ISOLATION AND ANALYSIS OF GRAPE SEEDS LIGNIN FOR POTENTIONAL APPLICATION IN POLYMERIC BLENDS

abstract

English

The utilization of waste materials is a crucial aspect of the circular economy. In this regard, this work focuses on processing agricultural waste, particularly from wineries, to isolate lignin. Lignin is a widely occurring biopolymer found in the cell walls of vascular plants. Nowadays, lignin is primarily obtained as a by-product of the pulp and paper industry and is directly utilized for energetic purposes. However, lignin has much broader application potential thanks to its unique properties such as antioxidant activity, antimicrobial properties and UV protection. This work deals with the isolation and analyses of lignin obtained from grape seeds. The isolation was carried out using the soda pulping method with sodium hydroxide. This method is advantageous because it yields sulfur-free lignin. The solubility of the isolated lignin fractions was assessed using various organic solvents, with the choice of solvent being crucial for further application. A comparison of these solvents revealed that dimethyl sulfoxide had the highest solubility of isolated lignin at 95%. Solubility was then confirmed by particle size analysis. The antioxidant activity of lignin was assessed by the ABTS radical scavenging method, as it can be beneficial for lignin applications. The antioxidant properties of lignin are related to its total phenolic content, which was determined spectrophotometrically. Lignin has numerous potential applications, including manufacturing green chemicals, adhesives, and fillers for polymers. This study also aimed to prepare blends of polyhydroxyalkanoate with grape seeds lignin. Adding 1 wt% grape seeds lignin enhanced Young's modulus and tensile strength of the blends by 60 MPa and 21 MPa, respectively, while maintaining the elasticity of the material. Furthermore, the lignin improved the degradation onset temperature by 15°C, which could help overcome challenges in processing polyhydroxyalkanoates. The presented work was supported through the internal Brno University of Technology project FCH-S-22-7909

Lignin, polyhydroxyalkanoates, polyhydroxybutyrate, waste valorisation

VOSTREJŠ, P.; HRUŠKOVÁ, L.; KOVALČÍK, A.

24. 4. 2023

AMCA, spol. s r.o

Praha

978-80-88214-40-3

Book of abstracts of the 10th International Conference on Chemical Technology

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