Nanofiber-Reinforced Composites

Cellulose nanofibers from different sources have showed remarkable characteristics as reinforcement material for optically transparent composites [160, 161], Iwamoto et al. [160] prepared optically transparent composites of transparent acrylic resin reinforced with cellulose nanofibers extracted from wood pulp fibers by fibrillation process. They showed that cellulose nanofiber-reinforced composites are able to retain the transparency of the matrix resin even at high fiber content (up to70 % wt). The aggregation of cellulose nanofibers also contributes to a significant improvement in the thermal expansion properties of plastics. 

Nogi M, Abe K, Handa K et al (2006a) Property enhancement of optically transparent bionanofiber composites by acetylation. Appl Phys Lett 89 233123 33121—233123/233123 Nogi M, Ifuku S, Abe K et al (2006b) Fiber-content dependency of the optical transparency and thermal expansion of bacterial nanofiber reinforced composites. Appl Phys Lett 88 133124/... 

All-cellulosic based composite films can be prepared from either isotropic or anisotropic cellulosic derivatives solutions. However, these composites cannot compete with mechanical properties of cellulose nanofiber reinforced composites. Pioneering studies reported by Favier et al. [35, 36], showed that small amounts of cellulose tunicate whiskers resulted in dramatic improvements in modulus above the glass transititMi temperature of an amorphous polymer matrix, due to the percolation of the cellulose nanofibers. Also recently, a completely new route to cellulose-based composites was proposed by Nishino and Arimoto [37], Soy-keabkaew et al. [38—40], They focused on approaches following self-reinforcing polymer concepts [41, 42] to create composites that often outperform traditional nanofiber reinforced composites [38,40],... 

Currently, the field of synthetic polymer-polymer composites (PPCs) is characterized by very rapid progress since new ideas form the basis of new technologies and often require new materials to be developed. Thus, new materials such as nanofibers and nanofiber reinforced composites can create newer ideas and further applications, which in turn, can result in the development of more specialized materials. The PPC industry requires advanced matrices, advanced reinforcements, advanced additives, advanced technologies and wider application fields. 

The mechanical performance of electrospun nanofibers concerning nanocomposites can be discussed at different levels such as mechanical properties of single nanofibers, nano-fibrous self-products, and nanofiber reinforced composites as well. When designing composites it is crucial to know the mechanical parameters, behavior and damage process of the nanofibrous materials. 

Ban W, Song J, Argyropoulos DS, Lucia LA (2006) Improving the physical and chemical functionality of starch-derived films with biopolymers. J Appl Polym Sci 100 2542-2548 Bhatnagar A (2005) Processing of Cellulose Nanofiber-reinforced Composites. J Reinf Plast Compos 24 1259-1268... 

In the field of tissue engineering, more information on and a better understanding of the wettability and permeability of nanofiber yams, as well as their structural properties as a function of biodegradation, should lead to the development of highly functional tissue scaffolds and wound dressings. Successful electrospinning of other materials, such as metals and non-oxide ceramics, and better control over the crystallinity of electrospun polymer fibers will lead to significant advances in nanofiber reinforced composite materials. 

Bhatnagar, A, andSain, M. (2005). Processing of cellulose nanofiber-reinforced composites,/ Reinforced Plast Compos, 24,1259-1268. 

Banerjee S, Kumar A (2010) Dielectric behavior and charge transport in polyaniline nanofiber reinforced PMMA composites. J Phys Chem Solids 71 381... 

Lee H, Mall S, He P, Shi DL, Narasimhadevara S, Yeo-Heung Y, Shanov V, Schulz MJ (2007) Characterization of carbon nanotube/nanofiber-reinforced polymer composites using an instrumented indentation technique. Composites Part B 38 58-65... 

Iwatake, A., Nogi, M., Yano, H., Cellulose nanofiber-reinforced polylactic acid. Composites Science and Technology. 9, 2103-2106 (2008), DOI http //dx.doi.0rg/lO.lOl6/j.compscitech.2008.03.006. 

Improved dispersion of nanoscaled fillers in polymers is expected to lead to better mechanical properties. The question is if by using a nano-modified matrix instead of a laminate with neat polymer as the matrix, in a fiber-reinforced composite can lead to improve delamination resistance. In the case of semicrystalline polymer matrices, the scenario is even more complicated as the microstructure is not only influenced by the processing but also by the presence of nanofillers. The addition of different types of nanoscaled reinforcements such as carbon nanotubes, nanofibers or... 

In a previous work, the same authors also observed that the composite peel strength was significantly increased by introducing interleaved films of the same polymer between the layers of woven oriented tapes [30]. They continued working on PP self-reinforced composites enhanced with the addition of CNT, trying to improve properties by the use of interleaved films [28]. Samples of single-polymer polypropylene composites were produced with and without interleaved films, and with and without carbon nanofibers, located either in the oriented polypropylene tapes, in the interleaved film or in both. Maximum peel strength was observed... 

Biodegradable polyester-based composites have been extensively studied for use in medical applications owing to their biocompatible and degradable properties in the human body. The major reported examples in biomedical products are fracture-fixation devices, such as sutures, screws, micro titration plates, and delivery systems [77]. Cellulosic nanofiber reinforced PLA composite materials... 

Iyengar PK et al (2013) Polymethyl methacrylate nanofiber-reinforced epoxy composite for shape-memory applications. High Perform PolymCT 25(8) 1000-1006... 

Lozano, K. Yang, S. Zeng, Q. Rheological analysis of vapor-grown carbon nanofiber- reinforced polyethylene composites. J. Appl Polym. Sci. 2004, 93, 155-162. 

These continuous fibers are used mostly in hybrid composites in combination with microfibers. In principle it is possible to reinforce composites with only nanofibers but knowledge so far is very limited in this field. 

Kelkar et al. [145] investigated the Mode I fracture toughness of glass fiber reinforced composites incorporated with tetraethyl-orthosilicate (TEOS) nanofibrous interlayers and alumina nanoparticles. They found no significant improvement, however only one interlaminar layer was placed between 10 layers of glass fabric. On the other hand, they experienced significant increase in Gju in the case of alumina nanoparticles. Nanoparticles can also be constructed from nanofibers through phase-separation. 

Fiber-reinforced polymer composites can contain short, discontinuous fibers (usually in thermoplastics see Fig. 1.14) or long, continuous fibers in thermoset resins. Fibers can vary from the usual glass fibers with thicknesses of some tens of micrometers up to nanofibers or carbon nanotubes (single-waiied or multiwalled, SWCNT or MWCNT) about 10 nm thick. The properties of fiber-reinforced composites depend on thickness, length, and volume content of the fibers, as well as on adhesion (interfacial strength) and matrix properties. 

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