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

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.

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Effect of temperature on damage mechanisms and mechanical behaviour of an acrylic-thermoplastic-matrix and glass-fibre-reinforced composite

Journal of Composite Materials ◽

10.1177/0021998320929056 ◽

2020 ◽

Vol 54 (27) ◽

pp. 4269-4282

Author(s):

E Boissin ◽

C Bois ◽

J-C Wahl ◽

T Palin-Luc

Keyword(s):

Glass Transition ◽

Transition Temperature ◽

Polymer Matrix ◽

Mechanical Response ◽

Polymer Matrix Composites ◽

Effect Of Temperature ◽

Matrix Composites ◽

Service Temperature ◽

Damage Mechanisms ◽

Temperature Range

The mechanical response of polymer matrix composites exhibits a temperature dependency even if the service temperature range is lower than the glass transition temperature of the polymer matrix. This dependency is mainly due to the temperature effect on the mechanical behaviour of the polymer matrix. However, the micro- and meso-structures driving the composite anisotropy and local stress distribution play an essential role regarding the effect of temperature on damage mechanisms specific to reinforced polymers. There are few data in the literature on the sensitivity to temperature of damage mechanisms and scenarios of polymer matrix composites regardless of loading type. In this paper, after a synthetic literature review of the effect of temperature on polymers and polymer composites, several complementary tests are proposed to analyse the temperature effect on damage mechanisms undergone by laminated composites under in-plane quasi static loadings. These tests are applied to an acrylic-thermoplastic composite reinforced by glass fibres in its service temperature range of –20℃ to 60℃. The results show that the testing temperature has a significant impact on the mechanical response and damage mechanisms of the composite material in the selected temperature range, which is markedly lower than the glass transition temperature (around 100℃). While the temperature rise generates a gradual decrease in matrix stiffness and strength, the increase in matrix ductility associated to the stress heterogeneity in the composite microstructure produces a rise in the transverse cracking threshold and removes this damage mode during quasi-static tensile tests when the temperature shifts from 15℃ to 40℃.

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Structure of intumescent epoxy composites with expandable graphite

E3S Web of Conferences ◽

10.1051/e3sconf/20199107015 ◽

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.

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