Polymeric composites have been an integral part of many industries in a variety of applications for decades. The qualities of the component materials determine the overall structural soundness, reliability, and performance of the designed polymer composites.
Image Credit: PRJ/Shutterstock.com
Naturally, the importance of high performance and cost-effectiveness cannot be overstated when designing structural components for aerospace, marine, civil, automotive, and other such industries. Because of these crucial industry needs, engineers have since long prioritized the development of high-strength, lightweight materials.
Polymer-based composites have piqued the interest of material scientists and engineers due to their inherent high strength-to-weight ratio. The majority of modern polymer composites are composed of epoxy, a thermosetting resin.
What is Epoxy?
Epoxy is the more common term used for the epoxide functional group. It is an important engineered thermosetting polymer with applications and uses in many industries. Epoxy resins provide excellent design versatility, remarkable thermal, mechanical, and chemical qualities and are also compatible with a wide range of reinforcing substances.
Because of these outstanding qualities, epoxy resin is a popular choice for several high-performance technical applications. Epoxy resins are critical to the electronic, civil, automotive, marine, and aerospace sectors and are extensively used for adhesive purposes.
Despite this incredible versatility and superior properties, epoxy composites have new avenues and possibilities to increase their performance, resistance to harsh environmental conditions, and longevity.
By distributing second phase material in epoxy resin polymers, the performances and properties of the composites are enhanced. Efforts have been undertaken in recent decades to improve the performance of epoxy-based composites by adding second-phase fillers.
Graphite, silicon carbide, rubber particles, and elastomers were discovered to increase the mechanical and thermal properties of epoxy composites by forming interfacial attachments with the matrix when utilized as micro-fillers.
The qualities of composites have been dramatically enhanced by lowering particle size. As a result, researchers determined that the particle size of fillers significantly influences mechanical characteristics.
How Are Epoxy Nanocomposites Made?
Over the last two decades, there has been a major emphasis on creating polymeric nanocomposites, where at least one of the filler material dimensions is on the scale of a nanometer.
The finished result does not have to be of the order of a nanometer; rather, it may even be microscopic or macroscopic in size. It is determined a nanocomposite of even just a singular dimension of the filler is small enough to be of a nanometer.
The integration of nanofillers in the epoxy matrix structure, which combines the advantages of epoxy with nanomaterials, is an effective way for fabricating advanced composites.
As a result, epoxy nanocomposites emerged as a revolutionary area of study for improving the mechanical characteristics of polymer composites. Recently, epoxy nanocomposites have been the focus of many scientific efforts, with more scientists looking for ways to enhance composite characteristics while maintaining structural integrity.
Unlike standard epoxy composites, dispersant addition of only a small quantity is needed to achieve considerable enhancements in properties of epoxy nanocomposites, making them suitable for aerospace applications.
Some enhancements include a rise in overall strength figures over the tensile, impact, interlaminar shear, flexural, and glass transition temperature values.
Interview: Improving Epoxy Resin with Flower-Like Nanoparticles.
Advantages of Going Nano
Physical characteristics change when we transition from microparticles to nanoparticles. For a given volume, nanoscale materials have a significantly greater surface area.
As surface characteristics determine many essential chemical and physical interactivities, the properties of a nanostructured material can differ considerably from those of a larger-dimensional material having the same basic composition.
The surface area per unit volume of particles and fibers is inversely related to the diameter of the material; consequently, the surface area per unit volume will be larger when the diameter is smaller.
The characteristics of nanomaterials differ significantly from those of ordinary materials due to two major factors: relatively greater surface area and quantum effects. Some nanocomposites may display properties mainly affected by interfacial interactions, while others may demonstrate quantum phenomena linked with nano-dimensional structures.
Challenges and Future Outlook
In terms of performance and possible applications, nanocomposites have the potential to reshape the world of conventional composite materials.
There is no question polymeric nanocomposites offer enormous commercial potential as replacements for existing composites as well as in the establishment of new markets due to their exceptional characteristics. However, creating the framework for processing–manufacturing technologies in sufficient quantity and value for commercialization would be one of the most pertinent challenges.
The crucial problem, for example, is nanoparticle dispersion or chemical compatibility with polymer matrices. Due to the great tendency of tiny particles to agglomerate, it is challenging to achieve a uniform dispersion of nanoparticles in a polymer matrix using pre-existing compounding procedures.
Another major issue that must be addressed when processing a nanocomposite is degassing. If air gets trapped when pouring the viscous material into the mold, it can cause cracking and specimen failure even under small strains.
The inception of innovative materials into the industry necessitates a risk assessment and a knowledge of the potential influence of nanomaterials on the environment, human health, and other biological species.
The potential of nanocomposites in several fields of scientific research and applications is tremendous, and it is garnering growing investment from governments and businesses worldwide. While nanotechnology has infiltrated certain niche areas of the market, the significant influence is expected to be at least a decade away.
Continue reading: What are Nanoporous Materials?
References and Further Reading
Balguri, P., Samuel, D. and Thumu, U., (2021) A review on mechanical properties of epoxy nanocomposites. Materials Today: Proceedings, 44, pp.346-355. Available at: https://doi.org/10.1016/j.matpr.2020.09.742
Gu, H., Ma, C., Gu, J., Guo, J., Yan, X., Huang, J., Zhang, Q. and Guo, Z., (2016). An overview of multifunctional epoxy nanocomposites. Journal of Materials Chemistry C, 4(25), pp.5890-5906. Available at: https://doi.org/10.1039/C6TC01210H
Hussain, F., Hojjati, M., Okamoto, M. and Gorga, R., (2006) Review article: Polymer-matrix Nanocomposites, Processing, Manufacturing, and Application: An Overview. Journal of Composite Materials, 40(17), pp.1511-1575. Available at: http://dx.doi.org/10.1177/0021998306067321
Reyhani, R., Zadhoush, A., Salman Tabrizi, N., Nazockdast, H. and Naeimirad, M., (2021) Fractural performance of epoxy nanocomposites reinforced with carbon aerogels in different structures. Theoretical and Applied Fracture Mechanics, 115, p.103079. Available at: https://doi.org/10.1016/j.tafmec.2021.103079