Influence of Microcrystalline Cellulose on Curing Kinetics, Mechanical and Thermo-Mechanical Properties of Epoxy Methyl Ricinoleate Toughened Epoxy Copolymer

In the present study, an attempt to enhance the mechanical properties and dimensional stability of Epoxy Methyl Ricinoleate (EMR) toughened epoxy was made by incorporating microcrystalline cellulose (MCC) as bio filler thereby encouraging the bio-based theme. The addition of MCC to EMR toughened epoxy enhanced the tensile and storage modulus by up to 43.2 and 22.7% respectively. The effect of MCC on curing kinetics of EMR modified epoxy blend was evaluated using differential scanning calorimetry in non-isothermal mode. The Kissinger-Akahira-Sunose method and autocatalytic model were employed to determine the kinetic parameters. The inclusion of bioresin decreased the activation energy of epoxy by reducing its viscosity, enabling improved interaction between the resin and the crosslinking agent. Conversely, the addition of MCC to the EMR/epoxy blend increased the activation energy required for curing because of the steric effect of MCC and the subsequent rise in viscosity. Dynamic Mechanical analysis revealed raise in storage modulus, glass transition temperature and crosslinking density with increase in MCC content. Thermo-mechanical analyzer confirmed that the incorporation of MCC into the modified epoxy blend led to a reduced coefficient of thermal expansion, indicating improved dimensional stability of the MCC composites. SEM analysis showed effective adhesion between MCC and the matrix, attributed to hydrogen bonding between the carbonyl and hydroxyl groups of EMR and the hydroxyl group of MCC. In brief, the enhanced mechanical and thermo-mechanical properties of the MCC-modified EPEMR20 make it a favorable choice for manufacturing hybrid composites suitable for automotive and semi-structural applications.