Electrospun Polyethylene Oxide/Cellulose Nanocrystal Composite Nanofibrous Mats with Homogeneous and Heterogeneous Microstructures

Abstract

An electrospinning process was successfully used to fabricate polyethylene oxide/cellulose nanocrystal (PEO/CNC) composite nanofibrous mats. Transition of homogeneous to heterogeneous microstructures was achieved by tailoring the concentration of PEO/CNC mixture in the solution from 5 to 7 wt %. Morphology investigation of the obtained nanofibers demonstrated that rod-shaped CNCs were well-dispersed in the as-spun nanofibers and highly aligned along the nanofiber long-axis. PEO/CNC nanofibers became more uniform and smaller in diameter with increased CNC-loading level. The heterogeneous composite mats were composed of rigid-flexible bimodal nanofibers. Results of structure characterization indicated that the incorporated CNCs interacted strongly with the PEO matrix through hydrogen bonding. Mechanical properties of both types of mats were effectively improved by using CNCs, with heterogeneous mats being stronger than their homogeneous counterparts for all compositions (0-20 wt % CNC contents). When a smaller diameter needle was used to form homogeneous mats, enhanced thermal and mechanical properties were obtained.

Recent Development in Applications of Cellulose Nanocrystals for Advanced Polymer-Based Nanocomposites by Novel Fabrication Strategies

“…It was found that humidity treatments on the PVA/CNC nanocomposite fibrous mats induced significant enhancement of strength as a result of the increased contact area and enhanced adhesion between the fibers (Peresin et al, 2010a). The heterogeneous fibrous mats composed of rigid-flexible bimodal PEO/CNC nanocomposite fibers was demonstrated to be higher in mechanical properties than their homogeneous counterparts (Zhou et al, 2011a). The reinforced mechanism was illustrated by morphology observation of the tensile process, as shown in Figure 7.…”

“…Recently, wood-based CNCs with a diameter of 10 ± 3 nm and a length of 112 ± 26 nm were processed into electrospun PEO fibers (Zhou et al, 2011a). Figure 4 shows that rod-shaped CNCs without obvious aggregation are well-dispersed in the as-spun nanofibers.…”

“…In addition to the reinforceing effect of CNCs on fibers, it was also found that the addition of CNCs could reduce electrospun fiber diameters and improved fiber uniformity attributed to the enhanced electric conductivity of electrospinning solutions in the presence of CNCs. This tends to increase the mechanical properties of mats because smaller fiber diameters yield higher overall relative bonded areas between fibers by increasing its surface area, bonding density, and distribution of bonds (Olsson et al, 2010;Peresin et al, 2010b;Zhou et al, 2011a). Moreover, the orientation of nanocomposite fibers within mats also influence greatly on the mechanical properties of mats (Wang et al, 2011).…”

Enhancing the mechanical properties of electrospun polyester mats by heat treatment

“…Interconnected fibers also improve the mechanical proper- ties of the fibrous materials [30], which are influenced by the structure of the fibers and the interactions between them, as well [31]. Enhancement of the mechanical parameters (tensile strength, yield stress, and Young's modulus) can be achieved in the presence of finer fibers (a nano-network) among the main fibers [32]. A major problem regarding the mechanical testing of electrospun micro-and nanofibrous materials is the lack of reliable standards for the performance of these tests.…”

Preparation of Nanostructured Cellulose via Cr(III)- and Mn(II)-Transition Metal Salt Catalyzed Acid Hydrolysis Approach

“…Chirayil et al (2014) mentioned that the addition of nanocomposites into thermoplastic starch could enhance the tensile strength of the product significantly compared with pure isolated thermoplastic starch, and the addition of sugar beet chip nanofibrils isolated via high-pressure homogenization to a phenol formaldehyde and polyvinyl alcohol matrix demonstrated excellent reinforcement properties (Chirayil et al 2014). Therefore, it is essential to isolate the nanocellulose from its micro-scale raw material with the purpose of maximizing the potential of the cellulose source to become the useful composite materials such as polyethylene oxide/cellulose nanocrystal (PEO/CNC) (Zhou et al 2011) and poly(vinyl alcohol)/cellulose nanocrystal (PVA/CNC) (Huan et al 2016).…”