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.
Abstract. Classic R&D in material science was based on statistical modeling. However, large number of control factors and the absence of universal computational method that can be used for numerical investigation at all structural levels of constructional composite dictate the necessity of multiscale approach in computational material science. In the present work we are focusing on the description of spatial scales and primary types of interactions that take place in different layers of building materials. The five spatial scales are considered. Three of them allow using the simplest and universal modeling method that is based on the representation of composite as a particle system; still, modeling requires taking into account some extra types of pair forces and forces that are arising due to technological actions.
Feasibility of the sulfur-based construction materials is caused by properties, availability and low cost of sulfur. There exist numerous ways to improve the operational properties, including the ways that are based on nanotechnology, and ab initio (quantum chemistry) studies. Unfortunately, both application and verification of numerical simulation within the same research are quite complex. In the present case study we present typical scheme of survey involving both experimental and numerical studies. As a test subject we have selected orthorhombic sulfur crystals grown from the solution in toluene. It was clearly shown that good correspondence between experimental and numerical results can be achieved for offered methodology; Raman shifts for isolated S8 molecule mostly correspond to the shifts of sulfur crystal. Computed frequencies for all primary modes are close to the experimental data. Similar correspondences can serve as proofs of conformity between unknown molecular structures in nanomodified sulfur-based material and selected structural models
Abstract-Properties of composite materials with different matrices and disperse phases are greatly affected by phenomena occurring at the phase boundary with largest area. This is a boundary between matrix and fine filler. Numerous processes take place during preparation, homogenization and curing of the thermoset composites. While the achieved overall result is strengthening, the nature of mentioned processes is in many cases still unknown. In the present work we have carried out model study of transition layer which can be formed at the phase boundary during production of nanomodified epoxy composite. Raman spectroscopy is used for investigation of structure and composition. It is shown that silicone precursor is chemically inert to the matrix material. Application of such precursor leads to formation of low modulus transition layer between matrix and filler, thus promoting relaxation of internal stresses during curing process.
Currently, numerous specific methods directed to the improvement of the building materials are developed. Many of such methods are intrinsically the implementations of the nanotechnology; the random reinforcement by nanoscale fibers is a well known way for the enhancement of operational properties. The later can be achieved if the fibers form the continuous percolation lattice. In the present work we have offered the simple algorithm for the assessment of the threshold content of fibers that correspond to the formation of such lattice. The algorithm couples simple geometry-based stochastic modeling with the regression analysis. Several numerical experiments are carried out; it is shown that for high aspect ratios (about 10 2) the percolation lattice can be formed even if the volumetric ratio of the fibers is relatively small (less than 1%).
Abstract. Particle system dynamics is the well known method that can be used in wide range of spatial scales -from molecular to astronomic. However, numerical experimentation with constructional composites requires adequate representation of peculiar forces that are due to solvation shells, steric conditions and technological actions. Thus, despite the fact that there is currently a lot of software suitable for particle system dynamics, the existing software is of limited use in constructional material science. In the present work we have developed the proper model of building material as dispersion with solvation shells. The software implementation of the developed model is also briefly described. The model and software were already successfully used in several basic and applied research works in material science.
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