance of the composites.

Development of Glass Fibers Laminates Toughened with Core–Shell Rubber Particles for Applications in Cold Environments

2025-06-13

Vito Gigante , Bianca Dal Pont , Chiara Montanelli +2 more | Polymers

This research focuses on developing high-performance glass fiber laminated composites with improved toughness, particularly for applications in cold environments where traditional composites can suffer from embrittlement and reduced impact resistance. … This research focuses on developing high-performance glass fiber laminated composites with improved toughness, particularly for applications in cold environments where traditional composites can suffer from embrittlement and reduced impact resistance. To address this issue, the toughness of Atlac® 580, a bisphenol A-based vinyl ester urethane resin, was enhanced by incorporating core–shell rubber (CSR) particles. Once a mixing procedure to better distribute the CSR particles was identified, the CSR particles were introduced in concentrations ranging from 5 to 15 wt.%. The optimal content for a significant improvement in fracture toughness was identified as 10 wt.%. Finally, three types of glass fiber fabrics with different grammages and weaves were integrated into the optimized resin–CSR system, and their mechanical, morphological, and impact properties were analyzed. The results demonstrated that the toughened resin composite outperformed the reference composite, confirming its enhanced durability and suitability for demanding applications in cold environments.

Study on the Effects of Composite Catalysts on the Curing Process and Pot Life of the <scp>HTPB</scp>/<scp>HDI</scp>‐Trimer Binder System

2025-06-09

Hui Ma , Jiahu Guo , Yucun Liu +6 more | Journal of Applied Polymer Science

ABSTRACT Hydroxyl‐terminated polybutadiene (HTPB), a linear liquid rubber with terminal hydroxyl groups, is a cornerstone binder in polymer‐bonded explosives (PBX) and composite propellants. Its cross‐linking with hexamethylene diisocyanate trimer (HDI‐trimer), … ABSTRACT Hydroxyl‐terminated polybutadiene (HTPB), a linear liquid rubber with terminal hydroxyl groups, is a cornerstone binder in polymer‐bonded explosives (PBX) and composite propellants. Its cross‐linking with hexamethylene diisocyanate trimer (HDI‐trimer), a trifunctional isocyanate crosslinker, faces critical challenges in balancing pot life and curing rates for industrial scalability. Traditional single‐catalyst systems, such as dibutyl tin dilaurate (DBTDL) and tin octoate (TECH), exhibit high catalytic activity and a relatively short pot life, which limit the industrial application. This study aims to resolve these limitations by engineering blended catalyst systems to synergistically modulate cross‐linking kinetics and expand industrial adaptability. Five catalysts, namely TECH, FeAA (iron acetylacetonate), DABCO (1,4‐Diazabicyclo[2.2.2]octane), TPB (triphenyl bismuth), and nano‐ZnO, were blended pairwise at 0.05 w.t.% (1:1 functional group molar ratio) within HTPB/HDI‐trimer binder systems. Viscosity build‐up of the binder systems during the curing process was monitored via rotational viscometry at 45°C (rotor #29, 0.5 rpm), with Arrhenius modeling to quantify rheological reaction rates (k η ) and pot life. Full curing at 45°C was achieved within 24 h, eliminating energy‐intensive thermal curing. This work pioneers a multi‐site catalytic strategy for HTPB systems, enabling energy‐efficient room‐temperature curing, which is a paradigm shift for PBX and solid composite propellant manufacturing. The composite catalysts significantly reduce energy consumption costs and provide tunable pot life to accommodate industrial processing requirements. Commercial applications span defense, aerospace, and automotive sectors, where rapid processing and material stability are paramount.

Enhancement of processability, thermal stability, and mechanical properties of phthalonitrile resins via 3-aminophenylacetylene modification

2025-06-05

Ling Lian , Xiang Bai , Fengchun Jiang +4 more | European Polymer Journal

Urea-Formaldehyde Microcapsules for the Detection of Microcracks in Polymer Composites

2025-06-02

Nisha Balachandran , Athira Ajayan , S. Vishnu +2 more | CRC Press eBooks

Thermoplastic coatings from precursor systems with extreme reactivity for in-line hybrid-fiber production

2025-06-01

Lea Senneka , Oliver I. Strube | Polymer

Effect of polyester addition on the tropological and thermal properties of epoxy

2025-06-01

Doaa J Abed , Shatha H. Mahdi | Journal of Physics Conference Series

Abstract In this study, epoxy resin was prepared with the addition of hardener, Unsaturated polyester resin was prepared with the addition of hardener, and the polymers were mixed in specific … Abstract In this study, epoxy resin was prepared with the addition of hardener, Unsaturated polyester resin was prepared with the addition of hardener, and the polymers were mixed in specific proportions. The samples were examined in thermal conductivity tests, mechanical degradation, and scanning electron microscopy. The results showed that, thermal conductivity test of the mixture showed that it decreased from (0.014) to (0.013) significantly, which helps in thermal insulation. The decrease in its thermal conductivity means that the structure of the base material is irregular, In the technique thermomechanical decomposition, Through the curves it is shown that the change in length as a function of temperature is within the limits of (20C-200C), and that the increase in temperature leads to an increase in the length of the samples, and the length is in the form of a quasi-linear. This condition occurs when the increase in length is beyond the glass transition temperature, In the technique, scanning electron microscopy. The results show that the distribution of epoxy resin with Unsaturated polyester resin is homogeneous and even, and clear cavities and cavities are visible in sample (b). In figure (c), we observe an increase in the homogeneity of the mixtures due to the increase in the cross-linking chains between the polymers, which may have been the reason for the improved corrosion resistance of the composite

Effects of micro-/submicron-diameter glass fibers on the properties of glass fiber paper reinforced PTFE microwave dielectric materials

2025-06-01

Xiaoyu Weng , Jin Long , Yu Song +3 more | Ceramics International

A Piecewise Vulcanization Kinetic Model of Rubber Composites and Application in Curing Process of Suspension Rubber Bearings

2025-06-01

Meimei Chen , Xingguo Zhao , Ke He +4 more | Polymer