Читать книгу Carbon Nanofibers - Группа авторов - Страница 55

Composites of CNF have been investigated in both fundamental scientific research and practical applications. The need for strong and lightweight materials is being met by promising materials created by reinforcing CNF in polymers for applications that include electrical devices, electrode materials for batteries and supercapacitors, and as sensors. In these applications, the electrical conductivity is a priority need, which depends on the dispersion and percolation status of CNFs in matrix materials. Other important considerations are the effects of the aspect ratio, percolation backbone structure and fractal characteristics of CNFs and the non-universality of the percolation critical exponents on the electrical properties. Apart from the electrical property, the thermal conductivity and mechanical properties of CNF composites also add to the utility of CNF composites, including the melt mixing and solution process, especially for their applications as sensors and electrode materials. Significant application of composite materials has contributed a lot in the defense, aeronautical and automobile industries because of their specific modulus and high strength characteristics. In composite material, CNF-reinforced mat with polymer epoxy resin composites and CNF/polyvinyl alcohol (PVA) mat have been found to improve the flexural strength of the epoxy resin, with 0.015% CNF in PVA giving a better mechanical strength. Cellulose is another plant metabolite which is also secreted by many bacteria and extracted from various marine filamentous algae. Cellulose nanofibers are considered as efficient replacements for conventional polymers due to their nano size, ease of preparation, low cost, tunable surface and enhanced mechanical properties. CNF obtained from algal sources is less compared to plants and bacterial sources. CNF finds a wide variety of applications such as drug carriers, tissue regenerating scaffolds, water purification, etc.