Nylon rheological properties

The rheological properties of insitu polymerized nanocomposites with end-tethered polymer chains were first described by Krisnamoorti and Giannelis [33]. The flow behavior of PCL- and Nylon 6-based nanocomposites differed extremely from that of the corresponding neat matrices, whereas the thermorheological properties of the nanocomposites were entirely determined by the behavior of the matrices [33]. The slope of G (co) and G"(co) versus flxco is much smaller than 2 and 1, respectively. Values of 2 and 1 are expected for linear mono-dispersed polymer melts, and the large deviation, especially in the presence of a very small amount of layered silicate loading, may be due to the formation of a network structure in the molten... 

Polymer Blends.—In addition to the work on polyester—polyamide blends reported in Section 2, several other papers describe the characteristics of various polymer formulations with polyamides. Biconstituent fibres have been formed from nylon-6 and poly(ethylene terephthalate). The same polyamide and nylon-12 have been blended with acrylonitrile-butadiene-styrene copolymer and the temperature and the concentration dependence of the dynamic modulus evaluated. The rheological properties of acrylonitrile-styrene copolymer/nylon-6 mixture have also been reported. Fourier transform infrared studies of nylon-6 and PVC have indicated the presence of specific interactions between the two polymers in both the molten and solid states. Finally X-r y studies carried out on injection-moulded blends of nylon-6, -12, and -66, have revealed that the addition of small amounts of the second component initiates formation of the y-crystalline phase within the nylon-6 polymer matrix. ... 

Exfoliated clay nanocomposites formed between organocation exchanged montmorillonites and thermoplastic Nylon-6 have recently been described by Toyota researchers (9-11). Clay exfoliation in the Nylon-6 matrix gave rise to greatly improved mechanical, thermal and rheological properties, mal g possible new materials applications of this polymer. However, it is relatively difficult to achieve complete exfoliation of smectite clays into a continuous polymer matrix, because of the strong electrostatic attraction between the silicate layers and the intergallery cations. 

The melt-spinning dynamics and rheological properties of nylon 6 have been studied together with eifects of drawing and of swelling and additive incorporation,and the effects of crystallite dimensions on structure and modulus. Crystallinity and crystallite size measurement in both polyamides and polyesters has also been reviewed. ... 

Pisipati, R. and Baird, D.G. (1981) Correlation of rheological properties of filled nylon melts with processing performance, SPE ANTEC, 27,32-4. 

The possibility of a synergistic combination of properties for SPS/nylon blends has been recognized, and, therefore, the structural and physical properties [46] as well as the morphology and mechanical properties [47] of PA 6,6 (nylon 6,6)/SPS blends have been the subject of two research articles. Below is a suimnary of the mechanical properties, rheological properties, moisture response, dimensional stability, USCAR test results, and solvent resistance of SPS/nylon blends that make these blends attractive for some applications, such... 

Rheological properties of the LCP (0.7 HBA/0.3 HNA) with PC, PBT, Nilon-6 blends were characterized by Beery et al. (1991). PC/LCP shows a non-Newtonian behavior and their viscosities are intermediate between the LCP and PC. Below 300 s the viscosity increases with LCP concentration but above this shear rate, the viscosity decreases with LCP content. The PBT containing blends shows a different rheological behavior. In this case the viscosities of the blends lie below those of the LCP in the whole shear rate range. For Nylon-6 the viscosities of the blends lie below to that of the pure constituents and the blend viscosity decreases with increasing LCP content. 

HOPE (rheological properties are given in Table 2.3) and nylon 6 (rheological properties are given in Table 7.3) are extruded through a film die both at a temperature of 220 °C. Determine the pressure gradient, G, required to produce an... 

Most of the polymer s characteristics stem from its molecular stmcture, which like POE, promotes solubiUty in a variety of solvents in addition to water. It exhibits Newtonian rheology and is mechanically stable relative to other thermoplastics. It also forms miscible blends with a variety of other polymers. The water solubiUty and hot meltable characteristics promote adhesion in a number of appHcations. PEOX has been observed to promote adhesion comparable with PVP and PVA on aluminum foil, cellophane, nylon, poly(methyl methacrylate), and poly(ethylene terephthalate), and in composite systems improved tensile strength and Izod impact properties have been noted. 

PP is probably the most thoroughly investigated system in the nanocomposite field next to nylon [127-132]. In most of the cases isotactic/syndiotactic-PP-based nanocomposites have been prepared with various clays using maleic anhydride as the compatibilizer. Sometimes maleic anhydride-grafted PP has also been used [127]. Nanocomposites have shown dramatic improvement over the pristine polymer in mechanical, rheological, thermal, and barrier properties [132-138]. Crystallization [139,140], thermodynamic behavior, and kinetic study [141] have also been done. 

Rheological studies of PET nanocomposites are not ample, but show very interesting features. In the low frequency range, the nanocomposites display a more elastic behavior than that of PET. It appears that there are some physical network structures formed due to filler interactions, collapsed by shear force, and after all the interactions have collapsed, the melt state becomes isotropic and homogeneous. Linear viscoelastic properties of polycaprolactone and Nylon-6 [51] with MMT display a pseudo-solidlike behavior in the low frequency range of... 

Figure 4.29 The dependency of viscosity on temperature for several isotropic pitches, a mesophase pitch and a typical thermoplastic polymer Ashland 240 (isotropic petroleum pitch) Aerocarb 60 (isotropic pitch distilled from A240) Aerocarb 75 (isotropic pitch distilled from A240) Source. Sumner MB, Thermal properties of heavy isotropic petroleum pitches. Carbon 88, Proceedings of the International Conference on Carbon, University of Newcastle upon Tyne, 52-54, Sep 18-23,1988, Mesophase (produced by pyrolysis of A240) Nylon 6 (a typical melt spur synthetic polymer). Source Reprinted from Whitehouse S, Rand B, Rheology of mesophase pitch from A240. Carbon 88, Proceedings of the International Conference on Carbon, University of Newcastle upon Tyne, 175-176, Sep 18-23, 1988.

H. Aoki, J.L. White, and J.F. Fellers, "A Rheological and Optical Properties Investigation of Aliphatic (Nylon 66, P BLG) and Aromatic (Kevlar, Nomex) Polyamide Solutions," J. Appl. Polym. Sci. 23, 2293-2314 (1979). 

The rheological and thermal conductivity properties of the polymer matrix determine the heat necessary to melt the material. Relatively shear-sensitive materials become less viscous as they pass through the nozzle. For example, nylons form low viscous fluids when melted while polyethylene can undergo considerable mechanical working, producing heat necessary for plastica-tion. 

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