Kevlar ester

As mentioned earlier, amides are less reactive than esters, and diamides are even less reactive. An example of this trend is the low reactivity of the dibenzoyl amides of 1,3- and 1,4-diaminobenzene, which are model compounds for the polymers Nomex [poly(l,3-phenylene isophthalamide)] and Kevlar B [poly (1,4-phenylene terephthalamide)] [243]. 

The matrix resins for foamed composites include rigid pol)ruretha-nes, unsaturated polyesters, vinyl esters, and their hybrid resins, such as, unsaturated polyester-urethane hybrid resins and vinyl ester-urethane hybrid resins. The reinforcing fibers include glass fibers, carbon fibers, and organic fibers such as polyamide fiber (Kevlar, DuPont), polyamide-... 

Synthetic polymers are either polyolefins synthesized from olefin and alkene monomers by covalent bonding or polymers of esters, amides, urethanes, and some other functional group monomers. Polyethylene, polypropylene, polystyrene, polyvinyl chloride, and Teflon are some common examples of polyolefins and polyalkenes. PET, nylon, Kevlar, and Spandex are some examples of polyesters, amides, and urethanes. 

Figure 26 Illustration of the chemistry of a Switch-ester segment as a reversible structure breaking unit that forms kinks in the peptide backbone (left) and the pH-value-controlled rearrangement in the switch unit, resulting in the native peptide backbone by an O N acyl transfer rearrangement (middle and right). Analogs of the fully synthetic aramidic polymers (bottom) Nomex as a well-processable polymer with kinks in the main chain (left) and Kevlar as a polymer, which is difficult to handle due to strong chain-chain interactions (right).

Britten, a New Zealand motorcycle company, has used a composite subchassis made of carbon fiber/Kevlar Derakane epoxy vinyl ester resin laminate for their Britten VIOOO racing machine.The Aprila 250 uses cfrp wheels molded in two halves from a 2x2 HS twill... 

A modified epoxy matrix for Kevlar FRP composites was produced from ep>oxy/polyphenylene oxide (PPO) blends cured with multifunctional cyanate ester resin [94]. The effects of the PPO content on the cme behavior in the cyanate ester-cmed epoxy were investigated with FTIR. The cme reaction in the ep>oxy/PPO blends was faster than that of the neat epoxy system. FTIR analysis revealed that the cyanate fimctional group reactions were accelerated by adding PPO and that several co-reactions had occurred. Thermal mechanical analysis showed that the thermal stability of the epoxy/PPO matrix is improved by adding PPO. In the respective compursites, the ISS values between Kevlar fiber and the epoxy/PPO blends are almost the same as those between Kevlar fiber and neat epoxy. The ILSS in the respective laminates increases with the PPO content, which was attributed to an increase in the composites ductility. 

Wu S J, Lin T K, Zhang J X and Shyu S S (2000) Properties of cyanate ester-cured epoxy/poly-phenylene oxide blends as a matrix material for Kevlar fiber composites, J Adhes Sci Technol 14 1423-1438. 

This polymer, polyethylene terephthalate (PET), exhibits multiple ester linkages and is therefore called a polyester. PET is sold under many trade names, including Dacron and Mylar . It is primarily used in the manufacture of clothing. There are many different kinds of polyamides and polyesters, serving a variety of purposes. Kevlar, for example, is stronger than steel and is used in bulletproof vests ... 

The construction of radomes is one where constant innovation is taking place. The ongoing search for improved materials is leading to die use of new material combinations such as the current under-belly radome for AgustaWestland Helicopter s EHlOl Merlin (Fig. 73) which still uses the conventional sandwich bonding approach but now uses Kevlar/cyanate ester skins. 

The high-strength fiber NM-SO [32] with mechanical indexes equal to those of Kevlar, is prepared from isotropic solutions of an aromatic polyamide ester... 

Scrimp vinyl ester/glass —1— Vinyl ester/glass —Epoxy/glass —it— Epoxy/Kevlar —Epoxy/glass-Kevlar hybrid -—Epoxy/carbon ... 

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