Influence of Different Nanocellulose Additives on Processing and Performance of PAN-Based Carbon Fibers

Abstract

Nanocellulose, as a biobased versatile nanomaterial that can be derived with tailorable surface functionalities, dimensions, and morphologies, has considerable implications for modifying the rheology, mechanical reinforcement, and influencing the carbonization efficiency in the production of polyacrylonitrile (PAN)-based carbon fibers. Herein, we report the influence of three different nanocellulose types, varying in the derivatization method, source, and aspect ratio, on the mechanical properties and thermal transformations of solution-spun PAN/nanocellulose nanocomposite fibers into carbon fibers. The incorporation of 0.1 wt % nanocellulose into solution-spun PAN fibers led to a 7–19% increase in tensile modulus and 0–27% increase in tensile strength in the solution-spun fibers, compared to a control PAN fiber. These improvements varied depending on the nanocellulose type. After low-temperature carbonization at 1200 °C, improvements in the mechanical properties of the nanocellulose-reinforced carbon fibers, compared with a PAN fiber, were also observed. In contrast to the precursor fibers, the improvement % in the carbonized fibers was found to be dependent on the nanocellulose morphology and was linearly correlated with increasing aspect ratio of nanocellulose. For example, in carbon fibers with a cotton-derived low-aspect-ratio cellulose nanocrystal and spinifex-derived high-aspect-ratio CNC and nanofiber, up to 4, 87, and 172% improvements in tensile moduli were observed, respectively. Due to the processing methods used, the nanocellulose aspect ratio and crystallinity are inversely related, and as such, the increase in the carbon fiber mechanical properties was also related to a decrease in crystallinity of the nanocellulose reinforcers. Raman spectra and electron microscopy analysis suggest that mechanical improvement after carbonization is due to internal reinforcement by highly ordered regions surrounding the carbonized nanocellulose, within the turbostratic carbon fibers.

Recent Development and Environmental Applications of Nanocellulose-Based Membranes

“…The mechanical properties of nanocellulosebased membranes may also be affected by the type of nanocellulose used. Jiang et al (2019) [35] revealed that spinifex CNC (s-CNC) and cotton CNC (c-CNC) have greater reinforcing capabilities on PAN nanocomposites than the spinifex CNF (s-CNF) at 0.1 wt% nanocellulose composition.…”

Recent Developments in Cellulose Nanomaterial Composites

“…CNM nanocomposites have been prepared and investigated for a wide variety of thermoplastics including: poly(vinyl alcohol) (PVA), [ 64–69 ] poly(lactic acid) (PLA), [ 70–76 ] thermoplastic starch, [ 77 ] poly(vinyl acetate) (PVAc), [ 78 ] cellulose acetate, [ 79,80 ] thermoplastic polyurethane, [ 81 ] polypropylene (PP), [ 56 ] polyethylene (PE), [ 82,83 ] polyacrylonitrile (PAN), [ 84 ] poly(acrylonitrile‐styrene‐butadiene) (ABS), [ 85 ] polyamide 11, [ 63,86 ] and polyamide 12, [ 87,88 ] although this list should not be viewed as exhaustive. Early in the investigation of CNM/thermoplastic composites, solution‐processed nanocomposites dominated as water‐soluble polymers like PVA could be easily prepared and tested.…”

“…They discovered that, while only small differences were observed in strength (up to 19%) and stiffness (up to 27%) of the precursor fiber, that large differences resulted in the carbon fiber due to large differences in aspect ratio and CNM crystallinity; CNCs (low aspect ratio) strength improved by 4–87% while CNFs (large aspect ratio) improved by up to 172%. [ 84 ] Furthermore, these improvements were accompanied by a decrease in the extent of cyclization at low temperature in creating carbon fiber, a process essential to stabilizing the fiber during conversion.…”

Designing Materials and Processes for Strong Polyacrylonitrile Precursor Fibers

“…It was confirmed that the cellulose nanocrystal reinforcements also contributed to the advancement of the mechanical performance of carbon fibers [ 115 , 116 ]. In fact, the main purpose of the search for biomass additives, such as cellulose, lignin, and alpaca fiber, is eco-friendliness and cost effectiveness [ 114 , 117 , 118 , 119 , 120 , 121 , 122 , 123 , 124 ]. It is inevitable to avoid deterioration of the mechanical performance following the composition with the biomass-derived additives owing to the low carbon atomic content and ineffective molecular structure that is intended to be carbonized.…”