Utilizations of Lignin for Polymer Reinforcement and Carbon Fibers

Abstract

This chapter describes the performance of lignin as a reinforcement filler for thermoplastic polymers as well as its potential as a precursor for production of carbon fibers. Literature studies show that lignin could improve the antioxidant, thermal stability, mechanical performance, UV stability, and biodegradability of various thermoplastic polymers such as natural rubber, PE, PP, SBR, PVC, and polystyrene. However, the polarity and relatively large particle size of lignin could limit its miscibility with the polymeric matrix. To overcome this challenge, it is required to modify lignin to reduce its polarity before compounding with thermo- plastic polymers. In addition, lignin is a renewable source of carbon and can be utilized into carbon fibers. There are three categories of carbon fibers that incor- porate lignin in the manufacturing processes: (1) carbon fibers from raw lignin without any further modification, (2) carbon fibers from physical lignin/polymer blends, and (3) carbon fibers from modified lignin.