Investigation on Properties of Carbon Black/Lignin Filled NR/BR Composites Influenced by Silane Coupling Agents

Abstract

In this investigation, we explore the impact of silane coupling agents on the characteristics of composites comprising bis-(3-triethoxysilylpropyl) tetrasulfide (TESPT), 3-octanoyl-thiopropyl-triethoxy (NXT), and triethoxy (vinyl) (VTEO) with carbon black and lignin. The study delves into the role of these silane coupling agents, specifically focusing on their influence on the properties of the NR/BR composites filled with carbon black and lignin. TESPT, NXT, and VTEO were employed to enhance compatibility between an incompatible polar filler and non-polar rubber, forming a bridge between the filler and the rubber matrix during the mixing and vulcanization processes, thereby contributing to the improved performance of bio-filler-filled rubber compounds. The amounts of silane coupling agents added were in the range of 2-10 wt.% based on the lignin content to assess the optimum amount for interfacial bonding, rheological, and mechanical performance. A slight improvement has been observed in curing behavior, resulting in a shorter optimum cure time with the incorporation of TESPT and enhanced scorch safety with the inclusion of NXT in CB/lignin-filled NR/BR composites. Meanwhile, hardness values of the compounds with TESPT display higher values and thus higher crosslink density than NXT and VTEO compounds. The findings demonstrated the benefits of utilizing TESPT, NXT, and VTEO as effective silane coupling agents between CB/lignin fillers and rubber.