Facile Approach for the Potential Large-Scale Production of Polylactide Nanofiber Membranes with Enhanced Hydrophilic Properties

Abstract

Polylactide (PLA) nanofiber membranes with enhanced hydrophilic properties were prepared through electrospinning. As a result of their poor hydrophilic properties, common PLA nanofibers have poor hygroscopicity and separation efficiency when used as oil–water separation materials. In this research, cellulose diacetate (CDA) was used to improve the hydrophilic properties of PLA. The PLA/CDA blends were successfully electrospun to obtain nanofiber membranes with excellent hydrophilic properties and biodegradability. The effects of the additional amount of CDA on the surface morphology, crystalline structure, and hydrophilic properties of the PLA nanofiber membranes were investigated. The water flux of the PLA nanofiber membranes modified with different CDA amounts was also analyzed. The addition of CDA improved the hygroscopicity of the blended PLA membranes; the water contact angle of the PLA/CDA (6/4) fiber membrane was 97.8°, whereas that of the pure PLA fiber membrane was 134.9°. The addition of CDA enhanced hydrophilicity because it tended to decrease the diameter of PLA fibers and thus increased the specific surface area of the membranes. Blending PLA with CDA had no significant effect on the crystalline structure of the PLA fiber membranes. However, the tensile properties of the PLA/CDA nanofiber membranes worsened due to the poor compatibility between PLA and CDA. Interestingly, CDA endowed the nanofiber membranes with improved water flux. The water flux of the PLA/CDA (8/2) nanofiber membrane was 28540.81 L/m2·h, which was considerably higher than that of the pure PLA fiber membrane (387.47 L/m2·h). The PLA/CDA nanofiber membranes can be feasibly applied as an environmentally friendly oil–water separation material because of their improved hydrophilic properties and excellent biodegradability.

Large-Scale and Highly Efficient Production of Ultrafine PVA Fibers by Electro-Centrifugal Spinning for NH3 Adsorption

“…Although the obtained PVA fibers present lower adsorption capability than MOF (Metal-organic framework) materials for NH 3 adsorption [ 50 ], the much lower price of PVA products is still very competitive. In addition, the NH 3 adsorption performance of PVA fibers can be further improved by the introduction of hierarchically porous structures [ 11 , 51 ]. The optimal PVA fiber mats exhibit adsorption selectivity to NH 3 over CO 2 (shown in Figure 12 b) [ 52 ], and limited adsorption capacity can be noted for CO 2 in stark contrast to the decent adsorption capacity toward NH 3 .…”

“…A high electrostatic field is usually required to facilitate the conventional fiber production, thus generating high costs and safety issues [ 9 ]. Moreover, the electrospinning process is rather inefficient, with solution feeding rates of as small as 1 mL h −1 [ 10 , 11 , 12 ]. All these crucial limitations cause the commercial applicability of electrospun fibers to be restrained [ 13 ].…”