Preparation and characterization of poly(vinyl butyral) electrospun nanocomposite fibers reinforced with ultrasonically functionalized sepiolite

Abstract This study presents an investigation of the effects of the processing conditions on the uniformity, morphology and structure of patterned nanofibrous mats of electrospun poly(vinyl butyral)/sepiolite (PVB/Sep) nanocomposite fibers, which is a novel system for applications in materials for antiballistic protection, biomedical scaffolds and sorption for water purification. Aqueous suspensions of sepiolite exhibit thixotropic behavior because of their fibrous structure, porosity, large specific surface area and the presence of silanol groups on the surface. Functionalization of the sepiolite fibers in an aqueous thixotropic gel was realized on the surface of individual fibers using amino silanes as coupling agents. Different contents (3 wt%, 30 wt% and 50 wt%) of neat and modified sepiolite fibers were dispersed by ultrasonic irradiation in an ethanolic solution of PVB and were used to obtain nanocomposite fibers by electrospinning. The modified PVB/Sep nanocomposite fibers showed a decrease in the mean fiber diameter by about 75% and an increase in the composite storage modulus by about 31% in comparison to the neat PVB fibers. The optimal uniformity of the diameter of the fabricated nanofibers was obtained using a low flow rate (0.5 mL/h), high collector distance (15 cm) and a constant applied voltage of 24 kV. The advantages of the systems lay primarily in improved mechanical properties, which enabled proper manipulation through the achieved mechanical integrity of nanofilter structures in real applications.