Biocomposites of Bio-Polyethylene Reinforced with a Hydrothermal-Alkaline Sugarcane Bagasse Pulp and Coupled with a Bio-Based Compatibilizer

Abstract

Bio-polyethylene (BioPE, derived from sugarcane), sugarcane bagasse pulp, and two compatibilizers (fossil and bio-based), were used to manufacture biocomposite filaments for 3D printing. Biocomposite filaments were manufactured and characterized in detail, including measurement of water absorption, mechanical properties, thermal stability and decomposition temperature (thermo-gravimetric analysis (TGA)). Differential scanning calorimetry (DSC) was performed to measure the glass transition temperature (Tg). Scanning electron microscopy (SEM) was applied to assess the fracture area of the filaments after mechanical testing. Increases of up to 10% in water absorption were measured for the samples with 40 wt% fibers and the fossil compatibilizer. The mechanical properties were improved by increasing the fraction of bagasse fibers from 0% to 20% and 40%. The suitability of the biocomposite filaments was tested for 3D printing, and some shapes were printed as demonstrators. Importantly, in a cradle-to-gate life cycle analysis of the biocomposites, we demonstrated that replacing fossil compatibilizer with a bio-based compatibilizer contributes to a reduction in CO₂-eq emissions, and an increase in CO₂ capture, achieving a CO₂-eq storage of 2.12 kg CO₂ eq/kg for the biocomposite containing 40% bagasse fibers and 6% bio-based compatibilizer.

Keywords: 3D printing; bio-based filament; sugarcane bagasse pulp.

Figure 1

Scheme for the integral use of sugarcane, including the production of Bio-polyethylene (BioPE) and bagasse fibers.

Figure 2

SEM images of HT/Soda fibers. Left) Fibers and fines are exemplified (magnification 200×). Right) Fibers observed at 1000× magnification.

Figure 3

Water absorption of filaments with different percentages of fibers, using fossil- and bio-based compatibilizers.

Figure 4

SEM microphotograph of the tensile breaking area: (a) 40HT-F filament, (b) 20HT-F filament, (c) 40HT-B filament, and (d) 20HT-B.

Figure 5

Thermo-gravimetric analysis (a) and differential scanning calorimetric (b) of the filaments.

Figure 6

3D shapes printed with filaments containing BioPE and bagasse fibers (ValBio-3D project).

Figure 7

Greenhouse gas (GHG) emissions of 1 kg of fossil-based polyethylene (PE), BioPE and the corresponding biocomposites, from a cradle-to-gate perspective.

Figure 8

Relative contribution per life cycle stages for the production of fossil PE, BioPE and biocomposites. Results do not include carbon sequestration. Reported per functional unit: 1 kg of pellets.