COMPREHENSIVE OVERVIEW: TRANSPARENT POLYMER COMPOSITE MATERIALS

ОБЗОРНАЯ СТАТЬЯ: ПРОЗРАЧНЫЕ ПОЛИМЕРНЫЕ КОМПОЗИЦИОННЫЕ МАТЕРИАЛЫ

Шабунина Софья Сегеевна

студент, кафедра материаловедения и технологии материалов, Санкт-Петербургский государственный морской технический университет,

РФ, г. Санкт-Петербург

Шабунина Жанна Сергеевна

студент, кафедра материаловедения и технологии материалов, Санкт-Петербургский государственный морской технический университет,

РФ, г. Санкт-Петербург

Осипенко Елена Анатольевна

научный руководитель, канд. филол. наук, доц., Санкт-Петербургский государственный морской технический университет,

РФ, г. Санкт-Петербург

ABSTRACT

Transparent polymer composites are an innovative class of materials that combine the advantageous properties of polymer matrices and reinforcement materials, all while maintaining optical clarity. These materials are lightweight, durable, and versatile, making them ideal for applications in sectors like aerospace, automotive, electronics, and optics (Lin et al., 2020). Recent advances in nanotechnology have driven the development of transparent composites with enhanced mechanical, thermal, and functional properties. However, challenges such as refractive index mismatch, processing difficulties, and environmental durability remain to be addressed.

This article provides a comprehensive overview of transparent polymer composites, including their composition, applications, recent technological developments, and the challenges they face. Furthermore, future directions for this rapidly evolving field are discussed, emphasizing multifunctional composites and sustainability.

АННОТАЦИЯ

Прозрачные полимерные композиты - это инновационный класс материалов, которые сочетают в себе выгодные свойства полимерных матриц и армирующих материалов, сохраняя при этом оптическую прозрачность. Эти материалы легки, прочны и универсальны, что делает их идеальными для применения в таких отраслях, как аэрокосмическая, автомобильная, электронная и оптическая промышленность. Последние достижения в области нанотехнологий привели к созданию прозрачных композитов с улучшенными механическими, тепловыми и функциональными свойствами. Однако такие проблемы, как несоответствие показателя преломления, трудности обработки и устойчивость к воздействию окружающей среды, еще предстоит решить.

В этой статье представлен всеобъемлющий обзор прозрачных полимерных композитов, включая их состав, области применения, последние технологические разработки и проблемы, с которыми они сталкиваются. Кроме того, обсуждаются будущие направления развития этой быстро развивающейся области с акцентом на многофункциональные композиты и устойчивость.

Keywords: transparent polymer composite materials, optical polymers, optical composite materials, optical properties.

Ключевые слова: прозрачные полимерные композиционные материалы, оптические полимеры, оптические композиционные материалы, оптические свойства.

Transparent polymer composites consist of two main components: a polymer matrix and reinforcing materials, typically fillers or fibres, that improve the mechanical and functional characteristics of the polymer. Maintaining transparency in these composites is a delicate balance that requires the refractive index of both components to be closely matched [3]. If there is a mismatch, light scattering will occur, compromising the material's optical clarity.

The polymer matrix plays a vital role in defining the mechanical, thermal, and optical properties of the composite. Transparent polymer composites can be classified according to the polymer used in the matrix (Table 1).

Table 1

Classification based on the type of polymer matrix (Jan, 2011)

The reinforcing materials added to the polymer matrix enhance the mechanical, thermal, or electrical properties of the composite [1]. They can be classified into various categories represented in Table 2 [2].

Table 2

Classification based on the type of reinforcement material

Besides, transparent composite materials might be classified in accordance with its functional properties. In addition to optical properties, different functional properties, such as conductivity, self-healing ability, or UV resistance, enable the use of transparent composites in highly specialized applications glazing. For instance, self-healing Composites that repair damage (e.g., scratches) autonomously, useful in aerospace where maintaining integrity is key [6, p. 2115]. Combination transparency with electrical conductivity is ideal for touchscreens and solar cells [7, p. 219-226].

Designed to resist UV degradation, reinforced with nanoparticles like ZnO, they are used in outdoor coatings and glazing [5]. Incorporate antimicrobial nanoparticles, are suitable for medical devices and food packaging.

Finally, for advanced composites, a range of manufacturing methods is available. The choice of method typically depends on factors such as to predict performance and failure mechanisms of composites, fostering innovation, managing costs, predicting material behaviour, and promoting sustainability. The most common methods for transparent polymer composites are represented bellow [14, p. 539-541]

• Injection Molding: This method involves injecting molten polymer composite materials into a mold to create complex shapes. It is widely used for producing high-precision parts like lenses, automotive components, and other transparent items. Materials like polycarbonate (PC) and polymethyl methacrylate (PMMA) are often used in this process due to their excellent flow properties.
• Extrusion: In extrusion, the composite materials are heated and forced through a die to form continuous shapes, such as sheets, films, or tubes. This method is commonly employed to create transparent sheets and protective covers made from materials like PMMA and polycarbonate. The resulting products can be further processed or cut to size.
• Solution Casting: This technique involves dissolving the polymer in a solvent, mixing it with reinforcing materials, and then casting the mixture into molds or onto surfaces to form films or sheets. Solution casting is frequently used for producing transparent conductive films, particularly for applications in optoelectronics and flexible displays.
• Thermoforming: Thermoforming involves heating a sheet of transparent polymer until it becomes pliable, then shaping it over a mold. This method is often used for creating packaging materials, protective covers, and automotive parts. The resulting products maintain transparency while being molded into various shapes.
• 3D Printing (Additive Manufacturing): Advanced 3D printing techniques allow for the creation of transparent polymer composites by layer-by-layer deposition of materials. This method provides flexibility in design and enables the production of intricate shapes that might be difficult to achieve with traditional methods. Various polymers, including those with transparent properties, can be utilized.

Transparent polymer composites have broad applicability across a wide range of industries due to their unique combination of transparency, lightweight nature, and enhanced mechanical properties.

In automotive and aerospace sectors, these materials are replacing traditional glass in components to improve fuel efficiency and safety. In both sectors, reducing weight is essential for enhancing fuel efficiency, and transparent polymer composites offer an effective solution by replacing conventional glass, which is heavier and more susceptible to shattering. For instance, in the automotive industry, polycarbonate composites are now widely used in components such as headlights, sunroofs, and side windows. These materials not only offer better impact resistance than glass but also provide improved thermal insulation. In aerospace, transparent composites are essential in components like cowls and canopy covers, where high strength and clarity are crucial for functionality [8, p. 108281].

In optoelectronics, transparent polymer composites are particularly useful in the development of flexible and transparent displays, touch panels, and solar cells. Their high optical clarity and flexibility make them ideal for cutting-edge technologies like foldable smartphones and bendable displays [9].

Additionally, these materials are employed in transparent conductive films, which play a critical role in devices such as organic light-emitting diodes (OLEDs) and photovoltaic cells, contributing to advancements in energy-efficient and portable electronic devices [10]

Transparent polymer composites also have significant applications in protective shields and windows, most notably in the production of bulletproof glass. By combining transparency with high impact resistance, these materials are used extensively in security and defence sectors [9]. Typically, such composites consist of a polycarbonate matrix reinforced with glass fibres or nanoparticles, offering a lightweight but highly durable solution for protective windows in vehicles, buildings, and personal protective equipment.

Recent advancements in transparent polymer composites have expanded their functionality and potential applications. One of the most promising developments is the integration of graphene-based reinforcements [11]. Graphene, composed of a single layer of carbon atoms arranged in a hexagonal lattice, possesses exceptional mechanical, electrical, and thermal properties. When incorporated into polymer matrices, graphene can significantly enhance the composite’s strength and electrical conductivity while maintaining transparency. This makes graphene-reinforced composites suitable for use in applications such as transparent conductive films and flexible electronics. Researchers have even developed graphene-oxide-based composites with improved electrical conductivity, which are being explored for use in transparent electrodes for solar cells and touchscreens [12, p. 7]. The high thermal stability of these composites further extends their application to high-temperature environments, such as in aerospace technologies.

Another breakthrough in this field is the development of self-healing transparent composites. These materials can autonomously repair minor damage like cracks or scratches, which greatly extends their lifespan. This feature is particularly advantageous in industries like aerospace and automotive, where maintaining the integrity of transparent components is critical. Self-healing transparent composites often incorporate reversible chemical bonds or microcapsules filled with healing agents that activate upon damage, allowing the material to repair itself without external intervention [6, p. 2115].

Smart transparent composites represent another exciting innovation in the field. These materials are capable of responding to external stimuli such as light, temperature, or electrical signals, allowing them to dynamically alter their properties in response to environmental changes. For example, researchers are developing smart transparent composites for use in smart windows, which can adjust their opacity based on temperature or sunlight [13, p. 6]. This technology has the potential to revolutionize energy savings in buildings by reducing the need for air conditioning. Moreover, smart transparent composites could have a significant impact on automotive glazing, offering vehicles greater control over light transmission and energy efficiency.

Challenges

While transparent polymer composites offer many advantages, they also come with significant challenges:

1. Refractive Index Mismatch: One of the biggest challenges in producing transparent composites is matching the refractive index of the polymer matrix and the reinforcing materials. Any mismatch can lead to light scattering, reducing transparency.
2. Processing Techniques: Achieving uniform dispersion of reinforcing materials in the polymer matrix is crucial for maintaining transparency. Poor dispersion can lead to agglomerates, compromising both the mechanical and optical properties [11, p. 3364].
3. Durability: Despite improvements, polymer composites are still prone to environmental degradation, especially when exposed to UV radiation and moisture. Developing UV-resistant and weatherproof transparent polymer composites remains an ongoing challenge.

Future Directions

Looking forward, researchers aim to develop multifunctional transparent composites that combine transparency with properties like electrical conductivity, UV resistance, and self-healing capabilities. These innovations could lead to breakthroughs in fields like optoelectronics, smart packaging, and even energy storage, where transparent batteries and solar cells are currently under exploration.

In addition, sustainable alternatives are gaining traction, with a focus on bio-based polymers and eco-friendly reinforcements, which could help reduce the environmental impact of transparent composite materials.

Conclusion

Transparent polymer composite materials represent a versatile and growing field in material science, offering significant advantages in industries ranging from aerospace to electronics. The development of new nanocomposites, smart materials, and sustainable alternatives continues to expand the potential applications of these materials. However, challenges related to refractive index matching, processing, and durability must be addressed to fully realize their potential.

References:

1. Lin, Y., Bilotti, E., Bastiaansen, C.W.M. and Peijs, T. (2020). Transparent semi‐crystalline polymeric materials and their nanocomposites: A review. Polymer Engineering & Science, 60(10), pp.2351–2376. doi:https://doi.org/10.1002/pen.25489.
2. Jan W. G. (2011). Encyclopedic dictionary of polymers. Vol. 1, A-0. New York: Springer.
3. Loste, J., Lopez-Cuesta, J.-M., Billon, L., Garay, H. and Save, M. (2019). Transparent polymer nanocomposites: An overview on their synthesis and advanced properties. Progress in Polymer Science, 89, pp.133–158. doi:https://doi.org/10.1016/j.progpolymsci.2018.10.003.
4. Yang, Y., Lai, Y., Zhao, S., Chen, H., Li, R. and Wang, Y. (2023). Optically transparent and high-strength glass-fabric reinforced composite. Composites Science and Technology, 245, pp.110338–110338. doi:https://doi.org/10.1016/j.compscitech.2023.110338.
5. Zeng, N.X.-F., Li, N.X., Tao, N.X., Shen, N.Z.-G. and Chen, N.J.-F. (2010). Fabrication of highly transparent ZnO/PVB nanocomposite films with novel UV-shielding properties. doi:https://doi.org/10.1109/inec.2010.5424473.
6. Kontiza, A. and Kartsonakis, I.A. (2024). Smart Composite Materials with Self-Healing Properties: A Review on Design and Applications. Polymers, 16(15), p.2115. doi:https://doi.org/10.3390/polym16152115.
7. Ngo, I.-L., Jeon, S. and Byon, C. (2016). Thermal conductivity of transparent and flexible polymers containing fillers: A literature review. International Journal of Heat and Mass Transfer, [online] 98, pp.219–226. doi:https://doi.org/10.1016/j.ijheatmasstransfer.2016.02.082.
8. Zobeiry, N., Lee, A. and Mobuchon, C. (2020). Fabrication of transparent advanced composites. Composites Science and Technology, 197, p.108281. doi:https://doi.org/10.1016/j.compscitech.2020.108281.
9. Xiang, H., Li, Y., Meng, S., Lee, C., Chen, L. and Tang, J. (2018). Extremely Efficient Transparent Flexible Organic Light‐Emitting Diodes with Nanostructured Composite Electrodes. Advanced Optical Materials, 6(21). doi:https://doi.org/10.1002/adom.201800831.
10. New Atlas (2011). Graphene-based transparent touchscreens and solar panels a step closer. [online] New Atlas. Available at: https://newatlas.com/transparent-flexible-graphene-based-electrodes/19397/ [Accessed 24 Oct. 2024].
11. Gallo, L.S., Villas Boas, M.O.C., Rodrigues, A.C.M., Melo, F.C.L. and Zanotto, E.D. (2019). Transparent glass–ceramics for ballistic protection: materials and challenges. Journal of Materials Research and Technology, 8(3), pp.3357–3372. doi:https://doi.org/10.1016/j.jmrt.2019.05.006.
12. Hortense Le Ferrand, Sreenath Bolisetty, Demirörs, A.F., Libanori, R., Studart, A.R. and Raffaele Mezzenga (2016). Magnetic assembly of transparent and conducting graphene-based functional composites. Nature Communications, 7(1). doi:https://doi.org/10.1038/ncomms12078.
13. Shichao L., Wang, D., Tang, J., Liu, Z., Inoue, H., Tang, B., Sun, Z., Lothar Wondraczek, Qiu, J. and Zhou, S. (2024). Transparent composites for efficient neutron detection. Nature Communications, 15(1). doi:https://doi.org/10.1038/s41467-024-51119-w.
14. Brabazon, D. (2021). Introduction: Processing of Composite Materials and Physical Characteristics. Elsevier eBooks, pp.539–541. doi:https://doi.org/10.1016/b978-0-12-819724-0.00108-7.