Poly(methyl methacrylate) (PMMA)-microcrystalline cellulose composites with improved interfacial interaction were prepared by solution casting method using Bis-(3-triethoxysilylpropyl) tetrasulphide (Si69) as coupling agent. The incorporation of microcrystalline cellulose into PMMA enhanced the mechanical as well as thermal properties over that of base polymer but not remarkably. So in the current study Bis-(3-triethoxysilylpropyl) tetrasulphide (Si69) is used as a coupling agent to improve PMMA-Cellulose adhesion. The composites were characterized using FTIR, C-13 NMR, UV-Vis, Si-29 NMR, XRD and SEM analysis. The results indicated that Si69 formed chemical bonds with both PMMA and cellulose. The effect of Si69 on the physical and mechanical properties of PMMA/Cellulose composite was investigated. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) studies showed that the degradation temperature and glass transition temperature of PMMA shifted to higher temperature. The addition of silane coupling agent in to the PMMA/Cellulose improved the mechanical properties. The impact strength increased up to 72%, flexural strength by 37%. The composite exhibited 49% higher tensile strength and 50% storage modulus than pristine PMMA. The addition of cellulose to PMMA increased the dielectric constant and attained an AC conductivity of 1.4*10(-4) S/m. The result proved that Si69 is compactable to both PMMA and cellulose and can be used as an effective coupling agent for PMMA/Cellulose system. (C) 2017 Elsevier Ltd. All rights reserved.