This paper promotes the general paradigm that a composite’s internal structure can be micro-tailored to achieve a multifunctional physical response through the use of the Field Aided Micro Tailoring (FAiMTa) technique. The FAiMTa technique relies on curing a polymer composite while in its liquid state in the presence of an electric field. The particles within the composite align themselves in the direction of the electric field and create an orthotropic composite structure. This technology can lead to composite materials having a micro-tailored structure mimicking biological systems. As an initial step towards this goal, uniformly orthotropic composites, which are prepared by the FAiMTa technique, are mechanically characterized. Two epoxy based systems are considered: a composite having micro-sized graphite particles whereas the other has micro-sized aluminum particles. Mechanical tests show the change of material properties according to direction of the particle alignment within the composite. Optical microscopy also confirms the created orthotropic microstructure. The next step in development of FAiMTa technique is the reduction of stress concentration near a geometric discontinuity by properly orienting particulate structures within the composite. Our on-going efforts toward optimization of the composites are briefly outlined.
This paper introduces polymer composites with locally micro-tailored electric and thermal conductive properties. We concentrate on specially designed orthotropic composites that have modified thermal properties in one preferable direction. This preferable direction can vary from region to region in the composite part to fulfill design objectives. Required local micro-tailoring and optimization of structure for given thermal applications is achieved by exposing liquid polymer suspensions to an electric field and then curing the obtained structure. We present testing results for epoxy resin with various fillers including graphite, silica etc. Obtained orthotropic composites are tested for mechanical and thermal and electrical properties. Elastic modulus, thermal expansion, and thermal conduction are measured for various compositions, directions and degree of orthotropy. The potential of obtained materials for electronic, aerospace and automotive applications are briefly discussed.