Degradation of Technora aramid fibres in alkaline and neutral environments

Abstract

a b s t r a c tTechnora fibres are high performance aramid fibres which have been used in ropes and protective clothing for many years. They are also now being proposed as geotextiles for soil reinforcement. However, there is a lack of experience on the long-term behaviour of Technora fibres in an alkaline environment (lime-treated ground.). Consequently, aging studies have been performed under different conditions (deionised water, pH9 and pH11). Hydrolytic degradation has been evaluated by FTIR, viscometry, TGA, density measurements, SEM, and by tensile measurements. Some chain degradation and finish rearrangements have been highlighted, but Technora fibres retain their mechanical properties for all the conditions considered here.

Influence of finish treatment on the durability of aramid fibers aged under an alkaline environment

“…Whatever the aging conditions, the finish content does not have any significant influence on the tensile modulus: its value levels off throughout aging. As explained previously, 20 the structural changes induced by aging at pH 9 and pH 11 affect the tensile strength but not the tensile modulus. Figure 12 groups the tensile strength evolutions of Technora T240 and Technora T000 fibers aged at pH 11 and pH 9.…”

“…The logarithmic evolutions observed here have been previously interpreted as the result of two degradation processes at pH 11, namely the destruction of the tie-molecules/fibrils and the degradation of the crystallites, and one degradation process at pH 9, namely the destruction of the tie-molecules/fibrils only. 20 The results reveal that the finish content may not change the degradation mechanisms: the degradation curves of Twaron 1010 fibers seem to conserve a logarithmic relation with time. Moreover, it appears that higher the initial finish content, lower the degradation rate.…”

The evolution of structure and properties of poly(p‐phenylene terephthalamide) during the hydrothermal aging

“…Poly( p ‐phenylene terephthalamide) (PPTA) fiber has widely used in soft body armor and combat helmet, owing to his outstanding mechanical properties. As polyamide fiber, PPTA is prone to hydrolysis at elevated temperature1–4 and different aging environment 5–7. In order to predict the performance evolution of PPTA during its service period, it is important to understand the structure change caused by hydrothermal aging, as well as its influence on the fiber properties.…”

Evaluation of Long Term Behaviour of Polymers for Offshore Oil and Gas Applications

“…Tests in different environments also revealed the influence of water activity and pH, Table 1 [13]. Influence of immersion on a) dynamic stiffness of PA6 yarns at different mean load levels, 10% amplitude, shown as % average dry break load (Fr), and b) break load, after ageing for different periods in sea water at 40°C.…”

“…A recent study focussed on the ageing of these materials and tests on single fibres were performed after different ageing periods under different conditions. Full details of testing can be found in [12][13][14][15]. Figure 3 shows the influence of ageing test temperature on tensile properties of Twaron 1 000 aramid yarns.…”