Biobased Structurally Compatible Polymer Blends Based on Lignin and Thermoplastic Elastomer Polyurethane as Carbon Fiber Precursors

Abstract

The production of carbon fibers based on lignin reduces the cost and the environmental impact associated with carbon fiber manufacturing. However, the melt processing of lignin as a carbon fiber precursor is challenging due to its brittleness and limited thermoplastic behavior. For this reason we produce biopolymer blends based on Alcell organosolv hardwood lignin, hydroxypropyl modified Kraft hardwood, and a thermoplastic elastomer polyurethane (TPU). Samples with TPU content greater than 30% showed excellent melt processability and carbonization yield (35% carbon yield for the samples containing 30% of TPU). The thermal properties were analyzed by differential scanning calorimetry, rheology and thermogravimetric analysis. Fourier infrared measurements were utilized to explain the lignin/TPU interactions which governed the thermal and rheological behavior of the blends. SEM analysis showed that the blends produce a homogeneous structure which was void free after carbonization. These structurally complementary biopolymeric blends should open up new avenues for lignin valorization and bring closer the realization of the production of carbon fibers from biosources.

Bio‐derived Carbon Nanofibres from Lignin as High‐Performance Li‐Ion Anode Materials

“…Lignin/ TPU samples showedh igher carbon yields than lignin/PLA owing to both polymers (TPU and Lignin) contributing to the carbon phase. In contrast, lignin/TPU is ah omogeneous system,t hus both components participate in carbon formation through possible condensation reactions between both polymers, [23] which can produce as ynergistic effect in the formation of the graphite crystals. The Ramans pectra show two characteristic peaks centred at 1345 and 1585 cm À1 ,t he Dband andG -band, respectively.…”

“…Pure lignin solutionsd isplay av ery low viscosity owing to the low molecular weight of lignin and are therefore unsuitable for electrospinning. [23] As ar esult,l ignin blendsw ere developed. For the case of lignin/PLA blends, am ixture of solvent, DMF/ THF (1:1 w/w), is required because phase separation occurs when only one solventi su tilized.…”

“…For this reason, previous studies have used very slow heating ramp rates of 0.1 8Cmin À1 for stabilisation of lignin-based microfibres. [23] In this work, several isothermal steps were combined to preventm elting of the nanofibres during the stabilisation step. However,t he addition of MDI as crosslinker was crucial to maintain the shape of the nanofibres (see Figure S1 in the Supporting Information).…”

“…However,o ne of the main problemsa ssociated with graphite is its low energyd ensity,w ith its theoretical capacity of just 372 mAh g À1 .F or this reason, many studies have been focused on finding new carbon-based materials for use as anodesi n LIBs. [23][24][25][26][27][28][29] Lignin is the most abundant aromatic biopolymer on the planet. [12][13][14][15][16][17][18] However,t heir high cost and limitedp roduction throughput make their integration into industrial production difficult compared with traditional graphite.…”

“…[22] Lignin is considered av iable sustainable alternative to PANa sac arbon fibre precursor. [23][24][25][26][27][28][29] Lignin is the most abundant aromatic biopolymer on the planet. It is amorphous andi sp resenti nt he cell wall of plants.…”