ABSTRACT In this work, we studied the effect of calendering temperature on the morphology, structure, and mechanical properties of nonwoven fabrics produced by electrospinning from polyimide based on pyromellitic dianhydride (PMDA) and 4,4′‐oxydianiline (ODA). The formed samples were calendered at the polyamide acid stage, followed by thermal imidization. Scanning electron microscopy, Fourier transform IR spectroscopy, tensile testing, and permeability studies were used to analyze the changes. After imidization, the original nonwoven fabrics exhibited a chaotic porous structure with a predominant fiber diameter of 0.4–0.8 μm. The calendering process resulted in a significant improvement in mechanical properties: tensile strength increased by 5 times, and elastic modulus by more than 4 times compared to the original samples. It was shown that an increase in calendering temperature led to a decrease in material porosity from 71% to 38%. Thus, hot calendering is a highly efficient and technologically advanced processing method for targeted control of the properties of nonwoven polyimide materials.
Vaganov et al. (Fri,) studied this question.