High-strength, high-modulus fibres based on linear polymers: principles of production, structure, properties, use

Abstract

The evolution of modern technology, transportation, sports, and tourism is greatly determined by the use of new materials, especially materials capable of withstanding limiting mechanical loads. Materials with high specifi c mechanical characteristics that allow creating highly reliable articles and structures of minimum weight are promising [1][2][3][4][5][6][7][8]. The highstrength and high-modulus fi bres used for this purpose belong to the low-and medium-tonnage group. They are manufactured from different kinds of aromatic and some aliphatic polymers. The highly oriented structure, which makes it possible to attain extremal mechanical properties in highly loaded textile items and high-strength composites, is a distinctive feature of these fi bres.The basic kinds of high-strength, high-modulus fi bres used on large scales are fi bres made from aromatic p-polyamides. They were created in the 1970s at almost the same time in the USA and Russia [3][4][5][6][7]. As a result of conducting extensive research on synthesis of new fi bre-forming polymers, creating the corresponding technologies, and investigating the structure and properties of these types of fi bres, development was basically of several kinds: -high-strength and high-modulus para-aramid fi bres based on poly-p-phenylene terephthalamide (PPTA -Twaron, Netherlands, and Kevlar, USA) with a dynamic deformation modulus of 90 to 160 GPa and a mechanical deformation modulus of 70 to 120 GPa; -high-modulus para-aramid fi bres made from heterocyclic p-polyamides and the close copolyamides (SVM, Rusar, and Armos, Russia) with a dynamic deformation modulus of 120 to 160 GPa and a mechanical deformation modulus of 95 to 120 GPa. SVM fi bres (historically, the fi rst kind of high-modulus heterocyclic aromatic fi bres) have been based on polyamidobenzimidazole synthesized from heterocyclic p-diamine and terephthalochloride. The copolymeric heterocyclic para-aromatic fi bres Armos and Rusar are based on the same components, with incorporation of p-phenylenediamine as the third comonomer.Other kinds of high-strength and high-modulus fi bres have also been created: -fi bres made from a copolymer close in composition to poly-p-phenylene terephthalamide with a 5-15% aromatic comonomer content (Terlon, Russia). These fi bres differ little in composition and properties from PPTA fi bres;-high-strength fi bres based on para/meta-polyaramid synthesized from p-phenylenediamine, para/metadiaminodiphenyl oxide, and terephthalic acid with a dynamic deformation modulus of 90 to 110 GPa, mechanical deformation modulus of 60 to 80 GPa for high-strength textile articles and reinforcement of elastomeric composites, primarily rubbertextile items (Technora, Japan). 2

An Investigation of the High Performance of a Novel Type of Benzobisoxazole Fiber Based on 3,3-Diaminobenzidine

“…SVM fibers (historically, the first kind of high-modulus heterocyclic aromatic fibers) are based on polyamidobenzimidazole, which is synthesized from heterocyclic p -diamine and terephthalochloride. The copolymeric heterocyclic para-aromatic fibers Armos and Rusar are based on the same components and incorporate p -phenylenediamine as a third comonomer [ 11 ]. The present experience in the area of poly-heterocyclic-para-aramides (SVM, Rusar and Armos, Moscow, Russia) shows better results when the initial solution is non-liquid-crystalline (isotropic) and the transition to the liquid-crystalline state occurs during fiber structure formation.…”

“…The same situation is noted in the cases of semi-rigid polymer–cellulose and polyacrylonitrile in organic solutions. The limitations in the structuring and crystallization of these solutions during fiber formation result in a higher orientation and mechanical properties of the fibers [ 11 ].…”