Investigating the optical properties and molecular structure of PEEK fiber

Figures & data

Fig. 1 (a, b, c) Microinterferograms of duplicated and non-duplicated images of PEEK fiber using automatic VAWI technique.

Fig. 2 The spectral dispersion curves of refractive indices n^||, n^⊥ and n_iso, and birefringence Δn of PEEK highly oriented fiber.

Fig. 3 The refractive indices n^|| and n^⊥ as functions of 1/λ² to verify Cauchy's dispersion relation for PEEK fiber.

Table 1 The optical and dispersion parameters of PEEK fiber using automatic VAWI technique.

Direction of the light vector	Optical and dispersion parameters
	A	B × 10^3 nm^2	Ed (ev)	Eo (ev)	λ0 nm	n∞	So × 10^−5 nm^−2
Parallel	1.798	26	17.674	6.736	174.18	1.8164	7.579
Perpendicular	1.677	4.3	25.443	14.037	87.896	1.6771	0.234

Fig. 4 The plot of (n² − 1)⁻¹ versus the square of photon energy E² for PEEK fiber.

Fig. 5 The plot of (n² − 1)⁻¹ versus the inverse of the squared wavelength 1/λ² for PEEK fiber.

Fig. 6 The variation of the polarizability per unit volume Φ^||, Φ^⊥ and Φ_iso with the wavelength of the incident light.

Fig. 7 The variation of the density and the mean square density fluctuation for PEEK fibers with the wavelength of the incident light.

Fig. 8 The graphical representation of the mass fraction of the crystalline χ_m% and amorphous (1 − χ_m)% regions percentages of PEEK fiber with the wavelength of the incident light.

Fig. 9 The variation of the optical orientation factor and angle for PEEK fibers with the wavelength of the incident light.

Fig. 10 The linear relationship between the optical orientation factor P₂(θ) and the value of [Φ^|| − Φ^⊥]/[ [Φ^|| +2 Φ^⊥].

Fig. 11 The variation of the electric polarizability of monomer unit α^|| and α^⊥ for PEEK fibers with the wavelength of the incident light.

Fig. 12 The relationship between the optical stress coefficient C_s and the wavelength λ for PEEK fibers.