Composites aramid fiber-reinforced polymer

Properties of p-aramid fiber reinforced polymer composites... 

Short fiber reinforcement of TPEs has recently opened up a new era in the field of polymer technology. Vajrasthira et al. [22] studied the fiber-matrix interactions in short aramid fiber-reinforced thermoplastic polyurethane (TPU) composites. Campbell and Goettler [23] reported the reinforcement of TPE matrix by Santoweb fibers, whereas Akhtar et al. [24] reported the reinforcement of a TPE matrix by short silk fiber. The reinforcement of thermoplastic co-polyester and TPU by short aramid fiber was reported by Watson and Prances [25]. Roy and coworkers [26-28] studied the rheological, hysteresis, mechanical, and dynamic mechanical behavior of short carbon fiber-filled styrene-isoprene-styrene (SIS) block copolymers and TPEs derived from NR and high-density polyethylene (HOPE) blends. 

Epoxy resins are by far the most widely used polymer matrices for advanced structural composites and, if carbon, glass, and aramid fiber reinforced epoxies... 

It should be noted, however, that the thermal and mechanical properties of vegetable fiber reinforced polymer composites are notoriously lower than those of similar composites reinforced with synthetic fibers (e.g., carbon, glass, aramid) [1, 2,12]. The above-mentioned techniques, i.e., fiber drying and surface treatment or the addition of a compatibilizer, are mostly not enough to adjust the properties of vegetable fiber reinforced polymers to the desired level. Moreover, even though these treatments enhance adhesion, there is some controversy in the literature about their effect on the mechanical properties of the fiber itself and even when a more pronoxmced gain is noticed after treatment, the improvement for the composite is often within the scatter of the results. In addition, the cost and environmental impact of some of these treatments, especially of those more elaborated, often prevent their industrial scale applications. 

The use of fiber-reinforced polymer (FRP) composite materials in the reinforcement of concrete structures has shown important results. These interventions are based on the application of carbon fiber, glass, or aramid impregnated with thermosetting polymers. The effectiveness of these interventions is demonstrated both by extensive research in the laboratory and by applications to existing structures. 

In this subsection the physicochemical and mechanical properties of the most common p-aramid brands will be discussed. It is worth noting that mostly p-aramids are used for reinforcement of thermoset and thermoplastic polymer matrices where strength and stiffness are critical. However, in the case of elastomer-based composites where more important are the flame resistance, flexibility and the resistance to thermal, impulse and vibrational stresses, the m-aramid fiber reinforcement renders superior properties [3]. 

Klein N, Marom G and Wachtel E (1996) Microstructure of nylon 66 transcrystalline layers in carbon and aramid fiber reinforced composites. Polymer 37 .5493-5498. 

Of the three most common reinforcing fiber types used for polymer-reinforced composites (carbon, glass, and aramid), carbon fibers have the highest modulus of elasticity and strength in addition, they are the most expensive. Properties of these three (as well as other) fiber materials are compared in Table 16.4. Furthermore, carbon fiber-reinforced polymer composites have outstanding modulus- and strength-to-weight ratios. 

Glass, carbon, and the aramids are the most common fiber reinforcements incorporated into polymer matrices. Other fiber materials that are used to much lesser degrees are boron, silicon carbide, and aluminum oxide tensile moduli, tensile strengths, specific strengths, and specific moduli of these materials in fiber form are given in Table 16.4. Boron fiber-reinforced polymer composites have been used in military aircraft components, helicopter rotor blades, and sporting goods. Silicon carbide and aluminum oxide fibers are used in tennis rackets, circuit boards, military armor, and rocket nose cones. 

Composite In polymer technology a combination of a polymeric matrix and a reinforcing fiber with properties that the component materials do not have. The most common matrix resins are unsaturated thermosetting polyesters and epoxies, and reinforcing fibers are glass, carbon, and aramid fibers. The reinforcing fibers may be continuous or discontinuous. Some matrix resins are thermoplastics. 

The additional chain orientation in the direction of the fiber long axis, obtained from the nematic self-ordering in the system, leads to a dramatic enhancement of the mechanical properties of the polymer. A number of aromatic polyamides have thus achieved commercial importance because of the very high tensile strengths and moduli of the fibers that can be spun from the nematic solutions. These have consequently become attractive alternatives to metal or carbon fiber for use in composites as reinforcing material. The most significant of these aramid fibers are ... 

Aramid fibers are widely used as reinforcing fibers in high performance composites. One disadvantage is the poor adhesion to the matrix materials. This arises from the lack of functional groups in the polymer. To overcome the lack of adhesion, the fibers are treated by so-called finish formulations, which is essentially a surface treatment. 

CAS 250384)44) 90529-77-4 EINECS/ELINCS 2924)11-4 Uses Crosslinking reagenL adhesion promoter for fiber coatings reactive diluent with other polymers, in solv.-free coating systems, laminating resins, fiber-reinforc composites, coating of tech, polyester and Aramide fibers (as textile reinforcement in tires, conveyor belts) in the fiber, mbber and polymer industry Trade Names GE100... 

Description and general properties. Polymer matrix composites (PMCs) consist of a pol)oner matrix or resin reinforced with glass fibers and to a lesser extent carbon, boron and pol)r-aramide fibers. The resin systems used to manufacture advanced composites are of two basic types thermosets and thermoplastics (see Chapter 11). Thermosetting resins predominate today, while thermoplastics have only a minor role in advanced-composite manufacture. Thermoset resins require the addition of a curing agent or hardener and impregnation onto... 

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