Yarns, tensile properties

ISO 10618 2004 Carbon fibre - Determination of tensile properties of resin-impregnated yarn... 

Test Materials, contemporary silk. As reported earlier (11), fabrics were chosen over yarns for treatment because of their ease of preparation and handling. Tensile properties, however, were measured on yarns extracted from the fabrics to take advantage of the ease of handling fabrics and the ease of testing yarns. 

Table II. Tensile properties of vest yarns during environmental chamber exposure (50 C/60% RH, 0 days to 84 days, followed by 60 C/37 /o RH, 85...

Testing Procedures. The tensile properties of dry and wet warp yarns from control and treated samples were measured by ASTM D2256-66T on an Instron Tensile Tester, Model TM using a gauge length of 3 inches and a rate of extension of 33% per minute (Table I). Wrinkle recovery (dry and wet) values were determined by AATCC test method 66-1978 (Table 11). The felting shrinkage and alkali solubilities were determined by the methods outlined by Haron (14) (Table II). 

It Is of Interest to point out the Figure 2 spin line capillary diameter effect on the FOY yarn structure, where the 7 mil (0.018 cm) diameter capillary yielded no amorphous orientation change, but a significant crystallinity reduction relative to the 15 mil (0.38 cm) capillary. From the above discussion, the generally equal FOY tensile properties for yarns spun from the two capillaries are predicted from the equal amorphous orientation values at equivalent spinning speeds (Table I). The greatly reduced PTY broken filament count for the yarn textured from the higher crystallinity FOY spun from the 15 mil capillary I also consistent with the above discussion. 

The triangle shown In Figure 2 shows the Interrelation between the process, the structure of the resulting product, and physical properties. In a modeling situation, one generally starts with a knowledge of the process conditions from which It Is desired to determine structural and physical properties. A study(2) of spinning Poly(ethylene terephthalate) (PET) will be discussed where It was possible to use a model to calculate the stress at the solidification point, and then relate this to spun yarn tensile properties. 

These references are concerned with the mechanisms through which moisture is absorbed by the fiber. The effect it has on fiber properties however varies from fiber type to fiber type, and although the effects are wider than merely the effect on tensile properties, it is on these properties that the standard methods of test are mainly concerned. Many of the standard tests previously cited, such as ISO 5079. ISO 2062. ASTM D 2256. and ASTM D 3217. all make provision for conducting the tests with the fiber or yarn in the wet rather than the conditioned state. 

ASTM D 2256- 95 provides a method for the determination of the tensile properties of monofilament, multifilament, and spun yarns, wither single, plied, or cabled, providing that the yarns do not extend more than 5% when the tensile force is increa.scd from 5 mN tex to 10 mN tex. The method covers the measurement of breaking force and elongation at break, tenacity (at break), initial modulus, and breaking toughness. Options arc included for knotted and looped forms (for which sec also ISO 2062). 

ASTM D 2101-94(discontinucd in 1995) - Tensile properties of single niaii-made textile fibers taken from yarns and tows. 

ASTM D 2256 95—Tensile propertie.s of yarns by the single-strand method. 

From an extensive series of correlations between fiber properties and yarn properties, Mather concluded that the tensile properties of a yarn could be predicted from two measurements only on the raw fiber, namely, the linear density and the ballistic work of rupture of uncarded strands of fiber. 

Typical properties of commercial aramid fibers are given in Table 13.4. While yarns of m-aramids have tensile properties that are no greater than those of aliphatic polyamides, they do retain useful mechanical properties at significantly higher temperatures. The high glass... 

Yarns are available in a variety of deniers and merge types that vary in the balance of tensile properties. Special finishes can be applied to increase lubricity, improve fatigue in wet applications, or provide better UV resistance. Ropes using Kevlar or Twaron are particularly useful for static applications or where maximum modulus is required. Technora-based ropes are suited for dynamic applications where resistance to fatigue is important. 

Tensile properties The yarns present must have acceptably high tensile strengths to resist the inflationary pressure and subsequent impact forces. Fabrics must have high tear and bursting strengths... 

Yarn tensile properties-. No big difBsrences were observed between single strand, knotted and laced form. The mean values in breaking strength and deformation in single strand of warp and wrefl samples will be reported in Table 1. 

D2343- Tensile properties of glass fibre strands, yarns and rovings used in reinforced plastics 67... 

D4018- Tensile properties of continuous filament carbon and graphite yarns, strands, rovings and 81 tows... 

A major limitation of knitted fabrics is porosity, which, due to the nature of the loop structure, tends to be high and cannot be reduced below a certain minimum value. Figure 1.15b shows a knitted graft with visible pores. Also because the yarns are looped and bent, that is, not nearly as extended as with woven materials, the fabrics tend to be relatively weaker. A general comparison of the tensile properties of the three structures covered, assuming similar weights and yam material, is given in Fig. 1.17. 

Table 74.3 Tensile properties of yarns used in the project by Mizelle ...

Table 1. Tensile Properties of Nylon-6 and Nylon-6,6 Continuous-Filament Yarns ...

Zhou et al [163] also measured the tensile properties of carbonized PAN yarns. The 1000°C carbonized bundle had a tensile strength of 325 15 MPa and a modulus of 40 4 GPa. These values increased to 542 45 and 58 6 GPa, respectively, with the increase of the final graphitization temperature to 2200°C. The values are measured for the bundle which can differ from the properties of single fibers to a great extent. 

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