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Fibre reinforcements
Published in A.R. Bunsell, S. Joannès, A. Thionnet, Fundamentals of Fibre Reinforced Composite Materials, 2021
R. Bunsell, S. Joannes, A. Thionnet
The scientific literature shows continuing interest in the development of even higher performance fibres but whether they will become commercially attractive is uncertain. A fibre made from polypyridobisimidazole (PIPD) has been reported. It is called M5 and was produced by the researchers from the Dutch company AkzoNobel. It was then ceded to Magellan Systems International which in turn joined the DuPont™ company. The molecule is related to PBO and the Young's modulus claimed for the fibre of 330GPa is even higher. The producers claim that there is a highly significant difference in the behaviour of the PIPD fibre as lateral cohesion is determined by hydrogen bonds. As mentioned above, the PBO fibre relies on Van der Waals bonds for lateral cohesion which are very weak. Hydrogen bonds are ten times stronger which means that the M5 fibre has superior radial and compressive strengths. The presence of hydrogen bonds will probably mean that the fibre will absorb water however. The M5 fibre seems to be very interesting from a technical view point and addresses the problem of anisotropy of aromatic fibres. It has, inevitably attracted attention for use in body armour. However, it remains unclear if this fibre will ever become commercially available.
Improvement in the bending strength of FRP using the filament cover method
Published in The Journal of The Textile Institute, 2020
Limin Bao, Ryo Sakurada, Daiki Ichikawa, Fangtao Ruan
There are various ways to improve FRP’s in-plane compression characteristics. Leal, Deitzel, and Gillespie (2007) addressed the low axial compressive strength of materials such as carbon fiber (CF) by using M5 fiber, which has a high Young’s modulus and compressive strength, to increase FRP’s compressive strength. Ruan and Bao (2014) coated the surface of the ultrahigh-molecular-weight polyethylene fiber, which has low axial compression performance, with carbon nanotubes with a rigid surface to increase the fibers’ bending rigidity and compression characteristics. In FRP applications, materials such as GFRP with low compressive strength and high polymer AFRP are hybridized with CFs that have relatively high compression characteristics to improve their performance (Almeida, Amico, Botelho, & Amado, 2013; Cox, Dadkhah, Inman, Morris, & Zupon, 1992; Dong and Davies, 2012; Li, Xian, Choy, Guo, & Zhang, 1999). Subramaniyan and Sun (2006) attempted to denature resin in order to increase its hardness and as a result the compressive strength of FRP manufactured with it. There is demand from manufacturers for simple, effective methods for increasing the compressive strength of unidirectionally FRP.
Soft body armour
Published in Textile Progress, 2019
Unsanhame Mawkhlieng, Abhijit Majumdar
PIPD or M5 fibre is another high tenacity, high modulus fibre that has high potential for ballistic applications. Developed by Akzo Nobel, it is now produced by Magellan Systems International (a division of DuPont™) in the USA. Chemically, it is formed by condensation polymerization of tetraaminopyridine and dihydroxyterephthalic acid in the presence of diphosphorus pentoxide as a dehydrating agent [30,31]. The chemical structure of M5 fibre is shown in Figure 9.