Characterization and Performance Evaluation of Lignin-Modified Epoxy Resin for potential use in Natural Fiber Reinforced Composites
Topic(s) : Material science
Co-authors :
Zainab AL-MAQDASI (SWEDEN), Daniela RUSANOVA NAYDENOVA (SWEDEN), Roberts JOFFE , Maria Bohic (SWEDEN)Abstract :
The use of natural fiber reinforced composites has gained significant attention in various industries due to their potential to provide lightweight, eco-friendly alternatives to conventional materials. Epoxy resins, in particular, have been widely used as matrix materials in these composites due to their excellent mechanical and thermal properties. However, the incorporation of natural fibers into epoxy matrices can be challenging, as it often requires addition of modifiers to improve compatibility and adhesion between the fibers and resin [1]. Lignin, a highly abundant renewable polymer, has shown promise as a potential modifier for epoxy resins. Its inherited high aromatic content, rigidity, and antioxidant properties has made it an attractive option for resin modification.
Traditionally, lignin has been extracted from various lignocellulosic biomass via the Kraft process (in Pulp & Paper manufacturing) [2]. In recent years, researchers have focused on extracting lignin from different sources and evaluating its effectiveness as a modifier in natural fiber composites.
This study aims to characterize lignin-modified epoxy resins (LY 1564) altered with commercial Kraft lignin (CL) and evaluated against alternative new type of lignin (AL). The modified resin's potential for use in natural fiber reinforced composites is evaluated through the characterization of mechanical and thermal properties. The mechanical properties, including hardness, fracture toughness, and flexural properties, have been assessed to determine the resin's overall performance. Additionally, the glass transition temperature (Tg) is measured to gain insights into change of lignin-modified resin's thermal behavior.
The morphological studies conducted using optical and scanning electron microscopes reveal the ability for dispersion and/or agglomeration of the lignin particles within the epoxy matrix. Preliminary results suggest that the alternative lignin type exhibits higher dispersion and incorporation in the resin matrix without visible agglomerates formation up to 5 wt% lignin (see Figure 1).
Furthermore, the study evaluates the toughening effect of the lignin on the matrix flexural stress-strain response at different lignin concentrations (Figure 2, left). This underlines the resin's ability to withstand mechanical stresses and suitability for use with resilient natural fibers. Lastly, the study investigates the impact of lignin concentration on Tg of the epoxy-lignin composite (Figure 2, right). The results show that there is no defined effect of the lignin addition on Tg up to a concentration of 5 wt% where a notable reduction in Tg could be seen for the AL. Cross-correlation of data has been performed to pinpoint relation to various industrial applications.
Traditionally, lignin has been extracted from various lignocellulosic biomass via the Kraft process (in Pulp & Paper manufacturing) [2]. In recent years, researchers have focused on extracting lignin from different sources and evaluating its effectiveness as a modifier in natural fiber composites.
This study aims to characterize lignin-modified epoxy resins (LY 1564) altered with commercial Kraft lignin (CL) and evaluated against alternative new type of lignin (AL). The modified resin's potential for use in natural fiber reinforced composites is evaluated through the characterization of mechanical and thermal properties. The mechanical properties, including hardness, fracture toughness, and flexural properties, have been assessed to determine the resin's overall performance. Additionally, the glass transition temperature (Tg) is measured to gain insights into change of lignin-modified resin's thermal behavior.
The morphological studies conducted using optical and scanning electron microscopes reveal the ability for dispersion and/or agglomeration of the lignin particles within the epoxy matrix. Preliminary results suggest that the alternative lignin type exhibits higher dispersion and incorporation in the resin matrix without visible agglomerates formation up to 5 wt% lignin (see Figure 1).
Furthermore, the study evaluates the toughening effect of the lignin on the matrix flexural stress-strain response at different lignin concentrations (Figure 2, left). This underlines the resin's ability to withstand mechanical stresses and suitability for use with resilient natural fibers. Lastly, the study investigates the impact of lignin concentration on Tg of the epoxy-lignin composite (Figure 2, right). The results show that there is no defined effect of the lignin addition on Tg up to a concentration of 5 wt% where a notable reduction in Tg could be seen for the AL. Cross-correlation of data has been performed to pinpoint relation to various industrial applications.