Physicochemical properties of kevlar 49 fiber

Abstract

The high‐strength, high‐modulus Kevlar 49 fiber is widely used today because of its superior properties. In this paper, we discuss the fundamental physicochemical nature of the commercial fiber. It is an extended chain polymer, poly(p‐phenylene terephthalamide), which is highly crystalline. Extensive analysis shows that the material composition is quite consistent from lot to lot and is low in impurities. The fiber absorbs water reversibly; the extent of absorption is related to the ash content. The well‐known interaction of the fiber with ultraviolet light is illustrated with spectra, and the thermal stability of the fiber is demonstrated with various thermal analysis techniques.

Differential water sorption studies on KevlarTM 49 and as-polymerised poly (p-phenylene terephthalamide): adsorption and desorption isotherms

“…In the case of Na 2 SO 4 , it has been shown that it is present in Kevlar TM 49 ÿbres at concentrations of up to 1:5 wt% (Morgan and Pruneda, 1987), located predominantly between 60 nm microÿbrils within the ÿbre. While Penn and Table 2 Equilibrium moisture sorption characteristics of Kevlar TM aramid ÿbres (Fukuda et al, 1991) Larsen (1979) showed a direct correlation between sample 'ash' (inorganic component) content and equilibrium moisture content, more recent work conducted by Fukuda et al (1991) has shown no such correlation. Indeed, samples boiled for 30 days (in the process losing up to 50% of the sodium salt) showed no change in equilibrium moisture content compared to those of untreated samples.…”

Moisture Sorption Mechanism of Aromatic Polyamide Fibers. (Part 4). Effect of Water on the Crystal Structure of Regular Kevlar.

“…However, there are some weak reflections that do not obey the space group extinction law, as mentioned by Penn and Larsen (26).…”

Polar–polar interaction between the reinforcement and matrix for kevlar fiber‐reinforced composite: Effect of using the blend of polar polymers as matrix

“…The spectra of the polymer matrix-coated Kevlar cloth were obtained by the internal reflection spectroscopy (IRS) on 45" germanium element. 5 The coating of Kevlar cloth was made with 0.05% polymer solution in dichloromethane and the solvent was completely removed in a vacuum oven. The spectra of the mixture of polymer matrix with B were obtained by the transmission method on a sample film coated onto potassium bromide window.…”