Understanding the influence of key parameters on the stabilisation of cellulose-lignin composite fibres

Abstract

The high cost of carbon fibre continues to limit its use in industries like automotive, construction and energy. Since the cost is closely linked to the precursor, considerable research has focussed on the use of low-cost alternatives. A promising candidate is a composite fibre consisting of blended cellulose and lignin, which has the added benefit of being derived from sustainable resources. The benefits of blending cellulose and lignin reduce some of the negative aspects of converting single component cellulose and lignin fibres to carbon fibre, although the production from such a blend, remains largely underdeveloped. In this study, the effects of stabilisation temperature and the stabilisation process of the blended fibres are explored. Moreover, the viscoelastic properties of the cellulose-lignin fibre are investigated by DMA for the first time. Finally, the cause of fusion in the stabilisation is adressed and solved by applying a spin finish.Keywords Bio-polymer Á Cellulose-lignin composite fibres Á Low-cost carbon fibres Á DMA Á Stabilisation Á Viscoelastic Á Bio-resources

Continuous Stabilization and Carbonization of a Lignin–Cellulose Precursor to Carbon Fiber

“…To maximize the yield, a stabilization profile with a lower temperature and a longer residence time may be the best, since a temperature closer to the degradation temperature of the raw materials shortens the stabilization time but usually at the expense of the yield. 21 , 37 …”

Chemically Accelerated Stabilization of a Cellulose–Lignin Precursor as a Route to High Yield Carbon Fiber Production

“…The FTIR spectrum contains mostly H 2 O (at 1250–1500 and 3500–4000 cm –1 ) and CO 2 (at 2300–2400 cm –1 ). , A small peak at 1160 cm –1 accounts for C–O–C bonds, while another small band around 2700–3000 cm –1 accounts for C–H bonds. , Both peaks suggest the existence of trace amounts of cellulose or lignin monomers. , With negligible other pyrolysis products observed, other than H 2 O and CO 2 , it can be proposed that stabilization was conducted at a temperature that avoided severe pyrolysis and a reduction in char yield. Importantly, this temperature, which is typically chosen from the onset of degradation from the TGA curve, is still able to achieve a comparatively high stabilization rate …”

“…The increase in char yield is also higher for lignin compared to cellulose, further indicating the dependency of lignin stabilization on oxygen. Unlike cellulose, lignin is a complex mixture of polyphenolic polymers containing three basic aromatic monomer units as shown in Figure . , Therefore, because of the more thermally stable aromatic structure, oxygen is needed to transform these aromatic rings to aldehydes, ketones, quinones, or acids which can form a cross-linked network during stabilization. , …”

“…Also, the rate of mass loss of the untreated sample is higher than the treated sample accounting for a faster and more severe degradation of the untreated sample. This suggests a potential sudden release of a high volume of volatile compounds over a small temperature range from 300 to 350 °C, which is important as it may lead to the often observed fiber fusion. , …”

Lignin-Based High-Performance Fibers by Textile Spinning Techniques

“…The effects of processing parameters (i.e., draw ratio, stabilization/carbonization temperature, lignin content, etc.) on the structure and mechanical properties of lignin/cellulose precursor fibers and carbon fibers have been investigated systematically [ 139 , 155 , 156 , 157 ], from which it is concluded that the cellulose constituent dominates precursor fiber structure and mechanical performance. Increasing lignin content decreases fiber strength due to the disturbance of oriented cellulose crystallites [ 141 , 158 , 159 ] and increases carbon yield [ 160 ] due to lignin’s carbon-rich structure.…”