Tenacity fibre properties

Sikkema,D.J., Design,synthesis and properties of a novel rigid rod polymer,PIPD or M5 high modulus and tenacity fibres with substantial compressive strength, ... 

The optical properties of interest are refractive index and molecular refraction, polarisation, double refraction (birefringence) of isotropic and oriented PE, clarity, transparency, haze, and gloss (see Tables 3.1 and 3.9). PE granules are white and translucent, but the final appearance varies from hard, rigid, brightly coloured, glossy, flexible or transparent film to high-tenacity fibre. In the melt state the refractive index is 1.4297 and 1.4432 and the molar refractivity is 0.3297 and 0.32986 for HDPE and LDPE, respectively. 

The overall properties of the composites are dependent on the matrix properties, the fibre content (Figure 10.8), its modulus of elasticity, and the various means used to improve the fibre-matrix bond. A variety of different fibre types have been studied, including monofilaments of various diameters, fibres with buttons on their ends [21], twisted tapes [21], fibrillated mats [26], textile fabrics [18] and high tenacity fibres with frayed ends [7], Even with smooth monofilament... 

ISO 1346 2004 Fibre ropes - Polypropylene split film, monofilament and multifilament (PP2) and polypropylene high tenacity multifilament (PP3) - 3-, 4- and 8-strand ropes ISO 1873-1 1995 Plastics - Polypropylene (PP) moulding and extrusion materials - Part 1 Designation system and basis for specifications ISO 1873-2 1997 Plastics - Polypropylene (PP) moulding and extrusion materials - Part 2 Preparation of test specimens and determination of properties ISO 3213 1996 Polypropylene (PP) pipes - Effect of time and temperature on expected strength... 

Annealing fibres melt-spun from nematic mesophases can produce very significant changes in some of the physical properties, notably increases in both tenacity and extension to break. Some of the values of tenacity attainable in this way are among... 

The very wide range of the numerical values of the mechanical properties is evident. The modulus of organic polymer fibres varies between 1 and 350 GPa. The tenacities or tensile strengths may even vary from about 0.07 GPA (0.05 N/tex) for the weakest (cellulose acetate) to about 7 GPa (4 N/tex) for the strongest fibre (PIPD or M5 ) the compressive strengths reaches up to 1.7 GPa and the temperature resistance up to 400 °C. The ultimate elongation may vary from about 1% for the stiffest fibre (carbon) to about 600% for the most rubber-elastic. 

Potentially, at least, the mechanical properties of these fibres can be varied over a wide range, simply by varying the post-spinning heat treatment to which they are subjected. Unfortunately the increases in fibre initial moduli and tenacities brought about by heat treatment are normally accompanied by reduction in the extensibilities, as shown in Tables 2 and... 

The fibres that are used extensively for armour products are Kevlar , Spectra , Dyneema , and Zylon . The properties of the main fibre types used for slash resistance are summarised in Table 7.4. All the fibres listed provide excellent strength-to-weight (tenacity) properties and high modulus. 

Table 11.5 High tenacity, manufactured fibre, tensile properties... 

PPS fibres (e.g., Torcon (Toray), Procon (Evonik) and Diofort (Diolen)) have inherent fire resistance, chemical resistance and high tenacity properties, and are widely used in high temperature filtration applications and chemical protective clothing. 

Van Ruiten and co-workers [45] studied the drawability and attainable mechanical properties of PA 4,6 yarn using true stress-strain curves. The concept of the molecular network was applied to an analysis of these fibres and yarns and the mechanical properties of yarns with different draw ratios was evaluated in terms of the network draw ratio, which was determined by matching true stress-strain curves. The validity of the molecular network concept for these yarns and its suitability for predicting fibre drawability was assessed. A method for predicting the maximum attainable tenacity of drawn yarns under given drawing conditions from precursor mechanical properties is proposed. 

With the advance of LCP technology, considerable attention has been directed towards the blending of LCPs with conventional polymers (6-9). Indeed, the presence of a LCP as a minor component in a conventional synthetic fibre offers several major benefits. For example, the low melt or solution viscosity of the LCP facilitates fibre extrusion (7), and the fibre mechanical performance, notably tenacity and initial modulus, can be improved by virtue of the superior mechanical properties of the LCP (8,9). However, incompatibility between the conventional polymer and the LCP will result in poor interfacial adhesion between the two phases, with the result that the reinforcement offered by the LCP may be severely diminished. 

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