Aramid fiber filled

Measurements Aramid fiber-filled Epdm Silica- fiUed Epdm Bayhydrol 122-1- 15% Montmorillonite -1- 3% Hexcel carbon fibers... 

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. 

Fluoroelastomers Novikova et al. [32] reported unproved physico-mechanical properties of fluoro mbbers by reinforcement with chopped polyamide fibers. Other fiber reinforcements are covered by Grinblat et al. [33]. Watson and Francis [34] described the use of aramid (Kevlar) as short fiber reinforcement for vulcanized fluoroelastomer along with polychloroprene mbber and a co-polyester TPE in terms of improvement in the wear properties of the composites. Rubber diaphragms, made up of fluorosilicone mbbers, can be reinforced using aramid fiber in order to impart better mechanical properties to the composite, though surface modification of the fiber is needed to improve the adhesion between fluorosUicone mbber and the fiber [35]. Bhattacharya et al. [36] studied the crack growth resistance of fluoroelastomer vulcanizates filled with Kevlar fiber. 

Rigidite Carbon, aramid, glass fiber filled BASF PLASTICS... 

Quantitative predictions of the effects of fillers on the properties of the final product are difficult to make, considering that they also depend on the method of manufacture, which controls the dispersion and orientation of the filler and its distribution in the final part. Short-fiber- and flake-filled thermoplastics are usually anisotropic products with variable aspect ratio distribution and orientation varying across the thickness of a molded part. The situation becomes more complex if one considers anisotropy, not only in the macroscopic composite but also in the matrix (as a result of molecular orientation) and in the filler itself (e.g., graphite and aramid fibers and mica fiakes have directional properties). Thus, thermoplastic composites are not always amenable to rigorous analytical treatments, in contrast to continuous thermoset composites, which usually have controlled macrostructures and reinforcement orientation [8, 17]. 

Another approach to the characterization of fiber microstructure is the isoprene inclusion method (Section 4.4.2.5). This was applied to the study of PET fibers [57] and to aramid fibers [58] for the purpose of showing their radial microporous and fibrillar texture. Any holes or voids are filled by inclusion of isoprene in the fiber. They are then stained by the reaction of osmium tetroxide with the included isoprene. Longitudinal sections of high speed spim PET are shown in the TEM micrographs in Fig. 5.15A and B of fibers before and after the reaction, respectively. Similar views at lower magnification were shown (Fig. 4.12) in... 

Figures 7.1 and 7.2 show the variation of primary normal stress difference with shear stress for the various filled systems studied [29]. It is seen that glass beads hardly affect the values of Nj while the presence of Franklin fibers, titanium dioxide (Ti02), calcium carbonate (CaCOj), carbon black (CB) and mica, respectively, show greater and greater reductions in Nj. However, on the other hand, the addition of certain fibers like cellulose fiber, glass fiber and aramid fiber, respectively, increases Nj values to a larger and larger extent.

It is seen that spherical fillers like glass beads do not affect the normal stress difference. Particulate fillers like titanium dioxide, calcium carbonate and carbon black, reduce the normal stress difference whereas fibrous fillers like aramid, glass and cellulose fibers, increase it. The large increase in normal stresses of fiber filled polymer systems is explained on the basis of the hydrod)mamic particle effect, associated with orientation in the flow direction. Of course, if the fiber diameter is very small then the increase in normal stresses is small and at times may even show a decrease. 

X-ray diffraction was first used to detect fiber orientation in polymer compoimds by Schier-ding [86] and subsequently by Yoshida et al. [87] and by Menendez and White [88]. This technique was later applied by him et al. [89,90] to study fiber orientation development in processing short fiber-filled compoimds. Aramid fibers, which are highly crystalline and oriented, as well as giving sharp diffraction peaks, were used by the latter authors [89,90]. 

In a fiber form, LCPs are used in a similar manner as aramid fibers. In solid form, as is used in molding and extrusion, or even with thermoforming, LCPs are quite unique. In the molten phase, the molecular chains are oriented and aligned, without entanglements. This means the molten material can flow easily (like a liquid), allowing for fill of very thin sections at very low pressure. They then solidify... 

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