scholarly journals Structure of intumescent epoxy composites with expandable graphite

2019 ◽  
Vol 91 ◽  
pp. 07015
Author(s):  
Alexandr Evstigneev ◽  
Vladimir Smirnov ◽  
Vitaliy Gladkikh
Keyword(s):  
Heat Transfer ◽  
Particle Size ◽  
Polymer Matrix Composites ◽  
Protective Coatings ◽  
Epoxy Composites ◽  
Expandable Graphite ◽  
Matrix Composites ◽  
Char Residue ◽  
Heat Conductance ◽  
Limiting Values

Currently, thermoset-based polymer matrix composites are widely used for production of fire protective coatings. Intumescent properties of such coatings are highly dependent on composition. Expandable graphite is a prospective intumescent admixture; unfortunately, admixture of expandable graphite alone can lower the integrity of char residue down to unacceptable levels. The objective of the present work is to present the method that can be used for elimination of the mentioned drawback. The limiting values of expandable graphite in composite with two different admixtures - ammonium polyphosphate and ceramic cenospheres - were determined by means of study the structure of both intumescent epoxy composites and char residues of such composites. It was revealed that admixture of ceramic cenospheres leads to notable improvement of integrity of char residue. This improvement is mostly due to features of heat transfer in material with cenospheres which are characterized by low particle size and, at the same time, low heat conductance.

scholarly journals Design of Nanomodified Intumescent Polymer Matrix Coatings: Theory, Modeling, Experiments

2018 ◽  
Vol 251 ◽  
pp. 01033 ◽  
Author(s):  
Alexandr Evstigneev ◽  
Vladimir Smirnov ◽  
Evgenij Korolev
Keyword(s):  
Glass Transition ◽  
Polymer Matrix ◽  
Numerical Experiments ◽  
Polymer Matrix Composites ◽  
Protective Coatings ◽  
Steel Substrate ◽  
Matrix Composites ◽  
The Novel ◽  
Char Residue ◽  
Novel Design

Thermoset-based polymer matrix composites are widely used for production of intumescent fire protective coatings; many operational properties of such coatings can be further enhanced by means of nanoscale layers between matrix and disperse phases. The dependence between temperature of processing and temperature of glass transition of thermosetting matrix allows to produce gradient of glass transition temperature along the depth of the coating and lower exfoilation of char residue from steel substrate. In the present article we have offered the novel design scheme for such coating. Several results of laboratory and numerical experiments that are within the framework of the offered scheme are also presented. Application of the offered scheme allows to develop efficient fire protective coatings in purposely and precisely controlled manner.

scholarly journals Water absorption by multifunctional protective epoxy composites

2018 ◽  
Vol 193 ◽  
pp. 03028 ◽  
Author(s):  
Vladimir Smirnov ◽  
Evgeniy Korolev
Keyword(s):  
Water Absorption ◽  
Polymer Matrix ◽  
Polymer Matrix Composites ◽  
Epoxy Composites ◽  
Expandable Graphite ◽  
Matrix Composites ◽  
Limited Information ◽  
Asymptotic Values ◽  
Central Composite ◽  
High Chemical Stability

Currently, thermoset-based polymer matrix composites are widely used in many areas of construction industry. Such composites demonstrate high compressive and flexural strength and are often characterized by high chemical stability under severe environmental conditions. One of the new promising areas of application of thermoset-based polymer matrix composites is the intumescent protective coating for metals; in normal conditions, such coatings can prevent the corrosion of metal constructions; during fire, expanded layer can prolong the time before critical failure. Water absorption is one of the primary characteristics of corrosion-protective materials; however, till now, there is only limited information about water absorption of multifunctional protective thermoset-based polymer matrix composites for intumescent coatings. In the present work, asymptotic values of water absorption of epoxy composites with polysiloxanes and fluorine-chlorine liquids are examined. The boundaries of control variables, within which the materials with required properties can be made, are determined. Silica, intercalated (expandable) graphite, and asbestos are used as fillers. Experiments were carried out in accordance with central composite experimental designs for full second-order regression models. It is shown that some admixtures can lead to notable decrease of water absorption.

Tensile Behavior of Epoxy Composites Reinforced with Thinner Sisal Fibers

2016 ◽  
Vol 869 ◽  
pp. 249-254
Author(s):  
Lazaro Araújo Rohen ◽  
Anna Carolina Cerqueira Neves ◽  
Frederico Muylaert Margem ◽  
Carlos Maurício Fontes Vieira ◽  
Fabio de Oliveira Braga ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Polymer Matrix Composites ◽  
Low Cost ◽  
Natural Fibers ◽  
Tensile Behavior ◽  
Epoxy Composites ◽  
Matrix Composites ◽  
Synthetic Fibers ◽  
Sisal Fibers

The use of natural fibers as reinforcement in polymer matrix composites is replacing the use of synthetic fibers, especially from an environmental standpoint. Indeed, natural fibers are biodegradable and renewable, with no aggression to the environment. Moreover, they are worldwide abundant with relatively low cost. It was found that fine fibers of sisal, with the thinnest diameters can achieve tensile strength on the order of 1000 MPa. In this work, tensile specimens were prepared with 30% in volume of sisal fibers with diameters between 0.1 and 0.10mm incorporated in a continuous and aligned way into epoxy matrix. The results showed a significant increase in tensile strength and elastic modulus of the composites as a function of the incorporated amount of thinner sisal fibers.

Modeling of Depth of Cut in Abrasive Waterjet Cutting of Thick Kevlar-Epoxy Composites

2010 ◽  
Vol 443 ◽  
pp. 423-427 ◽  
Author(s):  
Tauseef Uddin Siddiqui ◽  
Mukul Shukla
Keyword(s):  
Polymer Matrix Composites ◽  
Linear Regression Analysis ◽  
Epoxy Composites ◽  
Abrasive Waterjet ◽  
Depth Of Cut ◽  
Matrix Composites ◽  
Water Jet Cutting ◽  
Abrasive Water Jet Cutting ◽  
Semi Empirical ◽  
Good Agreement

Abrasive water jet cutting (AWJC) is one of the widely used non-conventional techniques for cutting difficult-to-cut materials like composites, super alloys and ceramics. However, while conducting initial trials the inability of the jet to cut through the workpiece is a major problem particularly in thicker materials. Therefore an accurate prediction of depth of cut (DOC) is absolutely necessary to achieve through cuts and more so to minimize delamination in polymer matrix composites. In this paper, a semi-empirical model is developed using non-linear regression analysis for prediction of DOC in AWJC of thick Kevlar-epoxy composites. Further, the model is verified by conducting experiments within the investigated range of process parameters and a good agreement is obtained between the two.

Effect of thermo-oxidative aging on compressive behavior of carbon fiber polymer matrix composites

2016 ◽  
Vol 88 (5) ◽  
pp. 510-519 ◽  
Author(s):  
Wei Fan ◽  
Dan-dan Guo ◽  
Jia-lu Li ◽  
Ying-ying Zhou ◽  
Liang Gong ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Carbon Fiber ◽  
Polymer Matrix ◽  
Polymer Matrix Composites ◽  
Three Dimensional ◽  
Epoxy Composites ◽  
Matrix Composites ◽  
Oxidative Aging ◽  
Aging Conditions ◽  
Carbon Fiber Epoxy

The effects of reinforcement architecture on the compressive behaviors of carbon fiber polymer matrix composites (CF-PMCs) under thermo-oxidative aging conditions were investigated. Samples of three-dimensional and four-directional braided carbon fiber/epoxy composites (BC) and laminated plain woven carbon fiber/epoxy composites (LC) were subjected to isothermal aging at 80℃, 100℃, 120℃ and 140℃ in air circulating ovens for various durations up to 1200 h. The process resulted in progressive deterioration of the matrix reins and fiber/matrix interfaces, in the form of chain scissions, weight loss and fiber/matrix debonding, which significantly led to the decrease of the compressive strength. In addition, the compressive strength retention rates of BC were higher than those of LC at the same aging conditions due to the differences of their reinforcement architecture. On the one hand, LC lost more weight than BC because the percentage of exposure of fiber ends to air in the LC samples was five times more than that in the BC samples. Moreover, the BC samples could resist the compressive load as an integral structure and did not show delamination damage as in the case of LC samples, although the resin was damaged and the adhesive force between fiber bundles and resin decreased after thermo-oxidative aging. Therefore, adopting the three-dimensional and four-directional braided preform as the reinforcement of CF-PMCs is an effective way to improve their compressive strength under thermo-oxidative aging conditions.

Electron Beam Curing of Epoxide Modified MWNTs/Epoxy Composites

2011 ◽  
Vol 688 ◽  
pp. 69-73
Author(s):  
Yan Yan Lu ◽  
Hua Li ◽  
He Zhou Liu
Keyword(s):  
Carbon Nanotubes ◽  
Electron Beam ◽  
Epoxy Resin ◽  
Stress Reduction ◽  
Polymer Matrix Composites ◽  
Epoxy Composites ◽  
Matrix Composites ◽  
Pure Epoxy ◽  
Gel Content ◽  
Hazardous Chemical

Electron beam (EB) has been used in curing of polymers in view of its advantages over conventional curing processes including short curing time, lower thermal stress, reduction of hazardous chemical volatiles, higher production flexibility. Carbon nanotubes have been recognized as promising filler that can be used to change the mechanical, thermal and electrical properties of the polymer matrix composites. In this paper, EB curing of epoxide modified multi-walled carbon nanotubes (MWNTs)/epoxy composite has been investigated, and a bisphenol-A epoxy resin was used as matrix. MWNTs were chemical functionalized with epoxide monomer and the epoxide functionalized MWNTs were characterized by TG and FTIR. The gel content and Vicker’s hardness of the EB cured pure epoxy resin and the epoxide functionalized MWNTs/epoxy composites were measured and discussed as function of the concentration of the functionalized MWNTs. With the addition of epoxide modified MWNTs, both the gel content and Vicker’s hardness of the composites showed enhancement compared with EB cured pure epoxy.

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