(346b) Lignin As Reinforcing Filler for Elastomeric Compounds

Lignins possess strong mechanical properties and a number of reactive functional groups which qualify them as reinforcing fillers of polymer compounds. However, their polar nature makes them incompatible with non-polar rubber and their large particle sizes provide poor mechanical reinforcement.  In addition, lignins are known to retard curing of rubber compounds. This study deals with how the functional groups on the lignin surfaces can be used effectively to solve the very issues that they create. The first part of this study focuses on modification of lignin with cyclohexylamine (CA) to derive compatibility with the rubber matrix. CA reduces the polarity of lignin via proton transfer and hydrogen bonding interactions. The second part of this study deals with solving the issues associated with large size of lignin particles. The non-covalent interactions between lignin and carbon black are used to coat carbon black particles.  In this manner, the particle size of lignins is reduced in conjunction with a reduction of carbon-carbon particle networks. Both these effects lead to lower viscous dissipation and higher energy efficiency in rubber compounds. The effects of such hybrid fillers on tensile and dynamic mechanical properties of styrene butadiene rubber compounds are discussed