Polymer Composite Materials Reinforced with Diamonds Nanoparticles
Tech Area / Field
- MAT-ELE/Organic and Electronics Materials/Materials
8 Project completed
Senior Project Manager
Latynin K V
A.V. Topchiev Institute of Petrochemical Synthesis, Russia, Moscow
- MISIS (Steel and Alloys), Russia, Moscow\nNIKIMT (Institute of Assembly Technology), Russia, Moscow
- University of Missouri, USA, MO, St Louis
Project summaryThe constantly growing demand in industrial diamond materials is largely satisfied by production of synthetic diamonds, nanosize diamond powders including. One of the methods is detonation synthesis, in which an explosive is the source of carbon to form the diamond phase. Dismantled ammunition can be a source of explosive charges, so the use of detonation synthesis can contribute to the utilization of explosives. This will decrease weapons-dismantling expenses and in some cases will pay off or even bring profit.
This project is to expand potential applications of nanodiamonds.
A promising approach is modification of polymers and development of novel polymer–diamond nanocomposites. Introduction of strengthening particles (in this case, nanodiamond particles) into the polymer matrix will improve its mechanical properties (elasticity modulus and strength), increase its heat stability and resistance, and will also endow the polymer matrix with functional properties, e.g., insulating, abrasive, barrier, etc. properties, with the preservation of flexibility, high impact strength, reprocessibility by melting, etc.
Polymer materials play a major role in all spheres of life. The project will consider three groups of polymer materials:
- Structural materials, that is heavy-duty materials for components of machines, housings, holders, fasteners, etc. These materials mainly require increased rigidity and strength characteristics.
- Materials for friction components, in particular, gear–pinion pairs, pump components, sealing rings, etc. These materials mainly require increased wear resistance.
- Materials for gaskets and components operated under load in contact with other components. These materials require both increased mechanical characteristics and increased wear resistance.
Higher mechanical characteristics and wear resistance are only possible at high adhesion between the matrix and strengthening particles. A major part of the project will study the wetting and adhesion between the components of structural materials and will develop techniques for introduction of strengthening particles into the matrix to enhance the interaction between the matrix and the dispersion phase.
The polymer phase of the melt with the mixed components strongly shrinks in cooling, but the size of the diamond nanoparticles remains the same. The cooled thermoplastic would press the particles, and overstrained areas could emerge. To avoid these effects, the temperature modes of mixing and cooling the nanocomposite precursors should be thoroughly chosen and justified. Besides, the surface of the particles will be pretreated with various modifiers (as a rule, with surfactants) to regulate the surface energy of the particles and to reduce the negative effect of polymer-matrix shrinkage during the cooling.
An alternative approach is ultrasound treatment of particles in various modes and also plasma-chemical treatment of the surface to create a microrelief and, therefore, the area of the contact of polymer with diamond particles. Among the methods of rational introduction of particles into the polymer matrix, we will analyze pre-mixing in intermediate substances (e.g., surfactants), mixing in various temperature–time modes under high shear stress conditions and, in some cases, under high pressures, using pairs of blade rotor mixers of different profiles and single- and twin-screw extruders.
To measure adhesion and internal stress in the heterophase system, advanced methods and equipments will be used, e.g., tear and rupture tests under conditions of single-axis tension and shear, precision dilatometry in orthogonal directions, electron scanning microscopy, tunneling microscopy, atomic force microscopy, etc.
Advanced methods of differential scanning calorimetry, dynamic mechanical spectroscopy and gravimetry will make it possible to establish the value of the increase of heat stability and resistance of the polymers in the presence of diamond nanoparticles and to determine their new applications.
The materials developed will be used to fabricate specimens, which will be subjected to tests under experimental conditions close to real-life conditions. Only if all tests are successfully passed, a material will be recommended to be used.
The project includes the following major stages:
- Preparing the initial materials and equipment. Working out the methods of research.
- Working out the techniques of preparing the surface of diamond nanopowders. Working out the techniques and regimes of ultrasound and plasma-chemical treatment of the initial nanopowders.
- Working out the techniques of introduction of diamond nanopowders into the polymer matrix under conditions of shear stresses.
- Studying the structure of the materials developed, and also the dependence of the mechanical properties and wear resistance on the content of strengthening particles. Determining the optimal composition of the structural materials.
- Working out the techniques of forming items from polymer–diamond nanocomposites.
- Studying the topography of the surface of the composition materials developed.
- Conducting experimental tests close to real-life conditions under which the items are operated.
- Fabricating pilot batches of the materials developed.