Investigating the Absorption and Desorption Behavior of Methylene Chloride in the Poly(aryl ether ketone) Film with Different Crystallinities

Poly(aryl ether ketone) (PAEK) films with different crystallinities were obtained by controlling the cooling rate, which were subjected to the absorption and desorption of methylene chloride (CH2Cl2). We employed attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy analyses to investigate the diffusion behavior of CH2Cl2 in PAEK films with different crystallinities. According to the Fickian diffusion model, the calculated diffusion coefficients of CH2Cl2 in PAEK films were observed to decrease with increasing crystallinity. The effect of CH2Cl2 absorption and desorption on the mechanical properties of PAEK films with different crystallinity was further analyzed using tensile tests. The tensile tests exhibited that CH2Cl2 has two concurrent effects: plasticization and solvent-induced crystallization. Differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WXRD) techniques further confirmed solvent-induced crystallization behavior. The results would be beneficial to understand the solvent resistance of PAEK materials and consequently provide the practical application conditions of PAEK with a theoretical basis.